AGM Batteries

[vsheetz]

By abuse was not deffering to physical physical. Discharge abuse as I commented.

Originally Posted by Mr_D

Lifeline AGM's are certified for military and marine use. Very tough on batteries but the Lifelines do just fine.

[redhooker]

AGMs have their benefits, but I would never use them in a situation where I was truly deep cycling them. I you don’t boondock they would likely be a viable choice if you have a specific reason for choosing them.

If you do boondock and take your batteries down frequently they are not a good option.

They also have specific charging requirements if discharged below 90% so do make sure you have a charger designed for AGMs

[2Grands]

Thank you all for the information. We do boondock quite a bit, so AGM's may not be for us, I may just upgrade to a larger class flooded battery. The main issue is making sure I have enough power to run the wife's O2 concentrater all night.
Thanks again,
Bob

[LAKnox]

Originally Posted by 2Grands

Thank you all for the information. We do boondock quite a bit, so AGM's may not be for us, I may just upgrade to a larger class flooded battery. The main issue is making sure I have enough power to run the wife's O2 concentrater all night.
Thanks again,
Bob

Bob, if you have the money to spend on AGMs, spend a bit more for some Li batteries, or =make= them. My cousin and her husband are re-doing a '64 GMC bus for use as an RV and have chosen to go all-electric. They're using a Nissan Leaf battery (plus one module) and 8 400+ watt solar panels, to power the coach. If you want to see their entire build, with videos, you can check them out at Beginning from this Morning | Thoughts, stories and ideas..

Lyle

[19fisherman4]

I like to use Interstate Batteries. They are easy to find in many places. They have served me well. I would talk to them about any questions you have. I use the AGM type and do not take them out over winter. I leave the motorhome plugged in to keep them charged up.

[kdauto]

Originally Posted by 2Grands

I'd like to hear from people who have switch from wet cell batteries to AGM, what brands are good, what to look for, how they compare to the wet cell type.
I am going to use these in my RV, so deep cycle would be the best choice, right?
Thanks in advance!

I had Exide AGM batteries and I would NOT recommend them. We experienced a thermal event and almost set the RV on fire. It could easily have exploded as well when the 3 batteries blew out the vents and outgassed for hours.

I switched them to Northstars,2 years now and no issues. While some of the batteries mentioned are really great 3 to 6 k for batteries for our use was out of the question. Our Northstar cost 400$ each and do what we need.

[keymastr]

As mentioned, if you are always plugged in and just need them for running between stops AGMs are great. If you are very careful about using your generator when they get down to 50% they also could be right for you. If you occasionally may have a true deep discharge due to necessity or brain fart they could be an expense you don't need. If you have a good charger that goes into float mode then flooded batteries give off very little and almost never need water. I still check them but have to top off less than once a year. At about $1 per amp hour for FLA 6 volt deep cycles it is hard to beat.

[Persistent]

Don't believe the nay sayers about AGM's. Deep draw AGMs are ideal for RV and TT dry camping and booddocking. They cost more, but you get more.

AGM Pros:
usually provide more cycle life
don't need water and usually don't need cleaning to remove acid
usually don't cause acid damage to surroundings
usually don't emit hydrogen gas or acid when charging
last longer during disconnected storage
are not significantly damaged when drawn down flat.


AGM's are more resistant to full flat out discharge. The different physics and chemistry stop the discharge before plates are damaged. Sealed AGM's and GEL batteries are inherently better at this. I accidentally drained my pair of 100 AH GELs a few times. I sold the TT after about 10 years. They were still working perfectly. Just do a full 14 to 18 hour recharge as soon as possible.

AGM's are sensitive to overcharge, however they use the same charge profile as flooded cells. Overcharging a lot may cause venting. The vented water is permanently lost and will decrease performance.

AGM charging:
Bulk with gradually increasing voltage to 14.4 volts
Absorption 13.6 for 14 hours
Storage 13.2 volts or fully charge and disconnect for 6 to 12 months
Most AGM's do not need or recommend any conditioning cycles

