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best practices for long battery life

mrad
Explorer
Explorer
I cannot get more than 3 years out of my battery on my TT. Original battery was an interstate. It was replaced under warranty going into its third year. The replacement lasted two years. I then tried the walmart brand. This was it's third year. When putting it away for winter storage this year, it would not raise the tongue jack when not hooked up to shore power. When I checked the battery indicator in the TT, it showed it had no power 15 minutes after being disconnected from shore power.

I leave the TT plugged in all year once we start using it. Usually May- October. After that it goes in my basement and gets a charge every 2-4 week until ice fishing season. Then I take it to the fish house every weekend (Mid December through the end of February). I use it with a 750 watt inverter to run the tv and lights/ ceiling fan when I tune the generator off. I can usually get 6-7 hours on the battery before it needs to be charged. I then start the generator and charge it with my vector smart charger until it is full.

Should I be turning the disconnect switch off in the summer when it is plugged in at home, or is 2-3 years the average life span for a deep cycle battery?
55 REPLIES 55

Harvey51
Explorer
Explorer
I want to confess to murdering my first pair of batteries. My defence is ignorance - I thought the 3 little lights with the word โ€œbatteryโ€ meant something. We were on a long trip, driving every day and those idiot lights said โ€œfullโ€ every time I checked. We never plugged in because the batteries said they were full! Engine charging seemed sufficient. I had a meter which said the battery voltage was at least 12.6 every night. It was cold so we needed the furnace in the morning. One morning the furnace wouldnโ€™t go and the batteries had about 8 volts.

New batteries from Costco got us home. A battery monitor gave evidence that the batteries never actually got to 100% charge when travelling, though they did get to 12.6 volts. We boondock all the time so a good charger wasnโ€™t going to solve the problem. What did the trick was a single 100 watt solar panel, charging all day whether driving or camping. Those Costco batteries, now 6 years old, never get below 80% charge and they provide all the energy we need. Of course we would need more solar power if we watched TV, used a microwave or other electric heating appliance.
2004 E350 Adventurer (Canadian) 20 footer - Alberta, Canada
No TV + 100W solar = no generator needed

MEXICOWANDERER
Explorer
Explorer
I usually hear "just get by" excuses while sitting in the dark. Until 2000 ciclando profundo batteries did not exist down here. So folks who were obviously well off who screamed about ruined food and a ruined trip got it once again when they paid a hundred dollars for a car battery, only to have it three weeks then itself fail. Warranties were only good where the batteries were purchased SCREAMED LOUDER. I had to turn up the stereo.

Just
Get
By

Is a good philosophy when on horseback.

landyacht318
Explorer
Explorer
Trojans' 14.82 spec was likely arrived at as thay is what they expect would be able to achieve the highest state of charge in the average time to recharge in the average use that they expect their battery to be used in and thus reduce the possibility of warranty returns

Its not as if 14.4v cannot fully charge it, it just takes longer. Perhaps when older with a few hundred cycles 14.4v cannot max out electrolyte SG with enough time, but most batteries by then will never see max SG without an EQ charge anyway.

As far a AGMS being able to be drawn to 30% more often than flooded, my Northstar-27 is closing in on the 1000 cycle benchmark and IDGAF about how deep I discharge it. Hundreds of cycles well below 50% SOC. They key is the high amp recharge every so often and the true full recharge as often as possible as soon as possible.

The end amp figure is telling though, it now struggles to get below 0.4 amps at 14.7v and takes a long time to get there, and will eventually bottom out around 0.35amps then start increasing again where when new it would keep decreasing to somewhere under 0.05amps at 14.7 with enough time held there.

Voltage retention during overnight discharge is still ridiculously high. 12.2v under a 5 amp load with 45Ah removed for a 90Ah battery with nearly 1000 deep cycles and many thousands of engine starts accumulated over 5 years......color me impressed. Easily the best life from any lead acid battery I have cycled, but i can also treat it the best of any I have cycled

BFL13
Explorer II
Explorer II
Cydog15 wrote:
pianotuna wrote:
For some reason it appears that during winter the battery is being either deep cycled (below 50%) and/or chronically under charged.

Trojan wants 14.8 volts to fully charge their 12 volt products.

That is true and Probably why I would use the special version of the PD 9200 series designed specifically for it. That or the Boondocker you can adjust.


Since that 14.8v is only right for 80F, and the concern is for MN winters, where 14.8 is now 15.2 or so, why bother with a fixed 14.8?

You need 14.8 temp compensated, or adjust the voltage yourself to suit the temperature. That makes the Boondocker adjustable (a version of the PowerMax LK models) the better choice.
1. 1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
Photo in Profile
2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
See Profile for Electronic set-ups for 1. and 2.

MEXICOWANDERER
Explorer
Explorer
Also got gnus for folks who think over-discharge is equally degrading to flooded and AGM cells. An AGM will survive TWICE the number of discharge to 30% state of charges compared to garden variety flooded RV batteries.

