Keeping cab battery topped up with Solar

[BigDean]

Morning all,

I understand most people have a leisure battery, but at this time I have no use for one, so not had one installed.

Whilst my van is a "daily driver", I don't use it daily..... If I don't use it for a few days, the battery is dead :-(

I do have it booked in with VW for testing, but in any event there will be periods of weeks where I don't use the van, so will no doubt encounter a discharged battery if I do nothing.

I have just setup a portable solar panel in the windscreen connected to a Victron MPPT 75/15 which looks like it will give enough power to keep the battery topped up. I have connected it to the battery via the 12v socket on the dash.

My question is on the settings on the Victron. I don't want it screwing up the clever (!) VW battery monitoring, so what settings should I use?

I have it set to "AGM spiral cell" at the moment which shows and absorption voltage of 14.7 and float of 13.8. Do these make sense for the VW standard cab battery?

Currently have the max charge current set to 10A. Would this be better lower?

Any other advice welcome as always.

Thanks
BigDean

 

[yossarian]

What exact battery do you have? Usually the battery manufacturer will have specific charge recommendations.

 

[Pete C]

Our van lasts an easy 4 weeks without needing a charge, so don’t let VW fob you off.

Pete

 

[Pete C]

What power is the solar panel ?
Bear in mind that the tinted screen has a massive effect on the amount of power you will actually get.
I wouldn’t go above 8A on a cigarette lighter type socket.

Pete

 

[BigDean]

What exact battery do you have? Usually the battery manufacturer will have specific charge recommendations.

Its a EFB+ 420A 75A. Not found info so far....

 

[BigDean]

Our van lasts an easy 4 weeks without needing a charge, so don’t let VW fob you off.

Pete

Interesting Pete, thanks for that. I did not realise they would last that long. It makes sense though.....

 

[BigDean]

What power is the solar panel ?
Bear in mind that the tinted screen has a massive effect on the amount of power you will actually get.
I wouldn’t go above 8A on a cigarette lighter type socket.

Pete

It is working fine so far. Battery is nearly full after 3 hours. Could be because the battery is knackered of course.....

I thought cigarette lighter sockets were rated to 10A?

Thanks again.
Dean

 

[Pete C]

It is working fine so far. Battery is nearly full after 3 hours. Could be because the battery is knackered of course.....

I thought cigarette lighter sockets were rated to 10A?

Thanks again.
Dean

They are, but have you felt how hot they get after short usage at that current ?
I wouldn’t want that much current flowing in an unattended vehicle for a long time on a hot day !

Pete

 

[BigDean]

They are, but have you felt how hot they get after short usage at that current ?
I wouldn’t want that much current flowing in an unattended vehicle for a long time on a hot day !

Pete

Fair enough. Have throttled to 8a.

thanks