House Battery Questions and Opinions

[Donflem]

It’s just about time to replace batteries In coach. I have the 8 house and 2 chassis that I want to replace. I have a friend who thinks I should swap my liquid batteries with 4 AGM BUT I would have to get rid of 4 of the wet batteries because they wouldn’t all charge the same. I’m wondering what you guys think about that idea he thinks I would have plenty of power but I dry camp a lot so I’m not sure. I’m sending a picture of the AGM batteries he wants me to swap. I have to admit I don’t really understand how much battery power I need I just know it came from the factory the way it is. Any thoughts or suggestions?

Thanks Don

[cbr046]

AGMs might be "made" for deep cycling, as some dealers (and people) recommend, but IMO flooded batteries outperform AGMs in number of deep cycles and cost.  It's attractive to purchase a "no maintenance" battery but my next purchase, which will be sooner than later, will be flooded. 

Trojan T-105's seem to be the king of RV batteries . . . . but they cost a small fortune.  They are very well made and DO seem to last forever!  I priced Interstate batteries but couldn't find a decent price.  So in my case I'll probably just go to Sam's / Costco and buy golf cart batteries.  Those are in the $100 category and will probably last as long as I own the coach, another 10 years maybe.  Duracells (Sam's Club) have a recognized name but aren't all that special.  Keep in mind there are many many brands out there but they all come from only 3 manufacturing plants.  Trojan does make their own batteries outside the big 3. 

I'm sure others will go into more detail, but again this is my opinion (and we all have one!).

- bob

[jacwjames]

I think that the type of batteries you choose is dependent on how you use your coach.  If you don't dry camp much and drive from campground to campground then I'd say it may not be worth it other then the AGM is somewhat maintenance free. 

In 2021 I was looking for AGM's to replace my flooded batteries but none to found.   This was prior to a long trip.  I tested my batteries and all seemed good.  ~2 weeks into the trip one battery failed and I had to replace.  Couldn't find AGM in SD where I was so went with the flooded.  I do dry camp, have 325 watt of solar (not enough) but can get by with ~1.5 hours generator time.  I doubt going to AGM would improve it that much.

[Tom Cherry]

1 hour ago, cbr046 said:

AGMs might be "made" for deep cycling, as some dealers (and people) recommend, but IMO flooded batteries outperform AGMs in number of deep cycles and cost.  It's attractive to purchase a "no maintenance" battery but my next purchase, which will be sooner than later, will be flooded. 

Trojan T-105's seem to be the king of RV batteries . . . . but they cost a small fortune.  They are very well made and DO seem to last forever!  I priced Interstate batteries but couldn't find a decent price.  So in my case I'll probably just go to Sam's / Costco and buy golf cart batteries.  Those are in the $100 category and will probably last as long as I own the coach, another 10 years maybe.  Duracells (Sam's Club) have a recognized name but aren't all that special.  Keep in mind there are many many brands out there but they all come from only 3 manufacturing plants.  Trojan does make their own batteries outside the big 3. 

I'm sure others will go into more detail, but again this is my opinion (and we all have one!).

- bob

My experience, at least locally, is different.  I agree as do many experienced users here.  The “mystique” or perhaps the desire to reduce battery maintenance clouds some thinking.  AGM’s are nice, but way more delicate and prone to mistreatment if one thinks they are indestructible.  Careless charging will destroy or shorten their life much quicker than  flooded cell.  One needs to be very knowledgeable about setting up their inverter.

AGM’s need the SAME AMOUNT of TLC as flooded. They need to be exercised every 4 - 6 months, unless you run them down to 50% or more, frequently, by dry camping.  Otherwise, run down to 50%, 3 cycles.  

Be cautious about buying a “club” battery.  COSTCO sells a “Junior” Interstate RV/ Marine battery,  it weighs less and the amp hour rating is less, so if you don’t get 220/5 Amp Hours, you are not getting the original OEM size.  Just check the label.  I have found that the Interstate Distributor will be cost competitive with Costco.  I have also found that most Golf Cart dealers are competitive on Trojans as well.   Call and shop around.  The Trojan T-105 might be $5 - 510 higher than the OEM Interstate 225 that Monaco put in.

There is another thread on starting batteries going.  There is also a file on Battery 101.  Use the .search box.  Put in Battery and use Files from the drop down options. Many have found it informative as it was written for MH.

 

[vito.a]

The trend now is going to lithium batteries.  They are expensive and do not like cold or hot temperatures.  I considered building my own lithium packs but stayed with the tried-and-true Trojan T-105 6-volt golf cart batteries.  Our local golf shop has them for $129 each.  I have to periodically monitor the water level but the last set I had lasted almost 10 years.  

[96 EVO]

I don't think it would be a good idea to make a bank out of half AGM, and half flooded batteries.

[Ivylog]

Because of the battery compartment size it’s easier to go back with 4 L16s batteries, although I replaced mine with 8 100AH 12V AGMs… took a handful of cables.

The EVL16 is a deep cycle but more suited for an electric forklift… 1250 CCA. If you search “Solar L-16 batteries” most are lead acid 

[Donflem]

42 minutes ago, 96 EVO said:

I don't think it would be a good idea to make a bank out of half AGM, and half flooded batteries.

That’s what I was wondering two banks of 4 or just the 4 AGM they are huge compared to what I have now?

[96 EVO]

The 4 AGM L16's would probably serve you well!

[Tom Cherry]

4 hours ago, 96 EVO said:

I don't think it would be a good idea to make a bank out of half AGM, and half flooded batteries.

