Test Deep Cycle batteries capacity/condition, and what replacement/upgrade?

[Mark_K5LXP]

Bulk Mode will be maintained until the current draw drops to approximately five Amps,or until the timer reaches four hours (whichever happens first).

Four hours is plenty at 55A to fill a 100Ah lithium, probably enough for two, other loads notwithstanding. The trigger to start bulk mode is a full current draw which I also don't see a discharged lithium having any issue providing. The only complication with "auto" anything are the exceptions, like what happens after bulk mode is finished. The converter ramps down to 13.6V which means the battery picks up the load until it discharges to the point where the converter again senses a high draw and the cycle repeats. Unlike with lead acid where the battery would fully charge and stay topped off as long as the converter is active. Maybe in practice you wouldn't see dramatic cycling but it might be good to know what to expect.

Mark B.
Albuquerque, NM

 

[JoshH]

I am thinking that you have this one.
View attachment 174856

No that one has "auto detect". The link I posted above is what I have.

 

[JoshH]

It looks like it won't be too hard to upgrade my charger to one that has auto detect. I'm probably going to try a lithium deep cycle battery with my current charger and see how it does, if I run into problems it doesn't look like it will be too hard or expensive to upgrade the charger.

One thing that concerns me is that on the specs for one of the batteries I looked at is the low point for charging is 32F. I sometimes camp in the winter below freezing, I would like to be able to charge with solar if it is colder than that temp. I sent an email to another manufacture that didn't list their temp specs.

 

[Mark_K5LXP]

Your existing converter should work OK, I'd be up for at least trying it for a while and seeing how it works out. I recall they have converters that are manual switched, so if you have a mind to get another one you wouldn't have to rely on anything automatic. Guessing this is a travel trailer with the battery on the tongue? Yes, 32F or thereabouts is a hard stop for lithium unless it has a built in heater, or you provide heat. Since a lithium is much lighter and no spill or vent risk you could entertain relocating it somewhere inside in heated space and not have to specifically accommodate outside ambient temperatures.

Mark B.
Albuquerque, NM

 

[JoshH]

Your existing converter should work OK, I'd be up for at least trying it for a while and seeing how it works out. I recall they have converters that are manual switched, so if you have a mind to get another one you wouldn't have to rely on anything automatic. Guessing this is a travel trailer with the battery on the tongue? Yes, 32F or thereabouts is a hard stop for lithium unless it has a built in heater, or you provide heat. Since a lithium is much lighter and no spill or vent risk you could entertain relocating it somewhere inside in heated space and not have to specifically accommodate outside ambient temperatures.

Mark B.
Albuquerque, NM

Yeah I wouldn't mind moving the battery to the inside but moving the wiring would not be trivial.

 

[FunSteak]

It looks like it won't be too hard to upgrade my charger to one that has auto detect. I'm probably going to try a lithium deep cycle battery with my current charger and see how it does, if I run into problems it doesn't look like it will be too hard or expensive to upgrade the charger.

One thing that concerns me is that on the specs for one of the batteries I looked at is the low point for charging is 32F. I sometimes camp in the winter below freezing, I would like to be able to charge with solar if it is colder than that temp. I sent an email to another manufacture that didn't list their temp specs.

I upgraded the circuit board on my WFCO unit. If you have a look at yours, you might find a teeny little jumper that must be moved to best charge lithium batteries. Check the manual. New board wasn't too expensive.

I just went through the same situation earlier this year, and did a lithium upgrade. I just posted THIS THREAD about it, if you'd like a look. Happy to answer questions, too.

Best of luck - the Li upgrade is amazing!

Edited to add: It's true that most Li batteries won't charge under 32F. Mine will sense that and not accept charge. You can discharge down to, I think, -15F. There are some batteries out there with built-in heating for this issue, but I'm not sure if there are any in group 24 sizes.