Lithium rv trailer battery

[crispyboy]

Correct, I'm not wanting to go down the rabbit hole with this project. I will either get two - 100 ah batteries or a single 200 ah battery.
I had the old batteries load tested yesterday. While they show an ok surface charge they don't have the depth of charge and go down quickly. I am going to watch for black Friday and cyber Monday sales.
When the project is finished I will report back.

 

[Ozymandias]

Better have one Battery then 2 of them - except Victron battery's where the BMS can talk to each other.
It isn't a no-go, it is just desirable to have one unit over 2 if possible.

 

[AH64ID]

Correct, I'm not wanting to go down the rabbit hole with this project. I will either get two - 100 ah batteries or a single 200 ah battery.
I had the old batteries load tested yesterday. While they show an ok surface charge they don't have the depth of charge and go down quickly. I am going to watch for black Friday and cyber Monday sales.
When the project is finished I will report back.

How much boondocking do you do?

 

[crispyboy]

Up to now not too much. I do have some short off the grid trips planned for next year.
Today I ordered two LiTime 100 ah Group 31 batteries with heaters just in case. $197 each.

 

[Tuesdak]

A standard RV battery shouldn’t be drained more than 50%, so a 100AH battery has 50AH useable. On a lithium battery they can be discharged 100%, so the same size battery has twice the usable amp hours.

Interesting below, but in an RV application cycle count is the least of my concerns for murdering batteries. Capacity loss is a concern where the propane fridge is in low voltage alarm say after running the heater all night with weak batteries. I boondock for a week at a time. Getting the batteries charged on limited generator hours was my biggest problem I had to solve.

The same life reducing 100% DOD lead suffers appears to apply to the LiTime batteries. Marketing saying half the amp hours of lead is the same "price" when again I can get more out my lead batteries by trading off cycles. Yes, it's 4 times the life of lead at 50% DOD vs. LI at 100% DOD. However using only 40% of the Li battery 15,000 cycles... I don't use my RV that much. Lifeline also makes a LI battery now (IMO noncompetitive with a short warranty) however they mention expected life is 2000 cycles 100% DOD with 60% of battery capacity remaining. That 100 Ah is going to be 60 Ah when the battery is considered End Of Life worn out.

From LiTime's website.

AGM Lead from Lifetime's manual showing what happens to battery cycle life if I use 10%-100% DOD. It's NOT a direct comparison as lead is considered "worn out" at 80% of capacity in the chart below where Li gets 60% capacity.

 

[GAmes]

Today I ordered two LiTime 100 ah Group 31 batteries with heaters just in case. $197 each.

Thanks for the heads up. A friend of mine is switching to lithium for his boat and Li time is a great price right now.

 

[AH64ID]

Thanks for the heads up. A friend of mine is switching to lithium for his boat and Li time is a great price right now.

They are even cheaper on Amazon, plus a 6% off coupon showed up when I looked at them.

 

[Learjet]

Batteries and 40 amp charger are in...Converter switched to li mode and the extra 40 amp charger getting over 70 amps at the batteries.


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SOC hasn't reset yet for new batteries


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[Ozymandias]

Don't forget the to program the shunt for the Lithium too.

 

[AH64ID]

Batteries and 40 amp charger are in...Converter switched to li mode and the extra 40 amp charger getting over 70 amps at the batteries.


#ad
Click For Full-Size Image.

SOC hasn't reset yet for new batteries


#ad
Click For Full-Size Image.

Isn’t 70A of charging higher than recommended for that size bank?

 

[Ozymandias]

He splits the charge, 35A ist way below what they can take, usually it's at least 1C/3C for them.

 

[Learjet]

Don't forget the to program the shunt for the Lithium too.

yep, shunt re-programmed and solar settings changed.

 

[Learjet]

He splits the charge, 35A ist way below what they can take, usually it's at least 1C/3C for them.

yep, that works for me with the amount of boondocking I do, also want to manage the loads on my Onan 5500. It's definitely a balance act for each persons individual needs and situation. Also, have 600 watts of solar I will add to the mix when the sun is out.

 

[Ozymandias]

Nice setup, your good to go off grid. Consider an induction stove top over propane, much better.

 

[AH64ID]

He splits the charge, 35A ist way below what they can take, usually it's at least 1C/3C for them.

Went back and realized it’s a 600AH bank, I was thinking it was a 200AH bank.

70A charge rate is definitely not too much for battery longevity.

 

[Grumpy8811]

Nice setup, your good to go off grid. Consider an induction stove top over propane, much better.

what would make an induction stove better for off grid use than propane?

 

[Ozymandias]

what would make an induction stove better for off grid use than propane?

Not unnecessarily heating the interior, no moisture, no cost for fuel, convenient.
Having a stove top for free is great.
You need about 20-50Ah for a full three course meal, it is less then most people think and the solar recharges that easily during the day.

Same applies to a compressor refrigerator instead of a propane one.
Way better energy efficiency and constant interior temperature of the fridge no matter what outside temperatures are.

 

[Grumpy8811]

Not unnecessarily heating the interior, no moisture, no cost for fuel, convenient.
Having a stove top for free is great.
You need about 20-50Ah for a full three course meal, it is less then most people think and the solar recharges that easily during the day.

Same applies to a compressor refrigerator instead of a propane one.
Way better energy efficiency and constant interior temperature of the fridge no matter what outside temperatures are.

I prefer to conserve battery power when off grid, not consume larger quantities of it.. especially when a person cannot count on solar
I always thought that was the advantage of propane appliances.. propane makes more sense to me than spending thousands on a solar setup with Lithium batteries, all so you can get "FREE" electricity....

 

[Ozymandias]

I produce large amounts of energy and the sun rises every morning.
Worst case I run the generator as a backup for half an hour to an hour to recharge.
Even the AC runs from the battery bank through a powerful inverter.
No need to make noise for around 4 hours which is plenty of time to cool of the interior in the evening from the heat of the day without disturbing anyone around, including myself, with a genset ruining the sundowner time outside.

 

[Ozymandias]

Conclusion for 2024 - Lithium battery's are cheap, solar panels are cheap, solar controllers are cheap, powerful inverters are cheap, powerful battery chargers are cheap - there is no reason to stick to an old technology - except personal preferences.

When I started out with Lithium in 2016 - 8 years ago, it was already a well established technology because I'm not a Trendsetter, but it was still really expensive back then. Anyway I switched after my truck nearly burnt down because of a cell short in the Pb battery bank. Now after eight years of intense use I come close to replace my battery's and of course I stick to the technology. Even better with the new ones I'll increase my capacity by 30% at the same size batterys.

I can really not wrap my mind around why someone wants to stick to outdated stuff - except personal preference.