Solar Panels, and controller.

John
I upgraded the controller from the standard $15 unit, to a Powertec MP 3129, probably 6 to 8 months back, and stuck it with double sided tape, to the rear of the panels.

Big improvement over the "el cheepo" one that came with it.

Now for the next level....
I have just increased the delivery wire length to approx 7 mts, in order to take full advantage of the Sun. The wire I have chosen is 15 amp multi core, over the 6 amp std, so I expect voltage drop to be minimim.

I will give the above mention method a go.

Cheres
Bucky

Bucky,

Depending on how you're using the MP3129 controller, may be ok. I'd give it a go and measure the voltage at the battery terminals and at the controller to see what your losing. (Better still, measure the voltage between the ends of that cable.) If it's more than about 1/4 volt then it is wasting quite a bit of your charging capacity.

Another consideration - If you are connecting your loads, (especially the fridge) through the controller rather than directly to the battery, you will have extra losses in the long wiring running to the loads.

See how you go, but solar isn't cheap and I think you'd gain a lot (could be 20% or more of charging current) by moving the controller close to the battery. (Charging current is very dependent on voltage.)

Cheers

John

Keep Comments coming

Bucky

I gather you've moved the controller so it's close to the battery. Much better arrangement.

What's the rating of the panel / how big is it? Sounds as if your battery is pretty full so the controller is switching in and out. You probably won't get a sensible current reading while it's doing that, but all sounds good.

As usual with solar you could spend more money and improve performance. The next step would be to change to an MPPT type controller, which could improve your efficiency by another 20-25%. Peter (BV) can't advertise here, but if you did want to go MPPT, he sells one of the best that I'm aware of, and at a very reasonable price. You will probably find details in his profile.

Cheers

John

John

Solar Panel Size....120 Watt folding
Manufacturer...........Who Flung Dung Co. China ( heheheh )


Battery full ...............YES
I keep all batteries "topped up", as it extends their life by years.

Am playing with another battery now. And it must be stuffed.
Readings are all aver the place..

Camper Trailer Battery.......NEW, and is the one I did my first readings with
I suppose I could go hook up my cordless drill, (camper trailer conversion), and just use up some power. Then hook up the panels, and get a more positive result.

Cheers
Bucky '

Bucky,

All sounds good. Your panel should deliver about 7 amps into a discharged battery. I wouldn't bother discharging it just to prove that point. Fully agree with keeping them topped up - as you say it extends the life a lot.

I wouldn't abandon hope with your old battery. Unless it's really crook you should see some life. Discharge it a bit, remove load and check voltage - there's some hope if it's over about 10V. Then try charging using a mains charger and monitor the voltage - if it quickly climbs over about 14V suggest drop it in to a metal recycler! If though it starts slowly and builds up over a few hours, eventually reaching 13.5V or more, there may still be life left. I test my suspect ones by fully charging then discharging to about 10.8V using a lightbulb (that's almost a constant current load) and noting the current and time taken to discharge. Calculate amps x hours to get a rough idea of battery capacity.

Cheers

John
PS - my latest panel came from that same factory...... and it works well !!!

Don't know if this is a good test or not but this is what I do to test my Kits before they get sent away ..

I run my air compressor off the battery - it idles at 11 Amps ..
I run this for a few minutes until the battery voltages sort of stabilises around 12.6 V - Then I connect the Solar kit with panel in full bright Sun ( when possible ) and measure the charging current ...

Cheers

Steve

John
Panels producing to 20 Volts
Battery accepting 4.6 Amps
Battery 13.7 Volts

Going Well
Conditions 23c... cloudy 60/40 clear

Cheers
Bucky

Just loke top mounted intercoolers, front mounted are bore efficient, but top mount are cheaper to set up

It manufacturers had to place controllers in a separate box, and mount that box on a vehicle.

Cheers Bucky

John,

Fair question. The answer is probably to do with marketing, certainly not with performance. Costs very little to add a cheap one during manufacture and may give a marketing advantage.

Cheers

John