Restricting charge to LiFePo batteries.

[Refueler]

Have you seen significantly degraded LiFePo4 systems? Everyone I know of, and everything I've read suggests almost nobody has seen real world capacity loss, and those that have were down to hardware failure.
We do "capacity testing" all the time as we live on board and when away anchoring often get down very low. Everything is recorded to the VRM cloud in real time over Starlink so I can see the history going back years.

Degradation just isn't a sensible thing to be concerned about. I do think setting the charge system up properly is important, and your advice is good. I was simply pointing out that degradation has not been something lithium users have complained about or seemingly experienced. With battery prices dropping faster and faster it's just not an issue.

Come into the model world - albeit smaller capacity cells - but degradation is seen ...

 

[PaulRainbow]

Never said they were not ??

Was just adding to the discussion ..

With something that is totally unsuitable for the OPs purpose and is unlikely to work at all well with LFP anyway.

 

[Refueler]

With something that is totally unsuitable for the OPs purpose and is unlikely to work at all well with LFP anyway.

That is wrong anyway ... the units don't care what batterys ... but anyway - I was only adding to the thread ...

 

[wingcommander]

Curious as to what your insurance company policy is on boats left unattended whilst still charging lithium batteries. I disconnect mine ( mains and solar) when away for more than a day trying to keep it around 80% SOC .

 

[fredrussell]

That's better

Set absorption to 14.4V, it'll charge a little faster.

13.5V float will keep the batteries at about 95%, unless you're leaving the boat for months on end i'd leave it there. If you do leave it for months, turn the charger off or set absorption and float to 13.2V, that'll keep the batteries at about 70%

Set Max absorption time to 5m

Check the low temp cutoff is above 0c

Many thanks Paul, really appreciate it.

 

[PaulRainbow]

Curious as to what your insurance company policy is on boats left unattended whilst still charging lithium batteries. I disconnect mine ( mains and solar) when away for more than a day trying to keep it around 80% SOC .

For Heavens sake, don't start about insurance, again.

 

[PaulRainbow]

That is wrong anyway ... the units don't care what batterys ... but anyway - I was only adding to the thread ...

It isn't wrong.

LFP voltage doesn't change much at all across a wide range of SOC and that can be significantly distorted by charging or heavy loads. So you could set it to turn charging off at 13.4V, which is about 90% SOC at rest, but if the alternator (via a DC-DC charger) is charging at 14.4V charging will be cut off way short of a true 90% SOC. Similar errors would occur if a heavy load is turned on, lowering the apparent voltage and turning charging on early.

It's a well documented issue that using voltages for SOC etc with LFP is very difficult, if not impossible. I have done extensive testing with LFP and voltages and know this to be true.