Battery power construction equipment

SpaceNut · 2019-11-24 16:02:24

The mars of the future will need more work from companies that want to provide battery powered equipment for what could be used on the moon or mars with suttle changes.

Battery-Electric Heavy-Duty Equipment: It's Sort Of Like A Cybertruck

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Heavy-duty equipment is not nearly as sexy. However, this manufacturing sector is a big part of the US economy.
At construction sites, on farms, in warehouses, this kind of equipment is a frequent sight. They are, most often, powered by diesel engines. And those engines need a lot of maintenance. They’re big, heavy, and cost a small fortune to buy and to service.
They’re also a huge part of the US carbon footprint. The motors that power them are subject to federal emission standards that have been made more stringent in recent years. However, according to the EPA, this type of equipment is still responsible for 23% of greenhouse gas emissions from the US. That’s a huge impact.
Their solution to this pollution problem is electric heavy-duty equipment. They’ve created a single platform that can be easily modified to do any number of jobs. For instance, their flagship product, the Dannar 4.00, can accept over 250 attachments from CAT, John Deere, or Bobcat. Because this is a simple skateboard-like platform, owner-operators can do this work themselves in almost no time.
It’s a one-vehicle, many machines type of solution. That means a backhoe that’s useful all summer long, can be quickly and easily converted into a snowplow for winter. That’s one example but there are countless others. Having interoperability with so many different types of equipment, one platform can easily perform many tasks over the course of a year. This is a huge win for cash strapped municipalities. Why would a company or municipality opt to have a backhoe parked all winter long when it could be doing another job?
There’s even an available solar canopy available to boost its sustainability.

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At the heart of the Dannar 4.00 is the battery pack from the BMW i3. The standard model comes with three 42 kWh battery packs for a total of 126 kWh. That’s expandable right up to 625 kWh per machine. According to Dannar, this gives the 4.00 8-10 hours of operation on average. That, of course, depends on the work it’s doing.
That’s impressive. However, this same piece of equipment can power a cell tower for 12 days. The power export panel is capable of being configured with multiple 110VAC and 208VAC outlets. It’s also capable of charging and being charged via CCS at 60 kW.

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Not your everday pressurize rover but that s a horse of a different color for mars when we are trying to brute force mans will on the planet of mars.

louis · 2019-11-24 16:30:14

These look like a good starting point.

SpaceNut · 2019-11-24 16:35:20

First step is to change out the rubber tires as they will not last and even the cheap rims of the current rover design would not be any better...time to see if the next rovers will do any better to learn some more clues for driving on mars.

louis · 2019-11-24 18:22:03

Yep.

So what's the best option? I'm thinking steel tank tracks might be best.

SpaceNut wrote:

First step is to change out the rubber tires as they will not last and even the cheap rims of the current rover design would not be any better...time to see if the next rovers will do any better to learn some more clues for driving on mars.

SpaceNut · 2019-11-24 19:56:33

The tracks have been meantioned in the other rovers that we have talked about for solar, light mass and nuclear as the options to power and of design. The real reason is the beating from motion over the sharp rocks which is from rotation. So not sure that a track will be all that much better until its tried on mars with another rover.
There was a compression spring loaded track around a tire shape that also seemed plausible for mars to aid in the rotation pounding that mars dishes out.

kbd512 · 2019-11-25 00:21:43

SpaceNut,

Here on Earth, heavy off-road vehicles with low ground pressures required for good traction in loosely compacted soils, and thus cross-country mobility use tracks rather than wheels. This rule of thumb merely applies to the nth degree in very rough terrain such as rocky fields, steep sand dunes, or mountainous areas. The typically lower CG of tracked vehicles to achieve a given level of ground clearance is another added bonus. Wheeled vehicles can't and won't perform as well because far less surface area is in contact with the ground, increasing ground pressure and decreasing traction unless much larger diameter wheels are used to dramatically increase the surface area of the wheel actually in contact with the ground. Furthermore, a wheeled vehicle will be heavier than a tracked vehicle for equivalent mobility in rough terrain if it's carrying an equivalent payload. There are some scaling laws that apply here, but anything weighing several tons or more (anything with the weight of a Hummer or greater), which is exactly what we're talking about, is going to perform markedly better with tracks on Earth and on Mars in real rather than hypothetical off-road environments (anything that doesn't resemble a smooth hard-packed surface approximating asphalt).

