Replaced my house batteries...

[Desert_Captain]

My house batteries, two four+ year old group 27 Interstate {Wet} Deep Cycles, have been on their last legs for at least 6 months. I kept stretching their life carefully topping them up before every other trip. The Hydometer showed them failing fast but the readings were consistent across all of the cells so I kept at them.

To reach all of the cells to test or add water I had to disassemble most of the wiring harness which was always a PITA. My plan was to replace them with AGM's which while not maintenance free {there is no such thing folks} they are far less labor intensive and of course will never require adding water.

I shopped around the internet and found the best deal at Batteries Plus. Got two Duracell AGM Deep Cycle Group 27's for $219 each and the local store honored the internet discount of 10 percent. As I was driving to BP my bride texted me that the battery in her Toyota had died so I picked up a replacement as long as I was right there.

Dropped the new one into the Toyotoa then went to the coach and started the nasty job of cleaning out the old batteries, lots of corrosion in and around the old ones to get rid of. Flushed out the compartment and cleaned all of the connections and after an hour or so had everything back up and running...hooray! Returned the 3 old batteries and recovered the $58 core fee and at high noon I was done.

We leave next Saturday for a week of motorcycle riding some of Colorado's finest while staying in our Class C right on the San Juan River {at the River Side RV Park - a very nice venue} in Pagosa Springs. We use so little DC these new batteries will clearly be overkill but life just got simpler for this old guy.

:C

[wa8yxm]

Veebyes wrote:
Enjoy the AGMs. Replaced the 2 useless group 24s wet after only 2 years. In went a single Lifeline AGM 4D. Wish I had room for a 8D. Got 9 seasons out of that battery. Zero tending each year November to April other than complete disconnect.

Preferred the simplicity of only 2 terminals on the 4D rather than tethering 2 smaller batteries together. Maintenance?? What is that?

Difference between a 4D and 8D is not that great as I recall
Alas I'm going to have to import the chart from a shut down windows box back to this chromebook But I do not recall a lot of capacity difference between 4D-8D an a pair of GC-2

That said Good True DEEP CYCLE batteries give you over 2x the usable power of the same size MARINE/deep cycle starting batteries.

[Sam_Spade]

wa8yxm wrote:
Advantage AGM less likely to cause corrosion, Less (not zero) maintenance.

What maintenance ??
Unless you count LOOKING at them and maybe being sure the cables are tight.
A properly functioning AGM should cause ZERO corrosion.

[edatlanta]

I replaced the single 12v Deep Cycle battery that came with my 5'er in August 2010 with two Trojan T-105's. In full time service they lasted 8 years. When I replaced them last year also with T-105's I installed the Trojan watering system. I should have done this initially, but we all learn you know. Watering them was a bit of a pain and one of them was tighter to get to than the other one, but I did it every spring and fall religiously. Now watering them takes seconds.

[Desert_Captain]

A few thoughts on the previous posts...and thanks one and all for your input. My old batteries were "True" deep cycles but after 4+ years they were just tired, nothing wrong or unusual there. Stories of batteries lasting a millienium or longer are fequently found on internet forums, file them next to the I got 150,00 miles out of a set of brakes... :R

I sold batteries for years in the Marine industry, we were a Trojan dealer. AGM's charge just fine with a standard {wet cel} charger or converter as the ideal charging voltages {unlike Gel's} are very similar.

I never said I had to add water often... I checked them often and typically added a small amount as needed but checking or adding water was a PITA every time.{ I quickly learned in boating that the two greats lies in the English language are "waterproof and maintenance free".} I will continue to monitor/check my new AGM's but it will not involve disassembling the entire wiring harness to gain access {hooray}.

We use very little DC {most folks use less than they think}. We spend about 13 hours a day outside and at night, after a nice campfire we retreat to the coach for maybe an hour of reading, journaling {whatever} which involves running two incandescent lights that draw about an amp a piece.

The only significant draw is the furnace during the winter as the squirrel cage fan is the largest DC draw in the coach but with a 35K BTU furnace {in a 24' Class C} it just does not run much at all - about 5 minutes two or three times a night. We never watch TV, music comes from our i-Phones and Blue Tooth Speaker

Even with the old batteries at the normal end of their working life we could sit for 3 days without any need to run the genny {we have 84 hours on our genny and the coach is 7+ years old and 70 percent of our trips are off of the grid}. About 30 minutes of generator time brought them back up nicely and we usually move after 3 or 4 days at most. A few hours of driving and we are back to fully charged and the cycle starts anew.

Yep the AGM's cost twice what the old wet's did and I was happy to spend the money.

:C

[Veebyes]

Enjoy the AGMs. Replaced the 2 useless group 24s wet after only 2 years. In went a single Lifeline AGM 4D. Wish I had room for a 8D. Got 9 seasons out of that battery. Zero tending each year November to April other than complete disconnect.

Preferred the simplicity of only 2 terminals on the 4D rather than tethering 2 smaller batterys together. Maintenance?? What is that?

[wa8yxm]

Advantage AGM less likely to cause corrosion, Less (not zero) maintenance.

Disadvantage COST. but one more thing.. you said the OEM's lasted 4 years.
My OEM flooded wet's lasted 9..

One reason may be mine were TRUE deep cycle GC-2 Yours were Group 27 and most of those are MARINE/deep cycle. note my use of upper case for MARINE. they are really starting batteries.. If your AGM's are True deep cycle. they should last longer as well offsetting the cost.

[Sam_Spade]

garym114 wrote:
Charging requirements are not the same for AGM and wet cell batteries.

While that is true, AGMs will perform quite adequately using the settings for a conventional wet cell and most people won't notice the difference.

You mentioned having to top up the batteries often.
If that was indeed true, you really NEED to check the charging voltage coming from your converter/charger, especially after the batteries are fully charged. Your charger might be defective.

[garym114]

Charging requirements are not the same for AGM and wet cell batteries. Don't know how you are charging but many chargers have settings for the battery type you are using.
https://www.knowyourparts.com/technical-resources/blog/three-misconceptions-agm-batteries/
https://discoverbattery.com/EN/battery-101/general-charging-information-for-agm-and-gel-batteries/

[pianotuna]

Desert Captain,

I made the same decision--and I don't miss laying down in the snow to service the battery bank one little bit!

So far today, I've used the solar charged battery bank and inverter to boil two quarts of water--so the cleaning lady can have warm water for cleaning. I'll be putting it back into storage today--so it was good to give the batteries a nice work out. She'll also do some vacuuming.

Have a wonderful trip!