I’m building a couple of 12 and 24 v boxes. For camping etc wondering how to build in a low / high voltage cutoff with DIYbms
Circuit breaker with a shunt trip seems to be the way to go attached to the relay, something like this: https://www.ebay.com/itm/ABB-SACE-S3-S3B-3-Pole-225A-240VAC-Circuit-Breaker-Shunt-Trip-Aux-Switch-TESTED/132336226104
They do come up cheaper and if you don’t need the really high amps, I got 2 for $240 if you’re patient.
I’ve heard Stuart mentioning contactors in the past to achieve high current cut-out more cheaply.
Some commercial BMS are using them.
this is some cheaper 12 volt boxes im playing with have shunt trip on my batrium
It is only AC rated
Any updated solutions on this cutoff option?
What are people using from BMS to shut off the main power if a cell goes over/under voltage? I am on my boat and therefore have 24v house batteries running inverter, windlass, lights, nav, autopilot etc etc.
My thought was to have the BMS turn off a contactor (relay) like https://eveurope.eu/en/product/contactor-ev200-500-amp-9-36vdc-coil/ as a single point.
The contactor can come in 12 or 24v. What is the voltage coming from BMS? If 5v then i can put in a second relay between bms and contactor so it would be like… BMS → 5v/24v relay → 24v contactor.
Thoughts?
The relay is definitely just the thing to disconnect the battery. You can operate it with a maximum of 36V DC.
The relay is connected with the ground control line to battery minus.
Then you connect the plus control line of the relay with the relay 1 of the BMS.
Then take another line from the battery plus with a fuse and go with it also to the relay 1 of the BMS.
In the rules you must then define the disconnect conditions for relay 1
Just get back to me if you have any questions.
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