This doesn't apply to small RC cars of nominal weight moving at inches per second (high strength not required to support substantial weight), such as the MER / MSL rovers. Those vehicles don't remotely resemble heavy construction vehicles or pressurized man-rated exploration rovers in the gross vehicle weight department, but even there off-road performance would still be better with tracks. What won't be any better is power consumption. A wheeled vehicle on a paved road will always consume less power than a tracked vehicle to achieve a given speed because less friction (traction) exists between the wheel vs the track and the road surface. That's great for fuel economy on a road. There are no roads of any kind on Mars.

In the fine sands of Iraq and the mountain trails of Afghanistan, any place off of a road, or even an unimproved road, is a no-go zone for a Stryker, even if no water is involved. Hummers don't fare significantly better, despite being a lot lighter. The US Army re-proves this "theory" every time it's re-tested. Afterwards, they ignore the results because wheeled vehicles are faster on roads, boys love trucks more than uncommon sense, and all those ambushes that occur on roads give our brass another excuse to blow more of our tax money on newer / bigger / less practical / cooler looking trucks that still can't do what tracks do. All those good young men and women who come home in boxes or mangled beyond repair when their wheeled vehicles can't actually defy simple physics are just collateral damage. They actually created a map of all the places that were considered no-go zones for wheeled armored vehicles when Shinseki et al were promoting this wheeled fighting vehicle transformational blah blah idiocy. That was around the same time those wars began. It just so happened that the map included the very countries that we were actively fighting in, and still actively fighting in two decades later. We're still using wheeled vehicles and our boys and girls are still coming home in flag draped boxes because of them. Go figure.

The track systems from the 1950's were substantially more maintenance intensive and had significantly shorter lives than the ones in use today. There were a variety of reasons for that. They used lower grades of steel, unhardened or improperly hardened castings vs properly case hardened forgings, along with various types of tensioning systems that were more complex and thus prone to failure than those found in modern tracked vehicles. Since we won't use the engines, fabrication methods, materials, or track technology of the 1950's, my opinion is that Mars-rated tracked vehicles will be every bit as reliable as modern tracked vehicles are here on Earth.

The "off-road mobility theory" says tracks will be 20% to 30% lighter than equivalent wheeled vehicles capable of moving an equivalent payload through equivalent terrain, provided the terrain is not a paved road. Whenever paved roads become available, trucks would be better. I'd never argue that because physics dictates trucks on paved roads consume less energy than tracked vehicles on paved roads. That said, rolling resistance dictates that a train would be better still. If total resource and energy consumption is a factor, as it undoubtedly will be, then a cargo carrying blimp is going to be the most practical solution for global transport of heavy cargo on Mars. I've never heard of any "blimp excavators" or "blimp skid steers", so I'm presuming we're going to use Plain Jane tracked construction / transport vehicles until roads and blimps become available for transport, whereupon we will "switch" to using vehicles that consume less energy per ton of cargo delivered.

Calliban · 2019-11-25 08:01:34

Some thoughts.

1. A blimp is an interesting idea. A spherical hydrogen filled balloon 100m in diameter would lift about 6.5 tonnes on Mars. Subtracted from that would be the mass of the envelope, fuel and propulsion.

2. For short distances on well used tracks, roads could be constructed from corralled stone and gravel. Ice could be used as a bounding agent between stones, although gravity and friction would likely be sufficient.

3. As Mars is a dry and heavily oxidised environment, power could be supplied to some vehicles through a ground level power supply, i.e. through a third rail, embedded within the road. Two rails would be needed; one +ve and one –ve. Vehicles would draw power using pickup shoes much as subway trains do here on Earth.

4. A railway is a logical extension of the above idea.

5. For equipment that is used close to a specific location, power supply could be via cables, attached to a local grid. If power is delivered using DC, then loads could be directly coupled to solar panels. Motors will run more slowly or more quickly, depending upon the balance between load and supply, but battery storage is not necessarily needed.

6. Hydraulic capsule pipelines can be used to transport bulk materials. The capsules should be carefully ballasted for neutral buoyancy. The pipelines could be steel, plastic or maybe polymer lined trenches.

