How to build a LiFePo4 battery bank.

[StirCrazy]

A lot of people dont have any idea how easy it is to build a DIY LiFePo4 12V battery so I'll post a deicent video of how to do it so people can decide for themselves if it is in there capability.

this video is pretty decient on how to do it, what is missing is some sort of case. the Prismatic cells like to be clamped togeather slightly if you going to be running high currents. I have seen cases made out of wood with threaded rod providing the pressure, and several other ways also.

also I am not a fan of the BMS he uses, there are lot better ones, but he explains he needed the high capacity one to do a torture test on the cells.

so he builds a 280Ah 12V battery in this video, if you need more you could build 2 and then just tereat them like two 12V batterys and run them in parralell, or just build it all in series and do a 24V set up if you want to do the higher voltage systems.

280Ah LFP build

Steve

[StirCrazy]

pianotuna wrote:

StirCrazy wrote:


Ok so why is the video flawed?

From your first post:

this video is pretty decient on how to do it, what is missing is some sort of case. the Prismatic cells like to be clamped togeather slightly if you going to be running high currents. I have seen cases made out of wood with threaded rod providing the pressure, and several other ways also.

also I am not a fan of the BMS he uses, there are lot better ones, but he explains he needed the high capacity one to do a torture test on the cells.

280Ah LFP build

Your words. I find your comments are often flawed. I'm sure you feel the same way about mine.

because he is testing and not building a case you think it is flawed? ill tell you what I'll get a different link for you so you can understand it.

here is a different guy who is spicificly building for an rv. keep in mind shipping prices have come down even more since his videos. he does a build with added redundency which is actualy a neet way to do it.

componants

here is one using premade battery boxes. of course this is going to depnd on the size of cells you get.

another build

Steve

[pianotuna]

StirCrazy wrote:


Ok so why is the video flawed?

From your first post:

this video is pretty decient on how to do it, what is missing is some sort of case. the Prismatic cells like to be clamped togeather slightly if you going to be running high currents. I have seen cases made out of wood with threaded rod providing the pressure, and several other ways also.

also I am not a fan of the BMS he uses, there are lot better ones, but he explains he needed the high capacity one to do a torture test on the cells.

280Ah LFP build

Your words. I find your comments are often flawed. I'm sure you feel the same way about mine.

[StirCrazy]

theoldwizard1 wrote:
For those on a budget, these weed grade B cell and the author did make "studs" to use on the screw in terminals that were not in the best of shape. Cheap fix !

After the build, it was tested successfully to full capacity.

I would recomend making studs for the "A" grade also. the thread depth isnt that deep so when you start hooking stuff up its nice to have that extra lenght so your not striping the top threads out.

Steve

[StirCrazy]

FWC wrote:
The DIY LiFePO4 battery is a great way to go if you are:
(i) somewhat handy and understand the basics of electricity and electronics and
(ii) enjoy a DIY project.

Some useful resources:
LiFePO4 Cells are plentiful and probably cheapest on Alibaba and Xuba seems to be a company with a decent track record:
Shenzen Xuba
They are also available on Amazon:
Amazon 280Ah LiFePO4 Cells

There is well supported and easy to use bluetooth enabled BMS available from Overkill Solar:
Overkill 120A BMS
Also available for much less from the manufacturer:
LLT Power the OEM for Overkill Solar BMS

Good resorses, some of thoes I was going to add later. I dont even think you need to know much about electronics, just have to know how to charge a battery and monitor the voltage for the top ballancing which realy is the hardest thing in the build and thats not rocket sience. when you get down to it if you have all your BMS cell lines with ring crimps already it is about 5 to 10 min to actualy assemble the battery and then depending on your charger the top ballancing would take a bit of time.. but building a case if you want one would be the hardest part. I have seen everything from old tool boxes, to home made wooden boxes used to house them, you can be as elaborate as you like with the casing.

[StirCrazy]

pianotuna wrote:
Why post a flawed video?

If you want a 24 volt battery--then build that. Putting two 12 volts in series with LiFePo4 may cause the battery management system to not work well (or so I have been told by those who are supposed to know)

Ok so why is the video flawed? he shows how to build it the capacity testing is a bonus. if you are building a 24V battery you would buy a 8s BMS instead of a 4s, so it is one 8 cell battery, I guess I should have said that so you wouldnt get confused. or you can build two 12V and put them in parallel and the two BMS wont have an issue.

like you camping in -40 degree weather 99% of the people don't build 24v systems as it requires a lot more specialized equipment and the cost adds up fast, but if you want you can. there are even 16s 48V BMS if you got a system that big but there getting a little pricy like everything else you need when you go to a 48V system with any battery type. but, for 99% of the people a 120amp 4s BMS is what you'll want, you could go biger but do you realy need to drain your battery down in a hour.

the Daly unit he used is good (its the newer ones with bluetooth that have been having some issues) but I personaly wouldn't put one that big on a 280AH 12V battery, I would build two and use 120amp 4s BMS, and yes overkill is one of the good ones as was mentioned above but there are others that are just as good if not better.

Steve

[theoldwizard1]

For those on a budget, these weed grade B cell and the author did make "studs" to use on the screw in terminals that were not in the best of shape. Cheap fix !

After the build, it was tested successfully to full capacity.

[pianotuna]

Why post a flawed video?

If you want a 24 volt battery--then build that. Putting two 12 volts in series with LiFePo4 may cause the battery management system to not work well (or so I have been told by those who are supposed to know)

[FWC]

The DIY LiFePO4 battery is a great way to go if you are:
(i) somewhat handy and understand the basics of electricity and electronics and
(ii) enjoy a DIY project.

Some useful resources:
LiFePO4 Cells are plentiful and probably cheapest on Alibaba and Xuba seems to be a company with a decent track record:
Shenzen Xuba
They are also available on Amazon:
Amazon 280Ah LiFePO4 Cells

There is well supported and easy to use bluetooth enabled BMS available from Overkill Solar:
Overkill 120A BMS
Also available for much less from the manufacturer:
LLT Power the OEM for Overkill Solar BMS