Why did my AGM house batteries die in two months?

jasoev · 10-03-2018, 03:42 PM

In a previous thread I identified two NPP NP6-200Ah AGM Deep Cycle batteries purchased to upgrade my Harris battery on my 2019 Jayco GreyHawk.

After less than two months of the RV connected to power in my driveway, these batteries appear to be dead. As a test, I disconnect AC power, turn on my inverter, and turn on the TV. In 5 to 10 minutes my battery voltage drops from full charge (~12.6V) down 11.7 volts and lower, then I lose power.

When I first installed the batteries we did a test where we ran the inverter, watched a movie, and the charge remained full after a few hours.

I thought maybe my charge controller that is part of the Progressive Dynamics PD4060K Power Control Center has an issue with AGM batteries. I emailed them direct and they responded:

Quote:

The PD4060 will charge AGM batteries. You can leave it plugged continuously.

If it was working and then stopped there is a problem with the converter or the wiring to the battery.

Test the converter as per the test procedure. PD4000-Troubleshooting [progressivedyn.com]

As a second test I tried charging the batteries with my Zamp solar panel, and they appeared to charge quickly, but died again running the same load test.

It's hard to believe there is a problem with the wiring to the battery, or even with the converter. While the ZAMP panel was connected everything seemed to work fine. Also, when connected to shore power I am seeing a good charging voltage (14.3V).

My 200 AH system has gone down to a 0.2 AH system, and I have no clue why it happened.

If my onboard charge controller is not the problem, does anyone have any guesses what the problem might be? Could the batteries be defective?

Grumpy · 10-03-2018, 03:55 PM

Quote:

Originally Posted by jasoev

Could the batteries be defective?

That would be my guess based on your post, have you tried them one at a time?

Wertles · 10-03-2018, 03:56 PM

I had the same issue with my 2011 Greyhawk. I fried two batteries by leaving it plugged in. My on board charger didn’t have a float mode so I boiled two batteries to death. Once I charged them up, I would then hit the battery disconnect button and then the battery lasted years. Others have not had this problem but I certainly did.

jasoev · 10-03-2018, 04:32 PM

Grumpy, they are two 6V batteries, to test them individually are you saying I should measure the voltage of each one to see if one is substantially lower than the other while they are under load?

Grumpy · 10-03-2018, 04:40 PM

Quote:

Originally Posted by jasoev

Grumpy, they are two 6V batteries, to test them individually are you saying I should measure the voltage of each one to see if one is substantially lower than the other while they are under load?

Yes. Or have an auto parts check them.

jasoev · 10-03-2018, 04:46 PM

Wertles, my father-in-law said the same thing. He said he has fried motorcycle batteries on an external charger that supposedly was AGM safe for trickle charging. As I indicated in my first post the manufacturer of the onboard charger claims it's safe.

From the web for the PD4000 Series of Converter/Chargers:

Quote:

The PD4000 series incorporates a microprocessor to provide a three-stage charge profile to ensure rapid, yet safe recharging of 12 volt
batteries. These three separate stages BOOST, NORMAL, and STORAGE modes ensure that the battery is automatically recharged
and maintained with minimum maintenance (i.e. reduced need to add water).
BOOST MODE: If the converter senses that the battery voltage has dropped below a preset level the output voltage is increased to
approximately 14.4 volts DC to rapidly recharge the battery.
NORMAL MODE: Output voltage set at approximately 13.6 volts DC.
STORAGE MODE: When the converter senses that there has been no significant battery usage for 30 hours the output voltage is
reduced to 13.2 volts DC for minimal water usage. When in storage mode the microprocessor automatically increases the output voltage
to 14.4 volts DC for 15 minutes every 21 hours to help reduce sulfation of the battery plates.

What I don't know is whether the above applies to AGMs.

Another question I have is whether or not I should have paid more for a named brand. From my initial research it seemed like most AGMs come from China anyway, so I figured buying a no name brand like NPP from China wouldn't matter.

jd99336 · 10-03-2018, 04:51 PM

I have a two 6V set up that I had put in almost two years ago now with no real issues. It could be something as simple as a single cell in one of the batteries being defective, but only real way to test is with a draw down/load meter. I would go to a battery shop rather than parts store as I would not trust them to identify the 6V parallel set up. The batteries should be warrantied. I am not sure what the right test for the PD4000. However, if your charge voltage is 14.3V all the time, that is too much unless the batteries are bad. It may start at 14.3 but should as the charge approaches full, drop into the low 13's based on my experience. However if the controller is detecting less than a full charge, the voltage would stay high.

cabinetmaker · 10-03-2018, 04:54 PM

Quote:

Originally Posted by jasoev

Another question I have is whether or not I should have paid more for a named brand. From my initial research it seemed like most AGMs come from China anyway, so I figured buying a no name brand like NPP from China wouldn't matter.

