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Charge controller won't stay in float


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#1 radarcontact

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Posted 26 September 2018 - 03:21 AM

I recently replaced my Zamp charge controller w/a Blue Sky SB3000i.  I have 2 panels on my roof, both Zamp panels, a 160W and an 80W, connected in parallel through the roof plug.  For some reason unknown to me or Blue Sky, my controller won't stay in float mode once Vfloat is achieved or exceeded.  The controller amps out reads 0.0A in float mode, and the resting voltage drops steadily over a period of a minute or two to my set float voltage point, 13.5V.  Once it gets there it jumps out of float and back into absorption.  Voltage rises to 14.5 for less than a minute, enough for the battery to exceed 13.5V.  Then back to float, etc.  This can go on all day.  The problem is no amperage going out to the batteries in float mode.  The only load when this is happening is the LED lights on the charge controller (maybe 0.1-0.2A).  Everything else is turned off.

 

Can anyone think of anything that might be causing this in my camper?  I've connected each panel individually to the rooftop plug, and also to my sidewall plug, same scenario.  I've quadruple-checked all my connections, everything's good.  Blue Sky has been trying to help me - they sent me a replacement controller last week, but the same thing is happening.  Why would the controller not be sending out amperage in float mode?  It has to send out a trickle, otherwise you get this constant cycling back and forth from float to absorption.  I don't think it's the unit...probably something in my camper setup.  I've also hit the 'kill' switch and turned off the IOTA IQ4 converter, thinking that maybe it was knocking heads with the solar controller, but no joy.  Any input would be greatly appreciated.


Edited by radarcontact, 26 September 2018 - 03:34 AM.

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#2 pvstoy

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Posted 26 September 2018 - 04:34 AM

If you have checked every connection including the negative cables and fuses. Then you might try putting in a different battery and see if it stops. Process of elimination from battery to panel. All I can think of before bed time.
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#3 Old Crow

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Posted 26 September 2018 - 12:02 PM

I almost hesitate to ask this given I don't even have solar, much less a Blue Sky controller.  But here goes...

 

I see the manual (if I have the right one) says factory-default float voltage is 13.2 volts but you mention a 13.5 volt float.  Does the controller exhibit these symptoms on factory-default settings?

 

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#4 pvstoy

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Posted 26 September 2018 - 02:27 PM

Couple of thoughts. Loose wire? Use a volt meter and check the truck battery to see if it is happening ther also, defective separator.
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#5 radarcontact

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Posted 26 September 2018 - 02:57 PM

I've unplugged the camper from the truck, which would in effect disconnect the battery separator, no difference.  I had access to a new separator and put that in to see if by some miracle it would change things, no dice.

 

I tried setting the controller to factory defaults (i.e., 13.2V float) to see if that would work, it didn't.  

 

My batteries are brand new 6V 230Ah batteries wired in series.  Trying different batteries is a good suggestion, but I'd like to avoid that if I can, simply because I don't really want to go out and spend another $200-300 on a 12V that I'll most likely not need.  It may come down to that, though.

 

Racking my brain to figure out something else to try.  Doesn't make sense that two controllers would do the same thing, though I suppose it's possible.  Blue Sky has been great about trying to help me figure this out...they're mailing me a third controller (!) that they've bench-tested to make sure it stays in float once it gets there...doubt the controller is the issue.  I have a battery monitor as well, it confirms 0.0A are being output from the controller in float.  Net battery amperage when in float is -0.2A, which is what the LEDs are requiring to operate on the controller and monitor.  The controller should sense this output of amperage from the battery and compensate, plus add a tenth or two of an amp to keep the batteries in float mode, but it's not doing that.  Blue Sky feels it may be a problem in the PV to controller wiring, but I don't think so....I've switched the panels from the rooftop solar plug to the sidewall plug, and I still get the same issue.  Two sets of wires having the same problem is like two controllers having the same problem - not likely.  Also, the panels are sending a small amount of amperage to the controller in float mode, around 0.1-0.2A, and the voltage of the panels in float is ~20V.  Just nothing coming out of the controller.


Edited by radarcontact, 26 September 2018 - 03:06 PM.

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#6 rando

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Posted 26 September 2018 - 03:28 PM

This also sounds like a wiring issue to me - between the controller and battery.   It seems that the controller is not sensing the battery voltage correctly.   How is the charge controller wired to the battery, and are there any loads while you do this test - particularly loads that switch on/off like a fridge?


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#7 radarcontact

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Posted 26 September 2018 - 03:42 PM

10AWG wire to the battery directly from the controller, through a 30A ANL fuse.  The fuse was recently installed, but not the problem...I've run the connection without the fuse, still the same problem.  No load when testing this, other than what's required to run the LEDs on the controller, battery monitor and the IOTA converter.  No frig, no lights, nothing.

 

I'm in agreement with you, that my gut feeling is that the controller isn't sensing the voltage properly...but that doesn't explain why it does sense the battery voltage in general.  After it switches from absorption to float it displays the drop in voltage, from around 13.8 to 13.5 before it goes back to absorption, so it 'knows' what the battery voltage is, but for some reason it's not connecting that information with maintaining the float.  

 

One thing I could try is getting some more wire, disconnect my current controller to battery wires and run a temporary connection from the controller to the battery and see if that makes a difference.  Just have to cut some wire and crimp on a few connectors.


Edited by radarcontact, 26 September 2018 - 03:47 PM.

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#8 radarcontact

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Posted 26 September 2018 - 04:31 PM

Tried the new temp. wires from controller to battery, no change.


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#9 pvstoy

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Posted 26 September 2018 - 04:34 PM

I was not suggesting to buy new batteries for a "test" you could just use the truck battery.

This new controller has worked in the past? Is it programmable ? If so could there be a switch or menue that might have the wrong settings that is not matched to the batteries, or...?

Do a hands on pull tug with some effort to see if fittings are shorted while watching the meter. You could have a wire with a slight gap or break under the insulation or loose crimp that is causing the problem, both positive and negative wires.

Agree with Rando that there is something between the controller and battery that is amiss.
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#10 pvstoy

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Posted 26 September 2018 - 04:48 PM

On one of the manual pages.. just a thought.

PANEL TEMPERATURE AND THERMAL PROTECTION
Internal power control devices use the front panel as a heatsink. It is normal for the front panel to become quite warm to the touch when the 3000i is operating normally. Front panel heating will be the greatest when the 3000i is processing either very high power or very low power. When mounted to a vertical surface with good ventilation, the 3000i can deliver full output in an ambient temperature of up to 45°C (113°F). If an over temperature condition exists, the 3000i will simply cycle on and off to keep internal temperature within acceptable limits.
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