diy solar

diy solar

So many new LiFePO4's popping up - How to verify you got a good one

OnTheRoadAgain

Solar Enthusiast
Joined
Feb 22, 2021
Messages
643
Hello,
I just recently ordered a Rebel LiFePO4 100Ah battery and it's scheduled to arrive Wednesday.
Seems there are a number of new ready made LiFePO4's coming on the market.

Since these batteries are sealed and you cannot open them to get to the BMS and cells, I am exploring options for verifying the battery is of good quality and will last.
The choices are overwhelming. So many brands with so many reviews. I ultimately decided to just go for ONE of them. I was going to go SOK but they were unavailable last week. I was going to go AmpereTime, but the price went up. I looked at Chins...to many bad reviews.

Sure it has a 5 year warranty, but that warranty is null and void if the company folds next year.

So the question ultimately becomes....HOW can you check your new battery?

A capacity test is about the only test I know.
Resistance? Is it even possible to test a LiFePO4 battery resistance if you cannot reach the BMS?

I have no reason to doubt Rebel. But as a former famous President once said....."Trust, but verify"
That said, I know full well that if I open it, the warranty is void, they even say so. So Will's way will not work for most of us.
Imagine I open it anyway and find some really crappy cells with wildly varying resistances and discharge rates?
At that point I have no warranty anyway.

Do you avoid totally sealed ready made LiFePO4 batteries for that reason?

As the prices for 100Ah LiFePO4 ready made batteries come down, I would venture a guess that we will see more and more of them sold.
So what if any ways are there to test the quality of these ready built, sealed LiFePO4 batteries?
 
Last edited:
By the time you have them in your possession to test it will already be too late. If you buy junk from a disreputable company you have no recourse.

Better to spend your efforts prior to purchase and buy quality merchandise from a reputable dealer. There are people on here that will help you do that but you have to be asking the right question first.

As someone once said: The disappointment of buying junk lives on long after the joy of getting a good price. (Or something like that)
 
For a product to be sold it will be sold on uniqueness, price, or quality, or a combination of the three.
I believe that most of these batteries are built to a price not a standard, so it's a flip of a coin if you get a good one.
The worst culprits for reducing quality in the name of costs are the established companies.
Snap-On for example. Once synonymous with the best quality made in the USA tools; now:
download (3).jpg

And the very worst offender in my opinion is Aston Martin.
An iconic British sports car now reduced to simply relying on the name to make sales:
Yes, this is an Aston Martin.
download (4).jpg
Sorry for the rant.
 
I get that it's a crap shoot unless you spend top dollar. But I will not be spending $900+ all at once for 100Ah.
I simply can't budget that at this time.
But I "might" spend $500 every 5 years for 100Ah.


Ok, let's say my new 100Ah battery tests out to 110Ah.

Am I golden for the next 5 years ?

If not, what else can be checked (on a sealed battery) to determine it's health and worth ?
 
If I could take the battery apart then could I determine the actual quality ?
If someone has the skills to take a battery apart and test and evaluate the parts, presumably that same person would have the skills to DIY one. Then it boils down to time and personal preferences influencing the value proposition. It all depends on where you are standing. I am retired, have lots of time and love to tinker so the decision is easy for me.
 
Last edited:
I also purchased a rebel 100ah. It has the JBD Bluetooth enabled Bms, so you can get a sense of what each individual cell voltage is without cutting it apart for what it’s worth.

For the gurus out there - is there useful data to be had here with regards to whether your battery/cells are reacting as expected to charge and discharge?

thanks
 
is there useful data to be had here with regards to whether your battery/cells are reacting as expected to charge and discharge?

thanks

Basically you want to see the individual cells stay very close to each other in voltage throughout the charge/discharge cycle.
 
I just got notice this afternoon that Amazon has these in stock

Battery Evo 12V Lithium LiFePO4 150Ah 2 Kwh​

with everything else coming from china and you waiting 2months it's hard not to order a set of these and test them.
 
You need a fortune teller or a time machine to get the answers you are looking for.

You need a fortune teller or a time machine to get the answers you are looking for.

I would venture a guess it would be as easy as identifying the manufacturer and lot....then getting the manufacturer to pill that information. They know.

Oh right...a fortune teller and time machine...now I get it
 
I also purchased a rebel 100ah. It has the JBD Bluetooth enabled Bms, so you can get a sense of what each individual cell voltage is without cutting it apart for what it’s worth.

For the gurus out there - is there useful data to be had here with regards to whether your battery/cells are reacting as expected to charge and discharge?

thanks

How long have you had it and what's your impression so far ?
 
I’ve had it for 2 weeks and boondocked a couple days with the travel trailer. Ran the furnace, and 12v electrics. Haven’t really “stressed” it since this is a low discharge situation and I wasn’t out there long enough to draw down past 50%.

I got the metal case which allowed me to lock it on my tongue this trip until I figure out how much electricity I need and move the wiring into the cargo bay.

the bms is nice; the metal case does seem to drop the range to 15ft when you factor in trailer walls or truck doors.

After it charged up, The battery comes to rest around 13.4v the morning after.

first lithium on the trailer so not much to compare to.

hope this helps
 
Following this thread since the well known good priced units like SOK are out of stock. Has anyone tried the Kilovault Will reviewed?
 
Back
Top