Heater Wiring

[Vandrederic]

Hi guys, I'm working on a little project within the van whilst I save up to have her sent to Dell for proper repairing.

I'm in the process of fitting a solar panel into the dashboard and wiring it directly to the vans heater/fan system.


The plan is that in the summer I can turn the engine/ignition off and leave the panel alone to power the internal fans to keep the van fresh without needing to use the battery.

Now the problem is, the fan circuit does not have an obvious starting point (i.e. where it gets it's initial positive feed), all I can find so far is the three positive and one negative wires that attach to the switch itself.

After some investigation I can see that it is connected to the 2nd ignition ON setting (i.e. fan comes on after 2nd key click, same setting that turns the fuel pump on). This is not good as a solar panel feed to this circuit would mean the fuel pump would also be running from the panel.


So...Can anyone point me in the direction of where the fan/heater gets it's initial positive feed from?, I'm then going to disconnect it and re-connect it to the first ignition ON setting. This setting is where (usually) only the lighter socket then goes live.

Meaning that when parked with no keys present the panel will provide direct power (without the vans battery involved) to the fans and lighter socket


Any help appreciated, worse comes to worse I'll trace back from the fuse box or take the dash out

[HP5Man]

What size of solar panel are you using? Will the output be enough to turn over the fan motor at a reasonable speed?

At a guess, I'd say that you might need a couple of amps to get the fan running and that would require a pretty substantial panel and some strong sunlight.

[Vandrederic]

Well the panel I have for this project is 3w. Which judging by the fan fuse is allot less than normally used.

However provided it can power the fan even at a very low speed, it would still give some ventilation when the van is just left idle. Though before I can 'test' my concept need to track down this particular voltage feed wire

Did try to test by running the entire van from the panel with everything turned off BUT the fan, however due to the vans wiring the fan system only kicks in with the ignition engaged thus taking all panel power to try and run the fuel pump.

So as yet I have been unable to test. If this panel does turn out not to be enough I am planning on eventually fitting a 100w panel to the roof for camping purposes, which would easily run the fans.

[Turnip lover]

Hi van, would it not be best to get a leisure battery with a trickle charger?  You could then charge the leisure battery whilst driving once your main van battery is charged.  You could then use the solar panel to keep the leisure battery topped up if you're not driving.  I use a leisure battery for camping and can run my laptop and lights for over a week using it every evening for many hours without charging.

[Vandrederic]

Well the larger plan does indeed involve a leisure battery + Panel to provide power during camping without needing to run the engine.

This little project is seperate from that, in that the little panel will be used PURELY to power the fan in the van.


So, e.g. hot day by beach... lock van, leave fans running entirely off the panel. Van battery does not get used, and the van itself stays relatively cool and fresh


I'll try and track down the main feed this weekend (if we get some sun) and report back if 3w is enough to even get a slight breeze going. As stated above, if it isn't then when the larger panel is added the fans can run off that/the battery amonst other things.

[HP5Man]

A 3 Watt panel will generate 250mA at 12V but only in strong direct sunshine. Place it behind a windscreen, tilt it to at an angle to the sunlight and the output will drop considerably. Even at it's rated output, I'd be surprised if it would supply enough current to turn the fan motor at all.

All that I can suggest is that you build a small scale version of your 100w panel and leisure battery project; use the small panel to charge up a lead acid battery (about 10AHr perhaps) and run the fan from that. It still wouldn't run the fan for more than a few hours but it might be sufficient for your needs.

[OddballDave]

Well the larger plan does indeed involve a leisure battery + Panel to provide power during camping without needing to run the engine.

This little project is seperate from that, in that the little panel will be used PURELY to power the fan in the van.

Auto projects for the evil genius gives a good cheap split charger circuit for adding a leisure battery to a vehicle.

Beware that wiring a solar panel into a vehicle circuit can fry the panel when the ignition is switched on. Not an electrician but my Maplins trickle charger specifically states that it needs to be removed when the ignition is on.

If your van fan is too heavy to run from the panel, look at some CPU/Computer case fans, these are designed to run at very low electric levels. Solar panel can charge a USB socket, laptop cooler then runs from a USB socket, you might want some sort of rechargeable battery to cushion the power supply.

YMMV
Dave

[HP5Man]

If you don't mind cutting a hole in your van, you could try a solar powered vent like this one:

http://www.machinemart.co.uk/shop/product/details/sunsei-sev-1000ss-solar-vent-stainless-steel

I know one person who has used a couple of these things on his yacht and they seem to do the job.

[milkanbeans]

Hi Van

Check out ebay item 330458452144 and it will save you all that hard work, they are quite small but I think if you put a couple on each sun visor I think it would do the job.

[Vandrederic]

Thanks for the info and suggestions guys.

Just to let you know, Traced the wiring and found the source.

It seems the heater fans use ~20-30w to function.


The 3w panel was not even enough to get the motor turning slowly, so it'll now get used for some other little projects.

When the time comes and I add ~100w panel/deep cycle battery I'll do a little re-wiring so the auxiliaries like the fan can just power direct from it.