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cclarkego · 07-20-2009, 04:01 PM

Help me! I cannot figure out why my new batteries don't seem to be charging all the way up or holding much of a charge with little useage.

It has been a challenge for me as a woman, that never gave a thought to electricity before, except for flicking on a switch for light, to learn to understand the intricacies of my solar panel system now that I own a 1965 Airstream with an elaborate set up that a previous owner had installed for him. I have read the manuals that were left to me, but several important ones were missing. I figured out how to get it working and it ran perfectly for a year out where I boondock it on a ranch, until the eight year old gel batteries started failing. There is no shore power out there and I depend on the solar to run only my lights and occasional use of the Fantastic Fan.

I replaced the two old batteries with slightly larger new AGMs and a friend hooked it all back up. I reset my inverter/charger via the remote panel to the inverter/charger as directed. The problem is that the voltmeter is showing the solar is charging the batteries only up to 12.6 in the afternoon, then starts dropping slowly to about 12.2 by evening with no load on it. If I turn on the lights for awhile, it goes down to 12. Then a warning light comes on. I have even tried hooking up to my car with it running which gives it a small boost back up for a bit. Then I climbed up on the trailer roof, cleaned the panels, cut back some overhanging tree branches and the next day it made it to 13.1, but dropped right back down to 12.3 by nightime.

Here is what I have:

1) Two new Lifeline AGM 80 amp hour batteries

Everything below was installed in 2000
2) Heart Interface Freedom 458 (10) 1000 watt Inverter/Charger with basis remote panel (not Link 1000 or 2000)
3) 1 Siemens solar panel mounted flat on roof (which I think is a 75 watt from looking at pictures on the internet and measuring it to compare) (no manual or paperwork at all on this)
4) Specialty Concepts Mark 20 Photo Voltaic Charge Controller (with no manual or paperwork for this either and I have not tried fiddling with this at all)

I get sunlight to the panel from about 11AM to 6 or 7PM due to tree cover in the mornings. I am trying to get help to cut it back for more sun exposure time.

Any help will be greatly appreciated as I fear I am ruining my new batteries!

Carol

Dakota's Dad · 07-20-2009, 05:35 PM

A) Gel cell batteries do not generally work well in your application. For the way you are using the system most would recommend a lead acid battery, preferably, marine deep cycle.

B) have you cleaned your solar panel lately? They need a wash every few weeks to run at their best. (sorry, see you did that and it helped)

C) 75 watts of panel is not enough to restore the charge of two batteries on a 7-8 hour sun cycle, most of that sunlight will not be "peak" and there for makeing way less then the advertised wattage. When manufacturers rate the wattage of the panel they are giving you the performance in "perfect" conditions.. real life isn't like that at all.. my brother is 100% off the grid in way back nowheres Nevada, and I helped him research and install his system. When we put it in his 175watt panels would make about 155 watts, peak for about an hour a day, and average, for daylight hours only about 90 watts per panel, and his are oriented to the sun, though non-tracking.

cclarkego · 07-20-2009, 05:56 PM

The OLD batteries were gel, these are AGM, I just called Sears to recheck about them.
Apparently they are not Lifeline, they are Diehard Platinum Deep Cycle Marine and the guy said they are 1,150 amp hour. I am not at the ranch where I can look at them now, but I am totally confused at this point...

**azflycaster** · 07-20-2009, 06:04 PM

1,150 amp hours is a bunch, maybe he meant CCA (cold crank amps).

Gel batteries and AGM batteries have different charge profiles. I believe that the charge controller would not be interchangeable between the two.

cclarkego · 07-20-2009, 06:42 PM

I am not sure what that means.... Shouldn't I be able to use most standard type batteries and adjust something to make it work?
Carol

BDandTTs · 07-20-2009, 07:14 PM

We had a Mark 20 controller for our 75W panel when installed with our Scamp. Here is a link to the Mark 20 instruction manual, from the Specialty Concepts website.

You might find some help here.

Dakota's Dad · 07-20-2009, 07:27 PM

What did you "reset" in your inverter/charger? Is your inverter producing 120v all the time, if it is, then it is pulling power from your battery to do so, and inverters are not really very efficient, it could be pulling your batteries down... Yes you should be able to use most standard type batteries, but some DO work better then others.

akflyer · 07-20-2009, 08:08 PM

Hmmm. A couple of thoughts come to mind.

First, gell cells are typically charged at lower voltages than AGMs. Depending on what literature you read, "they" say that you can either charge gel cells and AGMs at the same voltage, or that gel cells should be charged at a lower voltage. In any case, it's probably worth check the actual charge voltage that the solar charge controller is putting out (which will be somewhat higher than what the lower-voltage battery will "pull" it down to, if you measure them when they are connected - so you'd want to temporarily disconnect the charge output wires from the charge controllers, use a voltmeter to measure the output voltage from the charge controller, and adjust the controller as appropriate before reconnecting the wires). It should be around 14.5 volts for the AGM batteries. It's possible that the solar charge controller was set at a lower output voltage for the gel cells that used to be there, which simply might not be enough for the AGMs. It's probably worth checking, anyway.

