Speed Control for Fans (cos its ot ere)

[Dubwana]

I'm using 2 Just Kampers Fans in my poptop T25, trouble is they go real fast and kill the leisure battery dead in few hours. Great though when you stop for a few minutes and need to stay a bit cool.

Even so I also have a small battery operated fan, runs of 6 V, (4 batteries) that will run for 10 nights. So I figured I'd try two fans of the same type, re wire then in series so they work together off 12 V and see how long they run off the leisure battery. Same problem they go like crazy, then die off in a few hours.

I know this is not a a problem in the UK where your all looking to warm up just now... but if anyone has any simple suggestions on how to slow down the fans, some sort of speed regulator, so the battery will last, as they do when running on small batteries I'd be very interested to hear! I often go totally wild and the van can sit without running for a week. I don't want to go solar as its just one more thing that can be stolen from the vehicle, nor do I want to start running the vehicle for hours a day, using a generator etc etc, I'm just wondering if anyone has a suggestion for a speed control for the things.

Tx a bundle and apologies in advance for depressing anyone who loves the summer.

Dubwana
Kenya

[Oldiebut goodie]

Try running three in series - they will then be effectively running off 4v - running slower also.

[Dubwana]

That is an interesting idea. I'm wondering though if it could overheat the motors? I know when we get AC power of 160 V instead of 240 the washing machine motor blows... so we use a volt cut off unit... does that apply to 12 Volt as well.

Thanks for the creative thinking.

[Oldiebut goodie]

Shouldn't affect them .You are most probably running at 13v-14v or so anyway which is why the cheapies died. Computer fans are quite good - quiet and low power - if you can get hold of them cheaply out there.
You could always wave your bits of biltong faster for more breeze!

[Dubwana]

Computer fans are a great idea, small, low power, low noise. I'd seem them once when browsing on the internet for fans but hadn't pursued it. Absolutely available here as half the computers are clones. I'm going into the city tomorrow morning so will take a look at what is available. Have you tried them? I don't even know what voltage a computer runs at but I'm can find out tomorrow.

Thanks,

Dubwana

[Oldiebut goodie]

They are 12v - people use them for assisting the ventilation over the backs of fridges. The 120mm ones seem to be quieter than the smaller ones.The 120mm ones draw 0.3A, 80mm draw 0.18A,60mm draw 0.16A. I haven't heard of anyone having problems with coping with the varying voltages in a vehicle.

[Dubwana]

Excellent, thanks. I'll look around tomorrow. Dubwana

[New Kentish Campers]

I guess you could wire a Rheostat into the power line which would raise and lower the voltage; works on the same priciple as a domestic light dimmer switch. I would think Maplins would sell one for a 12v supply, though you could try a domestic 240v one, I would imagine that would work too.