Cordless lawn mower briefly starts then cuts out
I have had 5+ batteries brought to me that show full charge to no charge but do similar or slightly less.
In all of them they had been heavily discharged according to the owners.
All of them had melted a solder joint connecting to the battery pack. I was able to reflow the solder and save the packs in all of the cases.
2 of them showed no charge but it was the same as the others that showed full charge once properly connected they worked fine.
note these were all OEM battery packs and from 2 different manufacturers so it’s not an aftermarket issue. I would check the internal contacts first unless the mower has other troubleshooting guides like an unbalanced blade that shuts down for safety or an excessive current because of built up grass.