View Full Version : Waeco coolpower battery pack to lithium

31st October 2021, 05:30 PM
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 ?

1st November 2021, 11:38 AM
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?

1st November 2021, 11:44 AM
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.

1st November 2021, 12:03 PM
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.