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Author Topic: Solar charge controller problem  (Read 7035 times)
Stefan (S.T.E.F.)
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« on: March 22, 2011, 01:18:59 AM »

Sun came out today so I had a look at my charge controller and nearly had a heart attack. It was showing the battery voltage at 15.2V. Whipped my multimeter out which confirmed the voltage. Grabbed a black blanket and threw it over the solar panels, then got the laptop out to add a load and get voltage down quickly.

Why on earth is my charge controller not disconnecting the solar panels at 14.4V, as set in the menu ?

I haven't used the system in several weeks, batteries are obviously full to the brim. Wouldn't know if the charge controller was ever diconnecting properly as I have always used the system and voltage was always below 14V, even in full sunlight. batteries are 3x 105AH, solar panels 3x13W. All wired to the charge controller directly...

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stephendv
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« Reply #1 on: March 22, 2011, 06:50:03 AM »

Is it configured for automatic equalising? 
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Stefan (S.T.E.F.)
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« Reply #2 on: March 22, 2011, 11:39:21 AM »

Erm, there is no option in the menu for that..... is it maybe factory set ?
The red LED for charging starts flickering at 15.8V (just let it briefly go up to that).
I don't want to damage my batteries. Is it save to see what happens if I don't connect a load ?
Sun out sporadically today, so voltage is going up and down...
Not sure if it would go over 15.8V, the solar panels putting out 20.1V (3.2A) in full sun....
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profp
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« Reply #3 on: March 22, 2011, 11:45:19 AM »

Quote
3x13W panels
...and...
the solar panels putting out 20.1V (3.2A) in full sun....

3x13W = 39W

20.1V x 3.2A = 64W

Looks like your numbers might be a bit adrift somewhere?
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biff
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« Reply #4 on: March 22, 2011, 01:37:46 PM »

hi stef,
       from experience and not by the book, the two do conflict at times, your 3 x 13 = 39watt x 4times(experience)gives you an output of a handy 150watt at least in full sunshine.i doubt if you are set up for an automatic equalisation charge,? your batteries should be ok,that high charge would only be surface and if you switched off it would probley drop down to a float of 13volt on its own.if you are not sure of your controller,then put a fuse between the panels and the controller and use it to disconnect in emergencies,dont disconnect the batteries and reconnect seconds later under load,you will pop the controller(experience)
                                     biff
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Stefan (S.T.E.F.)
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« Reply #5 on: March 22, 2011, 03:21:36 PM »

Quote
3x13W panels
...and...
the solar panels putting out 20.1V (3.2A) in full sun....

3x13W = 39W

20.1V x 3.2A = 64W

Looks like your numbers might be a bit adrift somewhere?


Silly me...I've connected the 50W solar panel I had on my electric fencing to the motor home last night, as I didn't have a charge controller for it and it was overcharging the battery in the sun.... more useful on the motor home anyway as I need to start using the laptop regularly....

I've left it all connected in the sun for an hour without a load, the voltage is not going over 15.8V, so the controller is certainly capping it, but why at 15.8V and not 14.4V ? Highest I've seen is 4.1A charge.
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billi
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« Reply #6 on: March 22, 2011, 03:24:53 PM »

Hi What make is the controller ?

Is it outside and cold   and perhaps it has an internal temp sensor ?
  But even then its too high
« Last Edit: March 22, 2011, 03:32:42 PM by billi » Logged

1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
Stefan (S.T.E.F.)
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« Reply #7 on: March 22, 2011, 03:57:48 PM »

It's a JUTA CMP24, bought in Germany.
Now you are mentioning the temperature, it has an optional external sensor, which I don't have. Looking through the menu, the temperature says -32C...
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billi
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« Reply #8 on: March 22, 2011, 04:00:53 PM »

Quote
Looking through the menu, the temperature says -32C...
  Did your heatpump already arrive  and cools  Grin ralph
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1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
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« Reply #9 on: March 22, 2011, 04:07:11 PM »

 hysteria

http://www.jutasolar.com/en/product_more.asp?id=1184

Seems the missing temperature sensor could be the culprit... :-(

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billi
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« Reply #10 on: March 22, 2011, 04:20:59 PM »

 are you sure it is an external temp sensor that thing has ? not an inbuilt

Still at say 15 batt temp it should not be higher than 15 volt  (even below)
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1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
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« Reply #11 on: March 22, 2011, 04:40:17 PM »

Billi, look at the link, the temp sensor is the wire that comes out the top. I don't have a wire there, just a hole...

I have changed the charge off Voltage to 13V, if the unit compensates for the -32C then it should now float the batteries at 14.4V.... might find out in a moment if the sun stays out... 

Also emailed the company I bought the unit from to see if they can send me a sensor....
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Stefan (S.T.E.F.)
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« Reply #12 on: March 22, 2011, 04:55:53 PM »

Yes, batteries are now being charged to 14.4V, thanks everybody for pointing me into the right direction !

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billi
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« Reply #13 on: March 22, 2011, 05:41:26 PM »

stefan     

not sure if the temp sensor  will sort you out, or if there is something wrong with the controller ( when showing -32  wackoold)

Was the sensor optional or  just missing  , cause normally controllers work without temp-sensors ,  perhaps in the menu the you can switch off temp compensated charge ?

Anyway do not pay too much ( or ask for a free unit ) if the temp sensor is needed

Billi
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1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
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« Reply #14 on: March 22, 2011, 07:59:58 PM »

I'll only have the temp sensor if I can get a free one... as adjusting the cut off voltage to 13V solved the problem... would be nice to have the temp sensor though... I am not sure if it was missing or if it was optional...
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