Lithium system- what should I know how to do?

[MikeCondor]

Hi all- we have a Hanse 388 with two 12/2500 Mastervolt lithium batteries, Balmar alternator, EasyView control panel, 2500 W Mastervolt inverter.

We've had two bad experiences- one prior alternator, inadequately cooled, caused winding insulation to burn off with smoke and excitement; and more recently some sequence of C-zone overvoltage (14.82V); diode burnout on alternator, leading to uncontrolled current into Li batteries, shutting engine down stopped that.

I'm good at recording everything when something goes wrong- taking still and videos of any metering, etc, for later analysis.

My question is- what basic immediate operational procedures should I know? I didn't know how to stop the alternator charging using the EasyView panel (I plan to be taught). I am not sure whether it's safe to disconnect the batteries with their yellow isolator switches while they are charging- I assume it is if engine is off. Do any of you have a checklist of tasks one should know how to do with this sort of system? One might start with top five things that can go bad and how to mitigate and troubleshoot...I have read the Mastervolt manuals and have Nigel Calder's Mechanical and Electrical book.

[rgleason]

Just some ideas...

Are the Mastervolt lithium batteries disconnecting on overvoltage and frying the alternator?
Have you programmed your alternator regulator for lifepo4 batteries?
What regulator? If Balmar, see Marine How to Programming Balmar Regulators.

IMHO lifepo is not just plug and play even if you buy one of these packaged batteries with a BMS inside, you have to look at the entire system. I would want an external relay controlled by the BM to disconnect between to lifepo4 and the alternator to protect the batteries, but you should also have a simultaneous Alternator field wire disconnect to protect the alternator, unless you have an FLA battery directly connected to the alternator output, ready to accept the power. Otherwise you will get a dangerous condition and an expensive repair similar to what you experienced.

Not all packaged Lifepo4 + BMS packages have the ability to control an external relay and that is a problem in my opinion.


Disclaimer: I have not yet built or operated a lifepo4 BMS system. I have been reading up for several years.