my van won't start when the battery isn't fully charged, or drops to below 300 rpm. The local garage have tried everything to fix it. They are completely baffled. I need to drive it every day to keep battery charged but soon as any charge lost it stops starting. it's a new battery that's in the van. Auto electrics all checked. Everything seems to be fine. It runs great once it has started
Running Rough, Starting & Power Loss
Vital that you have correct battery with cranking amp , especially if it's a diesel. I would get the battery load tested ( even though it's new ) also alternator output .You could also check for any parasitic drain .