Hi All, I would appreciate any help with this. I have bought 4.8w solar panel on Monday, and have tried it out 3 different ways, 1. Connected it to van cigarette holder socket, caravan 3way switch ON volt meter reading 12.5+ - volts, 2. Switched OFF 3 way switch and volt meter goes off the scale. 3. Connected it straight to battery (battery out of van) tested solar terminals with meter (LED light type) and it is working fine. Question 1.why did volt meter needle go off the scale. Question 2.how hot do solar panels get, as the back of my solar panel was very hot after a few hours, is this normal with the panels?. Thanks
------------- If everything runs smoothly then I must have done something wrong
If in Doubt Check it Out.
Your solar panel should be connected directly to the battery via ether a charge controller which will stop the bi-directional flow of current back to the panel when it is not charging, or an inline dioide which only allows current to flow from the panel. A solar controllar would be better as they are current rated and you could get a 10 amp controller which would probably take 2 panels. You then wire the Solar Controller to your battery terminals.
------------- Nigel
March 2012 - Dove Meadows
6th July Moving to Hayle
Definitely need a charge controller in there, the panels self-drain in the dark is not high but still matters, also a large panel in strong light can over charge a battery.
I wouldn't expect it to show any voltage on the vans voltmeter with the battery disconnected. The vans onboard electrically will pull a 5 watt panel down to nothing. In bright sunlight your panel will just about run half a light bulb.
Quote: Originally posted by DaveCoaches on 10/8/2011In bright sunlight your panel will just about run half a light bulb.
True, but it will (and does) trickle charge a battery between trips (Supplemented by a conditioning charge from a smart charger every so often).
But if you are sat in the caravan with the light on expecting to see the voltmeter show 13 volts without a battery connected you are going to be disappointed. The light will pull it down to a couple of volts at most.
" I wouldn't expect it to show any voltage on the vans voltmeter with the battery disconnected. The vans onboard electrically will pull a 5 watt panel down to nothing. In bright sunlight your panel will just about run half a light bulb."
Hi all, Dave, I did not say I had a reading on the van voltmeter with the battery out. Step 1 and 2 battery in van, Step 3 below,
3. Connected it straight to battery (battery out of van) tested solar terminals with meter (LED light type) and it is working fine. Just wondered why (2. Switched OFF 3 way switch and volt meter goes off the scale.) and do the solar panels get very hot.
I an aware that the panel will only trickle charge the battery, and keep it topped up when not on EHU for long periods while in storage. Have copied the instruction sheet. sorry its so long.
------------- If everything runs smoothly then I must have done something wrong
If in Doubt Check it Out.
You say the meter goes off the scale with the panel plugged in to a lighter socket and the switch off?
That is because the panel can output 17.5v which is way above the 13v that the meter will be set for, it is also not expecting to see ANY voltage on the circuits when the switch is off, the meter will be wired after the switch but by using the cigarette socket, you are back-feeding the meter bypassing the switch.
I would wire it direct to the battery.
It says it has a blocking diode wired in so no need to worry about a charge controller.
The panel will get hot if it's in the sun . The meter you used, was it the caravans built-in meter , if it was you would be sending it about 17volts from the panel when you switched off the van switch . You shouldn't ( in my opinon ) need a charge controller for a 4.8watt panel charging a caravan battery . I would recommend that you connect the panel to the battery and make sure you have a fuse inline . Because your panel has a blocking diode it won't flatten the battery at night .
Hi, Thanks davek0974, thought that may have been the case with van meter.
Hi wizard, that’s very helpful, Yes. (Switched OFF vans 3 way switch and van volt meter goes off the scale). Will be wiring it straight to battery with the in line fuse, may invest in another panel of the same spec. and a charge control unit, at a later date. Only dipping my toes into the waters of solar power at present, so it will warrant further investigation to suite my requirements, regarding power, and the weight to my limited pay load. Thanks again for your help, and to all who contributed.
------------- If everything runs smoothly then I must have done something wrong
If in Doubt Check it Out.
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Topic: Help Solar Panel
