How to charge HV batteries off car?

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Dan--T
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How to charge HV batteries off car?

Post by Dan--T »

Hi, this is probably a newby question,. But what is the simplest way to charge HV automotive batteries up when they're not connected to the car?

I want to use my Lexus hybrid battery pack as a test battery to get things moving but I need to charge it up first,. And I guess I'll need to do the same once I have purchased my proper battery.

What is the recommended method?
(Please bear in mind I am not an electrical engineer so can't knock something up using a Prius inverter and some copper wire)

Thanks
Dan
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ZooKeeper
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Re: How to charge HV batteries off car?

Post by ZooKeeper »

For a hybrid pack, especially Toyota/Lexus ones, my suggestion would be one module at a time while secured in their case.
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Re: How to charge HV batteries off car?

Post by Isaac96 »

As ZooKeeper said. You can either use a proper charger or just a simple lab power supply - those have both current and voltage control so they charge batteries safely, also they're generally useful for EV conversion work.
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ZooKeeper
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Re: How to charge HV batteries off car?

Post by ZooKeeper »

Isaac96 wrote: Wed Jul 07, 2021 1:15 am As ZooKeeper said. You can either use a proper charger or just a simple lab power supply - those have both current and voltage control so they charge batteries safely, also they're generally useful for EV conversion work.
Yea, I know... so useful I am amassing a collection of them :ugeek:
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Re: How to charge HV batteries off car?

Post by arber333 »

Dan--T wrote: Tue Jul 06, 2021 11:21 pm Hi, this is probably a newby question,. But what is the simplest way to charge HV automotive batteries up when they're not connected to the car?

I want to use my Lexus hybrid battery pack as a test battery to get things moving but I need to charge it up first,. And I guess I'll need to do the same once I have purchased my proper battery.

What is the recommended method?
(Please bear in mind I am not an electrical engineer so can't knock something up using a Prius inverter and some copper wire)

Thanks
Dan
See here is a hard core method, but it works for every kind of automotive battery you can imagine :).
https://leafdriveblog.wordpress.com/202 ... r-charger/
You can get a smaller version autotransformer for single phase connection and it will work up to 300Vdc or so.

If you dont need to have a fast charging then i recommend you buy a simple PSU for voltage you need to get battery to.
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rstevens81
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Re: How to charge HV batteries off car?

Post by rstevens81 »

If they are in simple modules you can charge each module by themselves with a cheap lion charger from China land (if you open them up you can change the charge point voltage)
I did this 12 at a time to 3.75volts (45v) to put my modules into a storage state. I also monitored the BMS to be extra safe.
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Dan--T
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Re: How to charge HV batteries off car?

Post by Dan--T »

Ok, I ideally didn't want to have to split open the battery pack but if that's the best/ only feasible way to do it I can.

So I think each lexus cell is 7.2v,. So I just need to buy a power supply capable of over 7.2v and do them all one at a time?
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ZooKeeper
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Re: How to charge HV batteries off car?

Post by ZooKeeper »

Dan--T wrote: Thu Jul 08, 2021 9:42 pm So I think each lexus cell is 7.2v,. So I just need to buy a power supply capable of over 7.2v and do them all one at a time?
The modules are wired in series, the only way to do them all at once @ 7.2v is to turn every other one around so all the (-) & (+) terminals are on the same side.
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Re: How to charge HV batteries off car?

Post by RetroZero »

What about the prius gen 2 Inverter as charger? There's a thread and quite some work done. Needs some fine tuning and testing from what I understand. I hope to get into that part pretty soon as I too have a hybrid pack that needs recharging. If I understand correctly, if there is no bms, current and voltage has to be real low as the weakest modules are going to take most of the first phase of charging.
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Re: How to charge HV batteries off car?

Post by marcexec »

If you have to buy, I can recommend Meanwell LED power supplies. They come in various voltages and power levels and are current and voltage adjustable. I run a pair of waterproof HLGs to charge my bike overnight without issues (after switching to waterproof...).
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Re: How to charge HV batteries off car?

Post by Dxtawise »

I think you could use a bunch of LED power supplies connected in series for this job.
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