Charge holding, or not.

[Vinci]

Help please. I have two Yuasa batteries, specific engine and leisure ones. Have solar connected to leisure. Webasto heater wasn’t working, but found not faulty (by excellent A C Automotive in Gloucester ), the cause being low power in battery(s)…. Both it turned out. Question is, why are they not holding charge - both down to early 10’s? Both batteries are under guarantee, but supplier (who shall remain nameless until I assess their customer service) wants both out of the van to charge and test. Van is driven daily, probably 250 miles a week. Thanks in advance learned ones.

 

[whodat]

Sounds fair enough for the supplier to ask for them to be out of the van and charged and tested out of the van.
Until you know the batteries are at fault, they aren't under any obligation.

Do that, then get back to us.
As always, do the simple things first - rule them out, then dig deeper.

 

[Kind of Blue]

I would imagine charging the batteries disconnected and leave them a day or so unconnected and then take measurements. It could either be batteries not maintaining voltage or there is a significant drain. No way an expert but I have seen supposedly fully charged batteries fool garage mechanics when in fact the battery was a cell down and just holding charge for a very short while.