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Boatycall's avatar
Boatycall
Explorer
May 13, 2020

Need help shedding 3/4 ton - Lithium Battery project

Long story short - I'm an Electrical Engineer. Several years ago I was able to get some very expensive 145AH AGM batteries, brand new, literally by the pallet, for free.

Needless to say, I went to town - I set up my Eagle Cap 1160 with a half dozen, and my 24' trailer, "The Shotwagon", with 6 more. Well, they weigh 125lbs each. That's literally 3/4 ton just in batteries.
But as the system sits, I can easily run the roof air with both solar systems tied together, off the inverter.

Well, fast forward to 2020. It's been several years, and those batteries are starting to fade. Time to kill two birds with one stone.

I'm looking at Lithium batteries, to go on a diet. Both the Morning Star controllers and the Magnum Inverter/Charger support the voltage steps/modes necessary for lithium battery charging. And all the batteries I've been looking at have their own BMS built-in, so technically, they are 'plug and play'.

The setup I did - (The pic is kinda hard to read due to size limits)
TC -
(6) batteries
Magnum Technologies 3kw Inverter/125a DC Charger
(8) Grape solar 100w panels
Morning Star MPPT60 solar controller

The Shotwagon -
(6) batteries
(4) Unisolar 145watt 'Peel and Stick' solar panels
Morning Star MPPT45 controller
Xantrex 1800w inverter
*No* 110/DC charger - charges by either solar, or a 100a 4ga disconnect between the truck, TC, and trailer - truck charges while driving, camper's Magnum charger when parked.

My questions:

**Please help me out here and limit responses from actual Lithium Battery owners**

* Battleborn seem like the ideal setup, but they are the absolute most expensive of all the ones I've seen. What do you run?

* They say the "actual usable Amp Hours" of a Lithium battery is near 100%, where as lead-acid and AGM, they claim, is only 40-50% of rated AH - what is your experience? The claim is that 300AH's of Lithium can, in effect, replace 600AH's of AGM's.

* How does the truck charge wire handle being plugged into Lithium's?

* Any heat issues on high charge/discharges?

* Any special considerations when doing the swap besides a compatible set of charge voltages?


System design--


Grape Solar panels - 76 holes, only one small leak...found it and fixed it right after that rainy trip.


Three of the six batts in the trailer, inverter and solar controller --


Three of the six batteries in the TC - two facing and one to the right on it's side--



Here, on a good day, getting the full 60amps charge the TC's solar controller can do--

33 Replies

  • Kayteg1 wrote:
    Lithium batteries are often used in Sprinters conversions, where space and weight are at high premium, while money is no object.
    First thing owners do is installing battery to battery chargers and lithium require higher voltage.
    If your converter and solar module don't have adjustments, you will need to replace them.


    I'm seriously considering these, because the built-in BMS makes them 'plug and play', directly replace lead acid deep cycle or AGM's, on ANY charger, even a cheap OEM Magna-junk.

    Lion Energy Lithium Batteries

    Quote from their website-- "The Safari UT 1200 is the latest in Lithium battery technology. It replaces traditional deep cycle lead acid batteries with the safest Lithium – Iron Phosphate. It is a “plug and play”– simply remove the deep cycle lead acid battery from your RV or boat and replace it with this superior performing battery."
  • Lithium batteries are often used in Sprinters conversions, where space and weight are at high premium, while money is no object.
    First thing owners do is installing battery to battery chargers and lithium require higher voltage.
    If your converter and solar module don't have adjustments, you will need to replace them.