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Old Apr 23rd, 2018, 11:50   #5
canis
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Last Online: Oct 13th, 2023 05:46
Join Date: Apr 2010
Location: Chadderton, Oldham
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Quote:
Originally Posted by eternal optimist View Post
I wonder if that's true or not. There ought to be enough 'headroom' in the car's charging system to top up a caravan's battery whilst the car's on the move. It's no different in reality to a split charge system used in a mobile home
I think it's down to the length of wire, the wire has impedance, so the available voltage at the caravan end is lower. Too low to reach a full charge, although I'll accept that with a large enough battery 80% would be quite useable.

Having said that, the source was an online webpage whose description of ohms law and wire impedance was true but their javascript calculator was wildly inaccurate, and made me look a complete @rse when I quoted it. Their maths might be rubbish, but the idea is sound; Longer wire means more impedance overall, more impedance means less volts. I think. :-/

Quote:
Originally Posted by eternal optimist View Post
The energy wouldn't come for 'free'; the additional drag created by the alternator in charging the battery would have to be paid for in diesel/petrol by the car dragging the caravan in the first place; in addition to the cost of the alternator and control gear on the caravan.
Haha! You're quite right, energy is not free. But the energy has to be paid for in fuel no matter how it gets there, and you'd be suprised how much drag an alternator working hard puts on an engine. I've no figures on the subject, but you've probably noticed the tick-over speed drop when you couple a flat battery by jump leads.

Quote:
Originally Posted by ksmi View Post
does any body use Solar panels?
A lot of people use solar these days. It's still rather expensive to cover a van roof, and out of my lowly budget, but it's certainly cheaper than it used to be. I would imagine on a sunny summer holiday solar would give a significant boost to a battery.

Quote:
Originally Posted by 37 RUBY View Post
So many ideas but then when I think about how the uk caravan industry is hell bent on building leaky lightweight vans then the less electrics inside the better.
Yes, they do seem to emply a strange construction method, which leads me to my next question; Why don't them make them out of ABS?

Erm, anyone want to go into business with me? I've suddenly become the next Dyson, sort of, HAHA!
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