Unless the flooded owner upgrades to a Rolls battery with flooded batteries the difference are minor. Pencil out your battery expenses, buying, shipping, travel.

It all amounts to time and money...

LenSatic
Explorer
Explorer
profdant139 wrote:
So without getting into any more technical stuff, a word of advice for the OP -- many of the folks giving advice on this thread are true experts, who are essentially professionals when it comes to caring for batteries. I would follow their advice to the letter, if my life depended on it.

But it doesn't.

Most of us on this forum (and in the real world) are recreational battery consumers. Don't let the best be the enemy of the good, as the saying goes. If you try to adhere to all of the best practices described above, you will make yourself crazy (and you will spend money on a new converter).

Instead, just do a half-baked job, like most of us do (including me). Keep the battery charged up as much as possible. Make sure you have big enough batteries to do the job -- group 24s are pretty small. Get a multimeter (ten dollars?) and learn how to use it (easy -- go to youtube). Check on the state of charge pretty often -- try to keep it above 12.1 volts.

If you want to move up a notch in terms of battery care, get a cheap hydrometer -- it is a big eye dropper that tests the specific gravity of the battery water. It can give you a heads up when one of the cells is going bad -- that cell will have a lower reading than the others, and it is time for a new battery.

I boondock 90 days a year -- lots of heavy battery use -- and I get five years out of my Napa Marine Deep Cycle batteries. That is good enough for me.

No, I don't equalize. No, I did not replace my WFCO converter with the hottest version. My off-season battery charger is run of the mill, rather than a real smart charger.

Yes, I check my battery water. Yes, I use a hydrometer. Yes, I check the voltage. Yes, I do not let my battery get below 50 percent. (That was an expensive lesson, too slowly learned.)

I fully understand that my semi-sloppy behavior is not optimal and that it is upsetting to a true expert to see how I maintain my batteries. But camping is just a hobby -- I am not maintaining batteries for a submarine, where one false move is fatal. So I refuse to be a slave to my batteries. Adequate performance and battery life are, well, adequate. This does not have to be rocket science.


There you go! Great advice. I never know our MPH when towing and don't care, I'm going anyway. A new battery is a couple of tanks of gas for us. Don't sweat the small stuff.

Oh, BTW, for those who don't know, we live 100% off-grid on solar so we depend on batteries every minute of every day all year long. Just enjoy the scenery!
2008 Casita SD 17
2006 Chevy Tahoe LT 4x4
2009 Akita Inu
1956 Wife
1950 LenSatic

Cydog15
Explorer
Explorer
pianotuna wrote:
For some reason it appears that during winter the battery is being either deep cycled (below 50%) and/or chronically under charged.

Trojan wants 14.8 volts to fully charge their 12 volt products.

That is true and Probably why I would use the special version of the PD 9200 series designed specifically for it. That or the Boondocker you can adjust.

MEXICOWANDERER
Explorer
Explorer
  • Cheap price
  • Maintenance free
  • Battery CHARGER
  • Not a converter
  • Simple maintenance
  • No hydrometer
  • Plug n Play
  • Large energy reserve


Should you stumble over such a miracle hiding inside a monk's Tibetan cave let me know.

Could use the same positives for clothes, razor blades, etc.

Treated semi correctly a thick plate AGM will last an astonishingly long time. The main thing is getting it 100% recharged as soon as possible. If you want to nursemaid a wet cell battery that's fine. I've been doing that with 24 + 12 cells for decades.

Don't know about you. but a failed battery costs me a failed mission, time and energy to pull the battery, going to the store without having the hassle of time, parking and gasoline, then reaching for the wallet, and reversing the process. Tah Dah, carve a notch on the door frame. Six down, or is it seven?

An early failure of a calcium calcium junk battery really jammed this point up my ---. A 240 mile trip utterly wasted. Plans to buy cheaper food, and needed supplies shredded into confetti. The failure cost me the trip, too much time lost, plus unwarranted cost of a replacement.

Maybe I count stuff important to me differently. Money, Time, Frustration. A job timetable utterly ruined.

But it's a decision made on an individual basis. Back home battery maintenance is a morning ritual. And I have time planned to set aside. I was not amused to part with 250 dollars and a blown day then return home to remember all the stuff that has to remain unfixed. I live in a place where size 13 shoes and XXL clothes are as rare as a blue eyed iguana. In October the month following the battery an original starter motor in the toad gave out. Another trip blown. The cost of the starter was justified because it was so old but only had 110K miles on it. But it destroyed the trip. Two for two. Parts for my dodge are not available in Mexico at all.

Wednesday. Trip No 3. Car stays at home. Seventy dollar bus trip and a friend is ferrying me across the border. BUT WAIT! This time a new in-tank carter electric fuel pump awaits me at the PO Box. I even wandered over to Francisco Nava's repair shop. Lined up an appointment.

I'm sick of Breakdown Maintenance. I could have bought a Hung Chow special for a third the price of a Carter. But I know in the rear, I mean end, I would end up paying 10 times the difference.

