Off grid solar generator--wont charge past 11.8V

[jwpookie47]

I have a 50 W monocrystalline panel, 10 Amp CC-see pic below...both lights are green. There is no load on it: Everything on this setup is brand new.we bought the panel and CC from Renogy. I have it hooked up to a 12 V/35 AH Sealed Lead Acid battery (brand new)---we attached it all to a dolly for portability-so we could move it for best sun and also for using it in different areas.
Here is my question and problem: we can't get the battery to charge past 11.8 V We are not using the inverter on it, we'd been waiting until the battery was fully charged. We are in Michigan and it's winter but Ive been charging the battery for a full 7 days- the indicator on the charge controller is green which should mean that it's charging--still 11.8 V
Any guess out there as to whether the problem is with the solar panel or with the charge controller? Or how to test either to determine? OR...do these panels just really need full, bright sun to fully charge?
Any advice is very much appreciated. I'm a newbie to this stuff and I'm kind of on my own as hubby doesn't want any part of it.

[Logan005]

Your panels should be angled southish and unobstructed. There should be no shade. I would use a smart charger on this battery ASAP to minimize any damage you may have done by under charging it for the past 7 days. In your location I would recommend adding another 50 watt panel to insure proper charging and useable power for your needs.

[jwpookie47]

Thank you. I didn't even know that undercharging the battery could damage it. Will follow your advice. Much appreciated.

[Raj]

I agree with Logan005, you need 2 50 watt panels to charge the battery. The reason for this is that the PWM CC you have only converts 33 watts of the panels 50 watts into usable power. The 35 AH battery needs 5 to 7 amps to charge effectively. Your charging amps with one panel is only about 2.75 amps. 2 50 watt panels wired in parallel would give you about 5.5 amps, which should work well even in Michigan.

[PNjunction]

There is also the possibility that the battery is toast even though it is "new". Long periods of shelf-storage, high heat etc can do it in before it gets into your hands.

If you don't know what to look for, I agree with Logan - get a smart charger on it. My personal favorite for this type of setup would be a Tecmate-Optimate 6 charger. There are a lot of automative chargers out there that are too agressive, too loose in their specs, etc, but the Optimate 6 is a no brainer for decent charging, testing, and maintaining. Make the connections and walk away (no buttons to push), or totally geek out like we do deciphering the led status indicators.

Thing is, when the Optimate isn't maintaining or charging your battery when there just isn't any sun, you can also use it on your vehicle batteries keeping them in shape. Maybe the hubby will come around when he sees that!

[Wy_White_Wolf]

What order did you hook the wiring up in? You should hook the charge controller to the battery first and then hook up the solar panel.

WWW

[jwpookie47]

Update: I bought a digital voltmeter that is wired into the system. Today they sun shined all day and the reading got up to 14.4 and the green 'battery fully charged' light was blinking. Success! Thanks for all the advice. I am sure that the battery was damaged from being undercharged for so long.

[PNjunction]

Don't run away so fast!

Just because the led indicator says "done", it is NOT done charging! What is really done is the bulk, or possibly the absorb phase. We don't know what controller you are using, but none that I know say done, except for kits - and even they get this wrong in order to please you with a green light.

AGM's need a *minimum* of 8 hours of float to actually finish the charge! You can keep it on after this for maintenance purposes, but that critical 8 hours of float must not be skipped. And ESPECIALLY so with a new battery.

Many wheelchair / mobility chair chargers are also guilty of this leading the owner into a false sense of security until their battery dies prematurely. Even after the charger says "done", it need 8 hours / overnight to actually finish the charge.

So what to do? Put that solar kit you have back out there for at least another day to finish the charge. Under normal circumstances where people are cycling agm's daily, they have to make up for this lack of a finishing charge at some point in the weekly routine - or just buy batteries sooner than later over and over.

If you can't get this thing out into the sun often even when the controller says "done", then do invest in a maintenance charger to actually finish the charge when the sun isn't out.

The other issue is that your "new" battery may actually be toast - highly sulfated batteries are very quick to charge because internally they are very small in capacity relative to what they were new due to an abusive or ignorant environment, such as long retail storage etc.

This is where the Optimate 6 which performs testing and gives you indicators above what most other charger do can really help figure out if your battery is healthy or not.

[Wy_White_Wolf]

Don't run away so fast!

Just because the led indicator says "done", it is NOT done charging! What is really done is the bulk, or possibly the absorb phase. We don't know what controller you are using, but none that I know say done, except for kits - and even they get this wrong in order to please you with a green light.

AGM's need a *minimum* of 8 hours of float to actually finish the charge! You can keep it on after this for maintenance purposes, but that critical 8 hours of float must not be skipped. And ESPECIALLY so with a new battery...

PWM controller so she only has bulk and float. It's as done as the system can get it.