7. Pneumatic transport is also possible – basically blowing wheeled carriages through a tube.

8. Over rough terrain, ropeways can be used to transport bulk materials in hanging buckets.

kbd512 · 2019-11-25 21:16:36

Calliban,

The idea I had in mind for blimps was an inflatable torus covered in a thin film solar array to supply electrical power to ground vehicles and equipment. The blimp would be used to ferry bulk cargo (water, minerals, ores, tools, portable inflatable habitat modules) from a work site to a processing plant. The tracked vehicle would tow the blimp to and from the work site, receiving power from the blimp and negating the need for the tracked vehicle to bear the weight of or supply a lot of power to move the cargo. This offsets the need to lug batteries of additional fuel tanks to supply power to the electric motors. Mars has a tiny fraction of the Earth's atmosphere, so the blimp's resistance to movement through the Martian "air" is very low. Furthermore, the dynamic pressure of the winds acting on the blimp is very low.

The tracked vehicle would have lifting eyes / pads on all four corners (for lifting by cranes and for attachment of the blimps) where power cabling and lifting gas tubing connecting the blimp to the ground vehicle would be attached.

Use Google and have a look at the German Weasel or Japanese Type 60 106mm recoilless rifle carrier. That's the rough size of the tracked vehicle I had in mind. Something with dimensions close to that of the Type 60 but with the weight of the Weasel through extensive use of CNT composites. These vehicles won't have any weapons / metal armor (instead they're armored in a different way, against abrasion and radiation through the use of CNT) / Diesel engines (replaced by electric motors and non-contact magnetic gearing for power transmission), so they'll be significantly lighter for a given size, but still very much like their Earth-bound brethren in terms of performance. They're just low-speed and durable heavy vehicles with earth-moving torque to provide all-terrain capability while carrying heavy loads.

Concept of Operations:

1. Preparation for Transit at Base
A. unfurl the blimp, looking for any obvious signs of damage
B. attach the portable inflatable / life support cargo to the blimp's cargo straps
C. fill the blimp with Hydrogen gas from H2 cylinders onboard your rover, ensuring that the blimp holds pressure acceptably well (it's H2, so it won't last forever in an inflated condition, but it doesn't need to)
D. check all the connections between the blimp and rover (make sure you can raise / lower the blimp's altitude using the gas valves and ensure you're getting acceptable power to the rover)
E. exploration crew, if different from the prep crew, suits up and heads out to the rover (everything is double-checked by a fresh pair of eyes)
F. exploration crew receives their investigation target from the base (a potential ice pocket, ore deposit, etc) and that data is loaded into the rover's navigation computer, whereupon they select a route that avoids the roughest terrain to save wear and tear on their vehicle, make the transit less jarring to arrive in better condition to work, and avoid snagging the blimp on anything
G. This process is repeated for a second rover. Each rover seats 2 people, but 2 astronauts drive out in their individual rovers, ensuring that a backup vehicle is available, if required. The first rover carries the life support gear suspended from its blimp and the second rover carries the tools (a drill, shovel, dozer blade, bladders for water, or whatever else is required for the investigation / operation) suspended from its blimp.

2. Transit
A. The pair of crew uses their pair of rovers to transport their on-site life support and tools / equipment to their investigation target / work site. Transits are made during the day to make use of available solar / electrical power from the blimps, reduce power consumption associated with lights / night vision / batteries required for driving at night, and to maintain some semblance of a normal work day / sleep schedule.
B. If the ability of the terrain to support the weight of the rover is ever in doubt, then one astronaut departs their rover (the tool carrying rover, not the life support rover) and the other rover is used to remotely drive the test rover over the questionable terrain feature (lava tubes, for example).
C. Upon arrival at the work site, a status report is sent back to the base after additional checks of the grounded blimps / life support / tools and equipment are made. If all is satisfactory, then the investigation or operation will proceed. If not, then an assessment of field repair capability is made, repairs performed as required, and a proceed / return to base decision is made.

3. Investigation / Work Site Operation
A. The blimps provide on-site power to the rovers for any drilling or mining operations and life support. First order of business is to inflate and partially bury the portable inflatable to provide radiation protection from solar flares and a shower / toilet / hot meals / etc. The rovers themselves have enough shielding, but to keep the astronauts in a comfortable environment, we're going to ensure that that's taken care of first. As such, a dozer blade to heap regolith atop the inflatable (one of the tools carried to the work site) is attached to one of the rovers and the habitat is partially buried.
B. Say we found a massive chunk of Nickel-Iron from an asteroid impact and we want to cart that "find" back to base to smelt into steel. The chunk of metal ore is too large to carry back whole, so we're going to saw it in half and then decide if we'll come back later for the other half or try to cart all of it back to base in one operation.
C. The astronauts work to break their discovery apart into pieces small enough to carry home, and preferably hand-carry. The material is then wrapped in kevlar sacks / pouches, later to be tied down to the cargo bay of a rover or suspended from one of the blimps for the trip home.
D. After the material of interest has been gift wrapped suitably well, it's time to leave. The astronauts inform the base that they have what they came for. They use their rovers to drag their portable habitat out from under the pile of regolith and de-inflate it. Tools are re-packed for travel and an inventory of everything is taken and reported back to base. All equipment critical to travel is re-inspected. If rover tracks require re-tensioning or a road wheel looks like it needs replacement, then now is the time to do it. Similarly, the blimps are re-checked for leaks and gassed-up with H2, as required.
E. Anything that can't be suspended from the blimp for travel due to load carrying restrictions is instead loaded into the rover cargo bays. Perhaps the decision is made that each rover carries a chunk of the find to get all of it in a single operation, which means no new calculations to account for increased load are required.

