RV battery/minder storage question

[HSpiering]

I had a problem last year . My 3 year old battery that was on a battery minder. It would only hold a small charge for a couple day's then be pretty much dead. I charged with a charger, I keep it on a solar panel for two weeks got by ok. I put it back on the minder for the last year and now the battery will not hold a charge at all. I think the minder may have ruined the battery. I phone the company and will be sent a new minder. Not sure I trust it. Got to reading the info on my convertor on the trailer and it will bring up the charge and maintain the battery when plugged into 110V. If I take the battery out for storage. I read to put it back on the trailer for 8-10 hours to recharge every month. Anyone know if this will work as well as a battery minder to desulfate a battery??

 

[AH64ID]

I am honestly not sure you need to do most of that. I generally charge my batteries once at most in the off season and as long as they are disconnected and put away at a full charge there isn't an issue.

The 120V converter should drop to a float voltage after the battery reaches a full charge. Look at the model number and research its settings and capabilities.

My converter has a desulfate mode, every 21 hours it goes up to 14. 3ish volts for 15 minutes and then drops back to ~13. 2v.

Leaving something on a charger all winter seems like a waste of money to me.

 

[jelag]

the battery maintainer in my 5th wheel has a circuit to allow the batteries to drain down and than recharge them... for batteries to work as designed they just need to cycle... I've never had any luck leaving vehicles on a system to maintain them. . they never last more than 2 or 3 years... but batteries that drain, and than get charged back up... cars and trucks... ect always seem to last 5 - 6 years... .

 

[HSpiering]

Jim
Are you talking a minder or built in convertor?

I have a Magnetek 6300A convertor. As per manual and info off the net this is the type in most RV's. So as you say this would keep the battery in good condition. Sounds about what you have. As I gather it will charge at 0. 5 after bringing a battery up with 5 amps. That is what I was wondering, if keeps it from forming sulfication on the cells? So is this better than to keep jolting it with a minder? Maybe it would be best to use a minder on a boat, truck or tractor being they don't have a convertor to plug in. It would be nice if someone from TDR would figure the need and or best way to go with RV or storing batteries.

 

[TLane]

I've left batteries on various kinds of float chargers, including the one in the converter on the camper, and they all ended up with a shorted cell after about 3 years. The best advice that I've seen for storing a battery comes from the Trojan web site: allow the battery to sit disconnected, and recharge it when it reaches 70% state of charge. Beware that if you simply unplug your camper that things like the gas detector will drain the battery in about 2 weeks. You really have to disconnect the battery to let it sit. It's best to store it away from temperature extremes if possible.

There are a few battery chargers which will actually monitor a battery in storage and recharge it only when necessary, but they are rare. Most of them are some kind of trickle charger, and despite the seller claims to the contrary, the battery will eventually fail.

As far as the de-sulphators are concerned - don't get me started. Most of the little box (wall wart) styles are wishful thinking.

 

[B.G. Smith]

http://www.batterystuff.com/kb/articles/battery-articles/battery-basics.html bg

 

[Road Dog]

A lead-acid battery does best if it's kept fully charged. It's not like a NiCad that needs to be discharged and charged regularly. Battery minders are hit and miss. Some are simple trickle chargers that never fully charge a battery or (worse) overcharge and boil the battery dry. Better battery minder/chargers will measure the voltage and charge as needed. Of course they cost more money.

If the battery isn't fully charged then two things happen. Lead sulphate crystals form on the plates (sulphation) and the freezing point goes up (which matters in cold places). Letting a battery self-discharge to 70% before charging is a good way to shorten it's life. To desulphate a battery you need a special pulse charger that generate 20+ volt pulses to cook the sulphate crystals off the plates. It also takes days and weeks charging/discharging to bring back a battery.

The charger in my camper does a good job of keeping the battery charged but it draws 35W so it's not very efficient. At least it heats the camper in the Winter. In the Summer I use a separate smart charger to keep it fully charged.

 

[HSpiering]

road Dog
You said something that made me think. "overcharge and boil the battery dry". After about 2 years in this minder I did see wet acid on top and down the side of the battery. It did not go dry, but why was it boiling like that? This is I assume a good battery minder. I have read reviews got it at Camper World. Paid $75 for it.

