Solar panel help please.

R

RUSSH

Well-Known Member
Joined
8 Aug 2004
Messages
108
Visit site
I have done my inadequate best to search the forum, web and technical query to supplier to get the answer but to no avail so far. So over to you.

I recently purchased a Rutland 914 wind generator and an HRDI charge controller. I intend to also fit a single 100W solar panel via the charge controller. I see that the instructions for the charge controller states.

"Always fit an appropriate blocking diode to each solar panel input."

I have attached pictures of the solar panel connection box and the panel label. Looking at the connection box there appears to be a diode of some kind fitted.

My query is. Is this liable to be a blocking diode or a bypass diode? How do I tell the difference? If it is not an appropriate blocking diode and I need to purchase one what size/type would I require?
 
That looks like a bypass diode as it appears to be wired across the two terminals.
I would expect a blocking diode to be wired in series with the panel. The same diode could be used for either blocking or bypassing.
You need a diode that can take at least 10 amps. Go to Maplin and ask for a Shottky diode, which is a bit more efficient than other types. You'll probably end up with one that can handle 50 volts or more.

By the way, the diode in your picture doesn't look as if it has been soldered very well. I would re-solder it.
 
That's great. Thanks very much. I love this part of the forums. I suspected as much as the diode is as you say connected across the pos & neg but reassurance on electrics is always welcome to me. Good spot on the solder I'll give it some attention. Off to Maplins now. Thanks again.
 
Isn't a blocking diode only required when using more than one panel? I thought they were to prevent a shaded panel from "borrowing" the charge from the unshaded one.

*edit* nope, that's the bypass, blocking is to stop discharge of the battery for similar reasons
 
having bought a solar panel and controller and yet to fit it I cannot find any instruction either on the panel or the controller instructions to fit a blocking diode .Can I therefore safely assume that a blocking diode is either incorporated or not required ?Sorry to OP for drift
 
clyst said:
having bought a solar panel and controller and yet to fit it I cannot find any instruction either on the panel or the controller instructions to fit a blocking diode .Can I therefore safely assume that a blocking diode is either incorporated or not required ?Sorry to OP for drift
Click to expand...

Many solar panels are not fitted with a blocking diode (Kyocera have never had them). The theory is that the loss after dark is less than the loss of power through the diode. This is probably less true if it is a Schottky diode.
My 6 panels are feeding through an MPPT controller, which is fitted with blocking diode.
I'd suspect that a blocking diode is advisable above 65N, but probably not in the UK.
Bypass diodes are a standard fitment on all PV panels.
 
clyst said:
having bought a solar panel and controller and yet to fit it I cannot find any instruction either on the panel or the controller instructions to fit a blocking diode .Can I therefore safely assume that a blocking diode is either incorporated or not required ?Sorry to OP for drift
Click to expand...

You can test the panel by connecting it to a battery via an ampmeter. (no regulator) Cover the panel and select low amps range to measure actual reverse current. If there is none either it has a built in diode or does not need one. I f there is some reverse current then you can decide if that current is significant and if your regulator has a diode or similar effect. Try the same test with regulator fitted.
A silicon diode will reduce the panel voltage by .7 volt a schotky diode will reduce it by about .25volt. However a panel connected to a battery will generally exhibit 20 volts no load which drops to battery voltage when you connect it. The difference in voltage is lost in the internal resistance of the panel so mostly the volt drop of the diode will not matter. Only at low sun levels will it matter.
good luck olewill
 
clyst said:
having bought a solar panel and controller and yet to fit it I cannot find any instruction either on the panel or the controller instructions to fit a blocking diode .Can I therefore safely assume that a blocking diode is either incorporated or not required ?Sorry to OP for drift
Click to expand...

Sound advice from WilliamH.

In the OP's case the instructions for the HRDi regulator specifically say to fit a diode to (each) panel. I imagine not to prevent back feed from the battery but from the 914 wind turbine.
 
