Thread: Solar Panel Voltage Control

I have one of these on my 120w panel for camping, great bit of gear and from memory only around $120.00

https://www.victronenergy.com/solar-...llers/mppt7510

Originally Posted by BMKal

Any solar panel experts on here ?

I have a Projecta folding 80W solar panel kit, which includes a Projecta SC005 voltage controller / regulator. Over the past week or so, I have been using this to supply some power for electrolytic cleaning of some old cast iron cookware and an old workshop bench vice. So far, has been working well - but today I wanted to use the solar panel set-up to charge up an old "Thumper" battery that was sitting in the back of the shed.

When I checked the output voltage at the end of the leads (alligator clips) - I was getting 17.5 volts. And that was with the solar panels in the shade - when I moved them into direct sunlight, I was seeing output as high as 20 volts.
So I unplugged the SC005 voltage regulator and measured the voltage being produced directly from the solar panels (in the shade) at 18.1 volts.

From this, I assume that the Projecta voltage regulator is not worth two knobs of goat **** (I did note the "made in China" information on the face of the unit) and it will be removed tomorrow. For the purpose of continuing my electolytic cleaning processes, I have no problem with direct connecting the supply from the solar panels to the cathode & anode in my chemical bath - anything up to about 20 volts is quite OK for this purpose.

However, before I use the solar panel again to charge any batteries, I will need to install a decent regulator. I have been meaning to re-position the regulator for some time anyway, as I was advised a while back that it should be positioned as close as possible to the battery being charged to reduce voltage drop in the lines to the battery terminals - so now's as good a time as any.

Anyone have any good suggestions for a decent voltage regulator that doesn't cost the earth. Obviously, I'll be steering clear of any rubbish produced by Projecta, but there must be other reasonably priced units out there that do the job.

On its website Projector says it's peak power for 80 watt panels is 17.5 volts or 4.5 amps.
My panels have 10 amp regulators.
http://www.projecta.com.au/site/Defa...arPanel-1a.jpg

Originally Posted by dswatts

I have one of these on my 120w panel for camping, great bit of gear and from memory only around $120.00

https://www.victronenergy.com/solar-...llers/mppt7510

Same as what I've set up:

Camping solar for the D4

I'm certainly not a solar expert, but this seems to work OK - even though I haven't yet done any long term testing...

Originally Posted by DiscoMick

What limit is your regulator supposed to impose? Could it be 20 amps?

From their web site, is should be 7 amps at 12 volts. I haven't measured what amps I'm getting, but the fact that the output is at between 17 and 20 volts is what I am concerned about.



From the REDARC SOLAR FAQ's ....................
Why do I need a regulator?
A 12V solar panel is designed to output at least enough voltage to charge a 12V battery under worst case conditions (low light level, high temperature etc). A 12V battery needs at least 13.6 volts to charge, therefore under worst case conditions a solar panel needs to output at least 13.6 volts. This means that in perfect conditions a 12V solar panel may output around 17V or more. If you plug a solar panel, which is generating 17V, straight into your battery it is easy to understand how this can cause damage. Solar regulators are designed to accept the voltage from the solar panel, and output a voltage that is safe and useable to charge a battery. A good regulator will incorporate a 3 stage charging output.

From the above, I can understand why my solar panels are putting out 17+ volts. but this should then be regulated to around ~ 13.6 volts. I am getting 17 to 20 volts at the alligator clips, which suggests to me that the voltage regulator is not working.

Electrickery has never been my forte ..........................

Originally Posted by dswatts

I have one of these on my 120w panel for camping, great bit of gear and from memory only around $120.00

https://www.victronenergy.com/solar-...llers/mppt7510

Thanks for that - looks promising. I see they have a distributor in Ozzy Park - will give them a ring tomorrow to discuss what I need.

Brian.
I have a Plasmatronics unit in the shed,its 20A from memory.
I used it on one trip down south with small panels.I now have 2 x220W panels wich need a 30 to 40 amp controller.
The plasmatronics unit isn't MMPT,but probably has a lot more functions.
It was way more than $120 too.
Andrew

Here you go Brian.
Plasmatronics PL20 with LCD Display - 20 Amp - Regulators
Andrew

Originally Posted by BMKal

Any solar panel experts on here ?

I have a Projecta folding 80W solar panel kit, which includes a Projecta SC005 voltage controller / regulator. Over the past week or so, I have been using this to supply some power for electrolytic cleaning of some old cast iron cookware and an old workshop bench vice. So far, has been working well - but today I wanted to use the solar panel set-up to charge up an old "Thumper" battery that was sitting in the back of the shed.

When I checked the output voltage at the end of the leads (alligator clips) - I was getting 17.5 volts. And that was with the solar panels in the shade - when I moved them into direct sunlight, I was seeing output as high as 20 volts.
So I unplugged the SC005 voltage regulator and measured the voltage being produced directly from the solar panels (in the shade) at 18.1 volts.

From this, I assume that the Projecta voltage regulator is not worth two knobs of goat **** (I did note the "made in China" information on the face of the unit) and it will be removed tomorrow. For the purpose of continuing my electolytic cleaning processes, I have no problem with direct connecting the supply from the solar panels to the cathode & anode in my chemical bath - anything up to about 20 volts is quite OK for this purpose.

However, before I use the solar panel again to charge any batteries, I will need to install a decent regulator. I have been meaning to re-position the regulator for some time anyway, as I was advised a while back that it should be positioned as close as possible to the battery being charged to reduce voltage drop in the lines to the battery terminals - so now's as good a time as any.

Anyone have any good suggestions for a decent voltage regulator that doesn't cost the earth. Obviously, I'll be steering clear of any rubbish produced by Projecta, but there must be other reasonably priced units out there that do the job.

Brian I have a 240W solar panel, it runs without a regulator direct to my C-Tek DC to DC charger in my Camper Trailer. I have about 12 metres of cable from the solar panel to the C-Tek and it reads 19V at the charger, the charger feeds into 2 Optima yellow top batteries, the C-Tek will take up to (but not more than 21V) and has worked well so far, the long cable allows me to park in the shade and set the solar out in the sun, Regards Frank.