Waeco coolpower battery pack to lithium

[loanrangie]

I picked up a cheap waeco raps 36 portable battery pack with dud batteries, in the short term i'll put some used batteries in but considering repacking it with lithium cells.
Would need to small possibly 18650 ? cells and a suitable BMS, anyone looked at doing similar ?

[cjc_td5]

No, but its a good idea!
I've got one of those battery packs which I've reloaded with AGM batteries at least once. When it dies, Lithium replacements would be a option worth looking at.
I suppose an issue could be recharging it. The old AGM batteries can be just hooked up to the main vehicle system and charged off the alternator. Lithium batteries would require a specific charger to get the correct charge profile etc?

[loanrangie]

Yes, i think one of those buck converters might work for charging and would fit inside the lid quite easily. I'm getting a 40AH AGM for now but will look into a lithium upgrade for when it dies.

[reefmagnet]

A DC-DC converter should work. I recently purchased a small 8A 14.5VDC LFP charging unit from AliExpress that is about the size of a packet of smokes. I purchased it to allow a small outboard's alternator to top up a lithium bank without risking it frying. Haven't used it yet, but on paper these should make excellent LFP chargers at this output voltage.

Having said that, these won't protect from over discharge, so a small BMS may be a better choice if it can be made to fit.

[WacRod]

G'day all, same as most here, picked up a pack on marketplace with jiggered wire on the charge input for next to nothing.
Fixed the problem and used for a while. Have just replaced the agm's with 2x24 ahr ItechWorld.
Now weighs 6.9kg.
Spoke to them about this mod, as their product has a bms, you can charge with any multistage charger that best suits charging volts. I found gel profile is best suited.
Cheers.
Ps. Probably be some nay sayers?

[loanrangie]

G'day all, same as most here, picked up a pack on marketplace with jiggered wire on the charge input for next to nothing.
Fixed the problem and used for a while. Have just replaced the agm's with 2x24 ahr ItechWorld.
Now weighs 6.9kg.
Spoke to them about this mod, as their product has a bms, you can charge with any multistage charger that best suits charging volts. I found gel profile is best suited.
Cheers.
Ps. Probably be some nay sayers?Are they lithium batteries ? Mine is still going strong but heavy.

Just looked them up, wow $199 each is way over capitalising. Could buy a single bigger battery for less, can get a single 40ah on aliexpress with charger for under $60.