AGM battery aging out?

Aubrey

Well after a couple days of successful solar battery charging at a racing event, the weather turned and the battery dropped quickly.
Back at home, I fully charged the battery to 13V, then left it unhooked from shore power with only the fridge running. Less than 3 days later the battery is at 11.9V.
This looks to be the original 245amp hr AGM single battery that came with the trailer in 2017-2018.
I assume I should be getting more performance than this if the battery was new. At this rate of discharge I don't think we could boondock for more than a day or so, and the solar 200w suitcase really cant be helpful in spotty weather (great in the sun), but even on an overcast day shouldn't it be able to compensate for the fridge only?
It may be time for me to study up on battery replacement, and possibly adding a monitor. 
Is there an advantage to multiple 6v versus one large 12v?

Aubrey

My instinct is to stick with what fits stock, assuming my performance is way below standard.

GigHarborTom

WE pre cool  the frig with frozen bags of ice the night before launch. With previous T@G we would run on battery etc to the camp site. We had a new deepcycle RV and Marine battery. Boondocked for 3 nights. Used CPAP and frig on battery for three nights. Worked well for three years untill we sold. Our 2020 TAB has a Rennogy  battery that works fine also.  I do have a 150 watt solar suitcase that I just used one day to try out before moving up to the TAB.

Aubrey

I see my battery may be a dry-cell? It is an EV4DA-A by Discovery. 

Aubrey

Anyone tell if the date code is here? Little bit of rust on exposed washer on positive battery. Obviously my performance has dropped below boondocking level, but i would like to verify the date.

Aubrey

Denny16

If the first letters represent the date code, than this is a Mar. 2015 built battery, of the last letters are the date code,then it is Jan 2014, which is not likely on a 2017 build date on a 2018 TaB400.  

@Aubrey I assume you are in Canada, and this appears to be a Canadian built battery, different from the nüCamp provided battery used in the original 2018 TaB400s.  The nüCamp provided single 225AmpHr. batteries started failing after around two years of use.  Five years on one AGM is about average, if used a lot.  

We replaced ours with an Interstate 200Amp.Hr. AGM battery two years ago, and this battery has the ability to handle 4-5 days of Boondocking camping in NorCal area.  It mounts in the same space as the original single nüCamp provided battery:

This is an Interstate AGm4D 12VDC 200€Amp. Battery.  Sorry for upside image, but it keeps converting this way, original was right way round.
Cheers

Aubrey

Thanks, I wondered if it was original. I know by the end of 2018 NuCamp was using 2 6v batteries in series. It must have been an owner upgrade. It worked ok for awhile but the voltage drop I described above seems way to high 
(low).  How is the performance after 2 years?

Aubrey

I am in Ohio BTW

Aubrey

Does that battery have clamp 0n terminals or bolt on?

pthomas745

So: what are you monitoring this battery with?  You have about 117 amp hours available.

You charged the battery.  You ran the 2 way fridge for three days.  Lets say about 30 amp hours per day for the fridge, and I'll give it 6 amp hours a day for the parasitic drain.  Which is...about 118 amp hours.  Which would be about 50 percent of your available amp hours, and would approximately come out to 11.9 volts on a basic AGM state of charge chart.

If these numbers are anywhere close to what your power use was, it would seem this battery is perfectly fine.

What battery monitor/multimeter/shunt device are you using to determine your 11.9 end point after three days?

Aubrey

Interesting. I have read your other posts about amp hour use, but I must admit I dont have a great understanding yet about the system. I get alarmed if I get down to 12V but if I am dropping only to %50 SOC maybe I should calm down.
It was quite hot all weekend as well.
I believe the last fully charged-to- 11.9V drop only took little more than 2 days, but I had gathered from other forum users that they can get more than 2-3 days out of their 400 on 12v.   We were trying to avoid generator purchase and the accompanying hassles, and the 200w renogy did a fine job when the sunny was out, but I would love to be able to enjoy some dvd time and near constant fan use in the summer without limiting my stay to 2 days (or running a genny).

Replacement AGM are very hard to find around here (SEOHIO) as well. Time for another test I reckon. I am charging the battery now, then I will unplug, rest a bit, deploy solar panels and monitor for a few days again. Its a rainy week here so I should get a good idea of the limitations and such.

Sure do appreciate the forum members for sharing their time.

Marceline

If you intend to do a fair amount of boondocking, I recommend buying a Victron SmartShunt so you can accurately measure power consumption. IMO @pthomas745 is in the right ballpark with his calculations. And since it was "quite hot," your fridge was probably consuming even more power because the ambient temp inside the trailer was high. 

rh5555

It can take longer than you might think to fully charge that AGM battery using the standard converter.  Think multiple days...  If your solar monitor tells you when the battery enters float-charging mode, then you'll know when the battery is fully charged.

Aubrey

I would like a shunt, but I can watch the battery voltage on the solar control at least. The first day we used whatever we liked, and when the bright sun was out it went from low-ish 12V back to 13V by the afternoon. this weeks driveway test will help me learn the limitations under less than sunny to downright rainy weather. Also I should have mentioned no factory solar on the T@B, so the renogy charges directly to the battery with a SAE fitting, thanks to all!!

Denny16

Aubrey said:

Does that battery have clamp 0n terminals or bolt on?

