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Hitachi 12v Battery Rebuild
- Thread starter mbruffey
- Start date
bryanrj
Well-known member
I have been wanting to repair a battery or two for other brands. For the most part, the guts are similar. There are youtube videos on how to do it. You have to first (after taking it apart) determine which cell is faulty. The trick is that the individual cells are spot welded in place with nickle strips and to get good contact for the high battery drain, you need to spot weld the replacement battery back in. And the new battery needs to be very similar in its discharge capability.
I bought a small import spot welder circuit board, a BIFRC, but have not assembled it as yet. You need to add the spot weld leads and a couple other things. The videos I have watched use a Lithium Polymer battery like the ones used on large RC cars.
Best place to find a suitable lithium replacement cell is from another "dead" tool battery pack. It will be similar to what you need if it is a name brand battery pack.
It gets a little involved, but very doable. The only reason I am messing with it is that I also want to build a larger battery pack for one of those 24 volt Razor scooters for the grandkids, but get rid of the two heavy lead acid cells and boost the power a bit.
YouTube has most of the guidance you need to do the job...
Current model of the BIFRC: https://www.ebay.com/itm/393051883910
LiPo battery pack, Amazon: https://www.amazon.com/dp/B08V8CFFHN/?tag=atomicindus08-20 you will need a charger if you don't have one.
How to use BIFRC:
I bought a small import spot welder circuit board, a BIFRC, but have not assembled it as yet. You need to add the spot weld leads and a couple other things. The videos I have watched use a Lithium Polymer battery like the ones used on large RC cars.
Best place to find a suitable lithium replacement cell is from another "dead" tool battery pack. It will be similar to what you need if it is a name brand battery pack.
It gets a little involved, but very doable. The only reason I am messing with it is that I also want to build a larger battery pack for one of those 24 volt Razor scooters for the grandkids, but get rid of the two heavy lead acid cells and boost the power a bit.
YouTube has most of the guidance you need to do the job...
Current model of the BIFRC: https://www.ebay.com/itm/393051883910
LiPo battery pack, Amazon: https://www.amazon.com/dp/B08V8CFFHN/?tag=atomicindus08-20 you will need a charger if you don't have one.
How to use BIFRC:
Found this link. It implies that all three cells may go to zero state without triggering a BMS kill switch. A switch may be onboard, which would kill the pak under other circumstances, however.
-->>I need to get a single cell charger/conditoner before I proceed.
-->>I need to get a single cell charger/conditoner before I proceed.
bryanrj
Well-known member
You may be on to something worth trying out before replacing individual cells. In another of his videos, "Ryobi P104 Battery Repair", he is soldering the doner cells into the old battery pack rather than using a spot welder. In any case, to reset those CIDs, which are in the tip of the positive end of the battery cell, to put it back together you have to either solder or spot weld the contacts back in place. He also has a constant current power supply that can be set to limit the current to recharge the individual cells or groups of them. Handy to have for different projects. Inexpensive ones are available on the usual marketing avenues.
Just to make sure, as you did not specify in your original post, but your battery pack is lithium and not NiMh?
His soldering starts around the 10 minute mark in the video. Good video.
Just to make sure, as you did not specify in your original post, but your battery pack is lithium and not NiMh?
His soldering starts around the 10 minute mark in the video. Good video.
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