Battery Upgrade

[peirek]

First let me set the stage. We boondock 1-2 weeks a year. The rest of the time the trailer is plugged into shore power either in storage or at campground with hookups. We have one house GP27 wet cell battery in a rear storage compartment. The battery is in a sealed box and is vented bottom and top. The house battery is approximately 8' from charger (WFCO WF-8935AN-P) connected with 6AWG wire (I am estimating ~10' of wire). I have been taking a second deep cycle battery and connecting to front vehicle connector. This is approximately 20' from charger. I know this is not at all efficient and is mildly effective, but it has served us ok. We run the genny (Honda EU2000) for ~4 hours a day which gets the batteries back up but not fully charged.

I would like to add a second battery to the rear storage compartment but have to consider venting etc. I am leaning towards using two AGMs (6V or 12V?) so as to not worry about gassing and venting. The compartment is big enough to contain both batteries and it will still have a vent top and bottom.

I am looking for guidance on AGM batteries (6V or 12V) and brand. I have learned the Trojans are the best but are they needed for my situation (1-2 wks a year)? I suspect upgrades to the charger will be in order so would like opinions on that. I believe Progressive Dynamics is the preferred brand. I also believe the 14.8 is recommended for AGMs. Is the 6AWG sufficient for a 45A upgrade?

Thank you for your suggestions, directions, and opinions in advance.

[BFL13]

". It is more important to maintain a bulk charge level above 20% amp hour capacity."

Mex, does this apply to all deep cycle AGMs or just to Lifelines and perhaps others who call for that in their spec sheets?

My AGMs say nothing about a minimum amps recharge. They do give a max amps of "about 27a per 100AH" and a charging voltage (14.5-14.9), but no minimum amps.

It means a lot to me, because I do the recharge- to- full of my 450AH of AGMs at home, where anything more than my 55 amp charger in the RV pops a breaker in the house the way I have things. It just takes longer to get them full at 55 amps, but at home who cares about the time it takes?

However, if the 20% minimum does apply to all AGMs, then I have to change my routine.

[MEXICOWANDERER]

Yep, and at my age a jar of mayonnaise may have a "Lifetime Warranty" 🙂 If you run out of power it's jumper cables and prayer time to start the generator. Before you settle on jar car, wet batteries, only Rolls & Surrette offers 24 and 27 batteries that are truly cyclable. The rest of the lot are .040" plate batteries that are EXACT COPIES of DeSoto and Chrysler Imperial batteries from the 1960's. Neat huh?. But no tar tops. With Trojan, you get a car battery that is better quality like the old Globe Union Sears Die-Hard. But Trojan comes at a stiff price. When I had a cab over KAMP KING monster camper in the late sixties, RV batteries were unknown. They did not exist. I settled for group 27 Autolite tar top batteries. 105 amp hour jobs. They had a CCA of around 525 amps and were heavy. I griped at the cost of $44.00.

(Use the Wayback Machine and take today's Johnson Controls RV batteries back to the 1960's) Unhappy customers would probably have lynched you. That's how bad things have gotten with underprocessed recycle lead, typewriter thin and stacked like onionskin.

Up until the 1980's a person could count on truck 4-D, 6-D, 7-D and 8-D batteries as being naturally deep cycle. Not any more. Stuff 29 old fashioned plates per cell into a new battery and they would jut out the case ends by over two inches.

There are a few golf car battery companies that do things the old fashioned way. But Nation wide only Trojan refuses to cheapen their recipe. Premium lead used to cast grids is expensive and so is plate paste. Scumbag manufacturers measure out cheap paste by the milligram and it's not only the quality of the paste, it's the thickness applied to the grid. There are 1,001 ways to scumbag battery construction and guess who pays for it? Rolls flooded batteries have a top quality niche that is deserved.

