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Discussion Starter #1
Hiya,

I have a conversion which involves a Prius hybrid battery as a drive battery.Its a NHW-20 with 28 prismatic cells, total voltage about 235v. Does anyone know a way i can either make of buy a charger that i can use to charge the complete pack?

Cheers Barry
 

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If you are talking about the standard Prius Hybrid battery, those are NiMH cells. The original installation is basically balanced when new and the Toyota system only monitors the balance and alerts you with the Red Triangle of Death when it goes out of balance, usually years after installation.
 

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Thanks for that Tom, Yes you are correct. What i am looking for is a way of charging the complete pack as i have used it in a electric car conversion.

Cheers Barry
 

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Are you using more than one pack? I rebuild these for customers. I use a 250 vdc charger that I can preset to the voltage I want for the pack. Not really good for an EV since it only delivers up to 1a though.
 

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One Amp. I am charging a single Prius pack at say, 240vdc. A single pack is only around 5 ah.
 

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One Amp. I am charging a single Prius pack at say, 240vdc. A single pack is only around 5 ah.
Ah, the charger only delivers one amp... of course that makes sense and is what you meant, but I was thinking of the pack charge or discharge rate. Sorry for the confusion, and thanks for the response. :)
 

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Hiya, yes i am using 2 packs , at the moment i have configured one pack into a 115v pack but double the amp hour for testing. I would like to run 2 packs at full 235v . I do need to find a way to charge that pack . So i need some sort of DC power supply . If you have any suggestions that would be great.

Cheers Barry
 

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1amp is a 10 hour charge from fully depleted, which is ok...

The bigger curiosity is what on earth you're powering with only a 10Ah pack?
 

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IIRC there are serious issues when charging NIMH cells in parallel because of how the end of charge is detected. I got a Prius pack for free, and ultimately decided it wasn't worth using both due to the difficulties of finding a suitable charger and the safety concerns of paralleling the cells for charging. Are you planning on splitting the parallel strings while charging?
 

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I am interested in this 2 I have a friend that was given a 2002 prius and a 2004 prius. Both have been sitting for a very long time. He said if I fix the 2004 for him I ca have the 2002. After looking at them I am convinced the HV batteries are dead. They might be completely shot due to age, but i would like to try and charge them up and see. But i have no way to charge them.
 

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Thanks for that Tom, Yes you are correct. What i am looking for is a way of charging the complete pack as i have used it in a electric car conversion.

Cheers Barry
Hi Barry, I made a 'slow charger' based on the British supply system of 230 volts. Fully wave rectification of 230V gives a peak ripple on the dc of about 325 volts, in my case night time volts were up to 245 v giving my peak dc ripple of 346 volts. This was to perk up a mark1 prius (Japanese supply only ...grey import).
The charger comprised a 400 volt fullwave rectifier of 25 amp rating (over sized but fairly cheap!) and a selection of 400v capacitors in switched series / parallel to give a variety of charge rates.
The capacitors on the 230 volt ac supply side to the rectifier is 'wattless' current limiting rather than resistors that get hot even very hot. For one reason or another I had a lot of capacitors lying around! I was happy with about 0.5 amp and comfortable leaving it on overnight.
Depending on your max rated battery pack voltage, the device in my case was self limiting as the pack voltage was about 330 V. Hope that this is of interest. As a bye the bye, the short circuit current on the dc output can be quite low due to the high impedance nature of the circuit, so can charge devices of lower voltages, but warning, only under supervision, as if left, it could over volt and damage cells.
Cheers, Joe
 
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