DIY Grid Reconditioning Charger

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Abarnabe, Sep 13, 2020.

  1. Abarnabe

    Abarnabe Member

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    Yes, powerbrake is possible on G3 till 7 bars, but after 7 it accepts charge only by pushing intermittently and takes very long.
     
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  2. tvpierce

    tvpierce Senior Member

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    Hmmm. These power supplies are quite affordable here in the US: $45 delivered.

    There's another active thread where a member is trying to diagnose a persistent ICE starting/running problem. He's now at a point where the traction battery is so depleted that it can no longer attempt to start the ICE -- leaving him with no way to replenish the charge on the traction battery. One of these would come in handy in a situation like that.

    A couple of questions:

    1) The specs say the output is 257vdc max. When the current is adjusted down (via the potentiometer) is the voltage reduced too?

    2) If you connected two of these in parallel, would the resulting charging current be 700mA?
     
  3. Abarnabe

    Abarnabe Member

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    1) I have tried that, but nope, the voltage is costant at all current rates.
    2) in theory yes.

    With 350mA it takes about 18 hours to fully charge. At that rate nimh have 90% efficiency.
     
    #23 Abarnabe, Sep 20, 2020
    Last edited: Sep 20, 2020
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  4. Fred_H

    Fred_H Misoversimplifier

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    Hehe, that's what I figured. Don't you love it when you can justify your collection of junk?

    Thanks Abarnabe, now I understand your reasoning. I think that is a reasonable precaution in the case of uncertainty. Now I am also uncertain whether the Prolong max. voltage was specifically chosen for safety or other battery technical reasons, or if it is a more or less arbitrary byproduct of the components of the charger.

    The basic principle of top balancing (as I understand it) is to force a small current through the battery regardless of the voltage. When the individual cells reach their maximum charge, they "leak" current through, thereby self regulating the voltage. As long as the current is small enough, there should be little danger of damaging the battery.

    But if there is some sort of defect in the battery, which causes the voltage to be extremely high, then of course the voltage should be limited to a safe level. I would not consider the 257V maximum of your power source to be extremely far above the self regulating voltage of the battery, so the diodes are probably not necessary. But they do no harm as long as the charger max. voltage is above the normal battery self regulating voltage. If the max. charger voltage were less than the normal maximum battery voltage, then the battery might not be completely balanced.
     
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  5. Abarnabe

    Abarnabe Member

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    I have removed 2 of the 10 diodes, so that the max voltage output under load is 250.7v . I have charged the battery by stepping on the accelerator until reaching 7 bars.
    I have connected the battery with the grid charger and after 14 hours it reached a peak of 240.7v, than after 10 additional hours it slowly dropped to 238v. I have noticed that now while driving it takes longer to reach 7 bars by breaking so I think the battery is now better balanced than before. I have checked the modules one by one and #7 was 8.55v while the rest were between 8.49v and 8.50v.
    Also #1#2 #27 #28 are slightly higher than the mid ones.
     

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  6. tvpierce

    tvpierce Senior Member

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    Was the grid charger still connected for the additional 10 hours?

    By the way: I ordered an HLG-80H-C350A from Digikey, and a box of various diodes from Amazon (link).

    I haven't wired in any diodes yet, but did check the output of the power supply and it's spot on at 257v DC.
     
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  7. Abarnabe

    Abarnabe Member

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    Yes correct.
    My diodes come from old cell phone chargers :)
    The voltage is indeed 257v without load, if I remember well it stays the same with a 50w load. You may regulate the current up to 0.4 amp with a small crew driver, but the stock setting in 0.35 A, I suggest to leave it unchanged.
    I attached the voltage drop values before and after reconditioning
     

    Attached Files:

    #27 Abarnabe, Oct 4, 2020
    Last edited: Oct 4, 2020
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  8. tvpierce

    tvpierce Senior Member

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    Thank you so much for sharing your findings on this.
     
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  9. Chba

    Chba Junior Member

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  10. NewHybridOwner

    NewHybridOwner Active Member

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    You have a metal-case power supply with a ground connection (indicating that it is NOT double-insulated), but you have spliced the original power cord to a two-conductor power cord, meaning that that metal case is no longer grounded. I hope the unit does not develop an internal "hot"-to-case short and give you a nasty jolt or worse.
     
  11. Abarnabe

    Abarnabe Member

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    I use a EU grounded 3-conductor power cord. The ground is a female lateral contact.
    The battery pack alone is nasty enough ;)
     

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    #31 Abarnabe, Oct 5, 2020
    Last edited: Oct 5, 2020
  12. Abarnabe

    Abarnabe Member

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    I think block 6,7 and 8 are suspicious, but before replacing I would try to recondition the whole battery pack and run the test again.
    Each block is made of 2 modules, usually one is weaker than the other.
     
