Solar Panel Voltage Question

[Mr Librium]

Hi guy's,

I have a 120w solar panel installed which knocks out my Sargent power supply when connected.
There are no shorts etc, but the voltage is higher than what I would expect at 19 volts, or is this correct?

I have found that by turning the discharge of my Fogstar battery on, the Sargent ps turns off, however if I then turn on the charge of the battery and restart the Sargent ps from the panel, power stays on.
I don't get this issue when the solar panel is disconnected.

Is this to be expected with the combination of Lithium Battery, Sargent EC328 and a solar panel?

I would appreciate any comments.

Cheers.

Steve.

 

[GeoffnDee]

I would think that the Solar controller is faulty , there should be around 20v going in from the panel and about 13.5v leaving it going to the battery (when the battery is being charged) the Sargent unit will shut down if the voltage is to high to avoid damage to it and other electrical items.

 

[Mr Librium]

Well yes, this was my conclusion too, so I ordered a brand new replacement Sargent unit and the same happened.
I sent the new unit back to Sargent and they refunded me in full after testing.

I have been running the van with the solar panel disconnected, but decided to have another go when I ended up with a flat engine battery after a 2 week holiday away in Canada.

It's working now of sorts, but I have to go through the correct process to ensure it all works as it should.

 

[GeoffnDee]

Perhaps it would work better if you use the solar to just charge the leisure battery (leaving out the Sargent EC328 unit etc) and fit a Vanbitz battery master (or similar) that will keep your starter battery charged with a trickle charge from the leisure battery. (although I would not expect to see 19v at the leisure battery in this set up either , if the controller is ok.)

 

[Lenny HB]

The output from the panel should be between 17 - 24v so your panel is fine.

Those Sargent controllers are just cheap PWM controllers.
Fit a Victron MPPT and bypass the Sargent stuff.

^{_{Subscribers  do not see these advertisements}}

 

[Dall]

Perhaps it would work better if you use the solar to charge the leisure battery (leaving out the Sargent unit etc) and fit a Vanbitz battery master (or similar) that will keep your starter battery charged with a trickle charge from the leisure battery.

Or a Votronic solar controller, which will change the LB and trickle the SB at the same time.
BTW - my two panels in series put up to 65 volts into the Victron 100/50 controller with no issues at all.

 

[Mr Librium]

Perhaps it would work better if you use the solar to just charge the leisure battery (leaving out the Sargent EC328 unit etc) and fit a Vanbitz battery master (or similar) that will keep your starter battery charged with a trickle charge from the leisure battery. (although I would not expect to see 19v at the leisure battery in this set up either , if the controller is ok.)

As I have it at the moment, the EB gets a trickle charge from the solar panel and I only need to charge the LB if I am away for more than 3 days without EHU.
I think I can live with the current setup if I can remember what to switch when!
Thanks for the suggestion though, appreciated.

 

[Mr Librium]

Or a Votronic solar controller, which will change the LB and trickle the SB at the same time.
BTW - my two panels in series put up to 65 volts into the Victron 100/50 controller with no issues at all.

Thank's for the suggestion, appreciated.
Sounds like you have your panels connected in series, won't this reduce the current available for charging?

 

[Mr Librium]

The output from the panel should be between 17 - 24v so your panel is fine.

Those Sargent controllers are just cheap PWM controllers.
Fit a Victron MPPT and bypass the Sargent stuff.

Thanks Lenny, when I have a few more pounds to splash, I might do that... then again, it is an old van now!

 

[Dall]

Thank's for the suggestion, appreciated.
Sounds like you have your panels connected in series, won't this reduce the current available for charging?

The current from the panels stays the same as just one panel, but the voltage increases. The controller then does its magic and the charge current to the battery is correct for the total watts of the combined panels. If that makes sense...
Higher voltage means that the panels start producing earlier in the day and keep going longer than if they were wired in parallel. Much better also in poor solar conditions too.
This works for me - but not everyone.

^{_{Subscribers  do not see these advertisements}}

 

[IRHP]

The current from the panels stays the same as just one panel, but the voltage increases. The controller then does its magic and the charge current to the battery is correct for the total watts of the combined panels. If that makes sense...
Higher voltage means that the panels start producing earlier in the day and keep going longer than if they were wired in parallel. Much better also in poor solar conditions too.
This works for me - but not everyone.

Also means you can use thinner cable from the panel to the controller.