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Discussion Starter · #1 ·
Just out of curiosity, has anyone ever thought about dropping in a lightweight 12V battery. I'm not sure how much amps or CC amps the bolt really needs to get stuff done, can't imagine it being a lot.

So if someone was serious about dropping weight (12V + cruze eco rims and lighter tires) this could be an option.

https://www.jegs.com/i/Braille-Battery/147/B106/10002/-1
 

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When my Prius battery died, I replaced it with a LiFePO4 20Ah from batteryspace.com for about $120. It's about 7 lbs and can do 200A briefly. It's been in there for 3 years now. The difference is that the battery lives inside the cabin in a Prius, whereas the Bolt has it under the hood. Lithium ion based batteries are damaged when charged at temperatures below freezing, so this wouldn't be a good solution for the Bolt unless it was relocated inside the cabin.

I don't know the Bolt's startup energy demand, but it probably isn't much. It has to close the high voltage battery contactors, and after that, the hybrid pack is supplying 12v.
 

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I would love to replace my Bolt's 12v battery with a lithium, but would be wary of doing it because the Bolt's computerized charging system is programmed for lead acid batteries. The lithium battery may be damaged if using it instead of a lead acid. Would like to hear more opinions about this....
 

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Should be no problem to use a lithium ion battery as long as the max charged voltage is well above the Bolt's output voltage. Most cars will output up to 14.4v to charge the battery, so the lithium ion battery should have a max voltage higher than this. For a LiFePO4 battery, that is 4 cells connected in series.

I bought a cheap ($40) 4Ah LiFePO4 4s battery from HobbyKing to test the concept of replacing lead acid batteries with lithium. It works, but isn't a long term solution since only 4Ah doesn't give much of a buffer.


Here's what I run in the Prius:


The problem is still freezing temperatures. The battery shouldn't be charged when it's below freezing.

If I owned a Bolt, I'd probably put a small battery in the glove box and just be mindful not to let the dome lights on for a long time, or go weeks without driving.
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You can buy lithium batteries specifically designed to be drop-in replacements for PbA. They contain circuitry to adapt the PbA charge profile to better fit their lithium chemistry.
 

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I will be replacing my lead-acid 12 VDC battery in my 2014 Ford Fusion Hybrid with a li-ion version soon. Hybrids and EVs don't use much of the 12 VDC power since hybrids use the motor/generator to start the engine from the HV traction battery, and that same battery supplies power back to the 12 VDC battery through a DC-DC converter.

GM and other manufacturers will not change the lead-acid batteries as they have long term and large volume battery purchases from their suppliers. But GM and the others must offer the li-ion battery as a option if the customer wants it. Then when lithium supplies are cheaper and plentiful, the 12 VDC li-ion battery cost will drop enough to compete, and finally the lead-acid battery will be another obsolete and historical automobile item as the hand crank is, and as the gear-meshing starting motor will be.

Charles F. Kettering would be satisfied even if the electric starter and generator system he invented and developed in 1911 will be replaced by a fully electric motor system one hundred years later.

Here is the 1911 patent: https://patentimages.storage.googleapis.com/48/40/22/44dda58bbb621e/US1150523.pdf
 

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Call me paranoid, I wouldn't want to put a RC pack in my glove box for smokey reasons. I don't trust the QC on those things. There is a lot to be said for good old faithful lead, especially when you're talking a 3500 pound vehicle.
 

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The reason auto manufacturers use a lead acid battery still is because it's more durable in the environments they are subjected to. From below freezing to 150 degrees F under the hood, lead acid holds up.

Lithium ion batteries need environmental regulation (as evidenced by the heating/cooling for the traction battery). There's no reason for an auto manufacturer to replace the lead acid battery when that introduces more problems. The only thing I can see happening is a reserved part of the traction battery being used as a 12v source. Since it's part of the traction battery, the environmental controls are already there.

Call me paranoid, I wouldn't want to put a RC pack in my glove box for smokey reasons. I don't trust the QC on those things. There is a lot to be said for good old faithful lead, especially when you're talking a 3500 pound vehicle.
LiFePO4 isn't the smokey type.
 

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Gotcha been out of the loop for years, was not familiar with the 30c hk life packs. Just assumed it was lipo. I have actually used both life and lipo as starter batteries in my cars years ago. Cars a lot lighter than a Bolt though.. on track where I could feel a small difference.





Commuter 3500 pound cars I depend on for getting to work and school on time, yeah I'm ok with lead on that one.
 
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