Cab (Truck) and Cabin (RV) Outdoor Batteries - AGM or Lithium? Best Brand and Price Out There?

[Channelmarker]

I have 1998 Mercedes Benz Actros 2040 truck with 4 large truck size AGM batteries stored in the outside battery back behind the cab and underneath the cabin. The truck side of the batteries hold a charge. But the Cabin side are shot. So now I have to decide whether to continue going with AGM batteries, which are cheaper and can handle colder weather better, or lithium batteries which are much easier to maintain, hold a deeper charge, but don't hold up to cold as well.

So, should I go with some new AGM batteries which are cheaper and can handle colder weather? And if so, which brand, how big and powerful, and what is the best deal out there?
Or, should I go with new lithium batteries which hold more charge and are less finicky, but don't handle the weather as well? And if so, which brand, how big and powerful, and what is the best deal out there?

 

[Trail Talk]

2X amps @ 1/2 weight =

 

[DiploStrat]

To be clear, lithium iron batteries have no problem discharging at below freezing; they cannot be charged when below freezing.

Depending on how cold your battery area actually gets, you are probably fine with heated batteries, as sold by Battle Born and others.

 

[chet6.7]

This guy reviews a lot of batteries, has a forum as well.
https://www.youtube.com/@WillProwse/videos

 

[Channelmarker]

Thanks for everyone's responses. Very helpful.

However, right now I have a complete AGM Victron system that has not been updated to include Lithium batteries. I have some great lithiums from my old rig that I eventually want to install and I have a place to install them inside. But that is for a future project when I update the whole electrical system to include a 110 inverter (it currently has a 230 European system only) and I add in my 110 Honda 30000I generator).

It sounds to me that the best solution for now is to get two new AGM batteries for the cabin side only until I get the money up for the electrical overall that I want to do on the rig which may take a year or two.

Where is the best and cheapest but good quality place to buy big truck AGM batteries?

 

[Channelmarker]

You could have saved time by not asking about Lithium if you'd already made up your mind.

I didn't make up my mind until I read everyone's posts. Isn't that the purpose of the forum - to gather people's opinions and then make a decision and then see if it holds up to scrutiny, but not unnecessary sarcasm?

 

[chet6.7]

When I bought the batteries for the Cummins I found that group of batteries at O'Reilly Auto Parts was made by East Penn. Who knows now, I try and avoid Johnson Controls.

 

[Peter_n_Margaret]

I have a complete AGM Victron system that has not been updated to include Lithium batteries

What components can't be reprogrammed to suit Lithium or are not already suitable as they are?
I changed from AGM to LiFePO4 a while back and bought ZERO new bits. I continued to use my 20 year old solar controller. Just because it has not got "Lithium" written on it does not mean it is not 100% suitable.
Cheers,
Peter
OKA196 motorhome

 

[VinceAtReal4x4's]

What components can't be reprogrammed to suit Lithium or are not already suitable as they are?
I changed from AGM to LiFePO4 a while back and bought ZERO new bits. I continued to use my 20 year old solar controller. Just because it has not got "Lithium" written on it does not mean it is not 100% suitable.
Cheers,
Peter
OKA196 motorhome

You might want to look closer at the charge specs for 100% charge on your new batteries. There is no "old" controller that I know if that is suited to properly charge lithium fully. The profiles are different between lithium and AGM's, plus you have no temperature compensation like new controllers do. Yeah it might seem to work but the engineers say you aren't reaching 100% or even 80% depending...

 

[luthj]

LFP is typically fine with lead acid charge specs, at least middle of the road ones. LFP does not need to be charged to 100% either. It doesn't suffer from partial charge degredation like lead acid does.

For a 12V nominal LFP battery, absorb between 14-14.4V (difference of 2-5% in capacity), float at ~13.3-13.5V (depends on service the batteries will see). No equalize (and if there is its typically no more than 0.1V higher). No temperature compensation, ensure that its turned off if present. The difference in total capacity between 14.0 and 14.6V is less than 10%, typically in the 5% range. It does take a slightly longer absorb, but there isn't any need in most cases to push the pack to 100% with LFP. Instead having a reasonable absorb timer (15-60 minutes) with at least 14V ensures the BMS has time to perform balancing as required.

