Control BP-100 with SmartBMS


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gpn

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Joined
Jan 21, 2018
Messages
250
I am building a portable battery. It will power DC stuff with buck converters as well as 1000w victron phoenix inverter. I bought a BP-100 to be my main battery shut off and safety device. I have a Bluetooth smart BMS and I was wondering if it would be possible to wire up the BMS so that it would shut off the BP in an under voltage or over voltage situation. The BP has a pins for a remote and I was going to use that with a low power switch to turn the system on and off.

Would it be possible to wire the BMS in series with the switch so that if there is a problem the BMS interrupts the signal to turn on the BP-100 and shut down the system?
 

Korishan

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Jan 7, 2017
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I would say it is possible, as long as:

* The BMS has the functionality to do external triggering. Which most do not, especially the cheaper ones
* The Victron external switch is just a voltage based on/off. If it's pulse, or infro-red or anything other, probably not.
 

jonyjoe505

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Joined
Feb 28, 2018
Messages
229
if your battery pack is always in balance, you can use an overvoltage relay to trigger the bp100. In my diagram the bp100 would be where my 30 amp automotive relay is. The bp100 is just a giant smart relay. The overvoltage relay (cost about 6 dollars) in the picture also monitors for low voltage and can trigger in those situations. This monitors overall voltage on my 4s lifepo4 battery pack, I have it disconnect solar if the battery reaches 14.4 volts. I use active balancers so my battery is always in perfect balance.

If you want something that can monitor individual cells for over/under voltage, you need something like the chargery bms16, which can trigger external relays but that cost over 100 dollars. Thats fully programmable, example you don't want any cell to go above 4.1 volts.

The victron bp100 need a strong signal to trigger, the overvoltage relay actually has its on small relay that can handle up to 10 amps, so it will trigger any relay even the largest solenoids/contactors.


image_bsmtwj.jpg
 

gpn

Member
Joined
Jan 21, 2018
Messages
250
I don't think the smartbms has any external relay outputs. But it does has a charge and discharge fet to shut off input/output. I was wondering if I could use the discharge fet wired in series with a "system power switch" to the remote pins of the bp100. So if the BMS is good, and each cell is within parameters, it is outputting power from the discharge fet which would then switch on the high amperage bp100. Since the BMS is a chinese model rated for 60 amps on a 7s battery I would prefer to run the high amperage inverter directly off the battery so that I don't burn out the bms. That does limit my use of the bms as a safety device. I also like that I can control cell voltages from the bms. I can program it to stop charging at 4.1 and limit the bottom to 3 volts.

The bp100 does have a minorly adjustable voltage monitoring function but I don't plan to rely on that for battery protection.


After looking at it some more and understanding better I don't think I can do what I want to do. I would need an intermediate part between the BMS output and the bp100. Some kind of small relay that closes a second circuit when it is powered. I might just be able to use a regular dc relay that can take 7s voltage range input to close a contact on the output of the relay and allow the remote pins on the bp100 to close to turn on the bp100 for high amperage loads.
 
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