Lithium Batteries

[karollins1]

Hello, I am new to this forum. I recently bought a 2017 31w and took it out a couple of times dry camping. I had to run the generator way too much trying to keep the batteries charged. Is there anything that I need to change or do to put lithium batteries in?

I am also thinking about taking the electric fridge out and putting a 12v fridge in. Then solar eventually.

 

[david_reaves]

This recent thread has a ton of information about adding lithium.

https://www.thorforums.com/forums/f...s-based-capacity-size-bms-features-37838.html

 

[16ACE27]

Hello, I am new to this forum. I recently bought a 2017 31w and took it out a couple of times dry camping. I had to run the generator way too much trying to keep the batteries charged. Is there anything that I need to change or do to put lithium batteries in?

I am also thinking about taking the electric fridge out and putting a 12v fridge in. Then solar eventually.

You know a 12v fridge is electric.

Install a shunt based battery monitor to get your true state of charge of your house batteries. I use this:

https://www.amazon.com/gp/product/B07RP5B5P7/?th=1

But others have been happy with this cheaper unit also:

https://www.amazon.com/AiLi-Battery-Monitor-Voltmeter-Motorhome/dp/B07FGFFHC6?th=1

Then do your research. You will kiely need a new converter and a new chassis battery isolator like the Li-BIM 225.

Small inverter generator and solar are also methods people use to keep their house batteries charged when boondocking.

 

[Mark54]

Hello, I am new to this forum. I recently bought a 2017 31w and took it out a couple of times dry camping. I had to run the generator way too much trying to keep the batteries charged. Is there anything that I need to change or do to put lithium batteries in?

I am also thinking about taking the electric fridge out and putting a 12v fridge in. Then solar eventually.

Lots on the forum about that, but in short:
- Lithium batteries are lighter than lead-acid.

- Also more $$ but can be cost effective over time- can last 10+ yrs if kept at 20-80% SOC

- Also do not need liquid maintenance like lead-acid or 'wet-cells' (except AGM or SLA)
- LiPO4 ("LFP") is safer than Li-ion, that can have runaway reaction if punctured.

- LFP batteries can be drawn to 0% SOC but will decrease lifespan by as much as 3000 cycles.

- LFP batteries can be 'safely' inside coach, and do not off-gas H2SO4 (Hydrogen Sulfide, very toxic) like wet cell batteries, when charging.
- LFP batteries bulk charge at 14.6V instead of 13.6V, so you need a specific charger for LFP, or lithium batteries, or be able to change settings on your charger if it is set up to do so. Smart charger is recommended to "know' when to go to 'float charge' from bulk charge.

- Solar charge controller needs to be compatible with LFP batteries. MPPT is 97% efficient and PWM can be 70%, so MPPT is best.

In short- I love having LFP and solar to keep them alive-

I have 600AH (7200Wh) of lithium power in my rig, and 380W solar. I can leave my rig unplgged for days at a time when camping.

I also have a 12V roof AC and 12V fridge, which use a lot less amps (watts) than the 120V counterparts. That adds days to boondocking. The 12V roof AC is also a lot quieter.

It took me 5 days to just move my batteries off the bottom, and re-do my electrics in my RV, so be prepared for $$$ labor costs to change, unless you DIY like I did.

Renogy is a great resource for info as well. There are lots of videos and info on the web as well, of course. Also defines all the terms I used above that you may not understand, like PWM vs MPPT.
Good luck!!

 

[DavidEM]

Mark,

What brand of A/C is your 12V unit? Capacity?

David

 

[Mark54]

Mark,

What brand of A/C is your 12V unit? Capacity?

David

Hi David!

I replaced my Two ReLion 100A with two Weize 300Ah batteries, then replaced the 30A GoPower PWM solar controller, with a Victron MPPT 30A, added Victron monitor for solar and also added an SG200 Gateway for the Balmar. Also added a 2nd 190W solar panel, giving me 380W.
MPPT is 95+% efficient instead of PWM's 70%. I also added two 40A breaker switches to control solar input when working on electrical, and replaces the inline 20A fuse that was well hidden. (Ignore the "reverse Polarity" light- that is actually for the solar infeed voltage- see last pic.)

All electrical components under the chassis were moved up into the headrest/electrical compartment of pass. side.

After only 1 year since purchase- those components were all muddy, and starting to oxidise...

I kept all the wire gauges the same, since I am not using more power- actually less now. 2/0 gauge for batteries to buss and combimaster, with proper fusing.

The 12V AC is a Mabru, that uses less than 1/2 the watts (300-500W) and is 20-30dB more quiet. Add to that, I don't have to use the 30-40W for the inverter to use it, leaving more for microwave oven or TV...

So now I can boondock 3-5 days depending on AC need, sunlight, etc, but easily 1-2 nights at any spot w/o shoreline. We used it this spring in Utah in several places w/o hookups w/o any problems.
300A gives me 7200Wh of power.
Added benefit of being able to remove batteries for winters in VT and maintain on my workbench in my basement! Same with BMPro tablet- gets removed and maintained same as lithium batteries- kept at 50-60% and charged to 100% and drop back to 50-60% every 3 months.
I use a 1500W I/C to charge and draw back down to 50-60% using a 700W heater on the I/C.

I save $700 every winter storing at home!