I also see in the specs for the Freedom 458 inverter/charger, that it has a setting somewhere that allows you to tell it that you are using flooded cells, "Gel1", "Gel2", or AGM. Not sure how to properly select the proper setting there, but again, since they all operate at slightly different voltages and thresholds, it's probably worth verifying that the proper setting has been selected.

My guess is that it's one, or maybe both of the above issues which is causing your glitches. Since there's should be no difference in wiring between the two battery types otherwise, my guess is that it's a setting issue.

Good luck,

aJ

Campaz · 07-20-2009, 08:25 PM

Many inverter/chargers have a switch or setting to select the type of battery you are charging, lead acid, agm or gel. You might check and see if yours is of that type. It could be as simple as changing it from gel, the old batteries to agm, the new batteries.
You might also recheck your charging setpoint voltage on the charge controller. It should be 13.5 volts.
Another thought is your batteries may not have had much of a charge in them even though they are new. It depends on how long they sat around at Sears without having a maintenance charge put on them. If you look at the other things and they check out, try having a good full charge put on the new batteries and try again. your batteries did charge more on the second day. It might take several days before they can completely charge. Wiping PV panels off does very little unless they are filthy.
I lived off grid for 5 years or so and never cleaned mine and it doesn't rain here much. Hope you get it figured out and it's easy.

Mexray · 07-20-2009, 08:41 PM

If your battery system is discharging that quickly, your batteries have not been given a FULL charge initially...

Are you running some kind of 'load' (lights, etc.) when you are away from the trailer? This 'load' may be drawing the batteries 'down' faster than your single solar panel can 'recharge' the next day...

Don't leave your inverter ON when the trailer is unattended or you aren't using it - most inverters draw some current when in 'idle' and will discharge you batteries...

The voltage readings you have noted, are not a good indicator of your battery system's charge condition - after charging, your batteries need to 'rest' without any activity for the voltage reading to give you a direct indication of amount of charge...the rapid discharge rate you are experiencing leads me to believe your batteries are not getting fully charged!

If you can't plug in the trailer's shore power connection, and therefore use the builtin converter/charger to fully charge your batteries...you might try using an external generator to get the batteries up to a full charge - then you solar panel should be able to maintain the full charge, unless you have some kind of current 'drain' as mentioned above...

Keep in mind that your two 80 Amp Hr batteries (160 total AH's) are 'electron fuel tanks' and when depleted, must be filled back up with your charging system...

Your 75 watt solar panel only puts out about 4.5 Amps in direct, full on sunlight - in ONE HOUR you will be only replacing 4.5 Amp Hrs (less any loss in the system) in your battery system that totals 160 total Amp Hrs!

If your battery system was half depleted (80 amp Hrs needed for full charge), it would take about 18 hours (80/4.5=18) of direct, full sunshine to fully charge them - when the sun rotates at an angle, you'll probably only get a small fraction of the '4.5' Amp rating, therefore you must allow much more time to 'pump that 80 amp Hrs back into your batteries!

Again, I suspect your batteries have not been allowed to receive a full charge yet...get them fully charged first, and you solar will be able to keep that charged when you're away...

cclarkego · 07-21-2009, 12:57 AM

Okie Dokie, thank you one and all! That gives me a lot to think about.
So to answer some of your questions and after reading the whole ten page manual that BDandTTs sent me on the solar controller...

Basically I keep the inverter turned off. The only things I run come straight from the battery: one small fluorescent or halogen light at a time, a couple hours; one Fantastic Fan on a really hot day for an hour or two or the stereo for an hour once in awhile. I am only in the trailer about three days out of the week, then home for a few days. I even bring up an extra separate Diehard battery, one of those combo things (car jumper, air compressor, inverter, etc.) if I want to run my laptop or charge my cell phone since I am so worried about the low voltage lately.

I am thinking that possibly the batteries never did have a full charge when they were installed since I didn't even realize my friend had put the new ones in for me until two weeks after it was done and he told me about it. He had the batteries for two months at his house after I bought them... I just saw the rather low voltage on the meter and assumed the old failing batteries were still in there.

I don't think the wiring is a problem since for most of the first year I had the trailer the system worked beautifully, great voltage readings. Even boondocking in Montana for a month..

I reset the Heart Interface via the remote per directions in the manual to change it from gel to AGM and also up to the 80 amp hour setting when I found out the new batteries were in, BUT, I never changed the solar panel controller because I didn't have the manual for it until the one I received tonight via the forum. Now I am thinking I need to print it out, go up to the trailer tomorrow and maybe check the set point. Plus a friend told me they have a voltmeter so I might be able to check a few of the parts of the system independently.

Lastly, since there is no shore power at the ranch and moving the trailer is impossible right now, if I wanted to try to charge up each of my batteries, couldn't I use my extra Diehard battery combo somehow? A generator would be great, but I don't have one and I spent all the last piddly money I had buying these batteries. Anybody have one they want to give away after they upgraded???