In general this means that most lead acid chargers are totally fine with LFP. In fact I have seen quite a few chargers with "lithium" on their sell-sheets which are borderline abusive with 14.6V absorb and float voltages over 13.6V.

 

[IdaSHO]

To be clear, lithium iron batteries have no problem discharging at below freezing; they cannot be charged when below freezing.

Depending on how cold your battery area actually gets, you are probably fine with heated batteries, as sold by Battle Born and others.

To be even (MORE) clear

SOME lithium-iron batteries will discharge with little problem below freezing IF they create their own heat (and reduces their useable capacity). Not all batteries do this.
During cold temps, and below freezing the simple scientific fact is that (even when discharging) the cold slows ion movement and lowers the overall available amperage for lithium-ion.
It may not damage them, but it does slow them down. Changing in such temps (as mentioned) is a whole different story. It not only has the potential to damage a battery, but be terribly dangerous.

This effect on discharging in the cold it terribly evident for items like many lithium tools that refuse to run in the cold due to the batteries feeling the cold.
The overall voltage is reduced just enough that the tools refuse to operate below a certain voltage.
The trick on the job is to carry two batteries, one in your coveralls/jacket to keep them warm, and swap them out when the cold overcomes the battery in the tool
All that said, my old 18V lithium Makita batteries (and chargers) dont care about the cold. They will still "charge" in the cold if you let them.
Where some of the newer stuff has a low temp (safety) cutoff and refuses to even charge in the cold.

 

[luthj]

To be even (MORE) clear

SOME lithium-iron batteries will discharge with little problem below freezing IF they create their own heat (and reduces their useable capacity). Not all batteries do this.
During cold temps, and below freezing the simple scientific fact is that (even when discharging) the cold slows ion movement and lowers the overall available amperage for lithium-ion.
It may not damage them, but it does slow them down. Changing in such temps (as mentioned) is a whole different story. It not only has the potential to damage a battery, but be terribly dangerous.

This effect on discharging in the cold it terribly evident for items like many lithium tools that refuse to run in the cold due to the batteries feeling the cold.
The overall voltage is reduced just enough that the tools refuse to operate below a certain voltage.
The trick on the job is to carry two batteries, one in your coveralls/jacket to keep them warm, and swap them out when the cold overcomes the battery in the tool
All that said, my old 14V lithium Makita batteries (and chargers) dont care about the cold. They will still "charge" in the cold if you let them.
Where some of the newer stuff has a low temp (safety) cutoff and refuses to even charge in the cold.

Tool batteries tend to operate at high C rates (often over 1C). These larger loads tend to see the biggest impact from cold. A typical vehicle house system (not a starting battery) will operate at much less than 1C typically. So the effect of cold on ion mobility is much less pronounced.

I agree of course, cold temps reduce all batteries performance. The capacity hit is actually pretty similar between LFP and lead acid typically.

The primary issue with lithium ion types (LFP NMC etc) is that at low temps the ion mobility is lower. Thus the maximum charge current drops. If this current is exceeded (at any temp) you can get lithium plating of the anode. Its just at higher temps there are other limits which kick in before plating happens. Some manufacturers of cells even specify the charge rate for low temp charging. Its often quite low, less than 0.05C in some cases, so it isn't too practical, and most just state to not charge below freezing.

 

[IdaSHO]

Like I said, the actual chemistry of lithium ion, regardless of tech protecting or controlling the battery bank, will be effected by cold temps, both charging AND discharging.

How much it is effected discharging is going to be determined by discharge rate and state of charge.
As temps dip.... capacity drops, voltage drops and internal resistance increases. FAR from not being effected by the cold.

And while I agree that the charging while in the cold is an issue, so is discharging, and the effect should be considered when designing a system to make the numbers work.
At the end of the day the numbers win out. If those numbers show your system is just enough assuming the cold doesn't effect discharging, you have problems.

 

[DiploStrat]

Not arguing. The question was installing camper/house batteries outside of the heated envelope.

There are devils in the details, of course, but, for camper batteries in a system with reasonable reserves, the loss of power to cold usually does not keep the system from working. In other words, the increased capacity of lithium iron over AGM will probably compensate for any increased sensitivity to cold. As noted, AGM batteries lose power in cold, as well.

Were I the OP, I would not reinstall AGM batteries, but would rather go with Lithium iron. And, as they are outside of the camper, would spring for the heated model.

As always, YMMV.