# 24v battery for EV



## CaptConan (Jul 12, 2010)

How much do these batteries weigh? And how big are they? A single 24V battery at 600ah is something like 14.4KWh, which is a ton of energy, maybe larger than some folk's entire pack. Boosting from 24VDC to 230 VAC through an inverter will probably require a lot of battery current which has a bad effect of heating up the battery and losing battery life. The general rule of thumb is to use as high a voltage as your controller/motor can handle. This keeps things efficient and allows for higher top speed.


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## spdas (Nov 28, 2009)

freezerchief said:


> Hello,
> 
> new to the EV forum I am wondering if it is possible to use a 24volt 600ah battery to power an AC powered EV. I have lots of access to these batteries from pallet jacks (could also run a 36v 1000ah just alot heavier). could one buy an inverter 24v-230v 3phase and run this through a VFD. Where would any problem issues arise from this configuration.
> 
> ...


Won't work. Too low voltage vs too high current to get freeway speeds. YOu would not get 60 miles out of it. Battery is probably 1200# and quite big, BUT they are very durable and u can run them down repeatedly without damage as the plates inside are heavy duty, not like deep cell or car batteries. When using a "forklift" motor originally at 24v, most users bump the the voltage in to 72-96v at least. You would be wayyyyy up there in current draw for any kind of speed. Try looking at the thread. "Using a forklift motor and choosing a good one" (or something like that)
francis


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## freezerchief (Apr 26, 2011)

thanks,

yes they weigh in at about 1100 LBS,
I have an 04 dodge ram sitting in my yard with a blown motor,
and access to these batteries and free changes and charging.

what would be a good option to power this EV 
anyone have any links to such a heavy truck EV conversion


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## Guest (Apr 27, 2011)

Batteries may be good for some home fast charging using a bunch of these puppies. Charge them up with solar during the day and then use them to fast charge your ev in the evening time. That is one way to use them. 

Pete


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## Duncan (Dec 8, 2008)

Hi Freezer

If these batteries are free see if you can use them to run your house
charge them at night on the low tarrif (Night Rate)
and use them to run your house

Here night rate is about 1/3 of normal rate


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## icec0o1 (Sep 3, 2009)

Duncan said:


> Hi Freezer
> 
> If these batteries are free see if you can use them to run your house
> charge them at night on the low tarrif (Night Rate)
> ...


Not worth it with charging/discharging/inverter losses. Only worth it if he's installing sollar arrays.


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## piotrsko (Dec 9, 2007)

probably a bit heavy for the ram, unless it is a 1 ton, but the guy over in the motor section has battery needs for his bus.


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## Duncan (Dec 8, 2008)

Hi Ice

Suggest you buy a new inverter/charger 3:1 is real bad!!


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## icec0o1 (Sep 3, 2009)

Duncan said:


> Hi Ice
> 
> Suggest you buy a new inverter/charger 3:1 is real bad!!


LA batteries have charge efficiencies around 50% and discharge efficiency around 80-90% depending on the load. Only Lithium batts have 99% charge/discharge efficiency in most cases.


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## freezerchief (Apr 26, 2011)

would it be possible to run two seperate higher voltage lithium ion battery packs, and charge them with the 24V battery. one pack driving the vehicle while one is charging off the 24v battery.


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## icec0o1 (Sep 3, 2009)

freezerchief said:


> would it be possible to run two seperate higher voltage lithium ion battery packs, and charge them with the 24V battery. one pack driving the vehicle while one is charging off the 24v battery.


If you're asking a question like this, it's probably a good idea to not attempt to build an EV, at least before you delve a lot more into electricity and engineering.


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## Duncan (Dec 8, 2008)

Hey ICE
Stop spreading misinformation

*These tests indicate that from zero SOC to 84% SOC the average overall battery charging efficiency is 91%,*

http://photovoltaics.sandia.gov/docs/PDF/batpapsteve.pdf

Hi Freezer
Some people in the US already use large lead acid batteries to reduce their power bill by buying power at cheap times and using it during the day


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## Duncan (Dec 8, 2008)

*would it be possible to run two seperate higher voltage lithium ion battery packs, and charge them with the 24V battery. one pack driving the vehicle while one is charging off the 24v battery.*

possible Yes -BUT- probably not - it could work if you are using the vehicle for a lot of very short journeys


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