Bottom Line

I would go with CHINESE AGM batteries 10 to 1 versus trashbag car jar flooded batteries. Especially if you can find positive referrals for the battery. I have seen enough car jar garbage to be repulsed by it. Chinese AGM batteries versus Trojan T-105 batteries brings forth a much stiffer argument.

As for the 14.4 volts argument it has gotten out of hand here. Repeatedly undercharging an AGM battery takes it's toll after weeks of misuse. It is more important to maintain a bulk charge level above 20% amp hour capacity. When you get home, apply 14.4 volts for a week which will absolutely get the batteries 100% full. And a week's worth of 14.4 absolutely will not harm an AGM battery.

UNLESS it was done weekly over a long period of time like years. an occasional vacation does not enter into the misuse program.

Hard to service car jar flooded batteries are a nightmare. Like giving a birthday present McLaren to a 16-year-old. Flooded car jar batteries require TLC. Wanna devote hand's on TLC with hard to reach batteries?

My statements here are not directed at the OP solely. And are not meant as criticism. Hopefully others can take a hint about this subject. Toward the end of my battery testing I rejected new models of car jar wet battery tests as a waste of time. I made more money doing real work with GC, Scrubber, and L-16 testing. (Who makes the best Chef Boy Ar Dee canned spaghetti gets old fast)

The question may be to find reasonably reliable group 24 Chinese AGM batteries.

[CA_Traveler]

From your limited use get 2 flooded GC batteries which are deep cycle. Buy a box big enough to hold both. I bought a box that was easy to seal for my son, plus 2x Interstate GC's. We cut out the vents from his old box and used them on the new box. JB Weld glues almost anything forever.

12V batteries are NOT deep cycle except for a few very expensive ones. "Marine Deep Cycle" are only slightly better than starting batteries.

There are 6V AGM deep cycle batteries like my Lifelines and the absorb/bulk voltage is 14.4V. Normally they don't vent and if they do it's the end of the battery.

My toad has a 12V AGM starting battery that is completely enclosed and you attach a small vent line to it. That's because it's inside the car under the passenger seat. I'm not aware of any similar vented deep cycle AGM's.

[peirek]

@ BFL13: So an ammeter would need to be installed in the system to adequately monitor full charge of an AGM. Not a huge deal but another item to consider and install. I assume the charger is not able to measure and sense this because there is no programming for bank capacity (in Ah). Sounds like a nice feature to add to them.

@MEXICOWANDERER: The battery cases are 12.25" long inside so a 27/31 will not fit. Recall the battery(ies) are in an enclosed compartment in the rear of the trailer not out on the tongue. So they must be in vented cases. I have mounted a battery cutoff and digital voltage meter through the front of the existing case and the GP24 just fits.

As for the battery vs. tire debate. If I run out of power I can fire up the generator, start the truck, or turn on an LED lantern. If I blow a tire I can tear up my rig and be stranded who knows where.

For sure we agree on purchasing quality tools. NO debate here! HAHA

Decisions for me are about value. The best and most expensive is not always the best value.

And yes a top quality AGM is expensive and may outlive my rig (and maybe me). I cannot justify with 1-2 weeks boon docking a year.

[MEXICOWANDERER]

Why are you limiting a vast field to a mere (2) options?

If the tray can accept a 13" battery then it can accept a group 31 battery. If the tray can accept a pair of group 24 or 27 batteries then it can accept a pair of group 31 batteries.

Some people screech at the thought of spending money for a pair of AGM batteries then purchase 1500 dollars worth of tires while whistling dixie. And I can promise adequately cared for AGM batteries will live to see the grandkids of those tires. Unless of course the RV owner is convinced driving 100 miles on a vacation is considered long-distance.

But choosing AGM batteries by price alone is a real loser. I choose my new purchases using overwhelming mass positive reviews.

It seems like the cost of gasoline and the cost of batteries brings out a form of financial blindness or ignorance. (anyone who does not buy the very cheapest must be stupid). I don't buy plastic covered reclaimed foam over pine furniture, melmac dishes, and K-Mart blue light linens for a reason and it has nothing to do with snobbery.

