EXCESS SOLAR POWER DIVERTED.

[Kelvin12]

G'Day All,

Someone mentioned an idea for re-directing excess solar power to their hot water system rather than it being wasted. I have a suburban gas/elect, 22lt. HWS. What happens to the gas if I use the re-directed power, do I manually turn the gas off or I am guessing it wouldn't turn on if the water was at temperature anyhow. I read somewhere, probably in the user manual for the HWS that both 240v and gas can be used at the same time to speed up the heating of required so maybe the gas can be left on and used when the solar is inactive.

Thanks in advance for any ideas.

Dirk

[BruceS]

Depends which model you have Dirk.
I presume it is obviously a gas/240V one?
Does it have remote controls inside your motorhome?
If so it's a similar model to mine.
Yes you can have the gas on at the same time as 240V power although I've never done it.
I'd suggest to 'divert' the excess solar power to your water heater could be done automatically but I'd rather just do it manually if/when the situation arises.
You'd only save a few $$$ of gas anyway. You'd need to make sure your inverter was big enough !!

[Dot]

Ours is a suburban SW6 DEA it says to turn off the gas supply before turning on the 240v supply. Then this sentence, This procedure is necessary so as to prevent 240v element and gas heating from operating simultaneously.

[BruceS]

Yes, they assume you only want to use one source of energy or the other.
If you travel with your gas turned off or your hotwater heater (gas) turned off & the water is a bit cold and you pull up a bit late it can be very helpful to turn on both 240V as well as gas to very quickly heat up the water for a shower or to do the dishes etc.
It won't hurt anything.
In Dirk's example I'd suggest he 'burn up' the excess power by feeding it into the batteries and then using it through an inverter to the 240V hotwater unit.
I, personally, couldn't be bothered. Once I get lithium batteries I most definitely will look at it though. Why not?
I just looked up my model.
It's a 22.6 liters(sic)
Model SW6DEA
240V element is 1440 Watts (6Amp)

[nut17]

Over the summer when we have a surplus of solar I will run the fridge on 230v from the solar. The fridge is a 184lt Dometic with automatic energy sensing so as soon as the 230v is available to it, the gas function automatically shuts down. The inverter draws about 35 Amps to run the fridge and the solar will (from now till April) supply around 20 Amps. We can often run the fridge for 5 - 6 hours each day and still have the battery full again before sundown.

Our van is now wired so that when the inverter is switched on the whole van 230v system is automatically switched to inverter power. Just need to remember to switch off the battery charger and electric HWS and manually switch the fridge to gas when needed.

Cheers Chris

[Kelvin12]

HWS is the SW6DEA model. Remote switch up inside the bus. Inverter is a Gen Power 24v 3000-9000w. Doesn't sound like there is a real lot of benefit from the sounds of it.

Dirk

[dapope]

Thats a good sized inverter, similar to ours, if you are wired right, you should be just able to switch that on and heat the water from it, its one gas run you wont have to have. I am guessing you have the batteries to match

[Kelvin12]

I'll probably wire/pipe it for both at the moment. I wound up going for AGM's, (2 X 280AH). So will probably just use it via the inverter and go gas when the suns gone for a few days. Guess its just a, "see how it goes" thing when we are on the road and see how our power usage.

Dirk

[BruceS]

Dirk when you say "remote switch up inside the bus", does it have the square with a switch & a light on it ONLY?
Is there also a 240V on/off switch there near it as well or at the switchboard?
When I bought my MH that switch was unmarked are on the main switchboard area. Took me some tracing & testing to track it down as the 240V heater switch.
I've now put that right alongside the 12V gas on/off switch & light.
If you wished to put in a 240V switch over you'd want it after that switch I reckon. (Manual switchover)
TIP: if that 12V light comes on & stays on..... you have a gas problem. (not turned on, out of gas, etc)
It'll retry to light again in 30 seconds or so. on & on & on etc
PS. run a wire from the inverter back to there while you're building Dirk. (if not too late!)

[Kelvin12]

Bruce,

The switch I mentioned up inside is the white square on, "on-off" with a red reset button. I haven't fitted or wired this switch in, (next week is some wiring day) From memory this is the gas switch without digging out the manual. It wires into the heater control unit at the water tank. I think this is the switch, (below) that I'll need to connect the 240v side of the heater.
http://caravansplus.com.au/catalog/prod ... s_id=12223

Dirk