heater battery

[Detling]

Currently my Webasto heater is wired via the original (webasto labeled)harness to the domestic bank on the other side of the boat, the wire looks to be about 2.5mm(squared) and is some 6 metres total. This sometimes causes problems in the morning as the volt drop + a 50% charged battery bank is insufficient to start the Webasto (12.2ish volts on the battery terminals 10-12 amp current according to ammeter). I would like to put a new extra battery dedicated to the webaso near the heater so the cable run will be a lot shorter, and the battery volts should be higher in the morning. This battery will be charged via a split charge relay with the domestic bank.

My question is as the battery is only supplying the Webasto and that is allowed to be connected directly to a battery, do I need an isolator switch? or must the split charge relay go via an isolator switch, or can I feed the relay directly from the domestic bank.

[by'eck]

I had similar issue with hot air Webasto on a previous boat. Employing KISS rationale I just ran heavier gauge power cables to replace the equivalent ones in the loom - so much easier than the unnecessary complications of having a separate battery.

[Naughty Cal]

I had similar issue with hot air Webasto on a previous boat. Employing KISS rationale I just ran heavier gauge power cables to replace the equivalent ones in the loom - so much easier than the unnecessary complications of having a separate battery.

^This^

 

Why complicate matters?

[WotEver]

If you're not charging the domestic battery properly now, adding another battery isn't going to fix it.

 

1. Sort out your charging.

2. Fit larger cables.

[Detling]

No real problems with charging just this time of year. Couple hours extra lights, even though LED. tending to stop at 3:30-4:00 and not 5:00pm no real solar charging any way and that has given up by 4:00 not even enough to power the lights etc... the only thing that could be less is the fridge freezer but only if I don't use the solid fuel stove so the living area stays warm, The fridge stays on as the freezer is combined and full, I could keep milk in cratch but no point.

 

Point taken tho fatter cables are cheaper and as the calculator suggests currently about 0.5 volt drop, using 10mm will reduce that to 0.1 volt.

[WotEver]

No real problems with charging just this time of year. Couple hours extra lights, even though LED. tending to stop at 3:30-4:00 and not 5:00pm no real solar charging any way and that has given up by 4:00 not even enough to power the lights etc... the only thing that could be less is the fridge freezer but only if I don't use the solid fuel stove so the living area stays warm, The fridge stays on as the freezer is combined and full, I could keep milk in cratch but no point.

So there IS a problem with charging. You're talking about ways of reducing consumption. "Sort out your charging" means "find another way to charge your batteries fully". Whether that's by running the engine or a generator or a shore line is your choice, but it needs doing.

[Naughty Cal]

So there IS a problem with charging. You're talking about ways of reducing consumption. "Sort out your charging" means "find another way to charge your batteries fully". Whether that's by running the engine or a generator or a shore line is your choice, but it needs doing.

Yes.

 

And by the sounds of it the battery will be shot as well before long