BATTERY LIFESPAN survey...

I had one GP24 Sears die Hard that went just short of 10 years. From May to Sept each year it was hooked to a 15 watt panel, during those months I put in about 25-40 days of boondocking, the only recharge was on genny for about 30-45 minutes in the morning while running the electric coffee pot and toaster. I can't say fr sure how much power I used exactly, a couple of lights for maybe an hour a night, maybe an hour or two of TV and the odd night that the furnace ran.
During the off season that battery was connected full time to a VDC battery minder, I think I may have added distilled water to it once a year.

Alternatives. Some folks do not use power. My rental house here, power bill is SIGNIFICANTLY LESS in kWh than many solar systems on RV's. Try going 60 days on 112 kWh.

Simple, small systems are a lot easier to maintain than larger ones. A fortunate few need very little metering. Their austerity however is of little consolation to individuals that need help in managing energy.

My "learner" pair of 6s died a horrible death five years from new (six summer seasons). I learned how to look after them properly after their second season. Too late!

So IMO anything over five years is gravy now that I know what to do, thanks to this Forum and my Barre book I got back then.

http://www.bestconverter.com/Books_c_67.html

MEXICOWANDERER wrote:
Gjac, thank you.

What I have gleaned is few respondents have exercised their batteries deeply enough nor enough cycles to qualify for a valid test for cyclability. Batteries do age due to corrosion. Sulfation takes it's toll and your example is a valid entry showing most early battery demises are preventable.

BFL13 has a good handle on his batteries, and so do others like NinerBikes (others need to be mentioned but this is en breve)...

I am coming to the conclusion that an accurate, calibrated amp hour meter is the only way an average Joe stands a chance of knowing what is going on in the battery department. Most refuse to handle a hydrometer. Plug, Play and Ignore, means PAY PAY PAY.

For folks who wish to maintain their batteries with a minimum amount of manual interface, the inclusion of amp hour monitoring is not optional. it is mandatory. Too many early failures proves the point...

I have a pretty simple goal. Regardless of how much I used the night before, when the solar panel starts charging in the morning, if it's a sunny day, I'd like the battery to be 95% or better charged by 1 or 2pm, daily, regardless of season. I want electronic devices to pick up the lost surplus amps from the solar panel setup for recharging laptops, running the electric heater, watching the news on TV, etc, before the sun gets too low on the horizon, and amp harvest time is lost for the day.

If you don't use the amps the solar panels are giving you once near 95% SOC, for recharging other devices, smart phones, lap tops, Chromebooks, what ever, you lose it. So I always try to schedule accordingly. Of course, a good emergence of bugs on the river with a wide open bite can ruin the best of plans. Plan B would be to grab the surplus by running the generator first thing in the morning, and capture the surplus from the generator for charging duties of other small devices, run the water pump and shower while the generator is running too, in short maximize big hit electrical consumer users while the generator is already on , and get my moneys worth out of the gas consumption, if batteries need to be charged on the RV anyways by the generator.

I am not shy at all about wanting 14.8V- 15.0V from either the solar panel or the first hour or a bit more on a 30 amp power supply unit. The T-1275 deep cycle will handle what either puts out, without loss of electrolyte or water. Every 95 to 98% SOC I get back to, on a daily basis, is less risk of sulfation of the cells on the trip, and loss of potential capacity. Also less abuse and less to recoup once I get back home.

If this is done, I don't see the need to monitor what my usage was. What I do monitor is amp rate going back into the battery, and at what voltage. A few dips of the SG while noting V and amp charge rate will confirm how far charged up you are % wise at a certain amperage charge rate. You need to learn the idiosyncrasies of your batteries and charging devices.

I've no control over the number of charge cycles I will or won't get out of batteries. I get what I get, I just do my best to keep them top charged or as close as possible, daily, and I get what I get. I avoid continued depletion as much as possible... that is what beats a battery up. Keeping it as close to fully charged is what maximizes a batteries charge/dishcharge cycles during it's life.

We need landyacht318 to check in on his screwy 31's, to make mexicowanderer happy.

Many, many days of continuous dry camping, but very few deep cycles, sorry. Usually ~85-100's every other day.

But I too am interested to know how many folks realize battery lifetime is to be measured in cycles, not years.

MEXICOWANDERER wrote:
I cherry pick comments. Few things are as difficult as rendering relevant statistical answers out of a Hodge-podge of comments. So I am not after statistical data answers. The parameter of the question was presented. From there I have to glean the relevance of the response. I learned how to do this with customers over a forty year span. The methodology does not make clear sense to a lot of people, but it is there. Obtuse abstract deductions...

Very true, we all do this in many different ways.

RV.net is often used and viewed by many and often one learns from reading the posts and then, as you stated, cherry picks how it fits them, their needs and or their application. You not stating or sharing is disingenuous to the small group that are watching/reading the responses in how you resolve your methodology. I hope you will make your thought known, or not. Essentially you are either doing this for yourself or possibly helping others. The comments have been a great source for me. I hope it has been for others, no matter what you are seeking, mexicowanderer.

b

I cherry pick comments. Few things are as difficult as rendering relevant statistical answers out of a Hodge-podge of comments. So I am not after statistical data answers. The parameter of the question was presented. From there I have to glean the relevance of the response. I learned how to do this with customers over a forty year span. The methodology does not make clear sense to a lot of people, but it is there. Obtuse abstract deductions...

Huntindog wrote:
Surveys such as this are really kind of useless. Battery life is totally dependant on usage.
Just because I get say, 6 years out out of a certain battery doesn't mean that you will.
No two peoples usage will be the same.

I can say that under my USAGE, I have never gotten much more than a year out of a 12 volt. And I have had twe 6 volts going strong at 6 years when I sold the TT.

We boondock a LOT. Probably spend at least 60 days a year in the TT.

This is what I agree with. Your survey has too many variables.

I'll just throw this in;

I have had 2,007 consective nights in my RV. The first 730 nights were on a generator, topping of my batteries each day. The following 1,277 nights have been on Solar (What a life change. Lots of help from this forum to get where I am now. Thank you guys and gals).

From the beginning, I had 2 AGM 6v Batteries 240 AmpH. I abused them terribly, I mean down to readings of the high 10v, often in the 11.6v range. These batteries finally stopped holding a charge, while they would still charge up, during the Day with my solar harvesting. I relegated these batteries to my small solar array if 300w and figured I would just keep using them until they puked, which happened in October of 2014. I swapped them out for a pair of 6v Lifeline AGM 300 AmpH on the 17th of October. They are performing fine.

So to answer your question, I had almost 6 years of continuous cycle (complete use/discharge to full charge (90%)by generator for two years, every day and then for four years to 100% charge by solar. So, I got say 5 1/2 years of use or approximately 1,825 cycles out of a pair of 6v AGM during continuous use.

b


edit; Oh, of the 2007 nights in my camper, I have boondocked/dry camped 1,969 nights, with the remainder spent in 12 campgrounds in 6 years. So shore power is foreign to me.

The proof of the pudding lies in fully exercising the battery to 50%, recharging it correctly and render the maximum number of cycles. Back to kWh rendered I'm afraid. Doubling capacity, effecting shallower discharges has a bell curve for maximizing dollars for kWh service. The kWh rendered formula is hard to top.