Solar controller/monitor shows batteries charging all the time suddenly

[Pat]

I got some new AGM 12v batteries last spring.  Sealed, maintenance free.  Love them.  Really clean.  I'll never go back to watering batteries.

Suddenly this week the solar panel has switched from showing the batteries as charged (green light) to charging (yellow light) all the time.  Could that be an indication that a battery is going bad? 

The old batteries I replaced showed the yellow charging light all the time, and they were pronounced virtually dead when I replaced them. 

The indicated voltage is still around 13.4 or 5 when in use and 13.6 or 7 when not, so whether the solar panel or the converter is charging them, everything seems to be working.  Main monitor panel shows battery power full.  I thought maybe a battery cable was bad, but I would think the voltage would drop.

Or would this be a converter issue?  Another thing I noticed last night was that the little fan on the converter was clicking, and when I looked at it, it was not spinning smoothly, but rather jerking forward.  I tapped the back of the fan, and it started to spin.  Haven't seen it working today.  Tomorrow I plan to phone the converter manufacturer to ask about the fan. 

I have been running the furnace much of the time, and the fan is 12v, but even when I turn it off for hours on a sunny day, the yellow charging light stays on.

Just trying to understand what the indicators are telling me.

--pat

 

[Gary RV_Wizard]

Well, the yellow light says current is flowing to the batteries from the panels.  That's hardly unusual and at least some tiny current flows on green too. Hard to guess how much current it takes to go to yellow from green unless you have some specs on the solar monitor/regulator.

I would wonder whether the converter is charging like it used to be, though the battery voltage suggests that the bats are being charged. But maybe only via solar now?

 

[Ned]

I disconnected my solar controller from my AGM batteries as it was putting out a bit too much voltage for the AGMs.  The float voltage for AGM batteries is 13.2-13.3V and the solar controller was putting 13.4+V out and overcharging the batteries.  I believe this contributed to the shorter than expected life of my first set of AGMs.  The problem was the AGMs are fully charged at 13.2V and the controller wasn't shutting off at that voltage, thus overcharging the batteries.

 

[Pat]

Agreed about the possible overcharging.  I asked when I bought the batteries whether the 13.6 or 7 would be harmful.  Someone looked them up and said it was fine. 

The controller definitely works after dark when the solar panel is not working.  The battey charge indicators show all lights on through the upper greens. 

I do suspect a battery could be going bad, possibly from overcharging or from rust on the connections.  There's a lot of humidity here, and the connectors are rusty in places.  I'll take it into the battery place when I get to Mesa.

Regardless of the short life of these batteries, I sure love the maintenance free and won't go back to the water type.  I assume these things have some kind of warranty, so replacements won't be as expensive as the new originals.


--pat

 

[Ned]

13.6+V will definitely overcharge the AGM batteries and probably shorten their life.  The battery connections won't rust, the posts are lead and the cables and lugs should be copper and since the batteries are sealed, there is no source of acid for corrosion.  In all the years I've had AGM batteries, I've never seen any corrosion on the connections.

My Lifeline AGMs had a warranty and they did replace one after 4 years for a reduced price.  I think the warranty was 5 years.  I replaced the other 3 a year later.  Since disconnecting the solar charger, I expect to get up to 10 years from these batteries.

 

[Pat]

Ned:

How'd you disconnect the solar charger?  One of the lines going to the batteries? 

I have an Iota DLS45, I believe it is.  I have the IQ Smartcharge attachment.  After dark, when I assume the solar charger is not operational, the batteries are still kept at 13.6 or 7.  I think the IQ attachment does that.  The set point on the solar controller is 14.4.

Since these batteries are barely 2/3 of a year old, if one is dying, there should be a good prorated replacement value. 

I am so satisfied with these AGM batteries as far as maintenance (or lack thereof) is concerned.  Hope I find the expertise in Mesa to disconnect the solar monitor or configure the converter or both to keep AGM batteries working 5 or 10 years.


--pat

 

[Ned]

I just removed the wire from the controller to the battery and taped it off.  If the charger is set properly for AGM batteries, it should use a float voltage of 13.2-13.3 volts.  13.6 is for flooded cell batteries.  Of course, these values are for an ambient temperature of ~70F.  Higher temps will allow a lower float voltage, while lower temps will allow a higher float voltage.