    #32 Abarnabe, Oct 5, 2020
    Last edited: Oct 5, 2020
  13. Chba

    Chba Junior Member

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    Thanks again, I would like some advice for installing the cells. I ordered 8 battery cells from ebay.

    1- How to balance the voltage of the old cells against the new cells?

    2- Is it necessary to recondition the 20 old cells with charge and discharge cycles? if so, which charger would you recommend? Would a cheap ibmax 80w charger do the trick?

    I thought you just had to take the low performance battery cells apart and replace them with the new ones, and nothing else?

    I ask you these questions because I wish there is a huge difference between the old and the new cells.

    In short, what is the right procedure? Repair is very expensive for a professional here. I have some notions in electricity and I think I can do it myself.
    Posted via the PriusChat mobile app.
     
  14. Abarnabe

    Abarnabe Member

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    -1 To balance the battery pack I connected a HLG-80H-C350A power supply to the battery for 24 / 30 hours, the procedure is on prolong website.
    -2 yes do all of the at the same time, using an imax b6 for reconditioning it takes 4 days per module, there are 28 modules so it would take 3 months. Instead I used the HLG-80H-C350A power supply to do the whole battery in series in 4 days, also this procedure in on prolong website, sorry I can't post links, google prolong battery charger and read the product guide.
    Purchasing the charger would have been much cheaper than replacing the 8 modules, it costs 40 usd. After reconditioning my weakest modules became almost the same as the strongest.
    After reconditioning if you still see weak modules you can pair them to strongher ones so there is a lower chance they trigger errors.
    The prius 3 battery is made of 28 modules, each module is made of 6 cells for a total of 168 cells.
    The modules are monitored in blocks of 2, if the voltage difference is 0.3 v or higher it will trigger errors.
    P.s. never charge or discharge single modules if not compressed, otherwise they will swell irreversibly.
     
    #34 Abarnabe, Oct 15, 2020
    Last edited: Oct 15, 2020
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  15. Chba

    Chba Junior Member

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    i have diagnosed my cell block with Hybrid-Assistant. I know the faulty cells and I ordered 8 refurbished cells from eBay.
    Now I only want to take the block apart from the car and then replace the weakest cells.

    I don't want reconditioning the pack of cells with charge-discharge cycles.
    I just want to dismantle-replace-assemble and finally start the vehicle.

    Tell me if this procedure will work knowing that the voltage levels of old cells is different from new ones?

    Someone advised me to balance the voltage, but how do I do it?
    Posted via the PriusChat mobile app.
     
  16. Abarnabe

    Abarnabe Member

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    If the voltage difference between blocks is more than 0.3 v the car won't start, so balancing is mandatory

    If you have a 250 vdc constant current power supply, charge the whole battery at 350 mA until it stops rising, the peak is between 236v and 240v, then keep charging other 6 hours and that's it, the battery should be balanced.

    If you don't have a 250vdc charger, but only a b6 imax, bring the new modules at the same voltage of the old ones ( they need to be compressed when you charge them), then connect all modules in parallel and keep them this way for 24 hours. The second is a very primitive method, but I' ve seen people doing it.
     
  17. tvpierce

    tvpierce Senior Member

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    +1

    You can get the power supply from Digi-key for $55 delivered: LINK

    My itemized order:
    Items in Order: 1

    Subtotal: $38.60

    Shipping: $10.99

    Tariff: $3.86

    Sales Tax $2.34

    Total: $55.79


    And the Diodes from Amazon foro $10 delivered: LINK
     
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  18. tri4all

    tri4all Junior Member

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    Great work Abarnabe. in regards to the discharge set up using light bulbs:
    1. Are you using generic household light bulb sockets? the ones that require 120 Volts AC? wouldn't you have to charge halve of the battery pack at a time? since we are dealing with about 220 volts DC? or are you using some kind of inverter? thanks.
     
  19. Abarnabe

    Abarnabe Member

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    Thanks tri4all, I live in Europe so I use 240v ac bulbs and I do the whole battery at once. If you plan to use 120v bulbs you can put 2 of them in series, so an inverter is not needed.
     
    #39 Abarnabe, Nov 16, 2020
    Last edited: Nov 16, 2020
  20. edu4prius

    edu4prius New Member

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    Thank you for your post, @Abarnabe, I'm getting very inspired by your charger and discharger system and probably will make my own soon, since I can't afford the price of the Prolong system with shipping costs from USA to Spain and additional customs taxes (I think it would go up to nearly 1000€).

    At this point (and after trying to understand Prolong's instructins) I still have few questions:
    I see you are using 6 bulbs that work at 240V, but how many watts is each of them? At what voltages did you remove each bulb? At what voltage did you stop discharging and started to charge back?

    Thank you so much!
     
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