Wiring a BMS

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Eck182
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Wiring a BMS

I have a 48v 20ah lifepo4 battery pack and the BMS got fried a couple of weeks ago. I got a new one from BMS Battery in China. The battery pack has a 16 pin connector and the BMS has 17. I have sent about 10 emails to them, trying to figure out how to connect it as is or rewire it using the connector they provided. Possibly due to poor translation, all of their answers have provided little useful info. Any suggestions to help me get this thing hooked up would be appreciated.Picture 001.jpgN_capacity_BMS_LRG.jpg

antiscab
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Re: Wiring a BMS

there could be one of two explanations:

1) your new BMS is designed for 16 cells, but your battery has 15 cells.

or

2) your old BMS didn't have a separate negative wire for the first cell, but your new one does.

do you have a picture of your old BMS?

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
conversion

colin9876
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Re: Wiring a BMS

For the record I hate these kind of bms, parallel charging all cells from a 5v 20amp supply is what I personally prefer

Im now a big advocate of parallel charging, has many advantages and I hate fiddly BMS sysetms.

(The only BMS I would ever consider now are the shunts that go between cells)

Eck182
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Re: Wiring a BMS

Here's are pics of the old signalab, a top view of the new one and the battery pack. I find the diagram they sent confusing. Do you think they only show a 5 pin connector to save time? I also don't understand why they have p- connected to the load and charger, but nothing connected to out-. Also, does anyone know what the N and N+1 are supposed to represent?Picture 003.jpgPicture 002.jpgPicture 004.jpg

colin9876
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Re: Wiring a BMS

The N, N+1 is a shorthand way to save writing it out based on there being N cells.

So if the BMS is for a 15 cell pack then N=15 and the N, N+1 wires are the 15th and 16th, i.e. the last 2

depending on how many wires you have and what cell Number that was designed for may mean the OUT should be connected to the first cell

antiscab
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Re: Wiring a BMS

yup, that original BMS didn't use one of the thin connections to get to battery negative:

http://www.all-battery.com/protectioncircuitmodulefor3cellslifepo16batterypack30A-1.aspx

so thats why the new BMS has an extra wire.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
conversion

Eck182
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Re: Wiring a BMS

I wired it up according to the diagram and when I plugged it in, it instantly got very hot and started smoking. I'm not sure what I should do, send it back and hope I get a refund or tell them their diagram was incorrect and demand a refund.

strawhistle
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Last seen: 3 years 7 months ago
Joined: Monday, March 10, 2008 - 08:43
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Re: Wiring a BMS

Hi. I would tell them their diagram is incorrect and ask for a replacement and the correct directions !! when you get the replacement ask people like an electrician,radio, TV, computer store,music store, repair man, to help you !!! LaTeR

thank GOD I wake up above ground !!!!

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