help with electrics for campervan

qwertyphobia1

hi

Have solar panels that I hope will help keep my deepcycle battery topped up. I will also be running some wire from the van battery to the deepcycle. But I have some questions about that.

I want the engine to charge up it's battery first and then when it's fully charged for it to then feed any more charge into the deep cycle one. How do i go about this? is there a little off the shelf electronic kit I can buy which can regulate this.

I also want to make sure that my 12 volt system won't draw from the van battery and run it down.

Thanks

Aidan_M_M

Before You get into the wiring , are you doing it yourself , and how good are you with wiring etc?

paddyp

First question what solar panels do youhave and did you get a regulator/charge controller with them?

merc camper

What u are looking for is a voltage sensing relay.
http://www.rawcomponents.co.uk/relays-holders/12v/200-amp-12v-relay.html
It will charge the auxilary battery when the starter battery reaches a predetermined voltage then break the link when the van is off.
I have this one in my van its a bit more expensive http://www.sterling-power.com/products-battbatt-info.htm.
Make sure u use large cable and fuse them

qwertyphobia1

I have two of these panels for 119 euro http://www.maplin.co.uk/Module.aspx?ModuleNo=217850&OrderCode=N31CX

Merc camper that is exactly what I am looking for thanks.

Aidan I will be doing it myself with a family member who is a mechanic as back up.

I haven't got a leisure battery yet, should i be trying to get the best one I can afford or will my system best suit a particular capacity of battery?

paddyp

Average insolation (solar radiation) in dublin is 99W/m2
Your panel is specified to produce 12W at an insolation level of 1000W/m2

So the average annual output of your panel will be a little over a watt (it may be increased by angling correctly toward the sun)

Worst case average over the year: 1.2w x 24 hours x 365 days = 10.5kwH = €2 euro worth of mains electricity.

The panel has a blocking diode so that if the voltage on the alternator / battery side is higher than the panel voltage no current will flow to the battery.

Bear in mind that this will be the case a great deal of the time in ireland unless its very bright or the battery is virtually flat. Now you really don't want to be running down your battery like that as when the battery is virtually flat you will have sulfation going on and soon you'll need a new deep cycle battery.

By adding a switching regulator you will be able to get a lot more of that power into the battery but that is an additional cost.

Moral of the story pv cells ar a total waste of time unless you have a lot of them and or actually can't plug in a real charger as in you're in the desert or at sea. In which case you might be better off with a wind turbine anyway.

qwertyphobia1

PaddyP I will be in southern europe for the next 3 years so I hope to be getting a lot more then 99W/m2.

The voltage on the battery side will only by higher when I am driving. When I am parked up, which I hope to spend most of the time. The solar panels will be feeding power in the deepcycle battery. The only thing drawing power on these will be at max 12 volt lights and ocasionaly battery recharger for camera and phone.

For me the solar panels are to extend the time I can spend parked up off grid. They may not suit everyone but for me and the circumstances I will be in for the next three years I think they will work and provide value for money.

paddyp

qwertyphobia1 wrote: »

PaddyP I will be in southern europe for the next 3 years so I hope to be getting a lot more then 99W/m2.

The voltage on the battery side will only by higher when I am driving. When I am parked up, which I hope to spend most of the time. The solar panels will be feeding power in the deepcycle battery. The only thing drawing power on these will be at max 12 volt lights and ocasionaly battery recharger for camera and phone.

For me the solar panels are to extend the time I can spend parked up off grid. They may not suit everyone but for me and the circumstances I will be in for the next three years I think they will work and provide value for money.

Malaga is 215W/m2 average.
During summer you'll get 600W/m2 average during daylight hours (13).
If you could capture all than and put it in the battery:
Two panels 24W x 0.6 x 13 = 187W/h
Subtract 40% lost in the charge discharge process in the battery = 112W/h

During winter you'll get 200w/h during daylight hours (10.5)
If you could capture all than and put it in the battery:
Two panels 24W x 0.2 x 10.5 = 50.4W/h
Subtract 40% lost in the charge discharge process in the battery = 30.28W/h

Make sure you get led lamps.

There is no such thing as a 12V solar panel though the voltage will vary from zero to well over 20v depending on the light and load conditions I would at the very least buy a simple lighting charge controller .. these can be had for less than a tenner from hong kong and will stop your batery over dischargind and over charging.

qwertyphobia1

Thanks Paddy. Have both LED and oil lanterns as back up.

Will look at ordering a lighting charge controller