5th time lucky?

[Happy1]

solar controller #1 fitted by dealer supposed to be dual battery, turned out to be single, changed for
controller #2 voltronic 250 duo fitted by a specialist and "tested", dual battery but as panels >12v never charged battery as automatically cuts off when panel voltage over 50v, mine do 68v on a dull day, controller #3 again fitted by a specialist victron smart allowed batteries to receive 17v and fried one along with a fuse carrier, controller #4 just fitted by a specialist turns out to be another voltronic 250 duo so back to square one and well miffed.

question is what controller will do 68v panels into a 12v battery bank 300ah and actually charge the battery?!

any assistance gratefully received as tearing my hair out!!

 

[Vipar]

So sorry about your controller problems. Every cloud has its silver lining.
Can I have your hair please as I am beginning to thin out on top

 

[Ninjabob]

How many panels? What is the maximum voltage output of each panel? Are they all the same? How are they wired (likey in series for 68v)? Could they be wired differently to get the voltage below 50?

 

[Happy1]

two panels both the same
voc open circuit voltage 35.47v
isc short circuit current 4.39a
vmp max power voltage 29.10v
imp max current 3.8a
pmax power 110.58w

 

[Lenny HB]

Obviously you have been employing idiots.
The max solar input voltage on a Votronic duo MMP is 50 v.
You either need to rewire your panels so they are in parallel which it far better for Motorhome use or buy a suitable regulator that will accept the higher voltage of your series connected panels, I think the Victron ones will do it.

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[Happy1]

agree even gave them the panel specs prior to ordering latest controller

 

[Happy1]

parallel seems the way to go and if one in shade wont affect the other i assume?

 

[pappajohn]

Is the 68v a combined voltage from both panels?
Wiring in parallel should bring it down to 36v

 

[Happy1]

or do i get more amps at 12v in series?

 

[Happy1]

Is the 68v a combined voltage from both panels?
Wiring in parallel should bring it down to 36v

yes exactly

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[autorouter]

The Victron SmartSolar should have done the job. I don't know which model but the minimum is 75V. However they require the correct startup sequence, because they will automatically recognise the battery voltage on first startup. Because of that, you must connect the battery first, then the solar panels. If you do the solar panels first, there's a risk that the controller will interpret the solar output as the battery voltage, and go into 24V battery mode. I think that's why you got the 17V into the battery.

 

[autorouter]

never charged battery as automatically cuts off when panel voltage over 50v, mine do 68v on a dull day,

I don't know what model of Victron SmartSolar you used, but you should be careful because the 75V or 100V limit is a hard limit, not to be exceeded. The 75V is a bit too close for comfort, and can probably be exceeded on a bright cold day. Voltages are higher as the temperature falls. I'd be happier with a 100V model.

 

[Lenny HB]

Also sounds like you have fitted domestic panels as 12v panels the o/c voltage is 21v.

 

[autorouter]

or do i get more amps at 12v in series?

The amps at 12V, ie the output from the controller, will be the same whether the panels are in series or parallel. The controller changes whatever input power is available into an output suitable for charging a 12V battery.

On the input side, for two panels, series is twice the voltage but half the amps, parallel is half the voltage but twice the amps. Same power (volts x amps) either way.

 

[Happy1]

The Victron SmartSolar should have done the job. I don't know which model but the minimum is 75V. However they require the correct startup sequence, because they will automatically recognise the battery voltage on first startup. Because of that, you must connect the battery first, then the solar panels. If you do the solar panels first, there's a risk that the controller will interpret the solar output as the battery voltage, and go into 24V battery mode. I think that's why you got the 17V into the battery.

It was a 100 model and was running quite happily until one day it output 17v.
I will get the garage to wire in parallel as suggested,
many thanks for everyone's input (no pun intended!) very much appreciated.

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[Happy1]

All sorted!!
Thanks for the input