 

[Karl]

Pat,

According to the IOTA website, the DLS-45 with the IQ Smartcharge will output 2.26 volts per cell or 13.56 volts in float mode for a 12 volt battery. There is no mention I could find about using (or not using) the DLS series with AGM's, either with the IQ or without it. If that's the case, you could indeed be overcharging your batteries causing short life. Call their tech support, and if they can't give you a satisfactory answer, get a converter/charger that has a setting for AGM's. Like Ned said, 13.6 is for flooded cell batteries; not AGM's!

 

[Pat]

I'll email Iota again.  They responded well the other day when I had a question about the fan. 

When I bought the batteries, I asked at the battery shop about the Iota charger and read them the specs.  Their manager said the settings were fine, but I suspect it was a guess. 

I'll look into the correct charger.  This could get expensive and inconvenient changing batteries every 1/2 year.

--pat

 

[Gary RV_Wizard]

"Overcharging" is hardly a black & white situation.  While 13.6V is higher than necessary or optimum for an AGM, it is hardly "high" on an absolute scale.  14+ should probably be considered "high" though (your engine alternator typically charges at rates of 14.0-14.5VDC).

I would be very much surprised if your Iota  shortened your battery life to any measurable degree.

 

[Karl]

Gary,

14+ should probably be considered "high" though (your engine alternator typically charges at rates of 14.0-14.5VDC).

While I agree with everything you said, the engine alternator charge rate of 14-14.5V is a bit misleading. You typically will not charge from the engine for endless hours, but may be hooked up to shore power for days, weeks, or even months at a time. An occasional charge of 14-14.5 would be similar to an equalization cycle, but long term float voltage above the recommended may have long-term effects. Just my thoughts - I'm certainly no expert. 

 

[Gary RV_Wizard]

but long term float voltage above the recommended may have long-term effects.

I can't dispute that either Karl. But I don't think several months at 13.6 is going to have any measurable effect.  For what its worth, I have a 90A Iota in the Dolphin we just traded and my AGMs are still fine after two+ years at 13.6V float. I might also add that the 12V AGMS were paralleled with 6V GC wet cells all that time and the GCs were not new when I added the AGM bank in parallel (no isolator either).  Quite possibly they would have been in even better shape had I not done so, but  a few tenths of a volt in float charge or small mismatches in charge rates doeis not foretell the end of the civilization as we know it.

As you can tell, I'm no purist when it comes to batteries.    I watch 'em, water them (where appropriate) and use  'em. They are no where near as fragile as we are often led to believe.

 

[Karl]

Gary,

As you can tell, I'm no purist when it comes to batteries.  Wink  I watch 'em, water them (where appropriate) and use  'em.

Me neither, but no matter how much I water them, they never seem to grow any baby AAA cells. :'(

They are no where near as fragile as we are often led to believe.

Quite true. Maybe Pat's problem has to do with the solar controller set at 14.4V?

 

[Pat]

AGMs got back on green after I drove from OR to AZ into the sunshine, for whatever that's worth.  The controller always shows the batteries at about 13.6, so the set point on the controller doesn't seem to have an effect. 

I haven't been using the furnace till last night.? I'm watching to see if the furnace blower on the 12v power will again bring the AGMs into charging mode.? I asked IOTA about the equipment I have, and the respondent didn't know anything about AGMs and didn't understand the question.? Since these are becoming popular RV batteries, and RVs use the IOTA chargers, I'm surprised IOTA aren't working on something AGM-specific.?

The power went out for about an hour here the other night, and the AGMs worked fine.? All I had them doing was run the alarms and the fridge controller, while the fridge kicked over to gas.? Turned off the lights.  Sure is great to have a working battery system.?

My GCFI triggered twice within 12 hours of each other after the power outage, whether or not it was related.? I removed the small surge protector from the computer, and it hasn't triggered in 24 hours.? However, I also spoke to someone who said holding in the reset button longer will often keep it from triggering again, so maybe I did that as well.? I hate it when I do 2 or 3 things and then don't know which one fixed the problem.? A TrippLite surge protector definitely kept tripping the GCFI.? TrippLite said their leakage will do that, and they don't work on GCFI circuits - something they should have put on the packaging, so people don't buy them and have problems.?

--pat