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spasq0712 avatar image

Tesla / Victron Overland Vehicle Build - PLEASE CRITIQUE!

Hello! This is our planned system for our overland vehicle build (it's a 4x4 Freightliner Ambulance conversion). We'd love to get feedback on this plan. Is there anything you think we've overlooked, etc. Thanks in advance!

wiringwiring diagram
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2 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @spasq0712

Do -not- do this like this!!!

-I don't see a BMS that disconnects the batteries when something is wrong

-The Hobbyking 'bms' will imbalance your battery modules, imbalance + no disconnecting bms = fire


Please get an experienced party involved that can make your system safe, or (better option) buy safer batteries with internal disconnect or safer batteries with accompanied BMS

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Between the batteries and the relay there is a contactor that can manually disconnect the batteries from the rest of the system and will also be used for over current protection.

Can you please explain or provide some evidence of why the hobbyking bms would imbalance the batteries. Based on my research and understanding, it's made to monitor cell voltages and balance the cells. It's being used successfully in many Tesla/Victron systems for cell balancing.

@spasq0712

So how does that contactor know if there is a problem in the batteries? the BMV can -not- be used as overvoltage protection, it doesn't know the individual cell voltages and is in no way a safe way to do this.

about the hobby-king 'bms': because I've seen it happen with someone... he had 4 tesla modules with those hobby king things, and after 4 months in storage, all modules were severely out of balance. He trew the modules out and opted for a LiFePO4 battery bank. Expensive lesson, but free for you (as of yet)

These hobby king devices are made to be temporarily connected to a small RC pack, when you leave them connected, they draw a current that is not equal on all cells, so they unbalance the pack.

If you really want to use the Tesla modules, please investigate further on how to safely do so, there are a lot of dangers that need to be mitigated.

JohnC avatar image
JohnC answered ·

Hi @spasq0712

It's very hard for us to assess your proposed system, largely because we don't really know what you're trying to do.

That said, I wouldn't do it without a GX device. https://www.victronenergy.com/live/venus-os:start

Once you're well aware of what they can do, your diagram may well change quite a bit.

Their functionality is much the same between models, and deeper details are available from their manuals (see Victron website).

Yeh, just one contribution from me, but it may change your overland world markedly..

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