4. Return
A. The astronauts contact the base to inform them of their plan to return and then re-trace their path back to base. Maybe they find a suitable alternate driving path along the way that promises a smoother ride, so perhaps base will permit some minimal deviation to make the ride more tolerable.
B. After the astronauts return, their heavy metal cargo is unloaded and stacked next to the smelter, possibly to become replacement pins for their rovers' track links, or more likely, some head of state's new set of absurdly expensive "Made on Mars" silverware. The rovers are cleaned and inspected so they're ready for the next trip. Perhaps a nick is discovered in the insulation of a power cable, likely the result of being dragged over a sharp rock when the astronauts were man-handling power cords and cargo during cutting operations, so it's taken to the electrical repair shop for a minor insulation repair. The blimps are again inspected for holes, the solar panels are electrostatically cleaned, then deflated for storage in an outdoor equipment storage tent.

And so it goes... The endless hunt for readily available resources, just sitting there waiting to be discovered by some enterprising young man or woman with the determination to go out and take it, not so different from the gold and silver miners of the old west.

SpaceNut · 2019-11-25 22:25:06

I sort of like the idea of solar on the top of the blimp but laying them flat not aligned for the sun has a much lower output from them.
I have seen outputs of 1/9th of what is expected due to being level.
https://en.wikiversity.org/wiki/Practical_Solar_Power
https://us.sunpower.com/how-many-solar- … ut-factors
https://www.energymatters.com.au/reside … olar-faqs/
https://www.gonewiththewynns.com/tilt-rv-solar-panels

What if we use a two blimp stack up where the lower acts as a reflector to the bottom of the blimp above the lower one..the shape of the reflector can then be adjustable such that they point the energy to the panels, parabolic compound to direct the energy to the solar panels above.

Aluminized mylar. Or aluminized polymer film
http://newmars.com/forums/viewtopic.php … 57#p130457

Calliban · 2019-11-26 05:34:19

Solar powered dirigibles are an interesting idea, but depend upon the efficacy of extremely light-weight thin-film solar cells.

Going back to the example of a spherical hydrogen filled balloon 100m in diameter. The total lift provided would be 6.5tonnes. That is 0.207kg/m2 of envelope area. The solar cells, envelope, propulsion system and cargo, must weigh no more than 207 grams per square metre of envelope. Thin solar cells must operate at low voltage, which would lead to significant losses even across the circumference of the balloon. Maybe we can do clever things, like printing the cells on the inside of the envelope and using the envelope itself as a cover and UV shield for the cells?

A similar idea would be to cover the balloon in solar cells and tether it to a ground vehicle via an electrical cable. The balloon then carries the power supply for the vehicle; and the vehicle carries the payload. The top speed and payload capacity of the ground vehicle would be a function of sunlight intensity. Excess power would go into life support functions. At full sun on Mars, a 100m diameter balloon covered in 10% efficient solar cells would provide about 400kW of power. This would vary sinusoidally throughout the day. At night, power would be zero and driving would stop.

