Replacing afaulty BMS. What is the order of connection of a new one? B-, flat, C- ?
- Thread starter Petro
- Start date
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
1st order, NEVER EVER leave the Cell Harness attached to the BMS when connecting leads to the cells. Instant POOFDAH with the slightest of oppsies.
2nd order, Electronics do NOT like Static Electricity ! So many people forget that and fry their stuff... it is sad because it is so stupidly obvious.
3rd, ALWAYS verify the BMS leads from cell to Big Connector are in correct order/sequence and use a DVOM/DMM (Multi-Meter) to ensure the connection is good.
BMS Connections VARY depending on type & class of BMS... Same-Port, Separate-Port, Relays/Contactors or FET Based only. IT HELPS TO KNOW WHAT BMS YOU ARE TACKLING ! Even some FET Based BMS has a place to run the BATT POSITIVE through the BMS for the internal voltage sensing (as opposed to sensing from the BMS harness which is less accurate) but mix them up and POOF magic smoke appears and the crying begins.
The BMS Harness is just that. It connects the BMS to the cells to monitor independent cell voltages. "Some" BMS have Passive Balancing which is in the milliamp range up to 1.2A max (across the whole balancer) and that can occur over the standard harness. Very Few BMS' have Active Balancing which can move up to 10A (typically < 5a) across the balancer and that would have heavier gauge wire as well. Often people will install an Active Balancer as a separate device when warranted. Generally, with properly Matched & Batched cells this is not needed as Passive Balancing is usually adequate. Bolk/Commodity cells can be troublesome with runner cells and imbalance issues and often an Active Balancer cam "Compensate" for such to get better results from your cells.
2nd order, Electronics do NOT like Static Electricity ! So many people forget that and fry their stuff... it is sad because it is so stupidly obvious.
3rd, ALWAYS verify the BMS leads from cell to Big Connector are in correct order/sequence and use a DVOM/DMM (Multi-Meter) to ensure the connection is good.
BMS Connections VARY depending on type & class of BMS... Same-Port, Separate-Port, Relays/Contactors or FET Based only. IT HELPS TO KNOW WHAT BMS YOU ARE TACKLING ! Even some FET Based BMS has a place to run the BATT POSITIVE through the BMS for the internal voltage sensing (as opposed to sensing from the BMS harness which is less accurate) but mix them up and POOF magic smoke appears and the crying begins.
The BMS Harness is just that. It connects the BMS to the cells to monitor independent cell voltages. "Some" BMS have Passive Balancing which is in the milliamp range up to 1.2A max (across the whole balancer) and that can occur over the standard harness. Very Few BMS' have Active Balancing which can move up to 10A (typically < 5a) across the balancer and that would have heavier gauge wire as well. Often people will install an Active Balancer as a separate device when warranted. Generally, with properly Matched & Batched cells this is not needed as Passive Balancing is usually adequate. Bolk/Commodity cells can be troublesome with runner cells and imbalance issues and often an Active Balancer cam "Compensate" for such to get better results from your cells.
the BMS i have is JK BMS it is single port 2 heavy cables..
it has a balance cable, and 1 connector for the POS wire from the balance leads,
and it supposedly has active balancing as well..
i believe this is the one i ordered,, ( 3 units ) JK-B2A24S20P
the manual does not give specific instructions on connecting..
i have mine in a 14s configuration for a 48v system
it has a balance cable, and 1 connector for the POS wire from the balance leads,
and it supposedly has active balancing as well..
i believe this is the one i ordered,, ( 3 units ) JK-B2A24S20P
the manual does not give specific instructions on connecting..
i have mine in a 14s configuration for a 48v system
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