AMEN! Unless you have individual chargers with some diodes the size of a quart jar.  You will eventually kill the AGM!s and damage the flooded or not charge properly. Mixing is impossible unless you have separate charging boards….which I don’t know if they exist in any inverter….

 

15 hours ago, Donflem said:

It’s just about time to replace batteries In coach. I have the 8 house and 2 chassis that I want to replace. I have a friend who thinks I should swap my liquid batteries with 4 AGM BUT I would have to get rid of 4 of the wet batteries because they wouldn’t all charge the same. I’m wondering what you guys think about that idea he thinks I would have plenty of power but I dry camp a lot so I’m not sure. I’m sending a picture of the AGM batteries he wants me to swap. I have to admit I don’t really understand how much battery power I need I just know it came from the factory the way it is. Any thoughts or suggestions?

Thanks Don

My advice is not to swap until you could do a controlled “load teat”.  You have no guarantee that these AGM’s are capable of attaining or being charged back to 100%.  They may be perfect or they may be damaged.  You can not depend on the load test meters unless you go to a real battery shop or find a distributor that has specialized equipment.  I would drop them by a distributor Or dealer that has a rejuvenation charger….most Interstate or sometime lift truck battery dealers have them.  They need to be run down under an appropriate load for 3 cycles to say 40 - 50% and then recharged.  On the final recharge, you then use voltage to determine their true state of charge.  Anything below 80% (see the voltage chart in the Battery 101 file) of the original 100% is not worth messing with….

If they perform and go back to 90 plus %….  Great,  you COULD do the test yourself.  That is detailed in the Battery 101 How To file.  If they work….great.

But if not…you also need to know how to reconfigure your your Magnum remote setup for AGM…as well as determine if they are Type 1 or Type 2 as Magnum has two different charging profiles for AGM.  Us the incorrect one and you will damage and not get full life.  This is not like swapping brands of “D” cells in a flashlight….

[Gary 05 AMB DST]

I try to keep any replacements the same as what came from the factory. Everything is set up to manage as original. 

Gary 05 AMB DST

[cbr046]

7 hours ago, vito.a said:

. . . . Trojan T-105 6-volt golf cart batteries.  Our local golf shop has them for $129 each.

That's a GREAT price!  Is that new?  Best I could find is on ebay for $180 ea + shipping from NV.  Where is your local golf shop?

- bob

[Tom Cherry]

2 hours ago, cbr046 said:

That's a GREAT price!  Is that new?  Best I could find is on ebay for $180 ea + shipping from NV.  Where is your local golf shop?

- bob

That IS an excellent (gross UNDERSTATEMENT) price.  I paid $150 2 years ago....but that was during one of the many crises going around.  In addition my old buddy sold the shop and the value of his in stock inventory increased overnight....  Buy a Trailer Load and we'll all meet you...LOL

Thanks for the info...

[Mike H]

I pulled out my 8 Interstate flooded batteries 2 years ago and installed 8 Duracell AGM's from SAM's Club ($179 ea).  I got tired of having to top off the Interstates EVERY MONTH!  It would take just short of 1 gallon of Di water to top them off plus having to deal with the corrosion factor.  I've been real happy ever since.  I may boondock maybe once or twice a year is all.  I do recommend the PowerPulse Battery Maintenance system as they do extend the life of your batteries ($35 - $55).  I have one across the two starter batteries and one on each bank of the 4 house batteries.  Now all I have to do is check the tightness of the battery terminals once a month.

[cbr046]

6 hours ago, Mike H said:

. . . .  It would take just short of 1 gallon of Di water to top them off . . . .

DON'T use Di water as it's bad for flooded acid batteries.  Use distilled water only.

There was a discussion on this some time ago.  Di BAD, Distilled GOOD.

- bob

[Tom Cherry]

51 minutes ago, cbr046 said:

DON'T use Di water as it's bad for flooded acid batteries.  Use distilled water only.

There was a discussion on this some time ago.  Di BAD, Distilled GOOD.

- bob

yes....I made that slip in a post. I meant Distilled, but out of habit, typed DI....  Distilled Water is what is needed.  Deionized Water (commonly called DI) is not recommended.  It is too pure....LOL.  BUT, it is what is used in most commercial and cleaning operations.  Distilled (as in Jack Daniels) Water is commonly available in all pharmacies or supermarkets major department stores with groceries is what you need to add to the electrolyte.

[Mike H]

Interesting conclusions.  I had a very informative conversation with the tech folks at Interstate Batteries several year ago about that and they said they only used Di-ionized water.  At the time I was inquiring about at what level of purity the Di water needed to be and they said they keep their battery water supply to less than 20ppm (20 TDS).  It's all of the contaminates in the water, even distilled water and even soft water that raises havoc with flooded batteries.  You can't be 'too pure'.  I have my own Di Rinse filter that makes Di-ionizing water.  I have since 'upgraded' to AGM batteries so it's of no concern to me now but I do use the Di water as a final rinse when washing our coach.  I have even used it when washing our house windows for nice spot free windows.  The only 'bad' thing about Di water is that you can't drink it.

[cbr046]

I was using Di water to top off our departmental golf cart until some PhD researchers at Ga Tech recommended NOT using Di H2O as the atoms would leach metals out of whatever they contacted.  These were the same PhD's that ran the lab that generated (and used) Di water for their research (they made crystalline structures that had to be absolutely pure).  The cool part was I could simply turn on the tap and get as much as I wanted.  No problem, I just went to another section of the lab and got distilled water after that.  Working there was a cool gig, even if I was one of the peons. 

Now I get distilled water from our basement dehumidifier. 

- bob