A better amperage

[GeeMac]

I have ten 12 volt 15 watt  solar panels. I`d like to have a more powerful system, but the budget won`t allow it.

Amperage = Watts divided by volts. Or in my case Amperage = 150 divided by 12.

Amerage = 10.83

On a bright and sunny day at noon my charger tells me that the amperage it sees is approximately 4.3

There is about thirty feet of wire delivering the power to the charger.

The panels are parallel

Can I improve the amperage in my system?

Does more amperage better charge better?

[Bruce S]

GeeMac;

 I'm thinking you may have a panel or more not putting out much of anything.

Unless the 30 feet of wire is overly large or small it not really long enough to cause such a drop.

Are they were you can test each panel removed from the rest? This would be a good starting point. A quick check with multi-meter will tell the tale.

If these are pretty new , now is a good time to check and get them swapped under warranty.

I have 6 of the HF panels and I'm getting more than 4.3 on average.

Hope this helps. If these are HF panels , lately they have gotten a lot better about warranty swaps. At least in my area.

After testing mine to make sure everything was working right, I combined all of them into a small water tight box and ran one wire to my controller. Made things look nicer too.

Cheers

Bruce S

[GeeMac]

I do have some smaller panels tied in and I thought I had separated them using diodes. I'll take a quick trip to my roof with my trusty snippers, disconnect them, then check the charger for a better reading.  I'll post the result here to let you know what happened.

[zeusmorg]

 A few answers to some questions may help..

 Are the panels seeing full sun? (no shadows anywhere on them) What type of panels?

 Have you checked output of the individual panels?

What size (gauge) wire do you have running from them? Are you using any controllers?

(like MPPT or a simple charge controller)

 Also how are you measuring this? under a full load? Have you checked the battery condition?

 If you're just going by an amperage gauge on your charge controller, is it accurate?

 You may check the diodes if they exist, if they don't it would be a good idea to add some.

[Clifford]

40-50% of your maximum rated voltage might not be too bad.

When I was monitoring my system, this was about the best time of year (on sunny days).

A number of factors go into the generation:

• Intensity of Sun (summer would be best, except for next point)
  
• Cool Panels are better than Hot panels
  
• Partial Shade.  Apparently much worse if arranged in serial, and partially obscured, but shade doesn't generate much power.
  
• Angles of panels.  Particularly a problem for flat panels on the roof.  Only at "optimum" angle twice a year at noon, unless you have an adjustable mount.
  
• Be careful of different types of diodes.  Schottky Diodes are supposed to be the best for solar applications.  But, only use them where you need them as they can reduce the power.
  
  

Also, not differences between "Short Circuit" amps, and say the amps at 12V or so.

I kind of play around with how my panels are connected a bit.  I have old Siemens panels, and they seem to do best at about 24V --> 14V or 16V or so.

You have a small system, so it probably isn't worth investing in a MPPT controller, but certainly worth considering for slightly larger systems.

[wdyasq]

My bet is the 150 Watts is at a 20V rating or more.....This means you only get 60% of the amps to start with.

Ron

[Jeff]

Don't forget! Even "float" charging Standard Lead-Acid batteries should be 13.8 volts. SO, your 150 watts divided by 13.8 volts is only 10.87 watts. Also, direct 90 degrees facing the sun on a good clear day is the only time you may see close to that. 150/12=12.5 amps, so there's a little question on your math there. Unless your batteries are already at 12v, there in need of charging anyway, and should draw the higher amp figure.

But, like the others have said, if it's easily done, check each panel by itself first

!

[GeeMac]

Okay, boys and girls, I have checked the original package for the solar panels and they are 12 Volt, 15 Watt and .8 amps per panel. So, the unattainable 100% would yield only 8 amps. so, I guess it's a special day when I see more than 2 amps on the meter.

Thank you for all the help. I'm adding mirrors to the system to try to gain a teeny bit more from them.

Carry on having fun.

Your Pal,