Switch to LIFePO4?

I thought that Relion had the LT version that had a built in heater? Thinking about it a bit more, I can’t recall the last time we were camping when it got down to -20C... but that’s me.

If only they would produce the cold weather version of Li batteries.....

Great information, will be digesting over the next couple of days, thank you. I pulled the trigger on 4x100 AH batteries, with the thought that I can always add a few more later on if needed. By having the 4 in parallel, that should give me 400A max draw which is way more than ample. We almost exclusively boondock but not full time.

I don't think there is overkill if you can afford it do right the first time.;). If they had a 600ah battery when I got mine I wouldn't have thought twice about it.

I did look up those batteries you're looking at, one thing that I don't like about those 2 300ah batteries is being limited to 200a draw but if you don't run 2 large items at one time that won't be problem. Most dropins with 300ah will allow 150a draw per battery in parallel.

Forgive me for going a little long in my response.

"What is typical use on the inverter", that is a loaded question because it depends on the time of day, season, location we're boondocking.

I do not turn my inverter/ system off, it has been on since day 1_ 24/7/365. When nothing is on the inverter will draw 2ah (26w +/-). A "typical use/ draw" would be 7-15 ah (90-200w), add the 12 cup coffee pot 84a (1,075w), microwave 142a (1,798w). During the summer I'll turn the Norcold fridge over to electric 28a (358w) add that with other loads that could be a " typical use/ draw" 35a (470w) continuous from 9am - 6pm with microwave use on that equaling 170a (2,142w). There has been an occasion or two that the coffee pot is on brewing and used the microwave with other misc items 231a (2,888w).

Once again depending on the season (day light hours) our nightly use in the summer is 25-30% DoD (75-150ah), winter can be 30-40% DoD (150-200ah). With the amount of flat mounted solar on the roof during the summer it will always recharge the batteries and cover all daily loads I can throw at it, unless it's a truely dank day.

In the winter the solar will normally cover our daily use and put some sort of charge into the batteries. Meaning the batteries will be in a PSoC range from 90-30%, 40+ days is the longest it's gone bouncing up and down , the norm though is 10 days before solar charges to full.

Here is an example from of what I mean during Jan 8-16 of this year.



I generally use the generator for charging when the batteries are 40% SoC in the afternoon/ evening when I know solar won't deliver anymore charging, which is not often. Then I'll run eu2000i generator for 2 hours which will put 200ah (40%) back in the bank. I rather not hear the "quiet" generator even my own. Then ground hog day starts over again.

Once you get over the $$ shock for lfp batteries you'll look back and think why didn't I do this sooner.

If it works here is link to recorded display readings. You can see SoC% and what was being used at the time. Blue/ green color is just to see separate days easier, if orange is seen that's when the generator was hooked up. The top row explains what the column reading are from whether it's the lfp battery display or from Magnum me-arc display.

DC display readings

Totals from the system not counting this year.



If you have a more specific question ask away. ;)

Itinerant1 wrote:
It has served us well, no complaints.

Very envious of your setup! I’m starting to think that 600AH is overkill (big surprise, I overkill on everything ;) what is your typical use on the inverter? Do you regularly draw down below 50% in a 24 hr period?

Right now with the wet cells I have, I usually wake up anywhere between 75-85% of full charge, then the solar tops me back up before noon weather permitting. If I assume 80% usable capacity on LIFePO4 batteries, then at 4x100AH batteries I would be in same capacity range as I am now. We typically turn on the inverter in the evening to run the TV, coffee maker etc. Wife also runs CPAP on 12v overnight.
See any advantages to going with larger capacity battery (300AH) vs multiple 100’s other than less wiring?

It has served us well, no complaints.

Itinerant1 wrote:
I have been living off of lfp/ solar for 37 months now of which 35+ months have been boondocking (877 day stretch right now). Equipment installed... 12v 500ah lithium batteries (GBS LFMP battery system, 20 prismatic cells 4S5P). 8 CTI 160 watt panels (1,280 watts), 2S4P. Panels lay flat on the roof. Magnum PT100 controller, Magnum 3012 hybrid inverter. There is a 7" display monitor and the ME-ARC 50 to read the performance of the system. A sub panel was added so everything in the 5th wheel except the water heater is running through the inverter. Entire weight of system 500#.
The batteries, inverter, controller are mounted in the front compartment. I insulated the walls better with 2" foam board cut to fit all area between the structure supports. One of these pieces can be removed during warmer weather to allow for air flow (cooling). My lfp packs actually have cell temp readings which is important if using in different environments. Last time I looked I don't think BB have cell temp displays (if wrong I stand corrected, check lifeblue lfp batteries IMO they're better than BB and same warranty).
I also have a thermometer in that compartment so temp can be seen, along with an outside thermometer. Now I don't do Canadian cold living but have been into the 20f range and the front compartment will be in 35-40f area with the lfp cells usally 5f warmer. I should say that there is always some draw on them from 2-7ah through the night so that might help keeping the cells warmer.
The cells do have protection for below 32f temps that won't allow charging but still can be used down to -4f. Once the EMS sees cell temps are above it will allow charging.
If I was going to be in colder weather or long stretches of that weather I'll get a reptile warming pad for the batteries.
As far charging I do nothing special let solar do what it can, if the lfp batteries get down to 25-30% soc and it looks like solar won't charge enough I'll hook up the eu2000i generator for 2 hours and give them a 200ah (40%) boost. In any given year the generator has not been used more than 12 times tops.

Nice system with all the right components.

I'm in it for a little longer ;)
He is quoting the 100AH units at $750 CAD, the 300AH units are $2250 (same price per AH. I'm not sure whether it would be better to go with 4 x 100AH to start and add a few more if really needed later. Limiting to 400AH would give me a higher C factor when spiking at 150A (0.4C vs <.3C at 600AH)
The other vendor (Total Battery) has not returned to me on my request for quote so far...
He's put it in writing on the quote that the batteries are returnable for full refund if I'm not satisfied.
I kind of like the idea of supporting this kind of entrepreneur, if the risk isn't outrageous, he seems like an interesting guy based on his other business.

PT, you are so right! I will be 77 next month. Gives you a perspective on what the "long run" is! :)

I remember my dad at my (now) age, buying a new car, and wondering if that would be his "last car". ( It was. :( )

OTOH, it is good to see all those 80+ year olds scampering around the campground! :)

Hi,

I think this comes down to cost. How much are 2 300 amp-hours? How much are 4 100 amp-hours?

I'm 71. I plan to RV for ten more years. Li do not make financial sense for me as I am no longer full time. Not to mention cold weather use where I am often well below -20 C.