installing solar power in a westy

[shepster]

Willy waving should be nearer the top I expect. Those in Eastbourne might be able to wave theirs more, when its not raining.

Solar panels have an extraordinary way to go before they really become that worthwhile. If someone gave me one, that might make it viable but they are not all that efficient even on a bright sunny day. Mind you, the hilarity concerning those mini solar battery chargers at the Pikey Escape meet lingers still. The fact it only had enough output to make the LED flash and would have taken a fortnight to charge a mobile phone was revealing enough. I'll stick with two leisure batteries for now and if I really want to watch Telly (I haven't watched the box for four years), I wouldn't go away.

I really think this is a case of 'if you want to fit a solar panel' then this thread has some good information in it, if you don't then thats fine.

Probably the longest thread in history is 'paint your van with a roller' or whatever it's called, again lots of info for those wanting to do so, I don't so haven't posted on it.

I think Martins setup was just over £100, a spare 110ah battery is almost as much, for me not having to carry batteries up and down the drive is justification enough.

I don't watch the TV when away either, my kids do occasionally now but 5 yrs ago evenings would see 7 or 8 of them in my van while parents were sat happily outside having a beer.

Just because you see no need for something other people do, how more efficient do they need to be when my battery never runs flat whatever I run and I never have to take it out to charge whereas before I needed 2 batteries and charged them between camps.

[shepster]

And I don't have a fancy control panel (thinking it was only offered a very minor improvement)

Mind you, I wonder what charge input you (Martin) would get with the battery somewhat depleted (compared to the 99% charged example) but without the control panel...

In the setup I've got, same as Kev's and Keith's, the controller is seperate to the 'display unit' and as far as I'm aware is simply a more detailed monitoring system so has no bearing on what happens to the power.

The controller is used to split the percentage of batt charge between 10%/90% to 90%/10% as I'm sure you're aware but the monitor then allows you to see things like batt voltage, current amps, max amps and a few other things I can't remember.

To back up what Martin has said the max I have seen is 6.2amps when first fitted and leisure was pretty flat, the most I seem to see after a night of use is around the 3amp mark and as the day progresses and the batt is getting full this will drop to as little as 0.5 which shows me things are working as they should.

[kevtherev]

I understand about and have seen the different charge rates due to charge state of battery.

I get the similar full sun reading as Martin, up to about 4 amps.

I just don't understand how Kev can get 8.2A out of his 100W panel.

I see it like this, the battery is under a 12 Amp load and at 11.8 V
whatever that panel can make from the sun it throws at the bat. The batt is flat to the controller.
The meter has not recorded a maximum amp output since.
My 4mm cables were warm to the touch

[California Dreamin]

As Kev says ^^^^^ I've not seen 8 amps but then, the battery has never really been discharged since installing the setup.
However, I have no doubt that if the setup was under flat charge conditions, with direct intense sunlight, that I might too see the heady 6 to 7 amp range.


Martin

[windysurfer]

Max output of a 100w panel ( when using all it's 100watts) is quoted at 5.18 amps.

Just saying

[shepster]

Max output of a 100w panel ( when using all it's 100watts) is quoted at 5.18 amps.

Just saying

I can only go on what the monitor says and It clearly states 'max 6.2amps', perhaps I'm misinterpreting the readings but to be fair I couldn't really care what it means because as stated both my starter and leisure remain fully charged no matter what I throw at them.

Happy days.

[keytouch]

Max output of a 100w panel ( when using all it's 100watts) is quoted at 5.18 amps.

Just saying

100watts/5.18amps = 19.30volts

If you have an intelligent controller that can vary the voltage then the amps will change

Eg.

100watts/16volts = 6.25amps

100watts/12.5volts = 8amps

Just saying

[shepster]

I often see 20v plus when the sun is strong, again what that equates to in amps I don't know but as said earlier I can only go on what the display shows me.

If the suns out tomorrow I'll get some photo's of whats going on.

[kevtherev]

Max output of a 100w panel ( when using all it's 100watts) is quoted at 5.18 amps.

Just saying

100watts/5.18amps = 19.30volts

If you have an intelligent controller that can vary the voltage then the amps will change

Eg.

100watts/16volts = 6.25amps

100watts/12volts = 8.33amps

Just saying

Ah ha!
I never thought about the voltage
Clever chap
...and my clever photonic universe controller

[CJH]

I often see 20v plus when the sun is strong...

Yes, that's what these panels typically produce in full sun. The job of the controller is to convert that voltage to a safe and useful charging voltage, say 14V (depending on the state of charge of the battery). As far as I know, there are at least two ways to do that.

If the controller were to simply put a (variable) resistor in to divide the voltage 14V:6V, and the panel was producing 100W at 20V then that's 5A, so dividing it 14:6 means there'd be 5A through the 14V side, but also 5A through the 6V side, which would be 30W - the controller would be a pretty good heater, and all that heat would be wasted power.

So a better way is to convert the 20V DC into high frequency AC, then use a transformer to reduce the voltage and then convert it back to DC. This preserves most of the panel's power, so you end up with higher current (100W/14V = 7.1A).

[shepster]

That makes more sense, again I often see the batteries up around the 14.4v mark during the day when the suns good but obviously drop when the sun goes down.

Be interesting to see if we're still talking about how good they are in a couple of years time if any faults start kicking in.

[kevtherev]

That makes more sense, again I often see the batteries up around the 14.4v mark during the day when the suns good but obviously drop when the sun goes down.

Be interesting to see if we're still talking about how good they are in a couple of years time if any faults start kicking in.

..or a helicopter lands on it

here it is deployed at 35 deg for the water heater



90% of the motor homes here had solar panels fitted, one of them had three panels the same size as mine!

[CovKid]

Listen to them

[keytouch]

What tilting mechanisms do people use? If any.

[kevtherev]

Mine sits on unistrut, 10mm all-thread rod and pipe clamps.
I can tilt it 4 ways, by unclamping one side, then propping the panel much the same as a car bonnet
fitting a compass helps to get the arc right, so I'm not re positioning it after midday.