question

Hartley Gardner avatar image
Hartley Gardner asked

What is the best way to protect against unexpected BMS Failure in SmartLithium 12/330a?

Back in August, our 3-month old Smart Lithium 12.8/330ah battery BMS failed - on a sunny afternoon at anchor a couple of hours after the battery was at 100%. There was no warning, no known stimulus (like lightning, engine start, firmware update, etc.) It simply disappeared from Bluetooth and opened both charge and load switches (BatteryProtect units). After 5 weeks, the internal BMS board was replaced under warranty, and the replacement has been 100%. [As an aside, the failure occurred only a couple miles from the Victron facility in Rockland. Maine - but we had no way of knowing this or contacting Victron at the time].

My question is. what can I do to protect vital systems from a similar failure in a situation where keeping power to critical systems (chartplotter, instruments, etc.) might be essential? I don't want to simply power them around the load disconnect, but I don't want my boat going black underway at night!

BMSsmart lithium
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1 Answer
bathnm avatar image
bathnm answered ·

@Hartley Gardner An interesting question and one that has multiple different views an opinions as to how to deal with. Some options might be

  1. Put an AGM battery in to drive your critical loads and use a DC/DC charger to keep it at float. If you have a failure, critical systems can continue to run.
  2. Insert a SBP between the Lithium battery and critical loads. Do not use the land disconnect, but set it to cut off at a given voltage, say 12v which will protect the Lithiums from excessive discharge
  3. I do not know which BMS you have, but maybe purchase a smallBMS, which can be swapped in as a result of a failure.

I my yacht I went with option 1, purely because I installed a 24v system and my critical loads are all 12v.

Have fun

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Related Resources

Additional resources still need to be added for this topic

Victron VE.Bus BMS product page

Victron 3rd party BMS compatibility page