Lithium iron phosphate hot climates

moltensurf · October 2020

I have a ram pro master I am fitting out with solar. I am trying to keep the weight down in my vehicle and would like to use lithium iron phosphate batteries. I travel a lot in hotter climates, and live in southern Texas. My van is well insulated, but I hear the lithium batteries do not like heat, and work better in cooler climates. Does anyone use lithium batteries to travel in hot climates? Should I go with another type of battery bank?

Dave Angelini · October 2020

I assume you are not talking about a starting battery. You should look at what the battery brand says about life in an RV. That is what you have right? Also search the brand for RV people using that battery over time. You want old users in the southwest. I would only look at LFP chemistry (lithium iron phosphate) as NMC used in cars is much more dangerous.

In general LFP batteries get the longest life at temperatures that humans like. Many measure temp/cycles for warranty.
Since it is so easy/cheap to buy flooded batteries at places like costco and all the others, I would look at price before lithium.

Lithium batteries do not like cold and that is the main reason they measure temp. If you charge on below 32F you can easily kill it.
Yes, and just one time!

mcgivor · October 2020

Welcome to the forum @moltensurf

Quite the contrary, LiFePo4 are more comfortable in higher temperatures than their lead acid counterparts, for this reason I abandoned lead acid in favor of LiFePo4 as the temperatures where I am rarely drop below the optimal value for lead acid which is 25°C.

Being more in the mid 30°C plus ambient, my observations are that LiFePo4 run cooler, due to their inherent .efficiency being close to 98%, as opposed to 80% for flooded lead acid, which manifest heat over time and have trouble dissapating the heat due to shear mass.

The downside of LiFePo4 is when temperatures drop to freezing 0°C or below. The optimal temperature for LiFePo4 is 30°C, making them suitable in warmer environments, if below freezing not predicted then LiFePo4 is the way to go.

Disclaimer, I've no experience with AGM lead acid but would assume the results would still be In favor of LiFePo4, all things considered.

moltensurf · October 2020

@mcgivor Have you ever traveled into the extreme cold with your batteries. I don’t live in the snow but sometimes go there. Thinking maybe battery bank could be put inside of an ice chest to keep it at a reasonable temperature?

Dave Angelini · October 2020

He is in Thailand I think. It is not just the cold which is why I suggested you pick a battery make and research it. I have had clients damage LFP in high heat. They will withstand it longer than cold. Read the warranty. Due diligence is on you to not just trust what people write here.
The store here on the site sells several LFP that might work for you.

You will be spending up to 4 times what a flooded battery will cost and 3 times what an AGM will cost. You really want to make sure you have the knowledge to make the risk worth the reward. If you are traveling make sure you can get a replacement. Pretty hard to not find a Costco in North America.

moltensurf · October 2020

@Dave Angelini I am pretty handy, and there are lots of resources online to build batteries. I was thinking of perhaps making a battery. I used to live on a sailboat for many years, I ran solar for most of my power. My battery bank was pretty heavy. I had golf cart batteries wired to twelve volts. I had 6 batteries in total.

Dave Angelini · October 2020

Sailed 18,000 miles myself but in those days solar was for satellites. Sounds like a good project for you but you have to insulate well for cold. Good Luck.

mcgivor · October 2020

moltensurf said:

@mcgivor Have you ever traveled into the extreme cold with your batteries. I don’t live in the snow but sometimes go there. Thinking maybe battery bank could be put inside of an ice chest to keep it at a reasonable temperature?

The batteries have never been subject to temperatures below 20°C as I'm in Thailand, the mean average is 27°C but during the months of April and May it's more like 35°C average with highs of 40-50°C.

When using lead acid during the hot months the battery temperature would manifest over time to be at a constant 40°C+, due to the thermal mass and high overnight temperature they were unable to cool. Because FLA batteries are ~80% efficient, 20% of whatever is put into them is wasted as heat in the batteries themselves, adding tu the challenge of high ambient temperatures.

