# Planing to add HV Nimh OEM pack to Gen2 Prius



## rmay635703 (Oct 23, 2008)

TexasCotton said:


> Hello
> I am planing to add a 28 module7.2volt Nimh OEM 201.6 volt to my existing Gen2 Prius. The additional pack will mean 56 total modules and 400. volt plus 100 pound weight. The adding of oem packs has been done by other people with the Prius with success.


??? I would think the packs would need to be in parallel not series, all series would do is make a big kaboom noise.


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## TexasCotton (Sep 18, 2008)

YES in parallel I know that part
back to topic

Does any 1 sell a cheaper nimh charger than 675 plus wait time
http://99mpg.com/Projectcars/gridcharger/
any1 first hand done this


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## rmay635703 (Oct 23, 2008)

TexasCotton said:


> YES in parallel I know that part
> back to topic
> 
> Does any 1 sell a cheaper nimh charger than 675 plus wait time
> ...


There is a $3 one


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## TexasCotton (Sep 18, 2008)

yea 
I do not think so and you gotta explain whatever that is. All I see is a meter, battery, and power strip , so not sure what you have


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## rmay635703 (Oct 23, 2008)

TexasCotton said:


> yea
> I do not think so and you gotta explain whatever that is. All I see is a meter, battery, and power strip , so not sure what you have


In that form it was an "advanced" version of this
http://www.alpharubicon.com/elect/3dollarbattggn.htm

The meter was being used just to test the amperage and voltage output.

I took a power strip that burned up the power surge circuit and rewired it so I could run a load in series through a battery & diode.

The charger is the diode and lightbulb.

I have since advanced the design of my power strip battery charger to include a cap and a bridge but I can toggle and choose capacitive or resistive charging in its current form.

That modification cost roughly $15 and is much more efficient.

The key to dumb charging is to have a timer and to keep the current very low so you can just go off the pack voltage, its not as efficient but it is safe and easy and cheap so long as you keep an eye on the thing.

110v can charge a pack up to an absolute limit of about 150v, 220v goes to about 300v albeit very slowly nearing the top.

NiMH are not like lithium, they will take a carefull, slow overcharge and this actually helps keep them balanced when done correctly.

Cheers
Ryan


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## TexasCotton (Sep 18, 2008)

rmay635703 said:


> In that form it was an "advanced" version of this
> http://www.alpharubicon.com/elect/3dollarbattggn.htm
> 
> The meter was being used just to test the amperage and voltage output.
> ...


 Yea
Once again I gonna pass on that .I am not gonna spend 20 or 675 dollars to charge even though the 675 is closer to what I need . I believe there is better out there than those two choices


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## rmay635703 (Oct 23, 2008)

TexasCotton said:


> Yea
> Once again I gonna pass on that .I am not gonna spend 20 or 675 dollars to charge even though the 675 is closer to what I need . I believe there is better out there than those two choices


I hate to break it to yah but I've been in the EV thing many more years than my age would suggest and I've picked up a little bit on how things work.

1. If you want a high voltage charger (one other than 12v) you gotta pay to play, the more voltage the more $$$ even if its not a high amp rate.

2. If you want to charge anything other than lead add even more $$$ to the cost of the charger.

3. If you want the charger to not only support NiMH but also to charge the NiMH correctly add more $$$

You will find that the chargers that are less than $675 and support more than 144v are likely not much better than the $20 capacitor charger for NiMH because few correctly support it.

Now not all hope is lost, there are plenty of used chargers on the market, in my mind you have a few options.

1. Open ReVolt, build your own charger from scratch, it could likely do it quickly and safely for less cost if you design the logic right. Since your pack requires such a low amp draw you could probably build it quite inexpensively by substituting a lot of less expensive low amp parts.

2. Buy an old NiCD charger(s) that will meet your volt requirement, your voltage is odd so you won't be able to get by with just one, trouble with these is they many times (for faster units) expected flooded NiCDs which can tolerate more overcharge than you NiMH ever could.

3. Buy a bunch of RC style chargers and bank charge the whole thing, your pack is a little tinker toy ahr wise and should be able to be handled by this type of setup.

4. Buy a more generic used or new charger, hope you can get the profile changed and build your own shutdown circuit (a shutdown circuit could add manners to any setup even a cap charger).

5. Buy or build a FLA charger that just happens to taper before the bend of your pack at your chosen amp rate so you can't fully charge but also can't enter the bend region where most NiMH chargers mess up. The prius doesn't much like fully charged packs anyway.

Good Luck
Ryan


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