If I have had agonizing short lifespan history with a certain tool I figure ten returns to a Lifetime Warranty vendor is more than a little challenge to my intelligence. So I choose Snap-On, MAC or Wiha. I purchased a pair of Wiha's eighteen dollar ALTERNATIVE BRAND flush cut diagonal pliers -- STUPID MOVE! In less than a year the tips, that top 30% of of them have SPREAD. Close the pliers and there is a .010" gap. For a mere ELEVEN DOLLARS postage Wiha will send me another pair of garbage dykes. The Second time Stupid is not my bag. I will spend the thirty dollars and end up with a good tool. Fifteen dollars down the *******. And I am screwed for flush cut pliers. This is intelligent?

Cutting OFC to 18 AWG should not have challenged the lifespan of the pliers. But my "saving" fifteen dollars makes me look like a *****'s ***

[BFL13]

You must have an ammeter to know when AGMs are truly full (when their amps acceptance tapers to 0.5a/100AH of bank at 14.x) And if you don't bring them to true full often, they sulphate. I use my Trimetric for that ammeter job.

You can tell when Wets are truly full with an hydrometer. You can overcharge Wets and just replace some water.

I have gone AGM but without my Trimetric I couldn't look after them. I also like that I can keep them inside the rig where it stays warm in the winter so they don't lose capacity in the cold just when I want lots of capacity with the furnace on so much. If the AGMS are outside in the cold, no advantage there.

[peirek]

PD 4655L MBA ordered.

Realized last night the GC2 profile is too tall for my cases. Doh! Not sure how I got twisted around the axle so bad..... I think the original thought of AGM eliminated any height issues as no case was needed. The cost of the wet cell GC2 pulled me in and I missed the height number.

What to do now?
Option 1: Two AGM GC2 - high $ & great capacity.
Option 2: Add another 12v GP 24 deep cycle wet cell - much lower cost with lower capacity. Still doubling what I have on board and equaling what I had taking an additional battery. One could argue an increase in performance with both batteries on board and new charger implementing bulk mode.


Need to ponder it a bit.

[BFL13]

Yes, the vented dust cover would have to come off so you could get at the lower portion. You could put the cover on hinges instead of screwed down if you are handy.

It is a lot easier to work one of these LKs as a deck mount where you can get at it plus see into the holes where the switches are inside the case.

[MEXICOWANDERER]

@MEXICOWANADERER: Thank you for your response. I fall into the weekend warrior category as I am in Texas where "80% of camping requires the use of AC and pedestal power. It is only in the winter and mountain trips where boon docking is feasible for us"

That really reduces the need to insist choosing a top drawer battery.

[peirek]

BFL13 wrote:


That is in the 3-stage mode. If 30 minutes isn't enough time, switch to single stage, set 14.8 or whatever and it stays there as long as you like, then dial in some other voltage. See para 10 here:

http://powermaxconverters.com/wp-content/uploads/2018/05/PM3-12V-LK-Manual-2018.pdf

You do need a little screwdriver to adjust the pot and perhaps a flashlight to see what you are doing. Might have to get down to floor level to do that depending on where it is in the RV.

I like the older model with the big knob on top for adjusting the pot, but that would not work as a lower portion. Also the external knob ones cost way more.

I think all these newer LKs are on Amazon, but you can call Errin at PowerMax HQ and find out where you can buy one if not. Their dealers are still mostly selling off their old ones first.

Be sure to get an LK--you might order an older type MBA by mistake.
The pictures in the ads don't always show the right model. LKs have their fans inside, eg, so you can spot an older type from that.

https://www.amazon.com/PowerMax-PM3-55MBALK-Smart-Battery-Charger/dp/B01MT6H1RV/ref=sr_1_82?ie=UTF8&...

