Lithium battery conversion

[PPPPaul]

Hoping this will catch the eye of some folk who are experienced with Lithium.

I bought a 2018 MB Sprinter 2500 with a starting battery linked to 2 under-carriage AGM 6v cabin batteries, wired serially for 220a 12v and a 1100w inverter.

Built in California, it only had 1 solar panel atop (100w) and I unknowingly stressed the cabin batteries adding a small microwave and a Chinese diesel furnace despite tripling the solar panels for Seattle weather.

So I'm contemplating adding a dc-to-dc charger between front/rear and replacing AGM with with one of two lithium paths:

1) four 302a 3.2v cells https://amazon.com/ninthcit-Lifepo4-...p/B09FSS293P/r with independent BMS 150 or 200a

2) three 100a batteries each with built-in 50a BMS https://amazon.com/LOSSIGY-Rechargea...093L622N9?th=1

Both should provide 300a service against my electric needs which I total at 50a if everything is on at the same time (almost never).

My main concerns are supporting my travel/living needs, taking care of my investment without electronic burnout. (1 would have bluetooth monitoring, 2 would not). Warranty is also a concern (1 is only a year and requires shipment to China; 2 is five years and shipment to California).

Anything folks see that I'm missing in this consideration -- or recommendations one one path or the other?

Thanks in advance,
Paul

[PPPPaul]

Also, any thoughts on storing lithium batteries in the under-chassis tray? I think they should hold up better than AGM, but an AGM evangelist just told me he thinks it'l cut the lithium battery life.

[PPPPaul]

And now I'm getting conflicting recommendations: do I really need a DC-to-DC charger? Or should the BMS cut off any charging not within proper parameters?

[rowiebowie]

I refrained from answering since I do not have a Sprinter and therefore not familiar your setup.

However, I can say that yes, you'll need lithium charging profiles in all charging sources. That can be done for alternator charging with a DC to DC charger between your lead-acid chassis battery and your lithium coach batteries.

You'll also need a lithium charging profile when plugged in. This can be done with a combined Inverter/Charger or separate units. But again, this is necessary to make your expensive lithium batteries work to full capacity and for their long life.

In a rough estimate, figure whatever your lithium batteries will cost, then double that amount for new charging components. I gets spendy fast.

Also, mounting lithium batteries inside cures most high or low temperature concerns. I lost some interior storage by moving my batteries inside during my switch to lithiums. But gained some space back by repurposing the old outside battery compartment. Easy for me with a Chevy Express chasis with an exterior access door that your Sprinter lacks. But perhaps look as using the old exterior battery compartment for some kind of rarely accessed emergency items.

[@Michael]

I would not want the lithium batteries under the vehicle unless in a weather proof enclosure. As far as I've seen, the cases are not made for direct exposure, unlike regular batteries.

If I were going the DIY path with bare cells and bms, I would spend significant time researching, and would strongly prefer cells from a US based supplier.

And yes, the you'll have to make sure all your charge sources are compatible with the lithium chemistry.

[Davydd]

Are there any other RV lithium ion batteries other than Battle Born with integral self heating in the case?

[avanti]

Originally Posted by Davydd

Are there any other RV lithium ion batteries other than Battle Born with integral self heating in the case?

Yes. Quite a few, actually, and more and more are showing up all the time. Ones I know off hand:

Renogy:
https://www.renogy.com/12v-100ah-sma...ting-function/

Lithionics:
https://lithionicsbattery.com/produc...al-heater-kit/

Relion:
https://relionbattery.com/low-temperature-series-line

I think it is rapidly becoming a standard option.

You have to be careful, though. Some brands make the heater inputs directly available, and others don't. Of the latter, some make smart control decisions and others not so much.

This is all changing so rapidly that I am mostly ignoring the issue until the time to decide arrives, at which point I will shop carefully. But, I can't imagine buying a battery without this feature.

[rowiebowie]

I'm glad I put my lithiums inside my coach, but at the time I thought I was being overly cautious since I live in a mild climate and we generally travel in mild temperatures (Spring & Fall).

But in '2020 we got caught in 106 degree July heat when on a trip near Austin. The floor of our van was pretty darn hot after driving for hours on 130+ degree asphalt roads and then parking on a hot asphalt camp site. If the lithiums had been under the van, I would have suspected them to be about the same temps. Instead, the batteries were inside the air conditioned coach.

