Anyone with homemade lithium battery bank?

[Zil]

There are better choices to build a li battery bank than 18650's. You will be out on a big body of water when something goes wrong. I sugest you look at something like CALB, a company that has prismatic cells. Also for information, I spent a lot of time with these guys before dropping back to GC batteries. They do have some good deals on li batteries at times. EVTV Motor Verks - Custom Electric Car Conversion Instructional Videos

[getyourbone]

Try posting the link again…

Obviously only some of the design would be applicable to a sailboat as you're not likely to need an electric car charger because most boats do not have a garage or driveway.

[john61ct]

Be aware no insurer will touch you without ABYC compliance, and Maine Sail's hinted even with standard prismatics like CALB, there will also be a BMS requirement.

I reckon even conventional DIY setups will have a hard time passing, but once the rules are published perhaps experienced professionals will be able to cobble an approved setup together.

I doubt that will include recycled EV packs, much less what the OP is proposing.

Of course your boat, your family's lives your call.

[getyourbone]

Insurable…?
Good point… with some of the things that I have read/heard of that have kept boats from being insurable, it sure wouldn't surprise me if this also would be the same.

Something to think about.

[Locquatious]

Had developed my own PWM solar regulator for charging lead acid batteries. It still works brilliantly. Tried the same circuit on a lithium battery pack and barely got the overheating battery outside to safety quickly enough. Why I wondered? I had charged at the correct average voltage.

Pulse Width Modulation, a fancy term for a phenomenon that occurs naturally in most solar regulator charging circuits, works by connecting and disconnecting the solar cell from the battery. When connected, the solar panel voltage is at battery voltage, or slightly higher. When disconnected, the solar panel voltage jumps to open circuit or ~18.5V. But the solar panel also has some storage capacitance. When re-connected that stored 18.5V gives the battery a momentary high voltage jolt, which might be great for lead acid batteries, but is devastating for lithium batteries.

[opolily]

which is why we use mppt charge contoller paired with a BMS system ALL designed for LiFeP04 cells.

[BruceS]

Originally Posted by Locquatious

...deleted....
. When re-connected that stored 18.5V gives the battery a momentary high voltage jolt, which might be great for lead acid batteries, but is devastating for lithium batteries.

Which is why I have a softstart solar regulater, softstart inverter and a softstart 220V AC charger ...........
My "momentary high voltage jolt" can be up to 145V DC & never been a problem.

[hzcruiser]

Originally Posted by Locquatious

Had developed my own PWM solar regulator for charging lead acid batteries. It still works brilliantly. Tried the same circuit on a lithium battery pack and barely got the overheating battery outside to safety quickly enough. Why I wondered? I had charged at the correct average voltage.

Did your regulator have a properly sized output cap ? You should not see voltage spikes on the output as that can affect or even kill all the other devices on the bus.

Originally Posted by Locquatious

But the solar panel also has some storage capacitance. When re-connected that stored 18.5V gives the battery a momentary high voltage jolt,...

I've never heard of any significant capacitance of a solar panel itself? Where did you get that info from? It's not on any datasheet I've seen. Please advise, maybe a link or two, otherwise I'd call it bull dust. The voltage "jolt" is just the open circuit voltage. It's not recommended to connect a panel in full sun to a charge controller, yes. Hence put a blanket over it before connecting or disconnecting a larger panel.

[john61ct]

Originally Posted by BruceS

Which is why I have a softstart solar regulater, softstart inverter and a softstart 220V AC charger ...........
My "momentary high voltage jolt" can be up to 145V DC & never been a problem.

Possible to list, or link to your recommendations?

[BruceS]

No... it's not a recommendation at all John. It's just what I have.
You know we both know each other!!
Most have that built in anyway. Google soft start solar regulator?

[Zil]

No John, i did not mean used recycled cell. but just a link to prismatic cells. I hope any one that is planing to build a bank would know about management systems. At least when away from the dock. here is the store site. EVTV Motor Verks Store: CALB CA180FI 180Ah LiFePo4 Cell, Lithium Battery Cells, CA180

[TreblePlink]

I would never use lithium batteries on a boat. Their main advantage is energy density (low weight) - and that is rarely critical on a boat. BUT from a safety standpoint, Lithium and water do not mix, unless you like flame.

https://www.youtube.com/watch?v=vRKK6pliejs

[john61ct]

The terms Lithium and Lithium-ion are too general.

LiFePO4 or LFP, does not have the thermal runaway issues encountered with the many other chemistries.

Completely different, and increasingly used on high-end boats without safety issues for many years.

At least when done right, problems caused by DIY mistakes are just as potentially fatal as so common with lead banks.

[cptcptcpt]

on the grid habits work okay while off the grid but no where near as efficiently.

simple rule - noisy things kill batteries

blow dryers, loud music, etc, will not hurt a grid unless everybody in town runs them at the same time

blackouts are sometimes caused by all the air con's running hi during heatwaves

your boats system will be equal to a suburb only on shore power

if you follow the nice weather around you will not need air con, the other hi power demands will need to be timed according to the battery monitor's readout

a home made bank could be nifty for fitting into all the nooks and crannies of a boat, but when any size boat or ship is rolling, heaving or being thrown around by waves you will have a dangerous mess if things are not bolted in place

[TreblePlink]

Originally Posted by john61ct

The terms Lithium and Lithium-ion are too general.

LiFePO4 or LFP, does not have the thermal runaway issues encountered with the many other chemistries.

Completely different, and increasingly used on high-end boats without safety issues for many years.

At least when done right, problems caused by DIY mistakes are just as potentially fatal as so common with lead banks.

---

What type of "Lithium" batteries did Boeing have thermal problems with?