To access the power supply adjustments/mode setting I would need to remove the cover on the power center. Certainly not something I would want to do very often. I guess I would anticipate needing more than 30 minutes in Bulk/Boost mode. But maybe I am wrong since my WFCO never got above 13.6.....

The PD 4655L MBA, while more costly, has a few additional features (4 stage, charge wizard, and wired remote) but lacks the adjustable voltage. Decisions, decisions.

[BFL13]

peirek wrote:
Ahhh ...... direct replacement. Thanks.
Step 8 insinuates it will run in bulk mode (14.6v) for only 30 minutes. This leads me to believe it does not have any smarts but instead has a fixed bulk mode run time ( no monitoring of battery). Pure speculation but don’t find anything to the contrary.

That is in the 3-stage mode. If 30 minutes isn't enough time, switch to single stage, set 14.8 or whatever and it stays there as long as you like, then dial in some other voltage. See para 10 here:

http://powermaxconverters.com/wp-content/uploads/2018/05/PM3-12V-LK-Manual-2018.pdf

You do need a little screwdriver to adjust the pot and perhaps a flashlight to see what you are doing. Might have to get down to floor level to do that depending on where it is in the RV.

I like the older model with the big knob on top for adjusting the pot, but that would not work as a lower portion. Also the external knob ones cost way more.

I think all these newer LKs are on Amazon, but you can call Errin at PowerMax HQ and find out where you can buy one if not. Their dealers are still mostly selling off their old ones first.

Be sure to get an LK--you might order an older type MBA by mistake.
The pictures in the ads don't always show the right model. LKs have their fans inside, eg, so you can spot an older type from that.

https://www.amazon.com/PowerMax-PM3-55MBALK-Smart-Battery-Charger/dp/B01MT6H1RV/ref=sr_1_82?ie=UTF8&...

[peirek]

Ahhh ...... direct replacement. Thanks.
Step 8 insinuates it will run in bulk mode (14.6v) for only 30 minutes. This leads me to believe it does not have any smarts but instead has a fixed bulk mode run time ( no monitoring of battery). Pure speculation but don’t find anything to the contrary.

[BFL13]

"@BFL13: I believe the adjustable voltage would allow some compensation for wiring R (V loss) which would be a good thing. It would also allow optimum voltage for each battery type (should they be changed). The issue is where to mount it...."


This is the LK version of the "lower portion" replacement.

Check the link in this for installation --shows picture of where it goes.

http://powermaxconverters.com/product/pm3-mba/

[peirek]

The Duracell is made by Deka which I think is a pretty good brand.

Found a T-125 equivalent Duracell SLIGC125 (235Ah) @ Batteries + Bulbs for $129.99 + 10% discount if ordered on line ($117).

[peirek]

@MEXICOWANADERER: Thank you for your response. I fall into the weekend warrior category as I am in Texas where 80% of camping requires the use of AC and pedestal power. It is only in the winter and mountain trips where boon docking is feasible for us.

@time2roll: I have plenty of height so no issue with the added inch.

@pianotuna: I don't think I am looking to add a converter but rather upgrade what I have. I understand the increased value of the converters you point out. Installing directly next to the battery has some serious value that I should ponder. One concern, it will be in a non-vented/non-cooled compartment that may cause heat buildup. The batteries will be in vented battery boxes and vent from bottom to top and out.
On second thought this may could go behind my current converter and be mounted to the floor but again no fresh air and possible heat build up.

@Cydog15: This is how I am leaning. I believe I should consider upgrading the 6AWG to match the 55A. Need to investigate the feasibility and difficulty of this.

@Crabbypatty: The Trojan T-125 would fit my battery box and are pretty impressive performance wise (240Ah). About twice the price of the Duracell GC2 @ 215Ah. hmmm........

@BFL15: I believe the adjustable voltage would allow some compensation for wiring R (V loss) which would be a good thing. It would also allow optimum voltage for each battery type (should they be changed). The issue is where to mount it....