Had experimented with water bath cooling which was successful in itself but attracted animals, including snakes, seeking a drink as it is extremely dry at that time of the year. This added complexity prompted me to look into LiFePo4 as a possible solution, because without cooling FLA show signs of deterioration after about 500 cycles ultimately failing at about 3 years.

The replacement DIY LiFePo4 bank of equal capacity, 400Ah at 24V nominal, was about twice the cost of FLA including the BMS, they have been is service for 2 years without any problems, even during the hot months the battery temperature remains below ambient sometimes by 10°C, because of their inherent efficiency of 98% they don't self heat to the same degree being they have 75% less mass, this allows overnight cooling.

There are other benefits which came as a bonus, they can charge at higher currents without the need for long absorption, discharge at high current without significant voltage drop, tolerate partial states of charge without negative impact, have a larger usable capacity, smaller footprint with less mass, are protected at a cellular level via BMS and are essentially maintenance free.

Well worth the money all things considered since the life expectancy would likely exceed 3 sets of FLA given the environment they are subjected to here, so actually cheaper, time will tell. Lead acid batteries do not like heat, LiFePo4 do not like cold, both work best at 25°C choose what's best for you. Fully intergrated LiFePo4 battery systems with communication are available at higher cost which may be better suited to some.

Plucka · January 2021

I've just spent 3 years travelling in Western Australia where summer temps are regularly high 30C and often over 40C. No problem with lithium batteries but I feel the solar panels didn't like it . Had a noticeable difference in charging for two reasons .-the fridge and freezer ran a lot more in the heat and the other reason i've forgotten [I'm in my late 70's ] AAAhh remember now the inverter fans run constantly.in the heat.

KenMorgan · May 2021

moltensurf said:

@mcgivor Have you ever traveled into the extreme cold with your batteries. I don’t live in the snow but sometimes go there. Thinking maybe battery bank could be put inside of an ice chest to keep it at a reasonable temperature?

I am just building my battery bank and have been researching this very issue due to my location northwest flanks of Fuji are cold and temps drop below zero quite often (-15c).

Your BMS should stop charge and or discharge if the battery is to cold or to hot. The BMS itself protects the battery pack from being charged when too cold or too hot. Make sure to buy a BMS that does this as well. it should have temp sensors that you place over the battery pack at various locations for this. The reasoning for the below explanation is so that I can charge first thing in the morning when its still cold.

The course folks seem to take the most if the pack is not indoors in a warm space is a battery heater... some buy premade units, others build their own. I am building mine. 6mm aluminum plate for the bottom of the battery pack to spread heat evenly. 8 x 25 watt silicone heating pads on two separate heating circuits with separate temp controllers. Unit 2 is a complete backup to the unit 1 just set a few degrees lower so it will kick on if the primary does not. idiot lights for both circuits to show if the circuit has failed. mine will turn on at 5° C and shut off at 8° C. mine is in a stationary setup so I will be using 4" high R value foam to surround the battery bank on all sides, bottom and top. I got most of my ideas for this from a gentleman on youtube who travels in cold country a lot and he built his as a single circuit... I just decided to add a 2nd circuit as a backup. You can set them on a timer so that they do not turn on regardless of temp as discharge temps are safe down to -20 C (at least for mine) that way you do not waste energy heating them when they do not need to be heated as main concern is while charging and we want to get as much solar charging as possible if the battery is kept around 5°C youo can start charging as soon as the sun is up and not have to wait for the pack to warm up (if it even would if outdoors). these inks are for a set of the basic components YMMV.

https://www.amazon.com/gp/product/B08QZ5VRYC/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B075WVPP5Y/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&psc=1

you will also need small relays to go between the controlelrs and the heating pads these will vary depending upon your battery bank voltage. since mine is 48 nominal i had to find (thanks to the forum members who helped find this) a 48VDC relay that had a 12 VDC coil if you are running a 12 volt system, any normal automotive relay will work. if you are running 24, or 48 then you will have to search around a bit to find one compatible.

Lithium iron phosphate hot climates

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