Super Cheap Lithium Batteries (LiFePo4)

[sande005]

OK, I'm just going to ask. What is this .5C 1C thing please?

"C" is a rating of how "fast" one can charge/discharge. 1 C is the capacity of the battery in 1 hour. So charging at "1 C" means going from fully discharged to full in one hour. A 100 amp battery would need a charge rate of 100 amps to do that. A 50 amp would need 50 amps, etc. (In reality it takes somewhat longer).
Back in the day, old Nickel Cadmium batteries, for example, could not be charged faster than 1/10th C - 10 hrs, or in reality overnight. Any more would damage them.
I have some small versions of what we use in our campers that are rated to take a charge at 4C - meaning 15 minutes! But even if the camper batteries were so rated, it might be hard to find a 400 amp charger (!)
Anyway, if told to charge a 100amp battery at .5C, that would mean use 50 amp charging (.5 x Capacity), and it would then take 2 hours.

Same math for discharge - what rate can a battery dump all of its power? Some other lithium chemistries can dump at 60C - all their amps in 1 minute. Yow!

What is used in the camper is actually way over qualified in many cases. They can routinely be charged in an hour, and discharged fully in an hour with no harm at all. The issue comes in having enough charging power (external/solar) to do that and having wiring heavy enough to handle such large amounts of current.

[billriley777]

I was surfing on Amazon today and I came across a Super Cheap 100ah Lithium battery. The batteries ship from US and Canada warehouses so you don't have to wait months for them to arrive from China.

The Price is $239 + 40 shipping (you may save some shipping cost by buying multiple batteries).

It does not appear that these batteries have cold weather protection, however if you don't camp in cold weather, or are going to install them inside these should work well.

Here is the Link:

https://www.amazon.com/FEENCE-LiFePO...%2C127&sr=1-33

PS: Let us know if you buy any of these and how well they work for you.

I think you can get a really good cheep Lithium battery but be careful. Weize brand has both low and high temp protection and has been pretty well reviewed. There are others but they typically cost considerably more.

[jcschultz01]

I looked these up and you cannot charge them below 32F!!!
I live in MN and that would be a problem.

Anyone with cold temp experience?

[SolarPoweredRV]

I looked these up and you cannot charge them below 32F!!!
I live in MN and that would be a problem.

Anyone with cold temp experience?

Yes, that is one of the limitations of LiFePo4 batteries, they can't be charged below 32 degrees, however, you can discharge them below 32 degrees. This only becomes a limitation if you actually camp in cold weather, or you have a Solar system that could possibly charge your batteries when the temps are at, or below, 32 degrees while your camper is in storage. If you are just storing the batteries they can be stored inside the camper (or on the tongue) in the cold, just read your owners manual to ensure that they don't experience temps below the maximum allowed.

There are two ways to combat the "no charge below 32 degree" limitation: one, you can install the batteries inside a heated space within your coach (most common for 5th wheels is a heated hold area, for travel trailers the most common heated area is underneath the dinning table benches or bed), two, you can install a thermostatically controlled heating pad that can keep the battery temps above 32 degrees.

There are also batteries that have internal heating elements that automatically keep the batteries above freezing.

On my system, I installed the batteries inside the heated hold (under the steps leading to the bedroom), additionally, I configured my system to prevent charging below ~ 34 degrees. No temperature limitation on discharging below 32 degrees. Note: the 34 degree limitation is a protection against my Solar system charging the batteries while the coach is in storage (I leave my Solar and 12v system active while the coach is stored).

[Redapple63]

Yes, that is one of the limitations of LiFePo4 batteries, they can't be charged below 32 degrees, however, you can discharge them below 32 degrees. This only becomes a limitation if you actually camp in cold weather, or you have a Solar system that could possibly charge your batteries when the temps are at, or below, 32 degrees while your camper is in storage. If you are just storing the batteries they can be stored inside the camper (or on the tongue) in the cold, just read your owners manual to ensure that they don't experience temps below the maximum allowed.

There are two ways to combat the "no charge below 32 degree" limitation: one, you can install the batteries inside a heated space within your coach (most common for 5th wheels is a heated hold area, for travel trailers the most common heated area is underneath the dinning table benches or bed), two, you can install a thermostatically controlled heating pad that can keep the battery temps above 32 degrees.

There are also batteries that have internal heating elements that automatically keep the batteries above freezing.

On my system, I installed the batteries inside the heated hold (under the steps leading to the bedroom), additionally, I configured my system to prevent charging below ~ 34 degrees. No temperature limitation on discharging below 32 degrees. Note: the 34 degree limitation is a protection against my Solar system charging the batteries while the coach is in storage (I leave my Solar and 12v system active while the coach is stored).

Yes, I plan on putting mine in the bedroom closet. It’s a very big closet and where the washer/dryer setup would be is where I will put all that stuff. We are not full time, so I will set up the low temp cutoff at 34 or 35 degrees f on my Victron setup.

Bill

[dazcon5]

OK, I'm just going to ask. What is this .5C 1C thing please?

C is the rate of charge/discharge (how many amps over a set time period)

Check out https://diysolarforum.com/members/will-prowse.1/ for a more thorough explination