As for cold weather, last year we had the Texas freeze and later we camped two nights in October in Yellowstone (Madison campground) with overnight temps in the teens and low 20's. I both cases, outside lithiums batteries would not have been damaged and could be used (just not charged). But I never expected we'd encounter those temps, so I was glad the batteries were inside the heated coach.

So long as I can winterize the macerator & dump valves and run the tank heaters, the inside lithiums will never be a concern for extreme temperatures.

[PPPPaul]

Thanks for all the good feedback thus far -- any other input appreciated!

I do anticipate going to the mountains a few times a year and hot (100-110) a few times a year, but sense the batteries are not going to be impacted that dramatically for those few extremes -- am I crazy? Research/resources would be massively helpful.

[PPPPaul]

Yeah, I checked the specs on the 100ah battery and don't anticipate going outside this range: 10℉-122℉

[JohnnyFry]

I went a similar route to RowieBowie: I purchased 4 150AH cells from China via AliBabba. Delivery was about a month and they were new class A cells with proper QR codes. For BMS I selected a Xiaoxiang BMS from a US source. It has Bluetooth, Low temperature charging cut off, 10 Amp capacity and variable parameters. I used a Renogy 20 Amp DC/DC charger (although not available at the time I would have selected a 60 amp model switchable to 30 amps) and I kept the 750 watt TrippLite MSW inverter charger. I also added a AIMS 400 Watt PSW inverter for electronics.It is sufficient for my needs although I would like to have a 2,000 watt PSW inverter so I could use the microwave and induction cook-plate. I mounted everything inside where the "winter" 10 gallon water tank was. After a year of operation I would deem the set up a success. The TrippLite actually does a decent job of charging although it does not really have a LiFePO4 specific profile (the Renogy DC/DC does have that). At the time I did it Battleborn at $999 was about the only show in town but in the interim others have come to market with completely assembled batteries and prices have fallen sharply, so I would definitely look at those. As usual, carefully evaluate any potential battery as quality varies.

[PPPPaul]

JohnnyFry, does that mean you have 150ah or 600ah total?

Does anyone have experience mounting LiFePo4 batteries on their side? I'm reading mixed messages about this. In order to put these inside my cabinet, I'd have to do so.

[PPPPaul]

This manufacturer says no problem mounting on their side. Also note, Amazon upsells a 4-year warranty for $44 on this thousand-dollar purchase -- which would be NINE YEAR warranty. Slight catch, only applies to original owner -- and I know I want to upgrade before then

[JohnnyFry]

150 AH total. Cells do not have any mounting position limitations.

[PPPPaul]

Thanks for all the feedback thus far. Found my schematic and thought it might help shed light on my situation replacing the 2 AGM house batteries.

[JML]

2013 Excel TS. I just finished installing a Battle Born LiPo 270 GC3 AmpHr battery. I included a Victron 712 Monitor and Victron Non-isolated DC to DC charger and a new 1000 Watt Inverter. And earlier upgraded swapped out the Progressive Dynamics Charger converter. I also have a 30 Amp Renogy Adventurer Li Solar controller, 100 watt solar panel on the roof and I have a 100 watt and a 120 watt portable panel to use. The Battery fits under the sofa.

I took out the battery isolator under the hood and put in a 60 Amp CB there on the input side of the charger. I used the existing cable for the charger. I used the battery compartment (which previously had a 100 AmpHr LiPo that replaced the lead acid battery) to mount the charger, another CB on the output side of the charger, and a battery shut off switch. The cable (4 AWG) with the solar controller cable ran along the wheel well into the coach electric ottoman compartment, thru conduit between the ottoman and the rear garage, routed to a small box holding the Victron Monitor and a 300 AMP CB. I have the Victron BM display ready to mount in the back of the garage but might just leave it off.

[Nspekter]

Has anyone used Dakota Lithium batteries? They have a 12v 135 amp-hr dual purpose that looks very usable.
https://dakotalithium.com/product/dl...e-performance/
I've been looking for a lithium battery that I can install in the brackets underneath (in a battery box) my 2013 ERA 170A and leave there through outdoor winter storage here in Chicago. I think I've found them in these.

[Bud]

"that looks very usable"

What looks very usable? Appears to be Very Expensive..........

[booster]

Does the outside storage have electricity to run the battery heaters if needed?

[Nspekter]

These batteries have built in heating. I don’t know how quickly they use their charge to maintain the internal temperature they need. I’ll send them another email asking that.