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Battery pack IR

yathis

I had huge sag in some of my parallel strings. I would charge to maximum then they would lose so much, back down to storage volts.

They lost all their capacity.

 

I tried to solder them before and never could, do you think the heat fucked them up?

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2 minutes ago, yathis said:

I had huge sag in some of my parallel strings. I would charge to maximum then they would lose so much, back down to storage volts.

They lost all their capacity.

 

I tried to solder them before and never could, do you think the heat fucked them up?

well, we're gonna need a hell of a lot more info. Are they lithium, Nickel Cadmium, Nickel metal? What kind of cells are they? How many parallel cells and how many in series?

Generally you need to spot weld tabs onto the cell, then you can either solder or clamp them together. 

Yours faithfully

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LiFePO4 had 15S5P split in two. One half popped 5 cans, I snipped the connections and dumped that battery.

The 8S and spare cans I put into 2S, then wanted to add 1S to make 3S + 8S, well the 3S sagged huge at rest, while the 8S sagged 1V in 8S (3.6V/can max and 3.3V/nom/storage.

 

I did spot weld the 8S and I think thats what saved em. The 3S I soldered.

I made my own DIY spot welder from a MOT, and it worked good.

 

Long story short, I dumped them all. Dont wanna worry about that shit. Problem was 15A I dumped into 8S and 7S seperately. 10Ah pack, 1.5C aint too bad for charging.

 

I bought OTC pack from the department store. Back to pondering charger, their charger they want $130 for their fast charger. While www.ebikes.ca has a Satiator for $400. I am tempted to go all out and drop some coin. OTC packs were $600 with a good warranty.

 

I can attest to the LiFePO4 being ultra fucking safe. LiPo on the other hand I woulda had fireworks happenin. My LiPo problem was no LVC so I drained the fuck outta them, rock bottom, then low-ave charge = bad idea

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