I thought the OP's model had a blown air fan .. that uses about 2 amps..I have one ! Whilst the unit user a few amps to (about 4-5 ) to heat the glow plug on start up, It's pretty much self sustaining after that.
If your getting numerous flashes with fully charged batteries you have a problem and need to decipher the flashing code which is in the user manual.
I would advise calling Webasto and they will confirm how much drain is taken from the battery on start up and may advise on the flashing you are witnessing.
I've had mine now for 3.1/2 years , have never had it serviced and it's quiet as a kitten and a superb bit of kit. I run in for a minimum of 1 hour per month to keep everything in good working order.
I have never had a problem with running from the batteries alone, which I do quite often.
my mistake..I have a webasto water and warm air heater
It was already there Jim!RH100 was that a typo ? can't seem to find it.. but
found the pdf data sheet for the RHA 100 .. ?
amps are as follows..
Current input at 12V Summer mode < 1 A
Winter mode, heat and hot water 0.5 ~ 7 A
Stand-by 0.001 A
hope that helps..
Workshop manual now in resources
Hi Jimyou're welcome..
back to your amps.. just be aware, according to the manual, it uses 7 amps blowing hot air.. seems a lot .. but that's what it says.
Our average draw during a ski trip for all our 12 volt system is about 4 amps.thanks.. so my first guess was close to the mark.. cheers