Powering caravan pumps and lights

Submitted: Sunday, Mar 20, 2005 at 20:15
ThreadID: 21378 Views:3301 Replies:3 FollowUps:1
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I have a Golf Tourer with shower/toilet with 12v pumps through a 240/12 transformer. For roadside camping what is the simplest and cheapest way of powering the pumps and lights apart from a generator (which I have but prefer not to use), for, say, about 2 days. Would a deep cycle battery about 100 or so AH with a close linked inverter of say, 150w, with a short lead into the external 240v inlet work OK and provide power to the shower/toilet/sink pumps and a light?
Comments will be appreciated.
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Reply By: Redback - Sunday, Mar 20, 2005 at 20:30

Sunday, Mar 20, 2005 at 20:30
It will all depend on the power draw of all of these items, (ie) our lights only draw 1AH and our pump is only used intermitently, can't comment on the toilet as our shovel is not electric !!!! anyway we have a 75AH deepcycle battery and run 3 lights the pump and the laptop for up to 10 days without charging, if the battery does get low we used to charge it via an inverter from the car (running of coarse).

But we have 12 and 240v lights but only use the 240v lights when we are at a caravan park with 240v access or any other powered site.

Sorry didn't really answer your question did i, aaahhh no if your items are 240v but yes if the're 12v!! the inverter would draw too much power trying to cope with all these 240v items.


AnswerID: 103189

Reply By: Member - Rob J (WA) - Monday, Mar 21, 2005 at 01:37

Monday, Mar 21, 2005 at 01:37
I'll see if I can help by telling you what my new Jayco van has and go from there.
12v lights, pump, toilet, 12v plug for tv, gas and 240 hot water, 3 way fridge, gas and 240 hotplates and 240 oven don't think I've forgotten anything.
There is a battery under the bed that is charged from the vehicle, had to have heavier wiring on vehicle and van.
when the sparkie tested the voltage at the battery with the engine running at approx 1500 revs it was 13.2 so on a decent run the battery would charge even better.
Friends who have a similar Jayco say they get about 5 nights worth of lights and other 12v gear before they need to charge the battery. He doesn't charge from the vehicle, he has a charger fitted and needs to plug that into mains to charge.
By the way, the auto electrician said no need to go deep cycle, a normal sealed battery would do, his words.
If this is any help great, as this is all new to me.
Last van I took a genny, and ran the fridge on gas.
All these new gadgets, I think I'll still pack a gas light just in case.
All the best
AnswerID: 103240

Follow Up By: Billv - Monday, Mar 21, 2005 at 09:34

Monday, Mar 21, 2005 at 09:34
Many thanks. Rob, presumably your new Jayco has a transformer to power the pumps (shower, toilet and sink) so the important point is that clearly your battery is sufficient to power the pumps, apart from lights that is. I can't get a good look at the tranformer to see if it says what it's draw is. So perhaps my idea of a battery, inverter and lead to the 240v inlet should work, providing I don't go silly and put a heavy load on it. Any further comments from anyone? But again, many thanks.
FollowupID: 360846

Reply By: Doc - Monday, Mar 21, 2005 at 22:19

Monday, Mar 21, 2005 at 22:19
Do the pumps run off 12 V AC or 12 V DC - ie is there just a transformer, or is it a DC power supply? Assuming they are DC, it would seem to be double-dipping to convert from 12 V DC (battery) to 240 V AC (Inverter) then back to 12 V DC (Transformer / Power Supply. Each of these devices will be somewhat less than 100% efficient, meaning that power is lost (generally as heat), so you could well end up using say 50W of power to run a 30W pump (I just made those figures up, so no need to tell me they are wrong). Why not consider having a change-over switch or relay between the transformer (power supply) and the load (pumps and lights) so that you can choose to run from 240V AC or the battery, and when the battery is selected then the loads run directly off the battery's 12 V DC.
AnswerID: 103380

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