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 > AGM Mystery Capacity Crash Below 75% SOC UPDATE

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full_mosey

Oklahoma

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Posted: 09/28/19 03:47pm Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:


...

--When doing my capacity testing with Wets at the 20 hr rate,

..


Here's a bit of heresy. I don't know my SOC and my battery specs do not include any AH rating. I do not use an AH meter(fuel guage).

Ok, they are Eaton Powerware label AGMs and weigh 100.2lbs. 100lb AGMs have around 150AH ratings. I work with that. I have a PDF spec sheet but the link to the Eaton website is now broken. The spec sheet lists; 260 full discharges, 800A for 5 sec, 50A charging max, etc.

Apparently they are tel-com pulls. I have two sets; a set of 2 that I have used since 2015, and a set of 4 that I have used since 2018. The batteries are 5+ years old when I get them. The set of two are dated Oct 2009 and the set of 4 are dated Mar 2013. I believe they are UPS type.

When I bought the newer set last year, I also bought a inverter/charger. This his has a conditioning setting similar to the Lifeline 5.5 Conditioning procedure. I used this procedure on each battery before installation in my van.

The older set of two are going into my new TT along with a 1000W/50A Magnum.

I have had 2 AGMs fail since 2009 when I switched. One was a Bass-Pro(Deka 8A24M) and the other a Optima Blue 55AH. Both would only show 10+ Volts at rest after charging. Both failed suddenly and not over a period of time like yours.

I don't mix battery types.

Did you charge yours separately or all together as one big bank?

HTH;
John

full_mosey

Oklahoma

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Posted: 09/28/19 04:17pm Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

I do in fact adjust the charging voltage for temperature, so that when camping in February and ambient is 35F, I will set 15.2 instead of 14.7 as in July. The adjustable voltage PowerMax "LK" line of converters lets you do that manually.

My old VEC1093DBD portable charger has built in temperature comp and you can see it working when it operates at higher or lower voltages.
Neither compensates for battery internal temperature though, just ambient.

The AGM guides insist upon temp comp. If you set the spec 14.4 (for 77F) in February at 35F, you will be undercharging the AGM, with no way to see the SG failing to rise to the right amount.


With temp-comp charging, you do not manually set the charge Voltage.

There is no point in discussing SG with AGMs.

If you will read through my linked topic you will see that I use the .5% rule when charging. Float is optional and NOT a valid charging Voltage. You must eventually apply charging Voltage until the .5% rule is achieved.

My solar chargers will repeat and lengthen ABS daily as necessary until the .5% rule is done. I have graphs that show when the solar is falling behind and that is when the genny is used. Charging can be spread out over days within limits.

HTH;
John

BFL13

Victoria, BC

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Posted: 09/28/19 04:24pm Link  |  Quote  |  Print  |  Notify Moderator

100lb AGMs sound like 4Ds Some of those can be 200AH, while my 8D at 150 lbs is rated 250AH. AGMs except Lifeline seem to have spec max charging at about 30% charging rate. So 50 amps on 150AH works.

I had the 100AH AGMS for a year before they got in this MH and for the two years since they have been recharged per Mex's rules (20% bulk, 0.5/100) The 8D was second hand so I don't have its history. It has worked ok for a year until this started.

It seems to arise from repeated high amp draws where heat must build up inside and warps or cracks the plates somewhat. One high amp run I can get away with, maybe--we'll learn more about that when next out camping.

The mix of 27s with these AGMs is a quick-fix attempt to get more time with these AGMs before I have to get a new battery set. One of these days I will have four new batteries all the same, and have no more trouble [emoticon]


1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
See Profile for House electronics set-up.

full_mosey

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Posted: 09/28/19 05:31pm Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

100lb AGMs sound like 4Ds Some of those can be 200AH, while my 8D at 150 lbs is rated 250AH. AGMs except Lifeline seem to have spec max charging at about 30% charging rate. So 50 amps on 150AH works.

I had the 100AH AGMS for a year before they got in this MH and for the two years since they have been recharged per Mex's rules (20% bulk, 0.5/100) The 8D was second hand so I don't have its history. It has worked ok for a year until this started.

It seems to arise from repeated high amp draws where heat must build up inside and warps or cracks the plates somewhat. One high amp run I can get away with, maybe--we'll learn more about that when next out camping.

The mix of 27s with these AGMs is a quick-fix attempt to get more time with these AGMs before I have to get a new battery set. One of these days I will have four new batteries all the same, and have no more trouble [emoticon]


I use them like they are 150Ah. There is a 100lb Lifeline that is 150Ah. They are 13+in long and 11+in tall. I do have a G31 Johnson Controls and these are basically just taller.

I lifted the dinette seat and the label reads 'pwhr12500w4fr'. I have read that as 12V, 500W. I used the 2 with the 1000W inverter and the 4 are used with the 2200W inverter. The spec sheet includes a constant Watt chart.

I cannot meet the 20% rule with the 4. The charger is 75A and the 600Ah total for the 4 would call for 120A to get 20%. Adding 20A solar which usually is not usually coincident is only 95A. However, I am a stickler for getting to .5%.

