Charge controller won't stay in float

RA

radarcontact

Senior Member
Joined
Oct 24, 2015
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195
Location
Wyoming, USA
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.
 
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.
 
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?

.
 
Couple of thoughts. Loose wire? Use a volt meter and check the truck battery to see if it is happening ther also, defective separator.
 
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.
 
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?
 
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.
 
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.
 
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.
 
You mentioned the batteries are brand new. If you weren't having this problem prior to replacing the batteries, I would suspect a faulty new battery and/or recheck the connections to the batteries. I'm in the marine business and I see brand new batteries that are not good, its rare but does happen. You'll need the manufacturer's specs on the batteries to test, use a known good volt meter and hydrometer.
 
Thanks for the reply. I installed the charge controller after I installed the batteries, so can't do a comparison to prior to the new batteries. I will check then out, though, per your suggestion.
 
pv, thanks for your detailed reply. Can't believe I didn't think of using the truck battery for a test LOL. I'm a knucklehead.

Going to pull the truck battery this aft. and see if hooking it up to the camper makes a difference. I tried running new wires from the controller to my batteries but it didn't change anything, so it's not the wiring. If the problem is in the controller to battery connection, it has to be either 1) the batteries, or 2) the controller. I'll know if it's the battery(ies) today.

I thought of the heatsink high temperature issue, and if heat was building up behind the controller, but that's not it, either. I keep the camper in the garage at night, plugged into shore power. In the morning I pull it out into sunlight, and disconnect shore power prior to taking it out of the garage. This morning the temperature here in Jackson Hole was 26F. The controller started it's cycling in and out of float immediately, and continued to do so indefinitely.

Wanted to mention that I HAVE had it float a few times, the way it's supposed to. But that has happened maybe two or three times since I installed the controller, which was in mid-July. The couple of times it did float correctly didn't correlate with anything I was doing different, if that makes sense. Just checked it now...truck is in full sun, and it won't stay in float. I will yank on the connections and see if that makes a difference. I've taken them apart and reconnected them at least 4 times so far.....
 
Interesting.

System appears to operate OK, but will not switch between Bulk, Absorption & Float. Not set for 3-stage charge. Will not switch out of Bulk. Will not switch from Absorption to Float. Confirm Float voltage setpoint is not set to OFF. Available net charge current cannot bring battery voltage up to the present charge voltage setpoint. Battery state of charge may be too low, battery too large, PV power too low, and/or loads too high. PV’s should produce at least 3 amps per 100 amphours of battery –and– daily PV amp-hours produced must be greater than daily load amp-hours consumed. Battery not fully charged. Unit will not switch to Float until 3000i remains in Absorption continuously for the Absorption Charge Time period. Periodic load pulls battery voltage low causing 3000i to re-enter Bulk resetting the Absorption Charge Timer. Consider using a shorter Absorption Charge Time setting. Momentary decrease in PV power allows battery voltage to drop causing 3000i to reenter Bulk resetting the Absorption Charge Timer


The 3000i will return to Absorption should battery voltage remain below the Float Voltage setpoint for more than 10 seconds.

Something wired in you aren't aware of that might do that?
 
radarcontact said:
Beach I checked my 6V batteries w/my voltmeter....both are fine. Don't have a hydrometer but I'll pick one up when I can.
Click to expand...
Don't think you are going to know if your batteries are fine with just a volt meter without putting a load on them. Might find a local place that can test deep cycle 6 volt batteries.
 
Since those are likely GC2 golf cart batteries, you might check out your local golf course’s cart rental/maintenance shop. Bet they can easily test them.

Paul
 
All helpful responses, thanks to everyone. Last time I took my AGM batteries to a local place that said they were the end-all in battery testing they were wrong....they said they were fine, but the batteries were bad. But, I will test them more thoroughly. Paul, that's a great idea. I'll probably take them to our local CC and see what they say.

Jax, I was thinking the same thing...still wondering if my IOTA is butting heads with my controller. I'm going up to Yellowstone tomorrow and will have the camper off landline for a couple days, so I'll see if that makes a difference.

Craig, the one part of your post regarding the absorption charge time.....I have a compatible battery monitor that comes from Blue Sky, IPN Pro Remote. It communicates w/the controller continuously. One of the settings on the monitor is absorption charge time measured by current vs. time, which is called 'Float Transition Current' on the monitor....once the current drops below 1.5A per 100 Ah of battery capacity (or whatever you set it for, this is adjustable), the controller goes from absorption to float. I left the setting on factory default (1.5/100Ah), and my Ah capacity is 230Ah, so it transitions when the current drops below 3.45A. Supposedly it's a better way of transitioning, instead of doing a standard 4 hours of absorption, or whatever the time parameter is. In theory it makes sense, but have no idea how efficient it is in practice.

pv...I couldn't do the swap-out of my 12V truck battery. My connections from the controller to my 6V batteries are via the screw-on 1/2 in. threaded post....my truck battery only has the fatter terminals. I don't have any adapters, so I couldn't do it today.
 
That method makes more sense. I had to think I was misunderstanding something. The IOTA charger shouldn't be doing anything at all if you're not plugged in.
 
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