solar charger problem

[deep denial]

Hi. Having difficulty with solar panel. Removed the old one which wasn't charging, and replaced with a new 100W panel, running through a Steca Solsum 10.10F charge controller to a 240Ah 12v battery bank. Voltage out of the panel is good, but can't get any rise in voltage of the battery bank. Shows 12.45 volts whether panel connected or not (All polarities connected correctly!) As part of my investigations I have found that there is discontinuity between the two negative terminals on the charge controller, ie the one from the solar panel and the one from the battery. Surely the negative terminals should be electrically connected? Or is that not the case?

 

[Alan S]

It's often the case that the positives are connected together and the regulation is done via the negatives.

 

[deep denial]

It's often the case that the positives are connected together and the regulation is done via the negatives.

Do you know if that might be the case with this regulator?

 

[greeny]

http://www.europe-solarshop.com/document/steca/Solsum+F_Manual_EN.pdf
This should tell you. I have a similar but different make controller and as Alan S says, the positives are tied together and it uses the negative. Goes against normal thinking. It caught me out when I first wired mine.

 

[deep denial]

http://www.europe-solarshop.com/document/steca/Solsum+F_Manual_EN.pdf
This should tell you. I have a similar but different make controller and as Alan S says, the positives are tied together and it uses the negative. Goes against normal thinking. It caught me out when I first wired mine.

Thanks - I've already seen that, but it doesn't answer the question. Perhaps you're right about the regulation being done via the negatives, but I don't suppose that explains why the voltage of the battery doesn't change when I connect the charger. In general, when you connect a small 100w charger to a 220 ah battery bank, would you expect to see a large voltage increase?

 

[TSB240]

You don't have a 100w charger!

On a good day at noon with a well aligned SP in the UK with the sun shining you might just get 75w into your battery.

If you think your controller isn't working you can try wiring your small sp (In relation to battery bank) direct.
Monitor voltage and current and come and tell us your results.

Are you sure you don't have a dud in your bank?

I had found out on my first installation that a solsum pwm controller was as useful as a chocolate fireguard.

 

[greeny]

Thanks - I've already seen that, but it doesn't answer the question. Perhaps you're right about the regulation being done via the negatives, but I don't suppose that explains why the voltage of the battery doesn't change when I connect the charger. In general, when you connect a small 100w charger to a 220 ah battery bank, would you expect to see a large voltage increase?

I doubt you'll see much initial increase in voltage at all with a 100w feeding a 220 Ah battery bank. As TSB says, you'll be lucky to be getting 50/60 w in reality and that depends on the state of charge of your battery bank. I'd connect the panel up direct to the batteries and see what you get. You're not going to overcharge them with that setup in the short term if you monitor the system. Connect a multimeter on current setting in series with the S.Panel and see what you're actually getting going in without the regulator controller. That will give you a good guide as to what the reality is.

 

[Alan S]

Do you know if that might be the case with this regulator?

It probbably is. You could check by disconnecting it (solar panel first then battery) and with multimeter on Ohms x1 ckeck for 0 Ohms beteeen the 2 negs. By the way don'tbother using the load terminals unless perhaps if you have a fridge and want to prevent it completely discharging you battery.

 

[peteK]

When you first connected it all did you remember to connect batteries before solar panel.

 

[RupertW]

What amps (if any) are going into your batteries and what is the difference in voltage between panels and batteries?

 

[Alex_Blackwood]

Hi. Having difficulty with solar panel. Removed the old one which wasn't charging, and replaced with a new 100W panel, running through a Steca Solsum 10.10F charge controller to a 240Ah 12v battery bank. Voltage out of the panel is good, but can't get any rise in voltage of the battery bank. Shows 12.45 volts whether panel connected or not (All polarities connected correctly!) As part of my investigations I have found that there is discontinuity between the two negative terminals on the charge controller, ie the one from the solar panel and the one from the battery. Surely the negative terminals should be electrically connected? Or is that not the case?

What are the controller LED's telling you?

 

[deep denial]

What are the controller LED's telling you?

the controller leds just say medium charge (yellow light). As per earlier suggestions, I did connect the SP direct to the battery, without any noticeable difference in voltage, which was why I wondered if you would expect any.

 

[Alan S]

As Greeny says in post 7, you should check the current (with a multimeter set to the 10A range) into the battery direct from the solar panel. If it faces the sun even at this time of year into a battery at 12.45V I would expect 1 or 2 amps from a 100W panel.
edit...
In terms of Voltage you could expect to see only a small gradual change at first.

 

[William_H]

As said I would reiterate. Use your multimeter on amps range (you often have to move the +ve plug to another socket on the meter and don't forget to return the plug to normal for volts) Measure current from solar panel direct to battery. (when in sun) You should get 2 to 5 amps. If you do then connect up the controller and measure current controller to battery. Again you should get similar current (2 to 5 A) . As said actual voltage rise on battery might take a while. ol'will