 

[Road Dog]

A charger works simply by having a voltage higher than the battery voltage. Better chargers will measure the current (amps) and adjust the voltage up or down to get the desired current. As the battery gets close to fully charged it can't accept as much current. The excess current becomes heat (which damages the plates) and water gets converted to hydrogen and oxygen (not really boiling but the same result). A damaged cell in a battery will throw off the charging too since the voltages are never right. It's possible that the battery was damaged by the minder or by some other charger (trailer charger/converter). If you have a spare battery put it in the shop with the minder (i. e. not connected to anything) and see how it works. The battery might get a little warm to the touch but shouldn't get hot.

 

[K5IP]

Good job, could not have done better myself.
tnx

 

[HSpiering]

Well!!! I may have solved my problem. I hope. I went to a web site that had a “battery expert”. I told him of my problem and he had no good answer as to what happen to my battery with out having voltage readings. SO, I phoned the maker of my battery minder and did a lot of complaining that the minder may be bad. In the end they sent me a new model 1500 minder. I just returned from hunting and had bought two new batteries, one Kirkland one Exide. This new minder will do more checking of the battery. I had a dead tractor battery so I put it on to see what happens. 24 hr latter the unit said the battery was good and was in the desulfication mode. Next I put the Exide on. It was 12. 2V. after 8 hr my new minder started blinking red. Indication the new battery had a short. I then put the Kirkland on 24 hr later it was all ago. The Kirkland started at 12. 3V. It and the dead battery went up to 13. 4V under charge. As needed as to the instruction book. The Exide never went over 12. 6V. I E-mailed the “expert. ” He said the Exide was probably shorted and that was my problem with the old battery. It had a short and just tried to bring the voltage up and overcharge because it also had a short. He knew that because now I had voltage readings. That battery was also an Exide. He didn't no why he didn't think of that before. I got my money back on the Exide. So the moral of the story, do not trust a new battery. Have a good tester and charger. I must give very high marks to the Minder 1500. It saved me $90 on a bad battery.

 

[AMink]

I plug my trailer in to shore power and turn the converter breaker off. I plug in a battery minder to the trailer and use that to keep the batteries charged. I use two 6's in series and this seems to give me a better charge than just the converter. Judging by the construction of the rest of the trailer, the converter is probably the least expensive available. I use similar tenders on my motorcycle and quad with good results.

 

[DFrank]

I plug my trailer in to shore power and turn the converter breaker off. I plug in a battery minder to the trailer and use that to keep the batteries charged. I use two 6's in series and this seems to give me a better charge than just the converter. Judging by the construction of the rest of the trailer, the converter is probably the least expensive available. I use similar tenders on my motorcycle and quad with good results.

This is a great idea. I'd like to do this, but do not know how to make my converter charger not actually charge. It's in a truck camper without an isolator, so it should top off the truck batteries as well as the camper's. Ithink I'll tie it together with the block heater cord for the winter.

 

[Shadrach]

I run 2 six volts lead acid batteries on my TT. During the summer my solar panels keeps them charged up. In the winter the roof of the trailer is covered in snow so I remove them and put them on the bench in my unheated garage. The first of every month I hook up a regular old fashioned battery charger for 24 hours to keep them charged up. Being 6 volts I charge them together as one 12 volts just like they were on the trailer. I have gotten 7 years out of this pair as I did with the last pair. Even in the cold of winter ( last week it was -34*C or -29*F ) I have had no problems with them. I do use a C-Tek trickle charger on my truck as it will sit for 2 or 3 months during the winter without being used. David

 

[BIGNASTY]

On our TT that our Son now owns I installed one of these and plugged in a Battery Tender, I always made sure to turn the disconnect and plug in the Battery tender right after I dropped the TT so the batteries were always charged up from the truck. Battery Tender says it will charge batteries but I don't buy that and either does the guy that sold it to me at a battery specialty shop along with 4 6volt batts that are hooked up to look as thou its one LARGE 12V

The Battery disconnect is the best thing that I have put on ALL of our cars, trucks, equipment just a turn of the knob and the batteries are completely disconnected from the circuit. The gas trucks that our company had used these it saved a major gas rack fire one time. The truck was off and loading fuel at a rack I walked by the truck and smelled something hot walked around to the other side of the truck where the batteries were and they were on fire, one turn of the knob disconnected them from EVERYTHING hit them with a fire extinguisher pulled the rack shut down cord and ran like hell. On reviewing the video of the event as soon as I turned the Battery Disconnect the fire looked as if it were going to go out. I WASNT GOING TO HANG AROUND AND SEE

 

[p-Bar]

I just installed 2 6v Trojans in my fiver . Using the converter onboard to charge seems to be a smart charger. I used my VOM to see how much current was going in on high charge 7 amps and automatic topping .3 amps or 300 milliamps this should work good.