I think you'll find that is for multiple panel to panel isolation. The HRSI has a blocking diode installed (to stop darkness discharge), I expect the posher HDRI to be the same. If you only have one solar panel and one turbine, then they can be connected directly (up to 100w solar), using the dedicated HRSI terminals, without bypass. I have the 913 and one 20w solar panel. I did initially fit a schottky in series, until I measured the volt drop and realised the HRSI inputs already had it. You need all the voltage they can muster. My biggest problem is getting fishing line in the blades and wrapped around the shaft ;)
Windy day + invertor = free electric kettle...Brilliant!

RUSSH said:
I have done my inadequate best to search the forum, web and technical query to supplier to get the answer but to no avail so far. So over to you.

I recently purchased a Rutland 914 wind generator and an HRDI charge controller. I intend to also fit a single 100W solar panel via the charge controller. I see that the instructions for the charge controller states.

"Always fit an appropriate blocking diode to each solar panel input."

I have attached pictures of the solar panel connection box and the panel label. Looking at the connection box there appears to be a diode of some kind fitted.

My query is. Is this liable to be a blocking diode or a bypass diode? How do I tell the difference? If it is not an appropriate blocking diode and I need to purchase one what size/type would I require?
Click to expand...
 
I have the HRDi controller and a 904 W gen together with two 20 w panels, at first i had just the panels and some decent readings on the controller, then later i aquired the Wind Gen, its been fitted for a about 10 days now and the controller says its generated just 2 ah after 190 hours !! that cant be right. I havent phoned rutland yet but i suspect somethings amiss. The wind gen is spinning rapidly on some days but the Controller reads zero input from the wind gen, ive had the volt meter on the wind gen directly where it connects to the controller and its definitly giving a reading. Ive tried switching it off, ive tried resetting to manufactuerers default, cant think of anything else except phoning Rutland, does anyone have any ideas on here ?

Both solar panels are working fine still BTW
 
Yes i think so, i'm not one hundred percent sure though, the panels are good ones with blocking diodes fitted as standard, i have tried completly disconnecting the panels and theres still no reading on the regulator from the Wind Gen even though when i put the volt meter on the WG wires its giving a reading.
 
Little Sam said:
.......... does anyone have any ideas on here ?

........
Click to expand...

If your batteries are fully charged, the controller won't give any output whatever the wind generator & solar panels are doing - the controller is protecting the batteries from overcharging - that's what it is for.

Try putting a heavy load on the system, leave it for 5-10min, and then with the load still connected, look for output from the controller.
 
Little Sam said:
Yes i think so, i'm not one hundred percent sure though, the panels are good ones with blocking diodes fitted as standard, i have tried completly disconnecting the panels and theres still no reading on the regulator from the Wind Gen even though when i put the volt meter on the WG wires its giving a reading.
Click to expand...

The diodes on your panels may not be blocking diodes. They could be bypass diodes. There was a discussion about the difference earlier in the thread. However, that's irrelevant if you are still not getting any power from the WG when the panels are disconnected.

If you can give the voltage readings then somebody may be able to help but I have no experience of the Rutland to be able to comment other than to say, if it has brushes, it may be worth twiddling with those. If brushes were not properly seated then it could affect the output.

Beyond that, it's difficult to know if the problem is with the WG or the regulator without more information.
 
Last edited:
Rigger Mortice said:
The diodes on your panels may not be blocking diodes. They could be bypass diodes. There was a discussion about the difference earlier in the thread. However, that's irrelevant if you are still not getting any power from the WG when the panels are disconnected.

If you can give the voltage readings then somebody may be able to help but I have no experience of the Rutland to be able to comment other than to say, if it has brushes, it may be worth twiddling with those. If brushes were not properly seated then it could affect the output.

Beyond that, it's difficult to know if the problem is with the WG or the regulator without more information.
Click to expand...

My appologies. Its all working fine. The wind got up the other day . Wasn't aware of just how fast the wind gen has to be going to produce a reading. Thanks for all your help
 
You must log in or register to reply here.

Other threads that may be of interest

Refueler
80W Solar panel arrived with a 'crease'
2 3 4
Replies
60
Views
1K
Refueler
Refueler
N
Volvo Penta Alarm Module/Alternator Issues
Replies
1
Views
188
superheat6k
superheat6k

Share this page

Top