Input on AGM batteries

[Mr_D]

Originally Posted by jerichorick

The main consideration of AGM's is charging, as previously stated. They will give you more power over a longer period of time, true, but if not charged correctly they will soon become very heavy paperweights.

Add EXPENSIVE paperweights to that!

[jerichorick]

Originally Posted by PDXDisco

When I read the above posts over again, it became clear that the people who love AGM batteries either have a new coach that came with them, or have a newer charger, like the Magnum, that supports them well. My 2002 came with the old Heart/Interface charger/inverter (now Xantrex). I am thinking very seriously about replacing this, because I have a feeling that it may have contributed to the early demise of my AGMs. That and the 400 degree exhaust 1" away! A new Magnum 2800 watt is $1700-$2000, so it's not a small investment. I would not try AGMs again without doing the upgrade, however. I think that for those of use with "older" chargers, the only safe answer is good ole' flooded cell batteries. If you have a new coach with a charger that supports AGMs properly (mine has the setting, but I don't think it works well), AGMs make sense. I'm spending a little money and time to fabricate a heat shield, and have purchased Trojan's new battery watering system, which has a low-water indicator for the cells allowing a visual check without removing caps. I'm also fabricating and installing a custom battery slide (1/3 battery split and framing issues require custom).

Save your money on the Trojan watering system and use mineral oil. Many of us have been doing this for years. It greatly reduces the need to water and it keeps the corrosive activity of the gasses down to a minimum. You can check the history of this practice through the web. Here is one comment I just came across: Mineral oil additive to lead acid batteries - Boat Design Forums

The heat shield is a great idea. Also, install a remote temperature sensor. This will give you the real story up to the moment.

Size the inverter for your needs and this will save you a few bucks. But the idea of your old inverter is correct. AGM's don't do well if overcharged. I boiled mine dry when my inverter went bad... Xantrex.

Pound for pound, AGM's will give you more bang for the buck and last longer if cared for correctly. The other upside is that they like to discharge at a heavy rate and don't fade as quickly as wet cells do. Now that I am in a coach with a very well designed battery system I am experiencing just how good AGM's function in real life. to HAPPY CAMPING!

Thank you for taking the time to read all of our comments and suggestions AND for understanding our meaning. When communications works it is a wonderful thing. You now have a good introduction to AGM's, something you can work from. I know I am not speaking out of turn by saying we are all looking forward to "seeing" the results of all of your fine work.

Rick Y

[az bound]

Originally Posted by PDXDisco

When I read the above posts over again, it became clear that the people who love AGM batteries either have a new coach that came with them, or have a newer charger, like the Magnum, that supports them well. My 2002 came with the old Heart/Interface charger/inverter (now Xantrex). I am thinking very seriously about replacing this, because I have a feeling that it may have contributed to the early demise of my AGMs. That and the 400 degree exhaust 1" away! A new Magnum 2800 watt is $1700-$2000, so it's not a small investment. I would not try AGMs again without doing the upgrade, however. I think that for those of use with "older" chargers, the only safe answer is good ole' flooded cell batteries. If you have a new coach with a charger that supports AGMs properly (mine has the setting, but I don't think it works well), AGMs make sense. I'm spending a little money and time to fabricate a heat shield, and have purchased Trojan's new battery watering system, which has a low-water indicator for the cells allowing a visual check without removing caps. I'm also fabricating and installing a custom battery slide (1/3 battery split and framing issues require custom).

Check out thre Mattery Minder #BM 2012-AGM. Workes very well and much less expensive than a new charger/inverter.

[jerichorick]

Originally Posted by az bound

Check out thre Battery Minder #BM 2012-AGM. Workes very well and much less expensive than a new charger/inverter.

As I understand it, deep cycle AGM batteries like to be charged quickly. The above charges at a rate of 2A. It sees the Lifeline battery rep told me this when I was having troubles with my batteries several years ago. Over voltage is a definite AGM killer and my Xantrex did just that.

[az bound]

Originally Posted by jerichorick

As I understand it, deep cycle AGM batteries like to be charged quickly. The above charges at a rate of 2A. It sees the Lifeline battery rep told me this when I was having troubles with my batteries several years ago. Over voltage is a definite AGM killer and my Xantrex did just that.

It is a maintainer-charger/desulfater for AGM batterie, not a charger per-se.
www.batteryminder.com

Using a charger that is not designed for AGM batteries will kill them in short order. Using high voltage or high amp charger for desulfating/ equalizing AGM batteries, risks the chance of thermal runaway, which is probably what destroyed your batteries.
Many have switched to AGM batteries without regard to their charging requirements and had the same result, They place the blame on the batteries instead of their lack of knowleddge in the care and maintenance, including charging reqiurements.

