AGM vs Standard Battery

[DT6]

My stock twin 6V batteries are beginning to show wear and I'd like to have a plan in place for replacing them, possibly as early as the end of this summer.

Regarding use, the heaviest comes from our CPAP machines. Both my wife and I use one and I don't know how much they discharge the batteries overnight, but I would not be surprised if they went below 50-percent charge. This is based on my initial calculations of the advertised current draw of the CPAPs.

We have a solar panel, so by the time we wake up it has been light out for a bit and I assume the batteries have recharged some. Other than the CPAPs it is just the refrigerator (larger upgraded model) a light or two, and detectors.

I can easily replace the OEM batteries with the same which might be fine. But before I commit to that I wanted to ask if AGMs were worth considering as a replacement? I've heard they do not do well if you take them below 50-percent charge. I also do not know if you have to replace any of the stock charging/monitor electronics in the trailer to accommodate them?

Alternatively, is it possible to add a third Interstate stock battery to create more reserve or does that create issues?

Finally just for info, it is a 19-ft. We have one solar panel and the whole trailer wired for the inverter and opted for the power conditioner to monitor shore power. I considered LiFePO4, but since we recently purchased a Honda 2200i Inverter, the high expense of the LiFePO4 upgrade does not seem to make sense.

I've read through some of the threads on batteries, but I did not see any references comparing the durability of AGM vs. OEM batteries, especially if there is potential to take them below 50-percent on many/most evenings. I appreciate any comments anyone may have.

[cpaharley2008]

The only difference I'm aware of is the OEM require periodic maintenance over the AGM....

[Doug2000]

I was always disappointed by the short life I got from standard flooded batteries but impressed with the longevity of the AGM batteries. I can’t comment on which charges or discharges faster, I never really paid attention but I found the AGM batteries to hold a charge much longer ov r the winter. I check my AGM once a month and rarely see a voltage drop. I wouldn’t hesitate on AGM batteries but lithium doesn’t make sense to me.

[TTMartin]

Originally Posted by DT6

I can easily replace the OEM batteries with the same which might be fine. But before I commit to that I wanted to ask if AGMs were worth considering as a replacement? I've heard they do not do well if you take them below 50-percent charge. I also do not know if you have to replace any of the stock charging/monitor electronics in the trailer to accommodate them?

AGM batteries can be discharged 80% and will have similar number of cycles (life) as flooded lead acid batteries discharged to 50%.

Only discharging AGM batteries to 50% will give them a similar number of cycles as Lithium batteries.

So, I would certainly go with AGMs before adding a 3rd battery. Not to mention the two batteries are normally 6 volt, so you would need two additional batteries or switch battery type completely.

[gklott]

Originally Posted by DT6

My stock twin 6V batteries are beginning to show wear and I'd like to have a plan in place for replacing them, possibly as early as the end of this summer. I appreciate any comments anyone may have.

Before deciding, recomment seeing this blog and videos.

If you decide on AGM, we used Lifeline AGMs for 10+ years before moving to Battleborn lithium.

73/gus

[TTMartin]

Originally Posted by gklott

Before deciding, recomment seeing this blog and videos.

I recommend you ignore that video!!!

Morton's on the Move were compensated for that video.

Their methodology was FLAWED. You do can NOT determine battery capacity remaining on lead acid batteries (AGM or flooded) by voltage when under load.

To use voltage to determine state of charge of a lead acid battery it needs to be resting voltage (no load for over an hour).

Originally Posted by gklott

BIf you decide on AGM, we used Lifeline AGMs for 10+ years before moving to Battleborn lithium.

73/gus

How many sets of Lifeline AGM batteries did you go through in those 10 years?

[DT6]

So AGM batters CAN be a direct replacement for the stock lead-acid? No adjustments needed to the on-board charging/monitoring system?

Thanks for the replies everyone!

[Vermilye]

Originally Posted by DT6

So AGM batters CAN be a direct replacement for the stock lead-acid? No adjustments needed to the on-board charging/monitoring system?

