Replacing FLA with AGM, advice wanted

Topsail · 09-26-2020, 11:43 AM

I neglected adding water for too long and now my two 31DC FLA batteries need to be replaced. I want to avoid the water routine by switching to AGM's.

I'm the third owner and one of the previous owners upgraded to a PD9160A converter/charger by Progressive Dynamics. I have ordered the Charge Wizard PD9105 total charge management system, making this a suitable AGM charger system.

I've been looking at the various AGM batteries and frankly would like some input. Obviously, true deep cycle is preferred. We don't plan on serious boondocking anytime soon so for now simple is preferable. Can I get two decent batteries for 400-500?

Battery suggestions sure would be appreciated.

DavidM · 09-26-2020, 11:51 AM

These Renogy batteries should work: https://www.amazon.com/Renogy-Batter...xpY2s9dHJ1ZQ==

David

Winterbagoal · 09-26-2020, 12:33 PM

Those do look pretty good at that price.

Topsail · 09-26-2020, 12:57 PM

Those do look like a good solution and a great price. Thx David.

DavidM · 09-26-2020, 01:07 PM

Quote:

Originally Posted by Topsail

Those do look like a good solution and a great price. Thx David.

You are welcome.

Renogy is a brand, Chinese made no doubt, that started out on Amazon AFAIK and has developed a wide variety of DC power products for the boating and RV industry. I was leery of them when they first started, but now they have a sophisticated line of products like lithium batteries, solar panels, solar charge controllers and B2B chargers.

They are always priced well, always better than more well known names like Victron but not as low as the cheap no name Chinese stuff.

David

**creativepart** · 09-26-2020, 04:03 PM

That’s a great choice. Victron has some good AGMs at decent prices, too

https://www.solar-electric.com/victr...iABEgLuWvD_BwE

WBGO uses NAPA Commercial AGMs and my RV came with 4 of those standard. They’ve been great so far in my RV. But sell for a bit over $300 each.

Amazon is a good place to source deep cycle AGM just avoid “Marine/RV” batteries. Usually you can spot these by price - too low means not true deep cycle.

Topsail · 09-26-2020, 04:54 PM

i really don't mind bumping the budget up to get potentially better batteries. My only concern would be my converter/charger with the add on charge wizard. I looked at the Trojan 31 AGM and my set up may not be a perfect match. If it would shorten the life of otherwise long lasting batteries I may really be better off going cheaper.

**creativepart** · 09-26-2020, 05:09 PM

Generally, AGM batteries can do just fine with a FLA charge profile. It’s not perfect but very much close enough. If it was me, I wouldn’t worry about a slightly less than ideal charge profile.

How you use the batteries will matter the most in their longevity. Stay at 50% depth of discharge or less to get the longest life out of them. And don’t leave them discharged for long. Get them right back to full state of charge ASAP.

Lifeline makes a good battery but so do many other folks. Most US batteries are made by the same two companies, Eastern Penn and Deka anyway.

Topsail · 09-26-2020, 05:46 PM

Appreciate the input from you folks. I'll probably order two in a couple of days so I need to make up my mind.

bobmac · 09-30-2020, 05:02 PM

I have used 4 group 31 Sam's Club AGMs successfully since 2013. Replaced the originals in 2019, cost then was $179 per battery. I have 400 watts of solar on the roof that keeps the topped up year round. Wanted them for their low maintenance and highly recommend them along with a solar system on the roof. Personally, I think they are a great value and have performed very well for me. Good luck

JoeC · 09-30-2020, 07:05 PM

If you are not a big time boondocker, you should do just fine with the Renogy AGMs. I'm partial to lithium batteries as we boondock quite a bit and will be going to AK if and when the Canadian border opens up. But I can afford them and over the long term they will pay for themselves. Essentially, the more you use your coach batteries, the more you need to be seriously looking into lithium. Prices are coming down over time.

Old Navy · 09-30-2020, 07:33 PM

That big 200ah renogy is under $350. A bit of a beast to move around at 130 #, but good bang for your buck unless you need to buy a new battery box and/or cables.

Quote:

Originally Posted by JoeC

Essentially, the more you use your coach batteries, the more you need to be seriously looking into lithium. Prices are coming down over time.

I hope by the time my 6V batteries are dying, lithium is at about 1/2 current pricing. Actually, when it gets there, I'll probably start discharging the FLA's deeper, since even at 80% discharge, they'll probably last a couple years.

Wyatt · 09-30-2020, 08:58 PM

Quote:

Originally Posted by creativepart

Generally, AGM batteries can do just fine with a FLA charge profile. It’s not perfect but very much close enough. If it was me, I wouldn’t worry about a slightly less than ideal charge profile.

How you use the batteries will matter the most in their longevity. Stay at 50% depth of discharge or less to get the longest life out of them. And don’t leave them discharged for long. Get them right back to full state of charge ASAP.

Lifeline makes a good battery but so do many other folks. Most US batteries are made by the same two companies, Eastern Penn and Deka anyway.