Battery University
https://batteryuniversity.com/
How does the Lead Acid Battery Work? https://batteryuniversity.com/learn/article/lead_based_batteries
Summary Table of Lead-based Batteries https://batteryuniversity.com/learn/article/bu_214_summary_table_of_lead_based_batteries
Charging lead acid batteries https://batteryuniversity.com/learn/article/charging_the_lead_acid_battery
GEL https://batteryuniversity.com/learn/article/bu_201b_gel_lead_acid_battery
AGM https://batteryuniversity.com/learn/article/absorbent_glass_mat_agm
How to Charge and When to Charge? https://batteryuniversity.com/learn/article/how_to_charge_when_to_charge_table
How to Store Batteries https://batteryuniversity.com/learn/article/how_to_store_batteries
Summary of Do’s and Don’ts https://batteryuniversity.com/learn/article/do_and_dont_battery_table
What is a Deep Cycle Battery?
https://marinehowto.com/what-is-a-deep-cycle-battery/

[kdauto]

Originally Posted by keymastr

As mentioned, if you are always plugged in and just need them for running between stops AGMs are great. If you are very careful about using your generator when they get down to 50% they also could be right for you. If you occasionally may have a true deep discharge due to necessity or brain fart they could be an expense you don't need. If you have a good charger that goes into float mode then flooded batteries give off very little and almost never need water. I still check them but have to top off less than once a year. At about $1 per amp hour for FLA 6 volt deep cycles it is hard to beat.

Flooded Lead-acid sucks as far as required maintenance and corrosive gases. I always had corroded terminals and hardware. Boondocking made it necessary to add water several times per season.They needed to be removed for the cold winter season we have here. Too risky to have them freeze and then be kaput.

All this changes with AGM. Clean battery compartment. No corrosion. They seem to hold their charge longer. I can leave it in all winter, they cannot freeze and will tolerate flat discharges much much better than flooded batteries. No more lugging a bunch of 70 lb batteries.

[Mark_K5LXP]

Originally Posted by 2Grands

The main issue is making sure I have enough power to run the wife's O2 concentrater all night.

Have you run the numbers for what this device will draw in typical use? Once you know that, you can better determine what solution will work best for you.

Mark B.
Albuquerque, NM

[bigchick]

i have to ask.

there are many comments about AGM's not out gassing nor creating corrosion. many statements that FLA batteries out gas, cause corrosion, and need to have to water level monitored.

our trailer came with maintenance free sealed lead acid batteries (centennial MF27DC). they are going on 5 years old. they are in enclosed battery boxes with a tube type vent to the outside. i cannot check water levels. i have checked the terminals and there is not any indication of corrosion. these batteries are nearly the cost of a regular FLA battery and much less expensive than AGM.

i've got 5 years on them now. when (eventually) they need to be replaced i simply plan on replacing with the same. with the type of performance i have been getting i don't see that AGM's would add any benefit and i still avoid the maintenance hassle of the normal FLA batteries. i never see this type of battery recommended. am i missing something?

[wingnut60]

No, not missing anything. Sealed Lead Acid (SLA) batteries are a viable option to the regular style. Used them for several years without incident, but could not find one listed as 'deep cycle' only--every one I saw had a CCA rating, not an AH rating.

[twinboat]

I used flooded 6 volt batteries for 10 years.

With my new MH, the GC2 battery was to tall for them to fit, so I picked up 2 Sams Club, GP 31, maintance free, deep cycle batteries. They list 105 AH capacity each.

This is our second year heading to FL from NY with them and they are working great. No acid spills, clean connections and they last thru the night, with the heat on and 4 cups of Kurig coffee in the AM, while dry camping.

They do occasionally run down to 20% state of charge, but thats the cost of only having 200 AH of capacity with our comforts of home running.

If I get another season out of them, I'll be happy and just replace them.

[kdauto]

Originally Posted by bigchick

i have to ask.

there are many comments about AGM's not out gassing nor creating corrosion. many statements that FLA batteries out gas, cause corrosion, and need to have to water level monitored.

our trailer came with maintenance free sealed lead acid batteries (centennial MF27DC). they are going on 5 years old. they are in enclosed battery boxes with a tube type vent to the outside. i cannot check water levels. i have checked the terminals and there is not any indication of corrosion. these batteries are nearly the cost of a regular FLA battery and much less expensive than AGM.

i've got 5 years on them now. when (eventually) they need to be replaced i simply plan on replacing with the same. with the type of performance i have been getting i don't see that AGM's would add any benefit and i still avoid the maintenance hassle of the normal FLA batteries. i never see this type of battery recommended. am i missing something?

I have not seen any real deep cycle, sealed, flooded batteries up here. One of my considerations was leaving the battery array in the RV for the winter. The AGMs will survive freezing temps even if discharged. They will survive hundreds of 80% discharges too.

Removing,storing,charging the heavy batteries each winter was a PITA.