does anyone know the voltage draw on start up on a 9kw unit?,i'm about to choose a split charge relay but need to choose one which suits the webasto(if you have one you'll know what i mean)tia
Surely the start up power is irrelevent , your battery will only take a charge at a certain rate , depending on battery .
True, but the likes of Ionic usually provide a separate leisure battery (around 110 amph) for their diesel heaters.
I don't know the exact answer to your question, but my Eberspatcher Airtronic draws spikes of up to 18 amps on startup, but it not continuous. Its also over a short period of time. Once its fired up it draws about 2.5 amps on full throttle and about 1.8 amps on reduced mode. I recon overall it probably draws around the same current as a single Shurflo pump.
I think the problem with hydronic diesel heaters in our industry is the stop start they they have to deal with. So over a relatively short period of time a 110 amp leisure battery could be flat if not supplementary charged.
My advice is to get a heavy duty VSR. The one I have on my van is similar to the 140 amp Durite model with 75 amp cables. I've seen my alternator push 20 amps into my 110 amph leisure battery after a heavy day but with a few minutes it drops to about 10/11 amps and then drops further to around 7/8 amps.
As I've said before, we do very little mileage so I charge my leisure battery every 2nd night in summer and every night in winter. I plug the charger in at the same time I put the heater on.
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