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Help replacing/upgrading batteries

1668 Views 10 Replies 5 Participants Last post by  raphen
Hello community,
I have a Geo Metro electric conversion that needs its batteries upgraded. Currently installed are twelve Walmart branded 12 volt 114 amp hour deep-cycle lead-acid batteries. They got toasted trying to climb home. The road to my house has about 1/3 of a mile of 22% grade and nuked the batteries. It is an interesting feeling and experience climbing that hill as you can feel the electricity get pulled from the core of the batteries to the motor. It made it once but the second time had no chance of hitting the half-way mark and the brakes could not hold the weight. Thankful for my superb driving skills :rolleyes: :)

Anyway... I would like to upgrade my batteries to be able to use the vehicle. My aging CRV does not get very good gas mileage and need to watch the budget commuting to and from employment.

Have been interested in buying a salvaged LEAF or similar EV to scavenge the batteries and resale parts. That seems like the more economical route versus buying new "drop-in" batteries.

So this is why I come to the community. Looking for help in the calculations of what I will need. How many LEAF batteries? If I do the "drop-in" LiFeOS4 do I just match the number of batteries I currently have? What other alternative solutions may be out there?

Here are the details of the EV:

Motor: Netgain Impulse 9" motor
Controller: Open ReVolt 144 volt, 500 amp
Batteries: twelve 12 volt 114 amp hour deep-cycle lead-acid
System Voltage: 144 volts
Chargers(2): Quick Charge Octopus-AGM 10 Bank Charger
Quick Charge 2 Bank
DC/DC Converter: Kelly HWZ Series 144V TO 12V 300W
PakTrakr Battery Monitoring System, which monitors instantaneous
voltages of each battery in the pack.
Paktrakr Current Sensor, which monitors instantaneous
current delivered by the battery pack.
PakTrakr ES1R automatic logging serial interface for
recording instantaneous battery voltages and current.
The recorded data can be downloaded to a PC for detailed
analsys. 800.htm

Bluetooth RS-232 adapter for use with smartphone app
to display dashboard metrics on your smartphone.

adapter port, which allows it to accept a standard
Level 2 charging station J1772 plug.

And finally any suggestions on proper battery disconnect? Would like to remove old dead batteries so I can push the card around the yard and avoid potential damage from leakage etc.

Thank you in advanced!
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Thanks for the reply @Duncan. I see they are a few thousand for the battery pack. Which is totally reasonable since I figured doing the drop in replacement would be at least $12k if it was a one for one kinda thing. If do go that route is it a simple plug 'n play or is going to be more involved adding other components and modifications?
Hi again,
I feel more confused now after reading that post. Math and numbers added with internet forum short speak just will spin me upside down. But after a little deducing I may be on the right track. So here goes, please let me know if it is correct or not!

From what I understood from that post is that the Chevy Volt battery is 288v.

From what was stated above and in the post the battery pack is 7 batteries @ 2kwh each plus 2 batteries @ 1kwh.

The math of that is 16kwh.

16kwh is 16,000 volts.


Ok so realistically the 288v number is more of what I should be working off of. If my system is 144 volt max then I could assume that I would need half of the Chevy Volt batteries? I could do 4 @ 2kwh?

Update: @McRat says

Roughly 18 x 12 x 11 high for 2 x 2kWh in a block.

There are 4 blocks:

2kWh + 1kWh (72v)
2kWh + 2kWh (96v)
2kWh + 2kWh (96v)
2kWh + 2kWh + 1kWh (120v)

so I could do the 2+2+1 configuration.

Would be nice to be able to put the drivers seat back further so I could actually drive it.
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Yes, the nominal energy storage capacity of the first-generation Volt battery is 16 kWh, but those nine chunks are usually called "modules", not "batteries".

You certainly are confused! "kWh" is thousands of watt-hours, and watt-hours are not volts. Do you really not understand the difference between energy and voltage? Some basic electrical education may be in order... or maybe that was just a typo?
That was just a google search result site answer to my conversion. It seemed wrong and didn't make sense so i could have not included that part since i threw it out into the figuring.

And yes I do know basic electricity and confident with basic skills, just not the math :D . Thanks for the yes or no answers, that helped!

The 2kWh + 2kWh + 1kWh "block" is a set of modules which are bolted together in the Volt pack, so they are relatively easy to handle as one chunk, and there is work required to split that block into the three modules. If that combination works for you, a single block would be your car's entire battery pack... but it would have only 5 kWh of capacity, which isn't much.
With 5kWh of capacity determine the ability to climb a 22%+ grade over 1/3-1/2 mile? (The reason the current cheap walmart lead acid batteries are toast)

You have an Open Revolt - good controllers - I would run two "strings" each one would be three of the 2 kWh modules

The voltage would be 126 volts empty and 147 volts full
Which would give 45 x 2 = 90 Ah

That sound like less than your old 114 Ah batteries but with Lead acid you only get the 114 Ah at a very low discharge rate - far too low to be useful in an EV - in practice you would be lucky to get 60 Ah out of the 114 Ah batteries - so 90 Ah is about 50% more

That leaves one 2 kWh module and two 1 kWh modules left over - you could either get hold of another 2 kWh module to make up another string or use them for another project
@Duncan Thank you that helped answer some o my questions!

Thank you all for your time!
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