No converter just battery charger?

[Bogo]

Yes. Most likely the inverter only has a soft off. That is because the size of switch needed to turn on and off high amp loads is large and cost prohibitive. It'll draw some power all the time. Get a battery cutoff switch. You can go cheap or fancy with it. That don't matter.

[bdosborn]

The only item hooked up inline with the battery, not switched, is the inverter.

Oops, there's your problem. Inverters have caps on the front end that draw a little current, even when turned off.
Disconnect the inverter till you get it switched. AGMs are supposed to deal with deep discharges better; don't give up hope yet and keep charging it.

Bruce

[working on it]

The only item hooked up inline with the battery, not switched, is the inverter.

Oops, there's your problem. Inverters have caps on the front end that draw a little current, even when turned off.
Disconnect the inverter till you get it switched. AGMs are supposed to deal with deep discharges better; don't give up hope yet and keep charging it.

Bruce

Bruce- You've given me some hope! I never could figure why the Optima was losing power...I had even disconnected the constant power feed to the Pioneer radio (to keep channels in memory, and the clock on time) a few months ago, just in case that was it. Never suspected the inverter was the culprit (and must've also done in my other battery, since it was permanently hooked to the truck's battery, while it sat for months at a time, before I re-purposed it into my trailer). Just ten minutes ago, I went to check the battery (I charged it for two hours this time, cool-down for one hour following). The multi-meter showed 11.76vdc. Still not above 12vdc, but maybe following the next charge cycle?

[Dale M.]

My master disconnects are always between battery and FIRST item that connects to battery....

Dale

[bdosborn]

(I charged it for two hours this time, cool-down for one hour following). The multi-meter showed 11.76vdc. Still not above 12vdc, but maybe following the next charge cycle?

I would leave it on the charger for a day or so (if it's a smart charger). The longer the battery stays at a low voltage, the more sulphation (damage) occurs.

Bruce

[working on it]

(I charged it for two hours this time, cool-down for one hour following). The multi-meter showed 11.76vdc. Still not above 12vdc, but maybe following the next charge cycle?

I would leave it on the charger for a day or so (if it's a smart charger). The longer the battery stays at a low voltage, the more sulphation (damage) occurs.

Bruce

Bruce- Remember that my "smart charger is the Schumacher, which you, others, and I now don't trust to run unsupervised. What I'm charging with now is a "dumb" charger, and only capable of 2,15, 40, or 200amps. I would prefer a higher charge rate than the 2amps I'm using now (15amps for any period of time, except short "shocks", is verboten); the Schumacher offered 15/10/2amps...I would like to charge at 10amps on auto, but as we've seen, it may or may not shut-off or may jump to 15amps for too long a time...I'm not sure until I've used it more. But now is not the time; do you think an overnight charge with no automatic shut-down @ 2amps would boil it? After last night's charge session, it was at 11.76vdc, and 15 hours later was at 11.53vdc. I resumed the 2amp charge.

[bdosborn]

But now is not the time; do you think an overnight charge with no automatic shut-down @ 2amps would boil it? After last night's charge session, it was at 11.76vdc, and 15 hours later was at 11.53vdc. I resumed the 2amp charge.

Here's what I found for conditioning AGM batteries on the Big RV forum.

This is the way I condition AGM batteries

3% A/H constant amperage (3 amps for a 100 amp hour battery)

Allow voltage to rise to no more than 15.2 volts. This will take time and you will see the voltage "spill" occasionally .2 or even .3 and re-climb. This is healthy.

You should monitor cell temperatures. A scanning IR reader is ideal for this. At the rate listed above cell temperatures should not rise more than 5 degrees F over ambient at 68F. But this is a total permitted rise not a sudden rise. And it applies to each individual cell.

I would love to see an amp hour meter used and limit the conditioning charge to 120% of regular amp hour capacity, regardless of the 3% - 15.2 Volt 5 degrees formula. No more than 120% regardless of other factorials. But you must start off with a battery that has been maintained at 14.4 volts for at least 48 hours.