Thanks for the replies everyone!

Depending on the brand of AGMs, you may need to shut off the equalization stage of both the converter & the solar controller. The GoPower solar controller does have an AGM setting, I don't believe the WFCO converter does.

Another consideration is SiO2 batteries. A long thread discussing them on this forum is here. I don't have an opinion - I went with 300 amp hours of lithium...

[alanmalk]

When I purchased my E'21 in early 2015, I drove it home and replace the stock 12V single battery with a pair of AGM 12V batteries in parallel for double the AH capacity (at double the weight and triple the cost). The only change I made to the system was to turn off the equalization since that was the suggestion of the manufacture. I am just now considering a pair of replacement batteries.

The advantages for me were: No maintenance other than a visual inspection about once per year, no gasses or acids to worry about (Under normal service. Yes, they can vent in extreme cases...), and finally, as mentioned earlier, very little self-discharge which allows me to leave them installed in the trailer over our cold Colorado winters (although the winters used to be much colder when I was a kid-another topic).

Per the advertising, they can be discharged to a lower % than flooded batteries although I have never bothered to note how discharged my batteries were. Also, per the advertising, can take a faster charge, although there is no way to speed up the charge in an Escape other than replacing electronics at a very high price.

So, you pay your $$$ and make your choice.

For some background, before I even thought about camping in a trailer I was using an AGM battery with a trolling motor. It was working just fine - up to the day I purchased a lithium for 4X the cost and 1/3 the weight. Now the AGM sits neglected in the garage but just might be holding enough charge for another day of fishing.

[DT6]

I appreciate all of the comments, even those regarding new technology. They are sometimes very helpful. In this case, I've researched the LiFePO4 (Vermilye I believe actually wrote up a great report about his DIY installation, but it has been awhile since I read it so I may have the wrong individual). However, after purchasing a Honda 2200i inverter I made the decision to move away from the LiFePO4 option, mostly due to the expense and that I can charge the batteries with the generator when in shade or bad weather.

I am just looking to see if AGM can be a simple drop-in replacement, because the small(er) extra expense of AGM over the lead-acid is probably worth it.

I do have the GoPower (GP-PWM-30-UL) solar controller, but have not had a chance to check if it has an AGM setting - will do that tomorrow and report back.

I appreciate everyone's responses - thank you!

[oldwave]

Originally Posted by DT6

I appreciate all of the comments, even those regarding new technology. They are sometimes very helpful. In this case, I've researched the LiFePO4 (Vermilye I believe actually wrote up a great report about his DIY installation, but it has been awhile since I read it so I may have the wrong individual). However, after purchasing a Honda 2200i inverter I made the decision to move away from the LiFePO4 option, mostly due to the expense and that I can charge the batteries with the generator when in shade or bad weather.

I am just looking to see if AGM can be a simple drop-in replacement, because the small(er) extra expense of AGM over the lead-acid is probably worth it.

I do have the GoPower (GP-PWM-30-UL) solar controller, but have not had a chance to check if it has an AGM setting - will do that tomorrow and report back.

I appreciate everyone's responses - thank you!

I know my gopower solar controller has an agm setting

[Vermilye]

Unfortunately, a direct answer might well be misleading. Some manufacturers of AGM batteries allow, even recommend equalization, for example Lifeline. Others, such as Victron recommend not equalizing their batteries. As I mentioned in a previous post, the GoPower solar controller can be set for either.

On further checking, if you have the usual Escape provided WFCO 8955 converter, it is a 3 stage converter & does not have an equalization stage so it should be OK with anything except gel batteries.

[Bill and Earline]

Switching the controller from two 6 volt regular lead acid to two 6 volt AGMs is pretty quick and easy. Takes a few seconds after reading the manual. Takes longer to find and read the manual than it does to make the change by pushing a few buttons.

It eliminates equalization and I'm not even sure what that means.