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Discussion Starter · #1 ·
So, I was recently told that the weight of a lead battery determines how much energy it can store. I'm starting to think that they just meant that as an approximation because I always thought design could have an effect as well. Lead-Acid has become better from 50 years ago right?

Also, if this were true, then manufacturers/distributors are totally skewing their numbers.

Perhaps it's a little of both. Anyone know?
 

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Firefly Energy is betting construction makes a difference. Typical lead acid batteries use just a fraction of the available lead. Firefly greatly increases the available lead surface area via a carbon foam electrode.

http://www.fireflyenergy.com/
So, I was recently told that the weight of a lead battery determines how much energy it can store. I'm starting to think that they just meant that as an approximation because I always thought design could have an effect as well. Lead-Acid has become better from 50 years ago right?

Also, if this were true, then manufacturers/distributors are totally skewing their numbers.

Perhaps it's a little of both. Anyone know?
 

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There is a bit of deception there.

Realize lead acid batteries come in two basic flavors with some sub categories.


  • Cranking or Starting batteries
  • Deep Cucle Batteries.
Cranking or Starting batteries as obvious are used to start engines. They are built with many thin spongy plates to maximize surface area and deliver high short burst of current and recharge quickly by an alternator. Thus by volume in theory have higher AH ratings. However if pressed into deep cycle service the plates corrode, dissolve, or sulfate very quickly and will be lucky to make a year in service.

Deep cycle batteries have fewer plates which are much thicker and heavier by volume. You can guess the rest.

So for example you can buy a BCI GC battery with a Walmart name on it that weighs 50pounds, or Trojan that weighs 66 pounds. Which one will you choose?
 

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Discussion Starter · #4 ·
Thanks Sunking,
So it would appear that the myth is not a myth, but true when talking about traction batteries.

Are you familiar with US Batteries? They have a good reputation from what I've heard in the EV community.
http://www.usbattery.com/usb_index.html

I've also heard that there are really only about 3 manufacturers of these types of batteries, but that they get different labels slapped on them and get marketed differently.

The odd thing is that if you calculate the energy capacity of the battery for their 6V & 12V batties and divide by weight, the energy density is close but not the same. Should I chalk it up to a margin of error in their rating system?

For example,
6V - US-2200 is 61.73lbs & has rating of 232AH.
232*6/61.73 = 22.55 WH/lb

or

12V - US-12VXC is 86.40 & has rating of 155AH.
155*12/86.40 = 21.53 WH/lb


 
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