Last edited by Calliban (2019-11-26 05:36:04)

SpaceNut · 2019-11-26 10:39:17

Nasa has been looking into the blimp with solar cells on the upper surface for a venus mission so there is quite a bit of design which could be fed forward for this consept.
http://newmars.com/forums/viewtopic.php?id=7426
http://newmars.com/forums/viewtopic.php?id=5963&p=16
http://newmars.com/forums/viewtopic.php … 15#p135015

SpaceNut · 2019-11-26 19:15:16

This explains why we do not use Nickelmetalhydride (NiMH) batteries..

http://cba.mit.edu/docs/theses/06.08.Sun.pdf

Nickelmetalhydride (NiMH) batteries, the most environmentally (and people) friendly rechargeable battery type used in household photovoltaic systems, discharge a few percent per day at 70 °F, a temperate daytime temperature. In hot climates (86 °F – 104 °F), a NiMH battery will self discharge in one to three months, and in very hot climates (104 °F – 122 °F) or if the batteries are stored in a space which traps heat, a NiMH battery will self discharge completely in less than a month

kbd512 · 2019-11-30 21:15:32

Calliban,

Using a tracked ground vehicle as the propulsion system, in conjunction with a stationary inflatable habitat for onsite work, offloads the mass associated with life support, flight control, propulsion, and solar array pointing to the ground vehicle that those things are connected to. Otherwise, part of the blimp's useful load would have to be devoted to those things, increasing its size and mass.

The ground vehicle is still useful for construction and transport tasks around the base without the blimp, so the rover should follow a parallel development path. The initial blimp concept can be thought of as a lightweight and portable high-output power source and light cargo carrier enabling extended duration operations away from a base using a minimally capable ground vehicle and minimal complexity aerial vehicle.

If the basic concept proves successful in operation, then follow-on development of the blimp concept could eventually lead to aerial vehicles for both crew and cargo transport. While this technology is still experimental, I'd much rather see a failure that drops some cargo in the dust than a crash that leads to injury or death. For initial experimentation purposes, the only thing I want to hoist above this rover is a giant thin film solar array to supply power for driving. Payload suspension would come after the durability of the blimp has been proven.

The atmosphere doesn't provide any significant resistance to movement at 30kph, so very minimal amounts of power are required to drag the blimp along at that speed. The entire point of this design exercise is to produce a mobile solar power array that supplies enough power to the ground vehicle to move more mass and bulk than it otherwise could for a given structural weight and power requirement by reducing the tonnage of batteries required to move a given weight to a given distance. The exceptionally thin atmosphere dictates that moving a heavy vehicle and cargo across rough terrain consumes more power than towing a blimp through the air using a lightly loaded rover / tow vehicle.

SpaceNut · 2019-11-30 21:41:26

The length of cable to the blimp from the ground can be quite a bit shorter than what we would need here on earth since there are not trees and winds would have less effect on drifting.
Using some of the power to heat when needed the internal gas would also keep it at the proper altitude for mans safety.

repost on flexible thin film panels

louis wrote:

I think Flisom is probably the closest to what I envisage.
https://flisom.com/industries-customize … els-films/
There is no need for heavy supportive frames on Mars - there ain't gonna be no hail, no thunder and lightning, no powerful tornadoes, no earthquakes, no floods, no rainstorms, no snowstorms...
The thin PV film could be attached to v. lightweight steel supports at intervals.
SpaceNut wrote:
The thin film plastic flexible while its bendible the radius seems to be quite large for a sheet panel and its a 1/4 to to 1/2 due to the wiring attachment of the panels which will need to be wired together to form the voltage output that we desire.
https://www.alibaba.com/showroom/flexib … panel.html
https://www.alibaba.com/showroom/flexib … -roll.html

If we can make the first circumference 4 meters for the 4 panel layer for maximum bend and work to the inner diameter from the outer winding them in from the hatch door would be very difficult so its got to be from the top hatch for going in and out. That makes the inner diameter about 1.5 meters with the outer diameter say 3 meters. Panel is 1 cm depth per layer winding them in a circle inside each other.
So 70 layers of 4 panels on average is 280 possibly 300 max coiled up inside the Dragon.
That makes flexible only marginally better but at a 1/3 less power....

SpaceNut · 2020-07-25 17:37:00

coping a few posts that relate

tahanson43206 wrote:

This is a follow up to #143 ...
http://newmars.com/forums/viewtopic.php … 70#p169870
My friend with the Kohler generator received a visit from the friendly local maintenance team today. The problem turned out to be a battery failure.
I admit I have not yet absorbed more than a tiny fraction of what is knowable about lead acid batteries. Such batteries are likely to find employment on Mars, but whatever battery technology is chosen for service on Mars, I'll bet the same facts of deterioration will become problems for the maintenance teams.
The specific learning point I confronted today was a misunderstanding about voltage level as an indication of battery readiness-for-service.
I was asked to serve as a gopher, and at the local automotive parts store, the clerk showed me a fancy instrument they have (apparently) received recently. It showed that the old battery was unable to crank, despite having a voltage well in excess of the rated 12 VDC.
The replacement battery started the generator instantly.
My friend got away without what might have been a major service charge, and I got a lesson about battery deterioration. Fair exchange !!!
The battery had been in service for five years, which is one year past when I change automobile batteries, whether they need it or not.
(th)

This is an important ability with equipment that needs to be maintained.