Let me know,
Carol

cclarkego · 07-21-2009, 01:07 AM

PS The only load on the trailer that I can think of while I am gone is the propane gas detecter. I even turned off the frig which I had running on propane when I found out the "brain" that determines keeping the temp at the right setting causes a load.... There are also a few teeny lights on the remote panel for the Heart Interface telling me the battery condition.

cclarkego · 07-21-2009, 11:59 AM

One more question. How much charge is going to my trailer batteries when I hook the car up and leave it idling?

Dakota's Dad · 07-21-2009, 12:24 PM

Quote:

Originally Posted by cclarkego

One more question. How much charge is going to my trailer batteries when I hook the car up and leave it idling?

at idle? nearly none, if any.

akflyer · 07-21-2009, 12:52 PM

I know the last thing you want to do at this point is to throw more $ at the problem, but FWIW, one to consider for the longer run is a battery monitor, such as this one:

Xantrex Technology Inc. - Boats - LinkPRO Battery Monitor - Product Information

Unfortunately, they're a bit pricey to start out with (approx $250 street price for this one), but I installed it's predecessor in my sailboat to help monitor the battery system, and I have to say that the extra info it gives you at any time on your batteries makes any troubleshooting much easier. I can tell at a glance the charge state of the battery, its charging or discharging rate, and an estimated time til fully charged (or discharged). Very handy to determine the exact current draw of every battery-powered appliance for "off-the-grid" planning purposes.

At the very least, consider adding a digital multimeter, which also can measure current draws to your toolbox - you can find them new for under $25 and will prove invaluable to help track down electrical issues.

Again, good luck - tracking down "stray electrons" can always be a challenge!

aJ

cclarkego · 07-21-2009, 01:08 PM

Quote: "In any case, it's probably worth check the actual charge voltage that the solar charge controller is putting out (which will be somewhat higher than what the lower-voltage battery will "pull" it down to, if you measure them when they are connected - so you'd want to temporarily disconnect the charge output wires from the charge controllers, use a voltmeter to measure the output voltage from the charge controller, and adjust the controller as appropriate before reconnecting the wires). It should be around 14.5 volts for the AGM batteries."

I am going up to the trailer to first see what the charge set point is at, adjust it to 14.4 if it is not already, (which is what my new manual says), then see how that works.

If I decide to disconnect the wire as quoted above, where do I do this? The wires are all inside the wall. I looked at the schematic in the manual on page 4, (see link from BDandTTs in above response) but do not see where "charge output wire" is.

With zippo experience in any of this, I feel like I am sitting at one of those tiny desks in Electrical Nursery School, but I am trying hard to do this on my own...

Thanks, Carol

cclarkego · 07-21-2009, 01:17 PM

God, that Link Pro looks lovely, but living on an artist's income right now, as I toss another bunch of bills from the mail onto the unpaid pile, I don't even have the money to fix the screen the bear punched out in my trailer the other night. (See "Have you ever had a bear climb in" thread)

I need to keep tinkering with what I have until I drop....

Mexray · 07-21-2009, 05:23 PM

Your Diehard combo-jump starting gadget won't help to charge your AS batteries - those things only have small, sealed, lead-acid batteries in them, and it wouldn't run your AS's converter/charger very long, if at all!

Hooking your car up to the trailer's 7-way tow cord will charge your batteries to some extent, however, at 'idle' your alternator isn't cranking out much in the way of usable current to charge at a very high rate - you'd have to run the car at a 'fast idle' for several hours to see much effect...

You'll probably need at least a 1000 Amp portable generator to power up your converter/charger...I don't see any other way out...possibly you can borrow one for a couple of days - or maybe rent one - to get your batteries up to a full charge...then your solar panel will be able to keep with the small demand...

The 14.4 volts for the solar charge controller sounds about right for bulk charging your AGM batteries...provided you can get them up to full charge, the 'float' charge for AGM's is around 13.5 volts - you may wish to check if your charge controller will automatically change to the 'float' setting when the batteries are charged fully...

Good luck...is there a creek nearby...maybe you could build a water-wheel to get a 'charge'...

Gypsy Jo · 07-21-2009, 05:33 PM

I don't know how hard your batteries are to get out but you could take them home with you and charge them with a battery charger

Mexray · 07-21-2009, 05:42 PM

Right on - common sense prevails again!!! right, just haul em' back to town for a good charging session...why didn't I think of that???

Reminds me of the story that really happened near where I worked, years ago in San Francisco...

A large flat-bed truck was hauling an oversized transformer for a power company and had to go under a bridge-like girder of an elevated roadway in town...

You guessed it, the top of the transformer became lodged in the girder as they drove their intended route...someone missed the measurement on that one!

For several hours, the various 'officials' fretted about how to pull this heavy object from it's wedged position...when a passerby mentioned that they may wish to let some air out of the trailer's tires and drive it out...which of course is what they did!