[hes4all]

Originally Posted by az bound

Many have switched to AGM batteries without regard to their charging requirements and had the same result, They place the blame on the batteries instead of their lack of knowleddge in the care and maintenance, including charging requirements.

Right on the money!

[ladagobago]

I tend to disagree with the critical voltage charge of AGM. I have been using the same optima blue top batteries D34M for over 7 years now. for the first three years they were the starting batteries for my boat with two 454 big blocks. After the remainder of the time they have been in my MH as starter batteries for my isb. in all cases the engines fire up almost immediately.

I have never worried about the charge voltage or rate. the nice part of the optima is that alternator charge rate allowed is 13.5 to 15 volts at 10 amps max for up to 12 hours. they will also take a huge absorption charge at 15.6 volts with unlimited current until 1 amp/ float charge is 13.2 13.8 forever. I never really float the batteries.

this series of battery can be used for starting and deep cycle. the recommended alternator is 13.68 to 15 volts. that should cover about every MH out there.
Experience beat BS every time.

My house batteries are deep cycle Golf Cart four six volts charged with a progressive three stage charger. I gave up on the 12 volt marine deep cycle loooonggg ago.

[TQ60]

As starting batteries your agm startjng batteries should be fine...

In starting configuration they are not subject to constant out of tollerance voltages.

Too high of voltage will cause excessive charde current which results in gassing.

The chambers retain this gas until it pops the valve.

Starting batteries are designed for that duty cycle but a constant overcharge may result in different results.

[az bound]

Originally Posted by ladagobago

I tend to disagree with the critical voltage charge of AGM. I have been using the same optima blue top batteries D34M for over 7 years now. for the first three years they were the starting batteries for my boat with two 454 big blocks. After the remainder of the time they have been in my MH as starter batteries for my isb. in all cases the engines fire up almost immediately.

I have never worried about the charge voltage or rate. the nice part of the optima is that alternator charge rate allowed is 13.5 to 15 volts at 10 amps max for up to 12 hours. they will also take a huge absorption charge at 15.6 volts with unlimited current until 1 amp/ float charge is 13.2 13.8 forever. I never really float the batteries.

this series of battery can be used for starting and deep cycle. the recommended alternator is 13.68 to 15 volts. that should cover about every MH out there.
Experience beat BS every time.

My house batteries are deep cycle Golf Cart four six volts charged with a progressive three stage charger. I gave up on the 12 volt marine deep cycle loooonggg ago.

Optimas D34M batteries are a hybrid deepcycle/starting battery, not to be confused with a true deep cycle, therefore they are tolerant of a higher charging voltage. Heavier plates.

The recommended charge voltages for AGM deep cycle batteries is:

3 stage charger
Bulk 14.2-14.4
Acceptance 14.2-14.4
Float 13.2-13.3

2 stage charger
Bulk 14.2-14.4
Float 13.2-14.3

Single stage charger
Bulk 14.2 14.3

I suggest more research on the different types of AGM batteries.
Ie; Starting, Deep cycle, Deep cycle marine, Deep cycle marine/starting.
All three types are available.

[jerichorick]

This is what happened to me with Lifeline AGM's. My Xantrex 2000 W PSW inverter worked ok on my flooded deep cycle batteries but I was not getting the time I thought I should from them. I installed the AGM's and all was fine... for a while. Then I noticed that my charging voltage had started to rise. I tested the batteries and found the capacity had fallen a lot for the age of the batteries. Working with the Lifeline rep it was determined that the batteries had been dried out by the over voltage. The cause of the over voltage was a failure of the temperature sensing circuit in the inverter. It could not be repaired. As I recall the offensive charging voltage was around 15V. The temperature compensation is critical for the sustained longevity of the AGM battery string.

[az bound]

Correction to post# 51. All four types are available.

[PDXDisco]

After reviewing this thread many times, as well as other threads on AGM batteries, I think I made the right decision in purchasing flooded cell batteries instead of another set of AGMs. My existing charger/inverter is not the right choice to handle AGMs. I do not want to spend the additional money right now to buy a new charger/inverter, but I am confident that my existing Heart/Interface (Xantrex now) charging unit will be up to properly charging my Trojan T-105s. There are several things I will be doing differently with this set of batteries:

I am installing the heat shield I have designed and fabricated to bring the temperature around the batteries down to below 120 degrees. It is clear that the excessive heat in the Fleetwood design is not good for any battery.

I am installing a custom designed and fabricated set of slide-outs to allow me to properly inspect and maintain the batteries. I am also employing two plastic battery cases, designed for marine use, to keep the batteries relatively clean, since the current setup allows for road spray and grit to collect on them, making inspection and maintenance a chore due to the cleaning necessary before these can be done.

