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Selecting optimum battery type and capacity

Selecting optimum battery type and capacity

Selecting optimum battery type and capacity

(OP)
Have a machine in mind which is intended to be portable (hence weight and dimensions is a constraint), has a miniature refrigerant compressor (like those of Aspen) plus a blower of nominal wattage. Furthermore, the machine is desired to run on rechargeable batteries and give a backup of at least 8-10 hrs. Hence the primary power consuming thing is compressor itself. Following are the specs of intended compressor

Capacity: 360W Input: 12V or 24V or 48V (3 models) Max. Current: 9.5A, 9.5A or 7A respectively (Add-on info: Weight: Around 0.5KGs just) Battery Backup required: 8-10 hrs continuous operation but will have compressor trip-outs in between. Rechargeable Battery: Yes Battery Cycles: At least 100 cycles will be good. Desired cost: Off course minimum Desired Weight: Max. 4-5 KGs??? or what's the minimum I can get?

I don't know much about batteries, this is my first encounter. Have read quite a lot on net and stack but wanted to have exact and precise information rather than my not-sure-calculations as the whole idea depends on this battery thing.

So considering the current world of batteries, is it even possible to have a practical battery solution for this scenario? Because weight of battery and size is the biggest constraint. It should not be so heavy or bulky that it renders the equipment non-portable. I assume that for very accurate answers, more information on compressor (like current drawn in its tripped condition, if it just slows down instead of stopping etc is required but considering the given data, you can suggest a direction at least and approximate answers)

What can be the optimum battery type which I should search for? Liquid, Gel, Dry or anything else? 12V or 24V? Please suggest any brand or model too if possible so that I can find the supplier and evaluate the cost. What should be the capacity? (I have figured out that it should be around 300Ah, on 400W load (assuming an FOS, correct me if I am utterly wrong.)

RE: Selecting optimum battery type and capacity

Your numbers are a bit confusing. 12V*9.5A is nowhere near 360W, which would be more like 30A. This is car battery realm, and several, at that. The typical car battery has about 50 to 80 Ah capacity. To get to your supposed requirement requires up to 6 car batteries

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RE: Selecting optimum battery type and capacity

You could probably do a lot better in size and weight with LiIon batteries but it would bend you over to pay for them and you would need a fully engineered system to keep it all safe enough to minimize liability.

You should consider the alternative that would cost probably 15% of a battery solution and would probably weigh 10% of a battery solution. It also has vastly more run time:
ebay item

Keith Cress
kcress - http://www.flaminsystems.com

RE: Selecting optimum battery type and capacity

BTW: An inverter generator will throttle back to a very quiet idle when the refer unit has cycled off. A nice aspect of your application is that a few minutes power loss doesn't probably matter when fueling is needed.

(note: A "trip-off" implies a failure while cycle-off is a normal occurrence.)

Keith Cress
kcress - http://www.flaminsystems.com

RE: Selecting optimum battery type and capacity

Flooded NiCad strikes middle ground in terms of cost and weight - not as light as Li-ion but much better than lead-acid, but more expensive than lead-acid and a lot cheaper than Li-ion. But I like Keith's suggestion more. smile

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