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People that understand DC House electrics on boats are understandably wary about safety issues. Most boat fires are electrical, and that's just using lead!

The only non-lead chemistry any sane insurance company might cover are fully packaged and BMS protected systems from Victron, Mastervolt Lithionics etc.

If you really put a DIY system together from standard LFP prismatics like CALB or GBS, usually 100-180AH cells, plus a solid OVD/LVD from OTS parts, maybe a surveyor could be found to sign off on it.

But packs of what NMC stripped from a salvage car, separated out from all the protective electronics?

That's a Science Project, IMO needs to be done on land.

But if you are willing to be a pioneer, please let us know how it goes!

BTW decent sized 48-12V converters are not that expensive, are you looking to run a windlass or just screens, reefer & galley appliances?
 

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Yes that would be easier, lots of 48V to 12V conversion devices out there, I would do that then you can use standard much cheaper inverters if needed.

Buy you def want good BMS protection on a boat using a chemistry at risk of thermal runaway.

LFP would lots safer
 

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Yay! You did have me worried there.

Just realize a small mobile living space requires more care too even on land.

IMO save your pennies for LFP prismatics, sometimes good deals come up on eBay.
 

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Actually I'm pretty sure shorting out all the cells with highly conductive seawater would have unintended consequences even if they weren't in the middle of a thermal runaway catastrophe.

Not to mention most boat owners are doing their best to keep that salty wet stuff on the **out** side of the hull.

:cool:
 

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Everything get pricier at higher bank voltages except the wiring.

I would only go up from 24V if a huge consumer required it, e.g. aircon or propulsion.

Higher **panel** voltages are not relevant to output, that's between the MPPT SC and the bank.
 

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Why do you guys think that some chinese made cells are going to be any safer than a battery custom made to use in a car in a huge variety of conditions while being rattled about and have comparatively huge loads put into and taken out of it?

Something designed for a car is massively over specced for use as a battery bank in a boat!

As far as BMS's are concerned the ratio of batteries saved by BMS's to batteries killed by BMS's appears to be about 1:20

I would NOT have some low volume DIY BMS protecting my system - the Automotive ones would be OK
No one is talking about using the original vehicles BMS, they are only suitable for the EV parameters.

Chopping up salvaged auto packs then re-assembing into small lower voltage blocks is what you apparently don't realize you're talking about.

And doing that requires a much more stringent custom BMS in any case, and that's a much greater challenge than the simple LVD / OVD needed to protect standard prismatics.

The main point is, these non-LFP chemistries are inherently more dangerous.

The biggest buyers of LFP prismatics are military, in use cases much bouncier than civilian EVs.

China is irrelevant, it is the brand and sales channel that needs to be trustworthy.

I don't see that in most eBay sellers and junkyards myself.
 
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