Which sized lesuire battery?

[PC]

That’s fair enough mate

 

[spruce]

The other thing about lithium @PC is that it charges at a faster rate than lead acid batteries do.
My leisure battery would only accept a charge of 4 or 5 amps when it was 90% charged. This lithium battery will accept a charge of 30 amps even when nearing fully charged.

A 100 amp lithium battery will accept a charge of 100 amps, but the battery won't last long if done continually. I doubt the van's alternator would last long either But it can be charged at 50 amps without issue, although the recommendation is 30 amps for my 100 amp battery. Hence the reason why I have set the b2b charger's output at 30 amps rather than the default setting of 60 amps.

Victron have released a 50 amp unit recently I understand. The Australians are raving about it. I haven't seen them advertised here but then I haven't been looking.

 

[spruce]

Lithium ion has had a bad press of late. This has affected my thinking as well. So I'm treading cautiously with my dealings with this battery.

Lithium phosphate Lifepo4 is a much safer battery composition. But I believe I must err on the side of caution in these early days. @PC

Maybe I'm being too cautious, I don't know. I guess time will tell.

If anyone is worried about the safety aspect of lithium phosphate then I will always say to stick with what they have now.

 

[sleepyfolk]

That's s good question.

The instructions for use say that once the battery is fully charged to switch the charger off.
With our smart charger and leisure battery, the charger would identify when the battery was fully charged, and switch the charger onto a very small trickle charge, referred to as float mode. We are told a lead acid battery looses around 5% of it's state of charge every week under ideal conditions.

Fogstar say that the reason for this instruction is that the bms shouldn't be the last line of defence. Because of the battery's composition, it doesn't loose charge at the same rate a lead acid battery does.

They also state that excess charge can only be dissipated as heat. We don't want that. Remember the mobile phone saga a few years back.

Maybe my Sterling b2b charger will put itself into float mode once a certain point is reached. But I'm not going to test that to see if it's true.

The thing is that not all the experts in the lithium field agree on how to charge and maintain a lithium battery. For example, one YouTube poster says it should be charged at 14.2v and another 14.4v. they then say float should be set at 13.2v and another days 13.4v. then others say it should never be put into float mode in the first place.

My Sterling charger output is set at a charge rate of 13.8v by default. I can adjust that higher manually, but it seems to charge just fine the way it is. I have never pushed it further to see if it does go into float mode.

Nobody seems to answer the question of how the charger recognises it needs to go into float mode either.

Fogstar also recommend that the battery isn't kept in a full state of charge. Rather they recommend the charge be left to drop to around 30% before recharging.

All I'm doing is trying to work within the guide lines. This is all new technology for me. The batteries don't work the same way as our old lead acid batteries did.

Thanks for that, yes it’s interesting - I noticed that fogstar had stated an absorption voltage of 14.2v and float voltage of 13.6v in the full manual for the 230ah battery. I do quite a few miles so I was wondering if I could get away without buying a specific mains lithium charger and it sounds like my Victron in the van might well keep up.

 

[Part Timer]

We have a Sterling charger, and do quite a few miles. Never, ever, bench charged the batteries in over 4 years

 

[sleepyfolk]

We have a Sterling charger, and do quite a few miles. Never, ever, bench charged the batteries in over 4 years

Good to know - think I’ll order the fogstar over the weekend , and some resin, and another 100m hose - that burst today

 

[spruce]

Good to know - think I’ll order the fogstar over the weekend , and some resin, and another 100m hose - that burst today

The cold of winter is when things could change for me. At the moment my internal battery temperature is 12 degrees. ( It was yesterday.) So the moment my b2b charger kicks on, my battery is receiving a charge.

When the internal temperature of the battery drops below 5 degrees, the battery will not accept a charge. The bms switches the charge from my b2b charger to the internal heating blanket. So the low mileage I do will be mainly heating the battery rather than charging the battery. When I saw a charge of 10 amps going into the battery using my Victron battery monitor, I presumed the battery was being charged. It wasn't. It was the battery being warmed up before the charging process would begin.

When I bought the battery I also added a 20 amp charger to the order. I used that charger a few times last winter, but with no experience, I didn't really understand what exactly was going on. I had always put my old leisure battery on charge every night, so doing this with the new battery last winter was a normal thing for me to do.

This is why I need to experience this winter before I update my post on split charge relays on the diy section.