Fuse at Leisure Battery

The 20amp fuse next to the leisure battery blew at 7.00a.m. on Tuesday morning in our 10 month old Broadway.Only one small light was on in the van but we had left the heating on, with the fan at ECO, overnight. It was set at 12degrees. We hope to winter in Spain but the idea of having a persistent electrical problem is off putting.Does anyone have any idea why this happened? It was a particularly windy night.

Fuses can just blow! Try replacing it before you drive down to Worcestershire but … a brand new van … perhaps phone the dealer.

A 20A fuse should not just blow! IMO you're right to be concerned.

But it's hard to come up with a convincing reason. Do you have a solar panel? If so, is it reasonable that direct sunlight would have first hit the panel at 07:00? If so, you might be able to come up with a scenario where the smart charging was connected to the vehicle battery, while the leisure battery was discharging overnight, and that the sudden extra input from the solar caused it to switch over to a heavily discharged leisure battery, which took too much current from the charger? But TBH that doesn't sound very believable.

When you replaced the fuse, what state of charge was the leisure battery in?

When we replaced the fuse the leisure battery was reading 11.4.I do have a solar panel but sunrise where we were was after 8a.m.I doubt very much if my dealer would know. Autosleeper told me to replace the fuse but you are right ,a 20A fuse shouldn't blow!

jmmptl wrote:When we replaced the fuse the leisure battery was reading 11.4

That's at the core of the problem, then. 11.4V is verging on dead.

IMO you need to find out why the battery was in such a heavily discharged state.

If your van has a conventional split charge circuit (not sure - current models may have a more sophisticated charging system) then it's quite likely that fuse would have blown anyway as soon as you started the engine with the leisure battery that low - though quite why it happened at 7 am instead you'll probably never know!

Can I ask if the battery is "sealed". If not, what is the electrolyte level? If it's low, you might also check the electrolyte in the engine battery.
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If you are not sited with EHU's, you may be regularly discharging the battery to below 12V. In that case, you might need a larger capacity leisure battery or even a second battery. 
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 Having said so, a 10 month old battery should be holding up,  so definitely get the charger checked.

I wouldn't be too concerned at blowing 1 fuse   2 yes .