SpaceNut · 2020-07-25 17:37:55

GW Johnson wrote:

There is a simple tool called a battery load tester, made for lead-acid automotive batteries, that has a voltmeter with a specially-marked scale and a big resistor. It works on any larger or smaller engine-starting battery that is lead-acid.
You put the leads on the battery terminals and read the voltage. Presuming the battery is not discharged, you then use the "load" switch to short the battery into the resistor for several seconds, watching the voltage change under load.
If the voltage drops too sharply, the battery is "dying" or "dead" and must be replaced. A "good" 12 volt battery won't drop more than a volt or two. The special scale has color zones for weak or not, and for 6 volt and 12 volt batteries.
But you can use it on an 8-volt tractor battery, even though there is usually no 8 volt scale: just watch for a volt or two drop, versus 3 or more.
A good battery can test "bad" if it is discharged when you load test it, so trying charging the battery first, then load test it. But if a 12 volt reads only 10 volts after charging, you already know it is bad. Same for a 6 volt that reads 4, or an 8 volt that reads 6. That 2 volt drop is a dead cell.
These things are available in auto parts stores and hardware stores. Not very expensive, really. I use mine all the time.
GW

tahanson43206 wrote:

For GW Johnson re #158
Thanks for the helpful tip for maintaining a fleet of 12 Volt (or similar) batteries!
I'll start looking for a load test instrument as you've described it.
I keep a set of 12 volt batteries in a state of (intended) readiness, based only on voltage showing before and after charge.
The new instrument you've described would be well worth having in the collection here!
Thanks!
Edit#1: I took one of my "stock" (retired automobile) batteries to the job site this morning, and was dismayed to see that it did not have enough cranking power to start the generator. It did better than the dead battery in the machine, but not a lot better. The instrument you've described would have enabled me to skip the labor of carting that old battery around. It might still be good for emergency lighting, but it's no longer suitable for emergency equipment use.
(th)

SpaceNut · 2020-07-25 17:40:14

The open loop value of the batteries voltage is not a good indicator and that is why you need to put a load on it. The charging voltage is also another indicator as that will be 13.8 but not more than 14.5 when connected to the unit. Most likely the cells oxides with sulfur or other contaminant such that when you charge them you are trying to wake the cell back up. The lead acid batteries like to be in continual working operation and not idle. Other battery material types require other needs so as to not break down....

tahanson43206 wrote:

For SpaceNut re #160 ... thanks for adding to GW Johnson's advice on care (and testing) of lead acid batteries.
As a follow up to the earlier report of maintenance on a generator ... it occurs to me that the generator itself is providing a pretty good load test. It cranked right up to the day it stopped cranking. It is quite possible the sound of the cranking operation changes. A recording of the cranking operation could be programmed to start just before the scheduled weekly test.
I'll look for the kind of test instrument GW Johnson suggested.
The instrument at the local automobile parts store looked (to me at least) like a professional multi-hundred dollar unit.
It was similar to one I've seen in use at Batteries+ stores.
(th)

tahanson43206 wrote:

For GW Johnson re #158
This is a follow up ...
Thanks for the helpful tip for maintaining a fleet of 12 Volt (or similar) batteries!
I'll start looking for a load test instrument as you've described it.
I finally remembered to start looking for an instrument along the lines you described, and was taken aback by the number of offerings.
I'm going to ask a question, but the set up is that for all the years I've been working with technology of various kinds, I've not run across a book or other guide that covers care and maintenance of lead acid batteries.
It occurs to me (as I think about it now) that the US military ** must ** have training manuals on the subject, but my MOS never brought me into contact with one.
So the question is: Are you aware of a resource (along the lines of a training manual) that covers this subject.
I am mildly annoyed there are so many test devices. I have no idea of the relative merits of the various offerings.
(th)

