Lithium LiFePo4 Batteries

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MoInEd

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Joined
May 27, 2020
Posts
106
Location
Edmonton, AB
Still don't understand what the "problem" is this person has and why s/he member is deraling this thread (that I started).
 

Unanchored

Member
Joined
Dec 12, 2021
Posts
15
Location
Los Angeles California
MoinEd Please accept my most sincere apologies I do not understand how this whole thing started but since I bought this battery I received inquires ,questions and whatnot So I simply went ahead and answered But not once I meant to override your blog once again Im sorry oh by the way since you didn't know if it was a female or male . I'm a good ol male
 

Unanchored

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Joined
Dec 12, 2021
Posts
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Location
Los Angeles California
In my opinion, you obviously have a ways to go in learning the ins and out of LFP batteries. 11V cutoff (2.75V per cell) is a safe number for low voltage cutoff, and in fact there are lots of folks in the DIY build your own battery world that will use that number and even a bit higher. The hard bottom for a LFP battery is 2.5V per cell or 10V for a common 12V battery. The 2.75V setting gives you some "cushion" if you choose to run the battery down to near discharge. When I built my battery from four 302AH cells and got ready to test it for capacity, I set the BMS low cutoff at 2.55V per cell (10.2V battery).....I really had no desire to take it all the way to the bottom for testing purposes. Once my test was complete, I raised the LVC up to 2.6V per cell or 10.4V for the battery. And on the charging issue of 13.5V....if that is all you got it to, I would be looking at the charger as the source of problems OR the amount of time you had the charger on and trying to charge it....unless you have a cell that is hitting the high cutoff (3.65V) on it's way up and before the other cells. In that case, you likely need to do a top balance on the battery. An individual LFP cell is considered to be charge to right at 100% when it's voltage is at 3.45V.....which is 13.8V for the battery. Using higher voltages to charge the battery, like the typical 14.6V just speeds the process of charging along vs. using a 13.8 voltage
Wow!! well thanks a billion! This information was a very great learning path. Thank you for your kindness of explaining the amps and volts individually I was very surprised to place the battery to charge and it went up in no time I have two battery chargers, and one of them doesn't work with this type of battery at all . The solar panels charge controller it's a 30 amps Sun Force . and it has a button for the different types of batteries perhaps that's my problem there cause it has the Gel type and the other one it's Lead so Thanks for the heads up
 

xrated

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Joined
Oct 24, 2016
Posts
1,193
Location
"Murvil", E. TN.
Wow!! well thanks a billion! This information was a very great learning path. Thank you for your kindness of explaining the amps and volts individually I was very surprised to place the battery to charge and it went up in no time I have two battery chargers, and one of them doesn't work with this type of battery at all . The solar panels charge controller it's a 30 amps Sun Force . and it has a button for the different types of batteries perhaps that's my problem there cause it has the Gel type and the other one it's Lead so Thanks for the heads up
Glad I could help a little. A year ago, I knew absolutely nothing...zero...zilch about LFP batteries. I decided that I was going to need a battery upgrade for my future project of modding my Norcold fridge to a 12VDC twin compressor unit, which would need more battery than I had. So I dug in and pretty much went to work learning what I could and what I needed to be successful when I got ready to build my battery. The whole project went very well and I'm happy to be able to pass along info when I can.
 

MoInEd

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Joined
May 27, 2020
Posts
106
Location
Edmonton, AB
I tested the batteries today. For a 100amp pack it gave 1280WH before the voltage dropped to 10.5V at which point I stopped. I think this is pretty good and using the two packs at 200amp it should last more than the lead-acid batteries I had.lifepo4.jpg
 

dieseltruckdriver

New member
Joined
Jun 24, 2022
Posts
3
Location
Black Hills, South Dakota
Wow!! well thanks a billion! This information was a very great learning path. Thank you for your kindness of explaining the amps and volts individually I was very surprised to place the battery to charge and it went up in no time I have two battery chargers, and one of them doesn't work with this type of battery at all . The solar panels charge controller it's a 30 amps Sun Force . and it has a button for the different types of batteries perhaps that's my problem there cause it has the Gel type and the other one it's Lead so Thanks for the heads up
I went back and reread your posts in this thread, and you have never mentioned anything at all about your solar panels. How many watts are they and how many of them do you have? That can make all the difference in charging your battery.

You stated you have a 30 amp solar charge controller, but if you only have one 100 watt panel, you will be lucky to get 5 amps out of it. That would not recharge your battery and that would be on you, not the battery you purchased. Common rule of thumb is 1 watt of solar panel for every amp hour of battery. I have double that on my 5th wheel and I think that is barely adequate. I also don't have LiFePo4 batteries.

I am not trying to make fun of you or anything like that, I am just not so sure that you understand everything involved and am trying to help. I am new here and don't know if there is a place to see the equipment you have, if there is I don't know about it.
 

Unanchored

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Joined
Dec 12, 2021
Posts
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Location
Los Angeles California
I went back and reread your posts in this thread, and you have never mentioned anything at all about your solar panels. How many watts are they and how many of them do you have? That can make all the difference in charging your battery.

You stated you have a 30 amp solar charge controller, but if you only have one 100 watt panel, you will be lucky to get 5 amps out of it. That would not recharge your battery and that would be on you, not the battery you purchased. Common rule of thumb is 1 watt of solar panel for every amp hour of battery. I have double that on my 5th wheel and I think that is barely adequate. I also don't have LiFePo4 batteries.

I am not trying to make fun of you or anything like that, I am just not so sure that you understand everything involved and am trying to help. I am new here and don't know if there is a place to see the equipment you have, if there is I don't know about it.
Diesel Truck Driver ; I appreciate your modesty but it takes a whole lot more more for me to take offense I never felt like ,you were making fun of my naive ways You joined a great group of Guys that they can help out if you ask the right question I never read anything negative I don't think a wise guy or some smart ass person will fit in this forum I don't think that there's such a thing as placing the the type of system with photos and detail every person has their own set up for their own RV I was following a blog about their own transportation like the type of RV if it's a trailer or on a fifth wheel or one that is big as a Greyhound These guys are down to the core the fuel consumption vs. a class C RV whereas you get a queen size bed over head an older model vs a newer model So it was very instructional I think if you wanted to see the system set you will need to upload some files I don't have 100wWatts System I'm looking to have at least 300 watts system so I have one @ 40vw.and one at 100.w .o I'm gonna get rid of the 40 wats and get Two one hundred or one at 200 watts but then I learned that, Need to add whatever is gonna be using power how many flat screen TV.s the size of the fridge the lights Once is all added up Then you know that size of current it will take to get the proper size of panels to accommodate the needs
 

dieseltruckdriver

New member
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Jun 24, 2022
Posts
3
Location
Black Hills, South Dakota
300 watts will do better for sure. Your current panels will probably give you 25 amp hours if conditions are perfect. That's just a rough guess based on what my panels do.

We typically use about 50 amp hours a night, but we don't do much to conserve other than trying to minimize the furnace use.

MoInEd, sorry about the continued hijack of your thread.
 

MoInEd

Well-known member
Joined
May 27, 2020
Posts
106
Location
Edmonton, AB
300 watts will do better for sure. Your current panels will probably give you 25 amp hours if conditions are perfect. That's just a rough guess based on what my panels do.

We typically use about 50 amp hours a night, but we don't do much to conserve other than trying to minimize the furnace use.

MoInEd, sorry about the continued hijack of your thread.
Looks like he is getting somewhere at least, which is good.

We have 300w panels and on sunny days they provide about 200-250W of power which is usually more than enough to keep the batteries fully charged.
 
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