Pretty sure this is your problem. Where did you purchase these China AGM's?

jasoev · 10-03-2018, 05:14 PM

Grumpy, I just tested the voltage of each battery under the load of the inverter and TV. The battery on the positive load side was dropping fairly fast to 5 volts, but the negative load side battery was closer to 6.4V, and didn't seem to be dropping as quickly. Once I killed the inverter and TV (before the whole system went down) the positive load side battery rebounded to 6.22 V.

Is it worth just replacing the bad one, or are both likely damaged?

jasoev · 10-03-2018, 05:17 PM

CabinetMaker, I bought the batteries from Amazon:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Grumpy · 10-03-2018, 05:27 PM

Quote:

Originally Posted by jasoev

Is it worth just replacing the bad one, or are both likely damaged?

I've always been told that both should be done together, whether 6v in series or 12v in parallel. I've always replaced all at the same time.

jasoev · 10-03-2018, 05:41 PM

Quote:

Originally Posted by jd99336

I have a two 6V set up that I had put in almost two years ago now with no real issues.

JD, were yours AMGs? What brand? I assume you have a similar Progressive Dynamics converter/charge controller as my PD4060K.

PlayersZ28 · 10-03-2018, 06:41 PM

I have 4 Fullriver 6v AGM's that are now 3 yrs old. They are charged by solar when not in a full hookup park and when parked at home. The OE converter is a PD4500 and I occasionally use it to charge the batteries when at home. The longest they've stayed on the converter is maybe 6 weeks. No issues so far, they are sitting @ 12.5v right now with only parasitic loads and no charging (it's dark) according to my phone.

Some AGM's don't like the equalization charge (sulfation) although Fullriver told me it was okay for mine.

cabinetmaker · 10-03-2018, 06:52 PM

Quote:

Originally Posted by jasoev

CabinetMaker, I bought the batteries from Amazon:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I looked these up and it says they come with a one year warranty. Not much for a AGM but I would notify Amazon and send them back.

I don't completely trust Amazon. I have personally ordered stuff that when received seemed to be previously returned items and repackaged. Some were missing instructions or pieces. Some were seconds or out of date. If it's shipped from a third party you never know. Not saying that's what has happened here but that has been our experience.

jd99336 · 10-03-2018, 09:35 PM

I don't remember the make on my batteries (maybe Trojan T-105's, but this is just something I jotted down while discussing potential candidates), but went to a local respected battery store and had them do the work and installation. They said they were well rated and they weren't cheap ( I think $180 or more per battery).

GeorgiaRV · 10-04-2018, 07:35 AM

Jasoev

I am having similar issue with my VMax AGM batteries. I have three 155ah 12v batteries and same charger you have. I also called the battery manufacture (Vmax) and they stated that the progressive charger is fine with these batteries.

My batteries https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

hoppers4 · 10-04-2018, 08:00 AM

I posed that question to Progressive Dynamics and here's the response I got.

"Yes. It will work with AGM deep cycle.

David Watson

Service Department

Progressive Dynamics

On Wed, Nov 16, 2016 at 3:50 PM, D ... <.....@.....com> wrote:
Can I use this converter/charger for AGM batteries? I would like to replace the standard wet cell in my RV with AGMs.

Thanks,
Don
--
Service Department

8A.M-12PM & 1PM -5PM EST
Phone 269-781-4241

FAX 269-781-8729"

cabinetmaker · 10-04-2018, 02:27 PM

You guys are just asking for trouble using the stock converter with these expensive agm batteries. The stock converter Jayco uses is only a small step above terrible!

jasoev · 10-04-2018, 07:18 PM

Quote:

Originally Posted by cabinetmaker

You guys are just asking for trouble using the stock converter with these expensive agm batteries. The stock converter Jayco uses is only a small step above terrible!

CabinetMaker, do you think the stock converter/charger is sufficient for flooded-cells? What is it about the charger that you aren't crazy about? Have you upgraded yours?

hoppers4 · 10-04-2018, 07:49 PM

Quote:

Originally Posted by cabinetmaker

You guys are just asking for trouble using the stock converter with these expensive agm batteries. The stock converter Jayco uses is only a small step above terrible!

Uh oh, that's the first I've heard of that. I've read where they puke once in a while, like any other piece of electronic gear, but not that it's a POS.

I thought mine worked like it was supposed to in that it bulk charges at 14.4, drops down to around 3.8 for a while, and maintains float between 13.2 and 13.4. Is that bad news for an AGM?

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