SpaceNut · 2020-07-25 17:43:16

kbd512 wrote:

tahanson43206,
Review the following document:
THE U.S. ARMY BATTERY MAINTENANCE MANAGEMENT PROGRAM
It's not a complete technical manual, but it does outline the types of testing this corporation does to support the US Army's Lead-acid vehicle batteries and reduce battery consumption. It contains the NSN numbers of the products used and references to maintenance articles related to best practices. To understand what you're doing and why you're doing it, you really have to understand the battery design in question.
MIL-PRF-32565 spells out performance specifications for 6T form factor 24V / 28V Lithium-ion batteries, for example. When you understand how they're being tested and the purpose of the tests, you can generally understand what types of use cases the tests were intended to cover.
NFPA's report on Lithium-ion battery hazards is a good read for understanding failure modes and why Lithium-ion batteries require the storage and use protocols that government or industry mandate (also includes relevant Underwriters Laboratories Testing Standards):
Lithium-Ion Batteries Hazard and Use Assessment

Battery University has some good basic info on battery testing, which includes both Lead-acid and Lithium-ion batteries:
BU-901: Fundamentals in Battery Testing
Anyway, hope this helps a little.
Edit:
A very helpful link from the US Department of Defense that puts applicable battery regulations into a single document signed by the relevant authorities from each service branch:
UNIFIED FACILITIES CRITERIA (UFC) - STATIONARY AND MISSION BATTERIES
Edit #2:
A link to a company here in Texas that specializes in testing electric vehicle and aviation batteries:
Arbin Instruments - High Precision Battery Test Equipment
Arbin has done work with Ford Motor Company and ARPE-E to improve battery testing methodology and equipment. They do testing of both batteries and super capacitors, as well as selling the related test equipment to OEMs.

SpaceNut · 2020-07-25 17:45:47

tahanson43206 wrote:

For kbd512 re #175
Thank you for your comprehensive reply! That'll keep me busy for a while << grin >>
In particular, I did appreciate the update on US military training (and practice) manuals!
The online opportunity is a welcome change!
One thing that comes out of this discussion is an understanding of the need for specialists in these and related disciplines on Mars, just as soon as the community can be built out enough.
I'll check My Hacienda, but I'm pretty sure this specialization is not currently included there.
Edit#1: SearchTerm:BatteryMaintenance
SearchTerm:BatteryTesting
(th)

The skills to trouble shot battery problems will be in demand with equipment that will be exercising them each day to build the NewMars that we all dream of.

GW Johnson wrote:

Tahanson43206:
I posted a battery testing and maintenance article on "exrocketman". It is titled "Taking Care of Car Batteries", and is dated 7-25-2020. It applies to car batteries, tractor batteries, and batteries on lawn and garden equipment. Anything that is lead acid, and used to start engines. I tried to keep it simple and to-the-point.
http://exrocketman.blogspot.com/
GW

SeaDragon · 2020-07-25 18:07:04

My major issue with blimps is closure vs leakage - going with Calliban's post above, 200 grams per m^2 of blimp skin is only about 100 microns PET with 20 microns aluminium on top. Given the large surface area of such a blimp I'm concerned about the electricity cost of replacing lost hydrogen, that's really gonna eat into performance.

A straight up airplane running on liquid H2 in a single high pressure tank and combusting it with the CO2 atmosphere (the Sabatier process!) powering a propeller and using conventional wings gets way better lifting power to weight ratio than a solar cell powered blimp as well as lower leak rates (thicker tank wall, lower temperatures) so I'm biased towards conventional aviation for now. To be fair though, being able to operate without clearing huge landing strips is definitely a strong advantage for blimps that aeroplanes don't have.

As for batteries, I've been thinking a lot about the best kind of portable batteries to use for everyday equipment. Lithium ion is great but mining lithium is difficult and transporting across thousands of kilometres of Martian surface if your mine is in a remote location isn't going to be easy. Currently, I'm thinking Sodium ion batteries look very nice indeed.

Failing that, there's likely plenty of nickel and cadmium ores around (perhaps in veins under the Tharsis Montes?) for NiCd or NiMH.

Calliban · 2020-07-25 19:16:06

SeaDragon wrote:

My major issue with blimps is closure vs leakage - going with Calliban's post above, 200 grams per m^2 of blimp skin is only about 100 microns PET with 20 microns aluminium on top. Given the large surface area of such a blimp I'm concerned about the electricity cost of replacing lost hydrogen, that's really gonna eat into performance.
A straight up airplane running on liquid H2 in a single high pressure tank and combusting it with the CO2 atmosphere (the Sabatier process!) powering a propeller and using conventional wings gets way better lifting power to weight ratio than a solar cell powered blimp as well as lower leak rates (thicker tank wall, lower temperatures) so I'm biased towards conventional aviation for now. To be fair though, being able to operate without clearing huge landing strips is definitely a strong advantage for blimps that aeroplanes don't have.
As for batteries, I've been thinking a lot about the best kind of portable batteries to use for everyday equipment. Lithium ion is great but mining lithium is difficult and transporting across thousands of kilometres of Martian surface if your mine is in a remote location isn't going to be easy. Currently, I'm thinking Sodium ion batteries look very nice indeed.
Failing that, there's likely plenty of nickel and cadmium ores around (perhaps in veins under the Tharsis Montes?) for NiCd or NiMH.

