Solar trickle charger

Chas

Well-Known Member
Supporter
I've just bought a solar panel, one of these;
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... SA:GB:1123
I phoned the suppliers and I've been told that it's OK to have it connected with the engine running :thumbup: (because it has a diode to prevent reverse charging) but not when starting :thumbdown: , so where could I find a 'live' that's live with the ignition switched off so could be left plugged up permanently but is 'dead' when starting the engine, I’ve noticed that the indicator light on the 3 way ciggy lighter I’ve got goes out when turning the engine over, so should that be OK, yes?
Chas
 

Crispin

Administrator
Staff member
Guru
I doubt it would do any harm if left connected. When starting, the battery voltage would drop and the solar panel would try and provide for it but just not - it would appear like a momentary short to the panel.

However, I don't think it would be wise to leave it connected to the battery. The output voltage is 18V which will try and charge your batteries to that. At 170mA, it would take a very long time to do anything bad to them but a proper regulator would be a good idea if you want to leave it on for extended periods.

What was the reason for getting it? Just a top up? It would would not provide much in the way of keeping a fridge running etc.
 

Chas

Well-Known Member
Supporter
Crispin said:
I doubt it would do any harm if left connected. What was the reason for getting it? Just a top up? It would would not provide much in the way of keeping a fridge running etc.
I didn't expect it to actually run the fridge, I just thought it might be wise to compensate a bit, that's all, and I do love a new gadget :lol:
Chas
 

Andy Harvey

Well-Known Member
If you get yourself a 5 pole relay (has both 87 and 87a connectors) then you can use it switched from the ignition. If you connect to pin 87a then this is normallycosedn a current is apprlied to the switching circuit of the relay. So when the ignition is off, you get a connection, when the ignition is on or the engine is running then you get no connection - otherwise know as a Normally Closed or SPNC relay.
 

Chas

Well-Known Member
Supporter
Andy Harvey said:
If you get yourself a 5 pole relay (has both 87 and 87a connectors) then you can use it switched from the ignition. If you connect to pin 87a then this is normallycosedn a current is apprlied to the switching circuit of the relay. So when the ignition is off, you get a connection, when the ignition is on or the engine is running then you get no connection - otherwise know as a Normally Closed or SPNC relay.
Thanks Andy :thumbup: I'll look into that.
Chas
 

Andy Harvey

Well-Known Member
You can get them from vehicle wiring products, they call it a changeover relay though. Same thing however just don't connect anything to pin 87.
 

Lorin

Well-Known Member
This has got me thinking.... :shock:

What are the ideal stats for a solar charger for a leisure battery (I had a look on ebay and they range from 2-30+ watts output) if it was to be as close as possible to offsetting the running of a fridge with an average consumption of approx 2A - if such a thing is possible...?

Also, I assume the overcharging problem could be sorted with a charge regulator..?
 

24Seven

Well-Known Member
2 Amps = ~ 30W

A 30W solar panel will only put out 30W in optimum conditions (obviously) so maybe you would need around 120W.

Once you have that amount of potential amps going into your batteries you will need a regulator (IMO Chas will not)

Trouble is, it's going to cost a large amount money to get a solar setup capable of sustaining a fridge and then you have to park in the sun, which you really will not want to do if there is shade around.

IMO running the truck for an amount of time per day maybe the best option?
 

Jon Wildsmith

Super Moderator
Supporter
Guru
There was a good feature on solar panels in a recent issue of 4x4 Australia. Looking at the figures they quote a 120W would keep up, an 80W would not but it would reduce the battery discharge rate quite a lot. A 4W will apparently average 1.6W output for a 12 hour sunny day. That might compensate for the fridge light when you open it to get your beer out :mrgreen:
 

Chas

Well-Known Member
Supporter
Jon Wildsmith said:
That might compensate for the fridge light when you open it to get your beer out :mrgreen:
I should be OK then, my fridge doesn't have a light :lol: :lol:
Chas
 

itshowiplay

New Member
Ok so this is interesting. where do you plan to mount the charger?

Reason being is a few times a week I get the AMGs through the door for detailing and they are now favoring a glass roof approach with about a third being solar panel.

Now what i am considering is this: My dead sunroof (rotted away) needs to be replaced, I am going for a glass one at present but after discussion with Scotty today I am considering making the sunroof into a solar panel running to a USB in the center console to charge cell phones and the like.

Any thoughts of issues I will face from the tech experts out there?
 
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