[RWebb]

Thanks - I see a 3 stage one that appears to be something Stanley, B&D etc. slap their labels on...

https://www.walmart.com/ip/STANLEY-15-Amp-Battery-Charger-with-40-Amp-Engine-Start-BC15BS/38243759


I'm not sure why the smaller units aren't working, but capacity seems to be the only idea I can come up with.