Battery Life Expectancy?

[PJorgen]

My 2014 Hawk still has the original deep cycle AGM battery installed by FWC. It holds a charge and runs the appliances fine, but I'm wondering how much more life I can expect from this battery. Any thoughts?

What will be the first signs that it's giving up? I'm pretty good at detecting slow cranking when my vehicle batteries are about done. Is there something comparable with the camper battery?

 

[craig333]

Depends on the quality of the battery and how well you charge it. I think ten years is reasonable. Some people would rather replace them every three years than spend money on a decent charger and solar. I'm really curious to see what we wind up seeing people get out the LifePo4 batteries.

 

[Beach]

My last AGM died at approx 5 yrs., mainly because the solar controller failed and fried it. New one is almost 4 years and I'm noticing the voltage falling off quicker as it ages, even though my average daily amp draw is not changing on our trips, charging cell phone, led lights and fridge fan, is all we use it for. I would tell you to be observant how long it takes to recover to full charge and how long that charge holds during normal use. I have used optima batteries in the past but will get a true deep cycle next time, possibly a Renogy. If you regularly draw your battery down to very low levels, you will reduce the life of your battery. Rarely does my battery get below 12.2v and it is charged back up the next day via solar or truck.

 

[Spitfire]

My 2 are a year older than yours. Still hanging in there

 

[ckent323]

PJorgen,

You can't reasonably compare your vehicle AGM starting battery life to the camper deep cycle battery life.

The battery construction details are different and the use and charging of each is different.


Generally speaking vehicle starting batteries are frequently not fully recharged to float after discharging (often due to starting, onboard electronic draw and short trips not long enough to fully recharge). Another problem is the older charging systems employing a voltage regulator which do not charge in stages and may result in chronic slight undercharging (or in some cases overcharging).

These factors lead to sulfation which shortens battery life. The newer vehicles with smart battery charging electronics may do a better job keeping the starting battery properly charged than the older vehicles having simple voltage regulators.

The temperature environment that your vehicle battery survives in is probably harsher than what your camper house batteries survive in and that can shorten the battery life as well (high heat). The challenging operating environment for a starting battery usually results in starting batteries lasting less than 5 years and often less than 4 years in areas with high heat (Southwest for example).

If your camper house batteries are not frequently drawn down below 50% and they are always or almost always immediately fully recharged to float before drawing them down again (maybe because you have a good solar setup) then the house batteries could last a long time maybe 10 years or more. Also keeping camper house batteries in float during storage helps maximize life.

This is just a quick broadly generalized summary. There may be specific details in charging and use that lead to longer or shorter life for either your starting or house battery that are not discussed here.

 

[craig333]

Good point about the starting batteries.

 

[billharr]

Just installed new batteries today. Did a trip to TX where I am now. First day over 12 hours on the road and have 250w of solar on the roof. Next morning saw below 12v on my meter and my ice cream was melted. Compressor fridge. 2013 Hawk with original batteries. So Amazon prime and good as new. 7 1/2 years on the batteries not bad. I will take them back with me and do a load test to be sure. I would have gone Lithium but will be selling the camper in February, and would not sell with shot batteries.

 

[kmcintyre]

My last AGM lasted about 6 years. It wouldn't hold a charge for long.

I just completed my LifePO4 battery build. About the same price. You can search this forum or google LifePO4 batteries. They are a much better alternative (IMHO) than AGMs.

 

[craig333]

That doesn't seem right Bill. Are you sure they're still getting the appropriate charge?

 

[billharr]

That doesn't seem right Bill. Are you sure they're still getting the appropriate charge?

Yep, Victron MTTP controller and 8 gauge wire from the truck to the camper. Last time I used the camper I thought the voltage was getting a little low overnight. It was 110 degrees + all across southern cal and Arizona. So fridge was working hard. I know batteries may be a quick fix and they may be good. So I will take them home and check. Just don't want to sell my camper for what they are now selling for without new batteries.

 

[Advmoto18]

That's a tough question to answer since the answer is strictly dependent upon to what state of discharge you take your battery(ies).

Observe how deeply you discharge the battery and how many times you take it into a state of deep discharge (<50% state of charge). Further, failing to completely recharge the battery after a deep discharge will shorten longevity.

To further confuse the issue:
Your "state of charge" is expressed in percentage, ie, 0% is empty and 100% is full. Most new, digitally encoded batteries and smart chargers will provide this % on the charger display.

"Depth of discharge" is expressed in Ah. There is a formula for converting Ah to percentage. However, since we generally don't discharge our camper battery(ies) at a constant rate over time, the % formula doesn't do us much good. So I look to "state of charge" on a "smart" controller.

To enhance battery longevity, it is always best practice to never allow your batteries to go below 50% state of charge. Of course you can go below 50%, but doing so will reduce the battery's life span.