I will be running capacity tests in Oct. I expect to draw 150A for 2 hours to prove the bank is ready for next year. I too like a silent breakfast. That is extreme though. When I first started using a converter, I was happy to get 80A for 30 minutes from a 79Ah Deka.

The Spartan charger calculates ABS time during Bulk. The time can be from 1 to 12 hours. I can manually restart the Spartan and get an extra 1hr ABS as often as I want.

HTH;
John

pianotuna

Regina, SK, Canada

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Posted: 09/28/19 06:04pm Link  |  Quote  |  Print  |  Notify Moderator

Hi BFL13,

Mine weigh in at 115 lbs. Telecom jars are a surplus acid design. Capacity is 139 amp-hours each.


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp hours of AGM in two battery banks 12 volt batteries, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

BFL13

Victoria, BC

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Posted: 09/28/19 06:56pm Link  |  Quote  |  Print  |  Notify Moderator

To clarify if needed, my AGMs are not "telecoms" so I don't know how much of this might apply to telecoms. Several members here do have AGM telecoms in their RVs.

On the 20% rule, don't forget that is only for the Bulk stage when under about 75% SOC at the start of the recharge. At about 75%, the acceptance rate at 14.4 volts falls below 20%, so it is impossible to meet that rule after that point. You will go straight into the Absorption Stage and amps will taper.

That is not a bad thing as long as you do go to the final 0.5/100 thing often enough (somehow) when shallow cycling on solar.

I got one 27 back up in SG using Mex's advice. Low and slow all the way to 16v. Took about 18 hours. Started with the VEC1093DBD at 4 amps with Equalize blinking, so it would continue to 15.8. SG was just into the White when that stopped and it said FUL. Then I put on my PowerMax set to 16 volts and ran that for a few hours. Don't know what amps that was. SG came up nicely into the Green, and it is now on Float. Doing second 27 now.

Mex did say that 15.8 is NOT the same as 16!

What a difference from ten years ago fighting with those horrible 27s to get their SGs up into the Green! Sure helps when you know how and have the right equipment. Takes a lot of your time though. Wouldn't be good for a working stiff getting back from camping Sunday night and heading off to work Monday morning!

* This post was edited 09/28/19 07:12pm by BFL13 *

landyacht318

Near a large body of salty water

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Posted: 09/28/19 11:54pm Link  |  Quote  |  Print  |  Notify Moderator

BFL13, put an ammeter on the output of your adjustable voltage powermax. Best 20$ you will spend this month.

I just bought this one in the 50 amp version for my 40 amp meanwell, ships from Canada, should a got the 100amp:

">ZfKuBsQ86hjmFx0ncyeQTAhttps://www.ebay.com/itm/50A-100A-Voltage-DC-Voltmeter-Current-Power-Meter-Energy-tester-Charger-Ammeter/264288477006?hash=item3d88d21f4e[emoticon][emoticon]ZfKuBsQ86hjmFx0ncyeQTA

I like the external shunt and the very small clear OLED display.

The amperage is quite accurate, and has a tiny trim pot to dial it in closer.
Voltage on mine reads 0.1v low, which irritates me greatly, but I'll get over it.

Its unidirectional. Just counts juice flowing in one direction. Volts ,amps, watts, amp hours, watt hours, and has an ambient temp sensor on the backside of the display too. I put 45 amp anderson powerpoles on mine input and output, can discharge the battery with a load for x amount of time, note the Ah and WH Flip input and output around, reset it, then charge it, see how much WH and AH it takes before amps taper to 0.5% at Vabs.

Plenty of space in the casing of the Powermax to install the display in a rectangular hole you cut with a dremel and cut off wheel, with lid removed, and while you are in there get rid of the 270 degree potentiometer and install a Bourn's 10 turn potentiometer of the correct value. Makes fine tuning voltage to the 0.01v so much easier than the provided potentiometer.

BFL13

Victoria, BC

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Posted: 09/29/19 06:40am Link  |  Quote  |  Print  |  Notify Moderator

Here is something on full_mosey's AGM:

https://www.osibatteries.com/p-28573-eat........ware-pwhr12500w4fr-battery-12v-vrla.aspx

----------

Thanks LY, I will check that out. When I split the bank I can only have the Trimetric on one of the sets at a time, so having the ammeter on the second charger (converter rigged as a portable charger) would be handy for sure if doing two sets at once to speed things up.

I have never understood why they don't put an ammeter on converters same as they have on any portable charger. How hard can it be?

I will be able to use the Trimetric when finishing up the second 27 today, now the Tri is freed up from doing for the other batts. That will show the amps when using the converter at 16 volts after the VEC is done at its 15.8. (the VEC has its own ammeter)

The VEC is down to less than 4 amps when it gets to 15.8, so it won't likely be many amps getting to 16. Find out later today.

* This post was last edited 09/29/19 08:37am by BFL13 *   View edit history

MEXICOWANDERER

las peƱas, michoacan, mexico

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Posted: 09/29/19 01:09pm Link  |  Quote  |  Print  |  Notify Moderator

[emoticon] LY!
Excellent find. Kudos to the vendor for accurate description and honest caveats.

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