I did a lot of research into the lifeline batteries mentioned above. They’re made in the USA and appear to be a very robust battery. I ended up going with lithium in the end for the weight issue and charge profile, but if I was going to go AGM I would go Lifeline...

https://lifelinebatteries.com/

JerryP · 09-30-2020, 11:29 PM

I just added two GPL-4CT Lifeline batteries to my 17View24V. They cost a little bit more, but have very good reviews. I have a Progressive Dynamics PD9245C charger.

I talked to Lifeline and Progressive Dynamics tech support to verify that they are a good match.

I bought them from Powerstride. They shipped directly from the Lifeline factory. Actually they are manufactured by Concord in the USA.

https://www.powerstridebattery.com/

Good Luck, Jerry

Topsail · 10-01-2020, 08:33 AM

I've been following everybody's input and I'm in absorb mode (pun intended). Out of frustration, I went ahead and bought two Sam's Club AGM's due to price and immediate availability. These should provide good service while I learn more since I'm very interested in Lithium and solar.

The Duracell group 31's were a tight fit in my battery space and my knee is still complaining. Things sure have changed; 60-70 lbs used to be one repetition with a dumbbell. The idea of lighter batteries is very appealing.

While I have a basic knowledge using electricity I definitely need a refresher, especially as it pertains to RV's. If anyone wants to add some good reading links on this that would be appreciated.

jerichorick · 10-01-2020, 03:46 PM

Quote:

Originally Posted by Topsail

I neglected adding water for too long and now my two 31DC FLA batteries need to be replaced. I want to avoid the water routine by switching to AGM's.

I'm the third owner and one of the previous owners upgraded to a PD9160A converter/charger by Progressive Dynamics. I have ordered the Charge Wizard PD9105 total charge management system, making this a suitable AGM charger system.

I've been looking at the various AGM batteries and frankly would like some input. Obviously, true deep cycle is preferred. We don't plan on serious boondocking anytime soon so for now simple is preferable. Can I get two decent batteries for 400-500?

Battery suggestions sure would be appreciated.

https://www.bargainshore.com/Solar-Batteries_c_257.html
Select the battery you want, then call for availability. If they have it in stock, delivery time is very good. I am very pleased with this battery. Just replaced my 6 AGM's a few months ago.

Happy trails,
Rick Y

Sheilag1848 · 10-02-2020, 08:28 AM

I had that same experience with my 1st unit back in early 80s. I learned at that time that the draw on those batteries is constant and they need attending to on a REGULAR basis. Now, this first think I do when purchasing a new unit it install LIFE LINE BRAND batteries. Yes they are expensive, but durability is sooo important that to me - it is money well spent. Suggest you bite the bullet and purchase "maintenance free" batteries. No matter what brand, those are better than those cheap this that come in the units from factories.

**creativepart** · 10-02-2020, 11:06 AM

Quote:

Originally Posted by Sheilag1848

Suggest you bite the bullet and purchase "maintenance free" batteries. No matter what brand, those are better than those cheap this that come in the units from factories.

Hang on... not all "Maintenance Free" batteries are AGM. The better suggestion is to get AGMs and specifically AGM Deep Cycle. Don't be fooled into AGM Deep Cycle Marine/RV batteries. They are combination deep cycle / STARTING batteries made to start engines. They are much less robust and the cells are not nearly as thick. They are made to run marine outboards and trolling motors. Many use them on Travel Trailers but they are not ideal. The only plus is they are usually 50% cheaper than TRUE deep cycle AGMS.

Secondly, WBGO doesn't always install cheap batteries. My 2017 Adventurer came with 4-NAPA #9837 Commercial Deep Cycle batteries that retail for over $300 each and they do a great job. Mind you, my RV came with a Residential fridge option that includes the fridge, 2000w inverter and 2 extra batteries. I don't know if you get the same batteries without the residential fridge.

DavidM · 10-02-2020, 11:17 AM

I have always wondered if there was really any internal difference among AGM starting, starting/deep cycle and just deep cycle batteries. Optima is the only manufacturer that makes a distinction among these types with their different colored tops and AFAIK they may all be made the same internally. Most of the others just label theirs differently.

Lifeline does make a specific deep cycle AGM and for the price I hope they are built differently to maximize deep cycle performance.

Of the three characteristics of true deep cycle FLA batteries such as golf carts- filler caps, more headroom and foot room under/over the plates, thicker plates; only the thicker plates could be possible for AGMs and I don't know if the plate thickness is even relevant with AGMs.

Anyone really, truly know for sure?

David

**creativepart** · 10-02-2020, 12:03 PM

I don't know the answer David, but in the Napa line the Marine/RV batteries are lighter than the true deep cycle. Something like 4lbs difference. I'd like think it's heavier because of more lead in thicker plates. But when it comes to truth in advertising it's anybody's guess.

I used Walmart Marine/RV batteries in my travel trailer days and believed I was getting just the right batteries. BUT, I had no inverter, always carried a generator and didn't tax those batteries much at all.

I did go through 2-pair before I got smart enough to disconnect the batteries at the A-Frame and then even smarter to bring them to the house for trickle charging in between camping trips. After that I never had to replace another battery.