1. Charge at 14.4 for 48 hours

2. Apply 3% amp hours constant current

3. Monitor cell temps and cease charging if cell gain is more than 5F @ 68F

4. Curtail charge at 15.2 Volts or 120% of A/H whichever comes first.

5. 7 Hours at 3 amps sounds about right for a 100 amp hour battery.

6. Make sure NONE of those cells gets too warm. This is critical.

Bruce

[working on it]

But now is not the time; do you think an overnight charge with no automatic shut-down @ 2amps would boil it? After last night's charge session, it was at 11.76vdc, and 15 hours later was at 11.53vdc. I resumed the 2amp charge.

Here's what I found for conditioning AGM batteries on the Big RV forum.

This is the way I condition AGM batteries

3% A/H constant amperage (3 amps for a 100 amp hour battery)

Allow voltage to rise to no more than 15.2 volts. This will take time and you will see the voltage "spill" occasionally .2 or even .3 and re-climb. This is healthy.

You should monitor cell temperatures. A scanning IR reader is ideal for this. At the rate listed above cell temperatures should not rise more than 5 degrees F over ambient at 68F. But this is a total permitted rise not a sudden rise. And it applies to each individual cell.

I would love to see an amp hour meter used and limit the conditioning charge to 120% of regular amp hour capacity, regardless of the 3% - 15.2 Volt 5 degrees formula. No more than 120% regardless of other factorials. But you must start off with a battery that has been maintained at 14.4 volts for at least 48 hours.

1. Charge at 14.4 for 48 hours

2. Apply 3% amp hours constant current

3. Monitor cell temps and cease charging if cell gain is more than 5F @ 68F

4. Curtail charge at 15.2 Volts or 120% of A/H whichever comes first.

5. 7 Hours at 3 amps sounds about right for a 100 amp hour battery.

6. Make sure NONE of those cells gets too warm. This is critical.

Bruce

Once again Bruce, you've got me looking in the right direction. obviously, charging at 2amps isn't going to get me there, according to this info. I started looking for similar info, and came upon an Optima article on YouTube http://www.youtube.com/watch?v=Slqd73ZOQvI. It shows batteries as low as mine being successfully resuscitated. But, the method requires 10amps. Therefore, now that my AGM is at roughly 12vdc (after tonight's 2amp charging session), I'll put my 15/10/2 AGM charger on it tomorrow night ( without the inverter inline!). I won't charge it during the day though, my garage is 100+ degrees. I'll have to trust it overnight, and check it before I leave for work @ 5 am. Thanks.

[working on it]

I would leave it on the charger for a day or so (if it's a smart charger). The longer the battery stays at a low voltage, the more sulphation (damage) occurs.
Bruce

Bruce- when I got home today, the Optima still retained most of the previous night's charge, at 11.65vdc. I took the Schumacher XCS15 charger out of the inside cabin electrical panel, hooked the battery clamp set-up back on it (never noticed before, but I had reversed the positive/negative wires on the external clamps- glad I had to use it before the wife did). When I turned it on, and set it to AGM and 10 amp charge setting, the display read 11.5v and 18% charge. I have let it go for two hours now, and it reads 13.5v and 60%. The battery doesn't feel any warmer than when the charging commenced. So I guess I'll trust it to automatically charge/desulfate as it's supposed to, overnight, and will chaeck it again at 5 am. If its still within parameters (voltage not too high, battery not too warm, and no error messages) then I guess it is progressing back to functionality. But, I'll still not leave it on tomorrow day, I'll be away 12-14 hours (the wife will not check it), and will resume charging tomorrow night. Results to follow....

