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DIY HV Battery Pack ?

Discussion in 'Generation 1 Prius Discussion' started by TexomaEV, Jun 2, 2011.

  1. TexomaEV

    TexomaEV Member

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    Does anyone know how well the first Prius's with the "D" Cell battery packs held up over time? IE: Years of service?

    Thinking of experimenting with the build of an HV battery pack, using 10Ah NiMh, D cells. Ebay Item # 250817421687

    Curious:

    1. Longevity of these cells -vs- OEM modules. IE: Expected year(s) of service

    2. Would there be an issue of expansion, or need to keep compressed, like the OEM modules. (My MAIN concern !)

    3. Advantage of 10Ah -vs- OEM's 6.5Ah

    4. Combine this pack with the current experimental battery/capacitor pack in the car now.

    5. If the pack doesn't perform as a replacement by itself, merely use it as an addon of Ah, to an OEM pack once the experimental PbAcid pack ages beyond usability?

    What are your thoughts?

    This is for a 2002 Prius, which is currently running on a 7Ah PbAcid pack, combined with a capacitor bank to handle initial acceleration current. OEM NiMh cells have been since removed and recycled through Interstate Battery.
     
  2. stefano5777

    stefano5777 Member

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    Hey Mike do not know answer to your question but I thought it could be a good idea for you to contact Jack at enginer and see if they are willing to donate a system to your school project car you have going on down there. It is worth a shot. Who knows he may need the tax break and I'm sure he has enough refurbished parts laying around to help you out!
     
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  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Poorly. I suggest an Internet search for NHW10 Prius battery problems.

    One problem is figuring out how you will connect the D-cells together so that the connections will withstand peak current flow of ~100A or so.
     
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  4. adric22

    adric22 Ev and Hybrid Enthusiast

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    I have also heard the round cells did not hold up well. Interestingly enough, Honda and Ford still use round cells in their hybrids. (not sure if they are "D" cells or not). I would imagine you would have to solder them together in order to handle the amps.
     
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  5. seilerts

    seilerts Battery Curmudgeon

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    The bulk of Honda battery problems are inconsistent cooling, and lack of balancing of individual stick pairs. Constructing a pack for the Prius that would provide for consistent cooling would be a major challenge. For more details of D cell NiMH traction batteries, see Battery packs exposed - MIMA Honda Insight Modified Integrated Motor Assist

    You would also need to run your own HV battery ECU, since the primary SoC calculation is based on Coulomb counting. These batteries have a 30 amp discharge limit as well.

    I think you would be far better served to try using Headway cylindrical LiFePO4 cells or packs of A123 cells life pEEf did.
     
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  6. TexomaEV

    TexomaEV Member

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    Thanks for all your input folks, Looks like some interesting issues to be had here.

    We were very successful in getting the 2002 Prius on the road for around 6months without issue using the 24ea - 7Ah "F Connector" PbAcid battery pack. The capacitor banks are what helped overcome both the peak current required from a stop, when engine was not running, and the peukert effect with PbAcid batteries, but the pack is losing capacity fast.

    It did at least prove the car worthy of keeping alive, as everything else with it seems to work fine. Other than the "Shudder of Death" once in awhile in the dead of winter.

    I suspect as well David, that the "D" Cell NiMh cells might not have the same rated cycle life as the OEM modules do, since they state something like 1000 cycles only.

    On another note, if we did just merely go back with an OEM pack, where's the best place? Called three different dealers, got three different prices, lowest being $2029.00 + tax, with pickup at the dealership.

    Would rather purchase online, and have it delivered to school. Any reputable online dealerships out there?

    Thanks again for all your input/suggestions/info, priceless as always!
     
  7. stefano5777

    stefano5777 Member

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  8. TexomaEV

    TexomaEV Member

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    Good and Bad news for purchasing a new HV Battery from Toyota, starting June 2011.

    I was lucky enough to get a relatively local dealer to match an online price for a HV Battery, it even arrived at the dealership the next day (today). Went to pick it up, and learned that Toyota now requires a $1000 core deposit on the bad battery, until it's returned. Normally not such a bad thing, other than we already had Interstate Battery recycle our modules from the pack that were bad. Toyota will not accept a partial battery, etc.

    So learn from our mistake, take very good care of your old HV Battery if you want to get your deposit back.
     
  9. AdamOas

    AdamOas New Member

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    I'm a touch confused whether or not you're needing standard Gen1 cells or these funky D type cells that you're discussing here, but we've got a whole battery's worth of the standard Gen1 cells that are sitting in boxes in the garage... some of the cells are bad for sure but some are likely to be fine.

    If you have the outer casing and it's the same type that fits the type 1 cells we'll sell you these at $50 (plus shipping) and you can save yourself $950 or so.

    -Adam



     
  10. TexomaEV

    TexomaEV Member

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    Adam, thank you for the offer, I've sent you a PM regarding so.

    Originally we wanted to just build a replacement NiMh pack, close to what the NWH10 had in it. But it would seem the "D" cells might not have the cycle life, as what Toyota used.

    If Toyota won't give a waiver of the core, we'll certainly be forced to come up with an alternative solution.

    Possibly even going with a SUPER CAPACITOR bank, paralled with the PbAcid pack. Hoping to get through several start/stop instances without pulling the HV Battery down to low, before the Prius can get the HV hybrid battery recharged to par.

    I can obtain enough 2600 farad SuperCaps to buildup an HV Bank for just under $1000 from a friend. Gamble, yes, interesting concept, yes, will it work flawlessly possibly not, but a fun project to build it would be.
     
  11. adric22

    adric22 Ev and Hybrid Enthusiast

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    Well, it would certainly make for an interesting experiment. I'm not sure I'd be willing to shell out that kind of money without having a better idea if that would work.

    Perhaps if you paralleled the capacitors with some D-Cell NiMH batteries, maybe that would increase the chances of success? Of course, by the time you are done with all that, you could probably get a factory battery instead.

    By the way, are your rails and ECU cables all corroded? I was surprised that my new Toyota battery came with both. Apparently they didn't always come that way.
     
  12. TexomaEV

    TexomaEV Member

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    Yes corrosion everywhere, busbars, and sense wiring harness. Had to replace/clean/coat with "No Ox Id-A" to slow down the corrosion process, and reterminate the sense wire harness with new eylets.

    The dealer called this morning, they found a dealership with 8 cores in stock, not under the new core return constraints. This dealer is getting one of them to cover my core requirements. I can now go pickup the new battery. I'm hoping it has a new sense line harness and bussbars.

    Before this call came in, I was looking at these modules, made to use supposedly in Prii:

    www.aliexpress.com/product-gs/452992223-HEV-battery-6-5Ah-NiMH-wholesalers.html
     
  13. ryan123456

    ryan123456 New Member

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    The 14 modules 168 Chinese D cell prius replacement battery has become popular (some reports of 2 years 20,000 miles) but some cells are only 3ah. ( I think this pack lowers MPG and would only last 3 years, also a little slower) I would like to see this same design filled with 168 Tenergy brand quality 10AH D cells which can be had for 2300usd or 168 Tenergy 9.5AH cells which can be had for 1500usd.
     
  14. dolj

    dolj Senior Member

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    You are replying to a very old thread. The technology has moved on in the intervening 9 years.

    While I applaud your endeavor, maybe you want to limit your research to threads created in the 2-3 years.