Hi all

My portable power supply recently gave up the ghost and instead of throwing everything away I thought I would turn it into a diy project. And I would appreciate some advice.

Please keep in mind that I am a complete novice...

I’m pretty sure it was one (or more) of the cells in the battery pack that failed  and it looks like the bms is gone as well.

So my first questions are as follows:

1. Is it worth keeping the remaining working parts for a diy build

2. Is it possible to replace the BMS with something that can be sourced locally?

3. Can I change the battery type to LiFePo4

4. Is it possible to create a ‘removeable’ battery pack so I can add more packs in time?

5. Is there someone you can recommend to help put together such a battery pack? I only have very basic soldering skills and I also read that you can’t solder cells together and need to use a specific process / machine for doing that.

 

I will post pics of what I have as soon as possible...

Good day markusRoot

without knowing any details of the power station you mentioned here is my answers.

1. yes, but it will be a lot less hassle and cheaper to just build a new battery pack for your power station(or repair the current one)

2. yes it wil be, check electroman, bid or buy, ect ect

3. maybe, it depends on the power stations charging profile and battery voltage, if it has a 24v (7s NMC) battery then a 24v (8s lifepo4) will work fine, also for 48v (13s NMC or 14s NMC) to replace with a 15s or 16s lifepo4 battery configuration. the S stand for the amount of cells connected in series to achieve a certain overall voltage.

4. depends on the build of the power station, but it should be possible. what I will do in your situation is install a xt60,xt90 or A anderson plug(depends on the max amp drawn from battery will determine the plug to use) that is connected to the internal battery so that you can add external packs in parallel with the internal one(plug and play, just dont connect a full external with a empty internal batery, the inrush current can and probably will damage your bms/cells 

5 all you need to build battery packs is a spotwelder, nickel strips, cells, bms and some insulating material and GOOGLE, spotwelder for lithium batteries is less than R800 use 

whichever route you follow with your powerstaion just remember to have fun, be safe and learn, in the modern times we live in we totally forgot the immense feeling of accomplishment when something we build/repaired/modified ourselves successfully, is put to use ever day and becomes a necessity in your day to day life to offset a curveball(loadshedding) that life threw at you.    

I have added a few pics to this folder:

 

https://www.dropbox.com/scl/fo/dwma3r5s6i1uxpd9ma49g/h?rlkey=jnydnra6pifcsyoaelco0pgvm&dl=0

 

The unit was a Yoobao EN300WLPD 72000mAh PD Quick Charging Power Station

Thanks @stefan44 - I appreciate your quick response. I think the images I posted above will answer some of your questions - the old cells are all 3.2 V 6000mAh - I won't be able to tell you the total voltage though - (again, maybe the pics will help you with that).

I will go through your answers a bit more closely when I get a chance.

Thanks,

M

3.2v cells are lifepo4, 3.7v cells is other lithium chemistries commonly referred to as NMC.

I will have a look at the pics later tonight when I'm home.

found this teardown video: 

it is a 12.8v 4s lifepo4 battery, with 3 cells in parallel to make a 12.8v 18Ah lifepo4 battery.

the cells is 32700 or 32650 lifepo4, they are available from electroman not sure of other suppliers of these 

the BMS is propriety to the unit, will not get the same bms after market, but you should be able to get a similar one.