I am installing Trojan's new battery watering system, which has an indicator on each "bank" of vents (it replaces the six caps with three monolithic vents), so that it is not necessary to remove six vents to do inspections with a hydrometer, and checking water level is accomplished without having to remove the vents. I will follow Trojan's recommendations to fill the batteries AFTER charging them.

I am buying and installing a Noco Genius charger, which has separate leads to each battery, positive and negative, and a very sophisticated battery condition testing and five stage charging program. I will switch the house battery off with the marine battery switch I am installing between the house bank and the inverter before I store my coach, and plug the Noco charger into an outlet at storage. This will ensure that my house bank, and ONLY my house bank, are being properly maintained when I store my RV.

I will equalizing my new batteries before I install them, as per Trojan's instructions. I will then test them with a hydrometer, and continue to test them periodically, before storage, after removal from storage, and once a month at a minimum. I will not be adding mineral oil, as from everything I have read, including the above link, this was a technique used on old technology batteries, is inapplicable to the current batteries available, and will void my Trojan warranty. From every reputable source I can find, reduction in water level on lead acid batteries is normal, trying to prevent it is futile, and will damage the capacity and recharge capability of the batteries.

If this seems like a lot of maintenance, realize that it boils down (hopefully my batteries won't), to this:

1. Initial equalization charge to create optimal battery chemical balance and charge capacity before use.
2. Occasional pumping on the battery watering bulb if the indicator shows low water.
3. Once a month check with a hydrometer.

I think it will be a good thing that I pay a little more attention to my batteries, as it was all too easy to forget about my AGMs. Perhaps if I had paid attention regularly to my "no maintenance" batteries, I would have caught the damage before they were out of warranty, and I could have had the option to replace my inverter/charger, rather than my batteries. If sticking with Trojans saves me $1,000 on batteries, and $2,000 on a new inverter/charger, plus the $375 for the remote control and state of charge monitor, ($3375 total, minus the $300 for the Noco Genius charger) then I'm fine with it. I would be installing the slide-outs, battery boxes and heat shield either way, so that doesn't enter into my calculation.

[Mr_D]

Even our old 2002 Xantrex MSW inverter has a setting for AGM's. But I got 10 years out of the Interstate U-2200's so I can't see any advantage to going to AGM's

[Caflashbob]

Originally Posted by Mr_D

Even our old 2002 Xantrex MSW inverter has a setting for AGM's. But I got 10 years out of the Interstate U-2200's so I can't see any advantage to going to AGM's

Double the cycle life in AGM's versus flooded cells.

Flooded cells are freezeable. AGM's resist vibration better.

No outgassing means less maintenance of the terminals and cables. Twice a year minumum with flooded cells.

Dangerous gases from flooded cells. Battery water regularly.

I use the even more expensive DEKA 8g8'ds.

Double the cycle life of the AGM's.

500 cycles of 50% discharge in flooded cell.

1000 cycles of 50% discharge in AGM's

2000 cycles of 50% discharge with gels.

20% discharge on gels the life is 5,000 cycles.

My feb 97 Foretravels heart freedom 25 inverter has a three step charger and the proper settings for all three types of batteries.

No equalizing. No outgassing, low maintenance, no freezing, power down to -40 roughly.

Save money elsewhere in the world. Unless you want to live hooked up to a power pedestal the gels pay for themselves in longer life, less maintenance.

I was in the expensive Rv biz for many years long ago. First thing I did when I purchased our 15 year old coach three years ago was to go back to the original equipement batteries Foretravel put in the coach.

Three optima redtops for the engine start and three deka 8g8d's. Then added desulfators to both battery banks and an automatic charger from the house batteries to the engine batteries and a small 7amp 130 watt solar panel tied to the refer which is always tied to the house batteries in a Foretravel so if the cole Hersey house battery switch is turned off the refer still works.

Never hardly look in the battery compartment since. Three years. Mostly dry camp. No hot use although.

Runs the Aqua hot and dometic side by side refer and non led lighting for two days with no gen run time at all.

Cheaper than most campground fees in the long run.

I started as a sales manager for Foretravel in 1984 and rv'ed constantly in traded in coaches for 15 years.

No lead acid. No cars come with lead acid.

The cycle life charts are on the MK battery websites.

Three dollars an hour in diesel fuel and gen maintenace I skip and the noise.

old discussion on the foreforums web site.

Yes it's more money. Last thing I got for free was worth exactly what I paid for it.

I would pay more for any used Rv with top of the line batteries in it.

Means the owner took care of it better probably.

Higher amp start batteries load the starter less and less heating of the cabling.

AGM's and gels have much higher power at lower temperatures.

My old coach was probably less expensive than most posters here coaches but only the best batteries to avoid problems and have better power in the coach.

Yes I know they are twice as much money. Many times that better in quality IMO.