Modification for connecting a different spare battery.

Willow

New Member
Region
USA
Hi,

I’m hoping someone can help me with this dilemma. I have a Prodecotech Phantom X e-bike, (36 V, 500 W) A few months ago, I had someone put a new cell pack in my battery. Without informing me, he changed the connector, so I have to use another charger. He did intend to make the old pack a spare, but he had to leave town and he left me the old battery as shown in the photo. (a section of red wire is missing where the masking tape is that should go to the terminal along side the other red wire) The RCA connector for charging. The XT60 would be for connecting to the motor. I can solder pretty good, but I’m no e-bike battery tech. They did a crappy job, I had to fix a bad solder connection and redo the charging port, but they did put a new battery in and it works well. My questions are… Does this spare look correct? I don’t like the terminal thing, (seems like it should be straight wires). I have a perfect back pack type thing and I could put it in front in a basket that I never use. Is it possible to make a splice so that I can also use this spare battery? Is it something that I may be able to do myself or should I get a more experienced person to do it? What would be involved?

Thanks for any help.
 

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harryS

Well-Known Member
I don't like your wiring . I am assuming this is a typical two port BMS used in ebike batteries. In that case, the power connector and charger connector have a common positive, but separate negative returns.

wired_funny.JPG
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The bottom schematic is how they typically do it. The positive wire goes to both the XT60 and the RCA plug, Each connector uses a separate negative lead, and I guess that would be the yellow and blue wires, which you have tied together and fed as a common return to both connectors.

With a two port battery, one of the return circuits shuts off during charging when the battery hits full charge. The other one shuts off when the battery hits low charge. By tying them together, you lose both safety circuits.

I don't know the purpose of your red lead that is wrapped. Anyway, I think it's not safe as is, unless you know more about how the BMS is wired.



BMS_mos.jpg
 

harryS

Well-Known Member
There are BMS where the charge connector and the power connector use the same two wires, but if that were true, you wouldn't expect the yellow and blue?
 

Willow

New Member
Region
USA
Hi, Thanks for the response and info.

As I clearly explained...

1. I'm not a technician, I'm just a belt-swapper who can solder pretty good. :)
2. This was done by a person who moved out of town and left me this spare in this condition. (This is why I was inquiring about this spare in the first place, to see if it looked wired correctly) He changed the cell pack, but left other problems that I was able to fix myself. Now the new battery works ok.
3. I also explained that there is a piece of red wire missing where the masking tape is. It originally ran along the other red wire to the white terminal. I'm not saying that this was correct, just saying that is the way he left it. I temporarily lifted that piece of wire to do an emergency fix in the "new" battery case.
4. Who knows what colors they used for what.

Regardless, I guess you answered my main question anyway, which was "Can I do this myself?" It looks like a negative on that one. I'm not knowledgeable enough on that stuff.