It all depends on a person's prerogatives. Mine include minimum money and hassles.

pianotuna
Nomad II
Nomad II
Sorry for the triple post-rv.net would not allow me to submit it.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

pianotuna
Nomad II
Nomad II
For some reason it appears that during winter the battery is being either deep cycled (below 50%) and/or chronically under charged.

Trojan wants 14.8 volts to fully charge their 12 volt products.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

pianotuna
Nomad II
Nomad II
Some of the Vector chargers have a "recondition" mode. Whether it works or not is the question. However, its idea of ful is not 100% state of charge.

I believe you mentioned running the roof fan a weekend at a time during winter-is that on battery power only?
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

pianotuna
Nomad II
Nomad II
The WFCO may take about 168 hours to fully charge a battery.

Since you ALWAYS are on shore power that really doesn't matter much.

Is the winter storage also on a 30 amp supply?
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

pnichols
Explorer II
Explorer II
profdant139 wrote:
So without getting into any more technical stuff, a word of advice for the OP -- many of the folks giving advice on this thread are true experts, who are essentially professionals when it comes to caring for batteries. I would follow their advice to the letter, if my life depended on it.

But it doesn't.

Most of us on this forum (and in the real world) are recreational battery consumers. Don't let the best be the enemy of the good, as the saying goes. If you try to adhere to all of the best practices described above, you will make yourself crazy (and you will spend money on a new converter).

Instead, just do a half-baked job, like most of us do (including me). Keep the battery charged up as much as possible. Make sure you have big enough batteries to do the job -- group 24s are pretty small. Get a multimeter (ten dollars?) and learn how to use it (easy -- go to youtube). Check on the state of charge pretty often -- try to keep it above 12.1 volts.

If you want to move up a notch in terms of battery care, get a cheap hydrometer -- it is a big eye dropper that tests the specific gravity of the battery water. It can give you a heads up when one of the cells is going bad -- that cell will have a lower reading than the others, and it is time for a new battery.

I boondock 90 days a year -- lots of heavy battery use -- and I get five years out of my Napa Marine Deep Cycle batteries. That is good enough for me.

No, I don't equalize. No, I did not replace my WFCO converter with the hottest version. My off-season battery charger is run of the mill, rather than a real smart charger.

Yes, I check my battery water. Yes, I use a hydrometer. Yes, I check the voltage. Yes, I do not let my battery get below 50 percent. (That was an expensive lesson, too slowly learned.)

I fully understand that my semi-sloppy behavior is not optimal and that it is upsetting to a true expert to see how I maintain my batteries. But camping is just a hobby -- I am not maintaining batteries for a submarine, where one false move is fatal. So I refuse to be a slave to my batteries. Adequate performance and battery life are, well, adequate. This does not have to be rocket science.


Great post, Dan!

I just about do the same, except for one small difference - I use a couple of top notch Group 31 12 volt AGM batteries wired up in balanced parallel so I can really "set it and forget it" regarding my RV batteries. I dust them off maybe every one or two years.

I've had a stock single fixed voltage 13.8 volt converter in my RV for years. The AGM batteries like 13.8 volts for both charging up - or floating when at home between trips. I run the batts down to around 12.1 volts before either A) firing up a little tiny generator to charge them through the stock converter, or B) traveling to another campsite at which time the main engine alternator charges them. I can tell when they're fully charged from an ammeter I permanently installled inside the RV years ago - current going into them shows as 0 (zero) when they're fully charged.

K.I.S.S. is the name of the RV battery game ... but unfortunately I did have to figure out how to pay for those expensive AGM batteries one time.
2005 E450 Itasca 24V Class C

landyacht318
Explorer
Explorer
"best" can be taken to extremes, as others have pointed out.

The money spent on equipment which can perform the 'best' especially if one wants it to be semi automonous will cost more than a few new group 24's.

Good to very good means not overdischarging, and returning to full charge regularly, and fairly promptly.

Very good to excellent longevity means shallower discharges, more prompt rechrges to an absolute true full charge determined with an Hydrometer, and then temperature compensated float charge afterwards.

AN AGM battery is not immune to chronic undercharging, likely the opposite and for a higher price, but if one wants to insure a full charge, and can achieve absorption voltage easily, then an ammeter can easily show true full charge, as dipping a hydrometer into 6 or 12 cells is not something many people consider fun.

The Megawatt set to 14.4v can easily get the battery neophyte into the good to very good longevity for not very much money. The 'Smart' chargers are all marketing lies which are 'justfine' for a garage charger doing the occassional starting battery, but not a regularly deeply cycled marine battery, or actual deep cycle battery for that matter.

Getting a 'smart' charger to actually fully charge a regularly deeply cycled battery is an exercise in futility with few to no exceptions, and they hydrometer will prove this.

But there is bliss in ignorance and ignorance in bliss, and batteries are only rented, so draw a line in the sand and take it as far as you want.