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murphyslaw avatar image
murphyslaw asked

Protecting a Tesla battery...

Hey Everyone,

I am designing a massive solar upgrade for my 34' Bounder. I spend most of my time 'Boondocking' in US National Forests and my current electrical system, I love puns, is sorely lacking.

The new system will have 1600 watts of roof-mounted polycrystalline solar panels and a second 1000 watts of ground deployed flexible (5)-200w solar panels. I will be using Victron Smart Solar Controllers all built around a MultiPlus 24/3000 inverter charger.

I want to store all of that glorious 'Free' power in 2-Tesla Battery Modules wired in parallel. The modules I am planning to purchase have the 'Hacked' battery boards already connected to Tenergy 5-in-1's, so that takes care of cell-balancing. I have a thermostat and water circulator for temperature control.

If I am correct, the Multiplus charger and Solar Controllers will handle the over-voltage changing concerns.

So now I am down to low voltage cutoff. Like most I was looking at a BP-100 until the fire issues surfaced. I read an article able how you could reverse-current through the battery protects, but at a greatly reduced capacity.

I wanted to ask if anyone is having trouble with the BP-220 battery protect? The BP-100 fires are being caused by the MultiPlus bulk-charging and overloading the reduced reverse-current through the battery protect.

The BP-220 seems to be much more robust and I am wondering if its 'greater' reduced reverse current is enough to handle the MultiPlus 24/3000 charger?

Thanks,

ML



BMSBattery Protect
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2 Answers
Justin Cook avatar image
Justin Cook answered ·

@murphyslaw, the BP lines must not have reverse current applied to them period. Outside of the mA range, there is no "safe" amount of reverse current to run through them. They are unidirectional in operation only, and any article you may have encountered which says anything different is extremely incorrect.

See the updated user manual here: https://www.victronenergy.com/upload/documents/Manual-Smart-Battery-Protect-12V-24V-65-A-100-A--220-A-EN-NL-FR-SV-DE-PT-ES-IT-TR.pdf

As far as your low-voltage concerns go, the MultiPlus handles that as well, so you're all set. You should only use a BatteryProtect to provide low-voltage disconnection for other relatively small DC loads that you may have on the system. See the MultiPlus user manual here: https://www.victronenergy.com/upload/documents/Manual-MultiPlus-3k-120V-(firmware-xxxx4xx)-EN-.pdf

...and also see the screenshot I've attached showing the low-voltage disconnect setting for a Multi:


mp-low-voltage.jpg (74.5 KiB)
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murphyslaw avatar image
murphyslaw answered ·

Duh... I should have figured that one out. I only need it for the 12-24 buck transformer.

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