[working on it]

Update, 10 pm Thursday...checked the battery at 6 pm. It read 12.5vdc and 55% charge. It didn't drop as far as I had expected. Once again, I set the charger to 10amps and AGM, and aimed a fan at the charger and battery to keep both cool (102 degrees outside today, inside the garage was at least 110 degrees when I started). At 8:30 pm, I arrived at the scene as the battery reached 100% charge (at 15.60vdc). According to Optima, that's as high a voltage as you should go when charging (as long as battery temp is not 125 degrees or higher). I watched as the voltage reading fluctuated around 15.6vdc, for ten minutes, though the display said that charging was finished. I can only assume that it was desulfating, thus the fluctuating voltage. I needed to correct my plug ends being reversed ( see earlier post), so I disconnected. At 9:30 pm, I reconnected and the display read 13.3vdc,and 95% charge. I started it up again, and the readings rose quickly to 15.51vdc and soon 100% charged was reached (20 minutes). I disconnected for the night. I'm going to do it again Saturday morning, and let it run until it either shuts off automatically, the battery goes over 125 degrees, the voltage goes higher than 15.6vdc and stays there for a few minutes, or an error message is displayed. I think the battery has been saved, but now I need to determine if the charger is trustworthy on auto or not. Now is the time, not later, away from home.

[Dale M.]

Let the charger sit on battery for about 12 hours at float (100% charge) to desulfate and stabilize internally (chemically)... Then see what you have ..... 15.6 volts is a bit high but not dangerous, if internal temperatures are not extreme and battery is not bulging the is not a lot to worry about....

Dale

[working on it]

Let the charger sit on battery for about 12 hours at float (100% charge) to desulfate and stabilize internally (chemically)... Then see what you have ..... 15.6 volts is a bit high but not dangerous, if internal temperatures are not extreme and battery is not bulging the is not a lot to worry about....

Dale

I'm going to do that tomorrow, when I can monitor it all day. I'll be in the garage transferring the battery "home" to the tongue toolbox, from the galley area, for weight balance. I'm running 4 gauge cable, replacing the shorter run of 6 gauge I'm using now. And, of course, isolating the inverter from the battery with a switch. I got lucky, and didn't lose the battery, and will take precautions to maintain it now.

[working on it]

Let the charger sit on battery for about 12 hours at float (100% charge) to desulfate and stabilize internally (chemically)... Then see what you have ..... 15.6 volts is a bit high but not dangerous, if internal temperatures are not extreme and battery is not bulging the is not a lot to worry about....

Dale

I'm going to do that tomorrow, when I can monitor it all day. I'll be in the garage transferring the battery "home" to the tongue toolbox, from the galley area, for weight balance. I'm running 4 gauge cable, replacing the shorter run of 6 gauge I'm using now. And, of course, isolating the inverter from the battery with a switch. I got lucky, and didn't lose the battery, and will take precautions to maintain it now.

Hope this is my final post on this thread... First thing, I checked the battery voltage (12.8vdc, on my very accurate multi-meter), then did as I stated above, and let the charger do its "automatic" float/desulfate thing after 100% charge. Two hours later, after hovering around 15.6vdc (mostly around 15.54, as observed), the charger switched to the voltage display (= 13.4vdc), and to "std" (not AGM) and to "maintenance charge" (@ 2amps). I turned it off, repeated the steps, and one hour later, it did the same. Repeated this two more times. My conclusion is that the AGM battery, having reached 100% charge (12.8vdc being the normal full charge for AGMs) eventually reached a higher voltage than normal for AGMs (i.e.=13.4vdc). Then the charger would go to std/float at 2amps to maintain (2 amps is not the "recommended" default AGM charge). Verdict: battery saved, charger is adequate for my needs, but I will have to manually select charging state (10 amps or 15 amps, not 2 amps) as the charger fails to recognize that the AGM actually can lose capacity at 2 amp charging rate. Thanks to Dale M and bdosorn for their help and advice!

[working on it]

Just had to add this observation: after one week sitting disconnected from the power-leeching inverter, the Optima Yellowtop still has 12.86vdc as shown by my Micronta digital multi-meter. I can't tell you how glad that made me....Thanks again for the help guys.

[bdosborn]

Cool.
Bruce