The Interstate battery uses the wing nut terminal screws, no clamp.  Yes, if you bought this TaB used Aubrey, than it is possible a previous owner switched out the nüCamp OEM battery, which had a high failure rate after one year.  Still, according to the date code, the battery you now have is still more than 5 years old.  The Interstate 200 Amp AGM slides right in, and battery cables attach to the terminal screws on the battery.  

Another option, is to replace the failing battery with a 200 Amp Lithium battery, or two 100 Amp lithiums, both of which will fit in the original battery location.  You have solar, so that will keep a Lithium fully charged.  No need to swap out the converter’s charger.
 Cheers 

XenanMe

I had the exact same battery that came with my 2018 Tab 400 from the dealer.  So it must have been the stock battery for at least some of the trailers. With my 2-way fridge I got about 3 days before that battery would drop below 50% (without solar).  With age I imagine it may have lower capacity.  I switched mine out two years ago. 

Aubrey

Nice. Confirmation . Thanks! What battery did you switch to? 

Denny16

Yes, thanks for the update on the battery being an OEM from nüCamp @XenanMe.
Cheers

Aubrey

UPDATE
Well my battery use driveway test was slightly skewed by the fact that my fridge temporarily stopped running (odd problem from another discussion)
The fridge and fan are on for this test, not gonna use light just to get a baseline usage for warm weather nights.
1100 AM - 13v
1230 pm - 12.65v
230   pm - 12.55v     Thats 20% discharge in 3 hours or so...
fast forward to 930 AM next day I am at 11.8V or 70% discharge.
I think it is safe to assume my OEM 2018 battery has done its duty and has way to little capacity for dry camping.
Even without a smart shunt to verify I dont have some wild drain, the fact that the solar can keep up with appliances during a decent day tells me the battery is awfully tired.

A local vendor searched his warehouse for me and found ONE Brightway 4D AGM 200aH battery I believe should nearly match the dimensions of my battery.

Aubrey

It is a 4D Narrow, so the only thing I would need to do is move the one piece of wood locating the end of the battery  under the bed, unscrewing it and moving it about 2" outward. width is fine and height is lower (current battery nearly touches underside of bed so that is good).
I would be losing 35aH capacity, but since my battery has never been up to snuff for us I bet I wouldn't notice. 
It is $600, so I wanna make a good decision.
And that's why I hang out on the forum!

Aubrey

I suppose the only risk is screwing into something below deck

pthomas745

Are your battery measurements from a "rested" battery?  The battery switch is off when you took these? No solar charge coming in for the 13V readings?

Aubrey

Correct, charged, rested 13v, turn battery cut-off back to on, fridge running and no solar, several hours of fan. Depleted in less than 24hrs. 
Having a hard time finding any replacement 4D batteries in ohio, except for the Brightway i mentioned, but they want 600 bucks for it, seems high.
Thought about call rv dealer or nucamp to ask where to shop.

pthomas745

There are many AGM batteries of that "general" 4d size on Amazon, also.
https://www.amazon.com/Renogy-Self-Discharge-Discharge-Appliances-Maintenance-Free/dp/B075RGX1WR/ref=sr_1_1?crid=1G8PE41TVYUUU&keywords=200+amp+hour+battery+4d&qid=1659113094&sprefix=200+amp+hour+battery+4d,aps,114&sr=8-1

Aubrey

I swear, reading all the reviews has made shopping pretty difficult. Even the Regony battery has haters. Probably professional negative reviewers

Denny16

From what I have seen, the Regony battery is very good, and has a good warranty behind it.  As for what is under the false floor the battery sits on, it is a 2x2, see photo below.  I would just add a filler strip of wood if the gap is greater than 3/4 of an inch, moving the outboard brace strip a 3/4” or less should not be an issue.  A good AGM battery in this 200-Amp size are expensive, $500-600 dollars.  See if the local vendor will reduce the price any, but today’s limited supply, high demand market is tough. 

Cheers 

As you can see in photo below, the battery sits on a false floor covering the wiring and plumbing runs on the 2018/2019 TaB 400.  The ply is around 3/8” thick, and two 2x2s sit directly under the battery to support the weight.  So as long as you use the original screws, moving the brace strip should not be an issue.  The problem area shown in the bottom photo (which is usually deer the plywood floor), is at the end of the battery where the water pipes (PEX tubing) turns to go into the galley, do not put any screws in this area!

pthomas745

@Aubrey Thanks for the confirmation!  Wouldn't want you to buy a whole new battery unless you really need to.  You have done extensive testing and practicing.
Personally: I've always felt batteries were commodities.  There are few manufacturers.  As Denny points out, the Renogy has a good warranty and return policy.  Amazon reviews about anything "battery" are.....really strange sometimes.  

Denny16

That said, I would buy the battery direct from a dealer or Renogy directly, not from Amazon, which resells returned merchandise as new.  Amazon is fine for sealed items and hardware, but not for electronic or some electrical items in my experience.  The warehouse folks are not always careful with returns, and sometimes defective items end up back in the for sale stock.
 Cheers 

Aubrey

Excellent. The Renogy 200aH through them is around $400, so that beats rolling the dice on amazon. Says 2 yr warranty against failure. Gosh the internet is somehow less useful than it was years ago, and amazon seems like the wild west of shopping. 

Denny16

Excellent Aubrey,
These days, dealer support is more important than a good price, and worth the extra $.
 Cheers