The idea is to tether an H2 filled balloon with solar cells of top to an electric ground vehicle. The solar cells power the ground vehicle. So the blimp never has to land as it is tethered. The ground vehicle moves very heavy loads at low speed, so the air resistance of the balloon is not a problem.

I like the idea of an H2 powered Mars plane. Am I correct in assuming that one of the waste gases is methane? If so, regular aviation traffic on Mars would drive global warming. Which is a good thing on Mars. Boil-off would be less of a problem on Mars. Weaker sunlight and a thin atmosphere with weak convective heat losses. Also, a plane is a more practical liquid hydrogen vehicle than a car, because it is refilled shortly before takeoff and all fuel is burned within hours of takeoff. Hence, there is less need for tank insulation.

Last edited by Calliban (2020-07-25 19:20:36)

kbd512 · 2020-07-25 19:42:35

SeaDragon,

Takeoff and landing speeds for a practical airliner type aircraft would be near to Mars local Mach 1 for an aircraft that resembles an Earth-based airliner. A fully fueled jet powered glider like the Lockheed U-2 would simply weigh too much for the nearly non-existent atmosphere to generate sufficient lift, so a rocket powered aircraft would be more practical, thus fuel economy would be very similar to rockets, which seems a bit impractical since nobody flies aboard a rocket powered airliner here on Earth where liquid hydrocarbons are much easier to obtain. If that wasn't enough, Mars sea level is much like Earth at 130,000 feet. No jet powered aircraft flies that high here on Earth because there's not enough O2 to support combustion. I can't see how combusting H2 with CO2 would provide better performance.

Edit:
I could see a LOX/LH2 fuel cell powered vehicle providing reasonably good performance, up to the 1.5MW threshold where gas turbines provide superior power-to-weight ratios.

Last edited by kbd512 (2020-07-25 19:44:51)

SpaceNut · 2020-07-25 20:26:58

Here is another Dirigibles on Mars - A practical means of transport?

There could be another were we did talk about a tethered balloon approach to getting power to equipment.

SpaceNut · 2020-07-25 20:53:19

battery%2Btools%2B1.jpg

A nice long article goes with the image on GW's website

SeaDragon · 2020-07-27 05:22:45

Calliban wrote:

The idea is to tether an H2 filled balloon with solar cells of top to an electric ground vehicle. The solar cells power the ground vehicle. So the blimp never has to land as it is tethered. The ground vehicle moves very heavy loads at low speed, so the air resistance of the balloon is not a problem.
I like the idea of an H2 powered Mars plane. Am I correct in assuming that one of the waste gases is methane? If so, regular aviation traffic on Mars would drive global warming. Which is a good thing on Mars. Boil-off would be less of a problem on Mars. Weaker sunlight and a thin atmosphere with weak convective heat losses. Also, a plane is a more practical liquid hydrogen vehicle than a car, because it is refilled shortly before takeoff and all fuel is burned within hours of takeoff. Hence, there is less need for tank insulation.

Ah, sorry, I get it now! Having a blimp carry your solar cells at high altitudes (these could also hang down below the blimp if needed) could also give you longer hours in sunlight per day (since you're not so quickly blocked by the horizon). It might even mean getting above dust storms, which otherwise terrify me: barring proper nuclear reactors (which I’m told we might not be allowed to use!) are we supposed to go three weeks without electricity or heat?

Yes indeed, I’m going off the data in “The Case for Mars” by Dr Zubrin where it just quotes the performance for H2/CO2 but I can’t see any other exothermic reaction route that’s better than the following:

CO2 + 4H2 -> CH4 + 2H2O

The general idea being that you only have to bring H2 with you which is very light so that even though the energy released per mass of reactants isn’t that great the energy released per unit mass of H2 is pretty competitive. Storage of LH2 is also much easier since anything that boils off need not be vented during flight - it goes straight into the engine.

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