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Different voltage on same BMS negatives
#1
Hello Everyone, i´ve got a question that needs to be answered by someone of you smart people!

I have just changed the cells to a golf caddy battery and when i measure the tension i get 2 different readings on the negative conectors. The BMS is PCM-lo4s25-942 . im not an expert but it seems that the bms is withdrawing 0,4v from the total voltage which is close to 16,8 (4S). When connecting the iCharger X6 , voltages are different from the balance port to the main output so it doesnt work, connection error.....

Any ideas what can be happening? broken BMS? can i make it show same voltages on both connectors to make it work?

Thanks in advance and have a great day all of you! greetings from SPAIN!

Abe
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#2
On my x8 I found that loose connections are often the problem when I get error messages. a loose balance port connector or forgetting to hook up the leads to the positive and negative of the battery.
later floyd
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#3
You should not balance Charge a lithium through a bms. The bms Will cause this due to having electronica in between

Through the bms you utilize the bms to handle the balance part.
Abe and Crimp Daddy like this post
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#4
(10-14-2020, 12:54 AM)floydR Wrote: On my x8 I found that loose connections are often the problem when I get error  messages. a loose balance port connector or forgetting to hook up the leads to the positive and negative  of the battery.
later floyd
Thanks! i did check but same problem , i ended changing to another BMS. 

Good Day!

(10-14-2020, 06:15 AM)daromer Wrote: You should not balance Charge a lithium through a bms. The bms Will cause this due to having electronica in between

Through the bms you utilize the bms to handle the balance part.
Thanks Daromer, at that point i wasnt doing a balance charge but it´s great to know. IF we are balancing with I CHarger throught a BMS it´s like doubling the balancing action right? 

Good day!
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#5
You create confusion for the Charger. Dont have the balance Wires hooked up on oposite Side of the bms compare to the Charge port. Both should bypass the bms for it to work properly. The Charger cant handle the voltage drops induced by the electronica in between
NOTE! My links supplied in this message may be affiliated with Ebay and by clicking on them you agree on the terms.
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 100kWh LiFePo4 | 20kWh 14s 18650 |  66*260W Poly | ABB S3 and S5 Trip breakers
Upcoming: 14S 18650~30kWh
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#6
(10-16-2020, 06:12 AM)daromer Wrote: You create confusion for the Charger. Dont have the balance Wires hooked up on oposite Side of the bms compare to the Charge port. Both should bypass the bms for it to work properly. The Charger cant handle the voltage drops induced by the electronica in between
understood.

Thanks!
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