I bought a digital voltmeter that is wired into the system. Today they sun shined all day and the reading got up to 14.4 and the green 'battery fully charged' light was blinking. Success! Thanks for all the advice. I am sure that the battery was damaged from being undercharged for so long.

Down side is at 14.4 the controller is set for FLA batteries instead of AGM. They should only be taken to about 14.2V. If your controller has settings for AGM you need to change it. if it doesn't you need to get a different controller.

WWW

[jwpookie47]

Ok, here is my charge controller...it didn't say done. But the green light started blinking..which, in the user manual, indicates that the battery is fully charged. My battery is a 12 V 35H sealed lead acid battery. I am going to have to take a class in order to understand some of this stuff. By trade, I am a registered nurse..and I'm not considered a dummy, but some I need to learn about the difference between PWM and MPPT CC's. This little unit is hopefully going to be used to power a few things (a light, phone chargers) during power outages.

[Logan005]

You are getting there. and your interest in learning will get you through this. First get a better CC,and or a separate Low voltage Disconnect (LVD) the one you have will likely damage your battery and any future batteries you may buy. Second: get another 50 watt panel, as your system needs to be over sized to accommodate a worse case scenario. With cost in mind, Here are some CC;s I have worked with.

http://www.ebay.com/itm/301221639758?_trksid=p2057872.m2749.l2649&var=600274352263&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.com/itm/311374534055?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.com/itm/151481885806?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

the top link has adjustable (LVD), the bottom two links both have the LVD hard set and way too low, I like the second unit, it has USB and 12volt barrel jacks on the front and an informative display. the bottom link is for projects that require a waterproof CC,

[PNjunction]

Ok, here is my charge controller...it didn't say done. But the green light started blinking..which, in the user manual, indicates that the battery is fully charged.

Ok, I've seen those but don't know the actual make or model to guide you further. However, if you are getting up to at least 14.4v that's ok for agm. The previous reference to 14.2v is actually too low. For now you are fine voltage wise. Just keep that thing in the sun well AFTER the led blinks. If blinking means it finally arrived at float, you need at least 8 MORE hours to actually finish the charge. In other words, keep that thing in the sun as long as you can - at least initially during this week.

I don't want to throw too much at you at this point. Just be prepared to replace that battery possibly sooner than later - that is your "learner" battery that we ALL have been through at some point.

SAFETY - you want to get on top of this and develop good habits. Is there a FUSE anywhere in the leads going to the battery terminals? I don't see one from the photo. The idea here is not only to protect any shorted equipment, but to protect the wires! If that 35ah battery sees a short, your wiring will become the fuse instead when it burns. So look into that aspect.

Also, if that enclosure is totally sealed when you put a lid over it, that is a big NO GO. Make sure that enclosure is NOT air-tight. AGM's don't gas under *normal* circumstances like flooded batteries do, but if abused or by accident suffers from a large overcharge (controller failing etc), they DO gas, and you don't want an airtight box to prevent it from escaping.

At this stage, this will get you started and a lot more fun stuff to read about and learn!

[PNjunction]

Down side is at 14.4 the controller is set for FLA batteries instead of AGM. They should only be taken to about 14.2V. If your controller has settings for AGM you need to change it. if it doesn't you need to get a different controller.

She's fine as is since most agm's are actually spec'ed for 14.4 to 14.7v absorb in cyclic duty. Some can handle up to 15v even. (temp compensated of course).

14.2v is a poor no-man's land for voltage. Too low for agm, and a tad too high for many gel's.

Ideally, always follow the manufacturer's voltage specs, and make sure that the canned settings in charge controllers actually agree with this!

For example, with Morningstar Sunsaver pwm controllers, there is a jumper for "sealed" and "flooded". Unfortunately, many newcomers see that indeed their agm is "sealed", but when you look at the actual voltages assigned to the silkscreen labeling in the manual, that voltage is too low for agm. " "Sealed", on a Morningstar Sunsaver runs about 14.1 / 14.2v. That is ok for gel, but NOT for agm. In this instance, when running agm, one would choose the "flooded" jumper settings, since that voltage is around 14.6v or so.

[PNjunction]

With cost in mind, Here are some CC;s I have worked with.

Thing is, even with cost in mind, the controller is the very HEART of your system. Don't cheap out here if you can avoid it. The ones linked are barely beyond toys.

When a toy controller burns up your nice new Optima or Odyssey, there will be tears flowing.

Take a step up in quality and reliability when you want to get a bit serious. We're talking the typical Morningstar, Steca, Xantrex/Schneider, Samlex etc. - even for just the simpler pwm versions. Usually the docs alone make all the difference, nevermind the better product itself.

[jwpookie47]

The enclosure has no lid on it-it is just a rolling tool box that I am repurposing. The battery doesn't sit at the very bottom of it, it is lifted about 3 inches so I could build up the bottom to be level. I don't have a fuse. Guess I'll be reading all about fuses tonight. Thanks.