Solar with Lithium Battery

BFL13 wrote:
Yes, change your solar controller settings so it won't do more than 14.6v, and kill any temp comp for the same reason--nothing above 14.6v ever. No "equalize".

The sun won't shine any brighter by changing to LFP from your FLA so ignore all claims about "faster charging" with solar if only you swapped to LFP.

In the same way, a 55 amp converter will not do more than 55 amps either if you swap to LFP. Engage brain before believing the advertising! :(

You will get more usable AH but not twice as many. From a 100AH batt you will get 80 instead of 50 by following the guidelines for each type.
(20-100 vs 50-100)

Watch out for high temp limits on the LFP since you say Pueblo it might get hot there. Also low temp limits at night?

To go camping off-grid you need more than 100AH or be a tent camper, so that means you will need two of those very expensive LFPs, not just one. That also means your one batt now is not enough. Get your wallet out for a second one of whichever you choose.

A 100w panel will help a little but not much. 200w can do a useful day's work.

Now the good news! :) LFP works well with solar, because you don't have to get back to 100% SOC every day. Solar can kill FLAs for this reason, that the sun goes down before the batts get truly full, which eventually kills them from sulphation. No worries about that with LFPs (or SiO2 for that matter).

Also Battle Born is not the only pebble on the beach.

Faster charging is true since there is no absorption phase, just bulk.

Since the op went with a battle born they do get 99ah usable. Someone cut one up and found they built the 20% into the number of cells. So they actually have 120ah of cells inside.

I agree 200w would be better but you can always give it a try and add if needed.

HMS Beagle wrote:
100W is a little light but not nothing. I have 200W and without any measures to conserve electricity (refer on, furnace on, lights on, computer charging), I can camp indefinitely with no other charge source. By 10 or 11 AM the batteries are recharged and the controller has switched to float. With 100W it would be mid afternoon. Obviously if you park in the deep shade, things are different.

I live in Colorado we get ~ 300 days of sunshine a year. I'm only looking to be off grid 3-4 days. I also have a Predator 2000 watt generator in a pinch. I bought the generator to run the A/C which works fine as long as the microwave is off and refrigerator is on propane.

What I'd like to run for a few days would be MUST have: Indoor LED lights, pumps for water, fans and occasional charging for phones/iPads. Nice to have: TV, Stereo, Awning Lights.

The carbon monoxide detectors always stay on along with the Stereo backlight and TV LED.

I appreciate all the posts.

I have 100W on the roof and a portable 100W panel I move around to get max solar. I can't remember the last time I had to use my Honda EU2000i.

I don't have a microwave or TV but I do have LED lights, radio, pumps, fans, phone charging, furnace, etc. I have two 100AH SLA batteries and this setup works well for me.

"Faster charging is true since there is no absorption phase, just bulk."

That can make for significant gen time savings using higher amp chargers, but is fairly meaningless with low amp solar charging, since Bulk lasts into the low 90s SOC with FLAs too at low charging rates.

However, the OP is over 21, and it is his money.

BFL13 wrote:


You will get more usable AH but not twice as many. From a 100AH batt you will get 80 instead of 50 by following the guidelines for each type.
(20-100 vs 50-100)

I thought you learned from the other conversation battleborn advertises 100ah of usable energy as do most of them. so in that case he will get 100 usable ah

Steve

There is a difference between what they say you "can" do and what they say you "ought to" do. Here is a BB guy on that--some other things to wade through but it is all there.

https://www.solacity.com/how-to-keep-lifepo4-lithium-ion-batteries-happy/

BFL13 wrote:
There is a difference between what they say you "can" do and what they say you "ought to" do. Here is a BB guy on that--some other things to wade through but it is all there.

https://www.solacity.com/how-to-keep-lifepo4-lithium-ion-batteries-happy/

Don't understand. This is from the article link you posted.

"We are moving on to cycle life. It has become common to get thousands of cycles, even at a full 100% charge-discharge cycle, out of lithium-ion batteries. "

From BFL13's link:

"There is more to calendar life and how quickly a LiFePO4 battery will age: State-Of-Charge has something to do with it as well. While high temperatures are bad, these batteries really, really do not like to sit at 0% SOC and very high temperatures! Also bad, though not quite as bad as 0% SOC, is for them to sit at 100% SOC and high temperatures. Very low temperatures have less of an effect. As we discussed, you cannot (and the BMS will not let you) charge LFP batteries below freezing. As it turns out, discharging them below freezing, while possible, does have an accelerated effect on aging as well. Nowhere near as bad as letting your battery sit at a high temperature, but if you are going to subject your battery to freezing temperatures it is better to do so while it is neither charging nor discharging, and with some gas in the tank (though not a full tank). In a more general sense, it is better to put away these batteries at around 50% – 60% SOC if they need longer-term storage.

Melted battery

If you really want to know, what happens when a lithium-ion battery gets charged below freezing is that metallic lithium is deposited on the negative (carbon) electrode. Not in a nice way either, it grows in sharp, needle-like structures, that eventually puncture the membrane and short out the battery (leading to a spectacular Rapid Unscheduled Disassembly Event as NASA calls it, involving smoke, extreme heat, and quite possibly flames as well). Lucky for us, this is something the BMS prevents from happening."

So if you have solar--turn it off during storage. I don't like that.

This is the summary from the article:

"To sum up, for long and happy LFP battery life, in order of importance, you should be mindful of the following:

Keep the battery temperature under 45 Centigrade (under 30C if possible) – This is by far the most important!

Keep charge and discharge currents under 0.5C (0.2C preferred)

Keep battery temperature above 0 Centigrade (32 f) when discharging if possible – This, and everything below, is nowhere near as important as the first two

Do not cycle below 10% – 15% SOC unless you really need to

Do not float the battery at 100% SOC if possible

Do not charge to 100% SOC if you do not need it"

Here is some honest advertising by Relion LFP

"More Usable Capacity 25-50% more capacity than lead-acid equivalent"

The OP wants to camp off grid in a TC for a few days where he runs a few things but not the furnace or bigger inverter loads, so he seems to think one 100AH battery will be enough as long as he has enough solar to keep up. With furnace and the usual things, it takes one battery per day.

He could do his loads with two FLAs and "enough" solar. He is hoping the one LFP will do it, being like 1 and 1/2 batts, which it might with no furnace time.

The money side of things is obvious and up to the OP for what is "worth it" .

EDIT--"enough solar" is the same for either battery bank size. IMO he will need 200w or more and 100w is not enough. On my budget, YMMV, I would get more solar with the money I saved from getting FLA instead of LFP. But I am not the OP!