Help replacing/upgrading batteries

1664 Views 10 Replies 5 Participants Last post by raphen, Oct 16, 2019

raphen

Discussion Starter · Sep 3, 2019

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

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
http://www.chargingchargers.com/quick-charge/mb1210x2.html
DC/DC Converter: Kelly HWZ Series 144V TO 12V 300W
Instrumentation:
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.

http://www.mightyboyev.com/PakTrakr 800.htm

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

http://www.usconverters.com/serial-bluetooth-adapter?zenid=363893a35f5f08d888f59851b2bbb07b

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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brian_

· #10 · Oct 14, 2019

raphen said:
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.

You do appear to be confused. The first-generation Chevrolet Volt battery pack contains 288 cells; the full pack voltage is not 288 volts.

This GM document describes the two generations of Volt battery pack:
VOLT_BATTERY.pdf

raphen said:
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.

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".

raphen said:
16kwh is 16,000 volts.

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?

raphen said:
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.

First, the full Volt battery pack voltage is 360 V, not 288 V. So half a Volt pack would be 180 V (nominal), not 144 V. I don't know if your controller can handle that.

The discussion of the combinations, though, is reasonable. Yes, you can string together fewer than the full set of modules to get a lower voltage and lower energy capacity, with the same peak current capability.

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.

A small correction: normally module voltages are the nominal voltage (sort of an average between fully charged and fully discharged), and for the first-generation Volt modules that's 45 V (~2 kWh) and 22.5 V (~1 kWh).

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