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Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 12:41 am
by c130king
Fellow Mac Enthusiasts (and specifically those of you that are Battery Experts),
Situation: Batteries manufactured in May 2009. Installed in Sept 2009. Last used on Dec 30 2009. Leads disconnected but batteries sitting in the battery compartment since. Won't get back to the boat until probably late July or early August 2010.
ON EDIT: They are Interstate Deep Cycle Group 24 Batteries.
Questions: 1) How bad will the batteries be after sitting unused for 7+ months?
2) Assuming they can be recharged what is the best method to do this? I have a
Battery Minder but I don't have any other type of charger...but more than willing to get one.
I continue to refine my "to do" list as I plan my return to the U.S.
Thanks.
Cheers,
Jim
Sailing on König
Re: Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 3:36 am
by Buell_S1W
1)- Depends on what state they are at now i.e. 100 % charged or not and the temperature they will be stored at. After 7 months unattended they will be in need of a good slow recovery charge but would probably survive.
2)- Can your battery minder be connected up to the batteries while you are away? This would be the best choice.
Re: Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 3:44 am
by c130king
I will assume the batteries were nearly fully charged when put away in December. Didn't really check then but had done some motoring near the end which should have gotten them nearly fully charged.
And the batteries have not been touched since December 30 and they won't be touched again until late Jul/early Aug as I am still living overseas.
So the question I guess is a Battery Minder good to recharge batteries in this condition or should I buy some sort of bigger battery charger for use in the garage of my future home? I was sort of thinking the Battery Minder was more of a battery maintainer rather than a battery charger.
Do any of you use a bigger battery charger in your garage for deep cycle batteries? I don't have an in-boat recharging system other than the alternator on my engine.
Thanks,
Jim
Re: Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 5:25 am
by Retcoastie
Jim,
The battery minder is the best thing to use for batteries not being used. However, if you remember the instructions that came with it, they said it should not be used as a battery charger. If the battery is down, as I suspect yours are from internal leakage, they recommended using the battery minder with another battery charger initially until the battery comes up to about 12VDC. Then the minder would do the job of conditioning and maintaining on its own.
I have taken AGMs that acted like they had two dead cells and brought one back to full operation and one back to what appears to still be one bad cell. Currently the minder is working on a lead acid that had a bad cell, five cells with low water and one full of water measuring 10.46VDC. It now carries 12.68 after one day of rest. In each case I started with the minder and a cheap car charger for the first couple hours.
If you have someone who could get those batteries on the battery minder now, they would be like new when you return.
Anything on orders yet?
Ken
Re: Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 6:49 am
by c130king
Ken,
Nothing on orders yet...but I am thinking the DC area is looking more and more likely. Norfolk looks like it is out...but Langley AFB in Hampton, VA is still a possibility. But I think the one year remote to Iraq is no longer being pursued. I sure hope those clowns make a decision soon.
I am just going to have leave my batteries as is for another few months. My plan when I bought the thing was to use my Battery Minder to "maintain" the batteries. But I will have to recharge them with a regular charger first I guess.
Anyone have a recommendation for a decent battery charger that will work well with deep cycle batteries? Or will a standard car battery type charger that you can buy at any auto parts store work okay? To be honest, I have never used a battery charger before...never had a need.
Thanks,
Jim
Re: Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 6:55 am
by Trouts Dream
I have found that by bringing the batterys home during the (8 months of) winter I can recharge them twice over that period. I use a slow marine battery charger for deep cycles and have left the charger on for several days at times. It automatically drops to 2 amps and I am still using batteries that are 5 and 3 years old. Given the cost of a good battery, I think its worth some basic maintenence.
When on the boat I keep a couple of small trickle charge panels that I throw on the port deck and hook up with alligator clips to the batteries.
Biggest cause of battery death is the number of times the battery drops below 30-50% charge.
Re: Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 7:11 am
by c130king
Trout,
Completely agree. However, I don't have the option right now. It's tough when you live thousands of miles from your boat and you have to leave it in a storage yard.
And for the first two years of my time overseas this wasn't a big issue as my folks lived in Jacksonville and I could leave the batteries at my Dad's house on the Battery Minder. But they have moved, live in a 40' RV and no longer own a house, so I no longer have that option.
Hopefully I will move back to the U.S. and never be this far removed from my boat for such a long time ever again...of course I probably just jinxed myself by saying that.
Oh well.
Cheers,
Jim
Re: Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 7:28 am
by Trouts Dream
Thats a problem then.
Probably the best thing a fellow could do is place a couple of those trickle charge units tied down on the deck and have a friend wipe the dust off every 2-3 months. Maybe someone where the boat is stored could do that. I think a small trickle charge could go a long way to keeping the batteries healthy.
I sort of understand where you are coming from. The reservoir where I store my boat doesn't fill till early June and no sailing by October (we are in the Rocky mountain foothills). That leaves 4 sailing months and then clients offer big jobs somewhere else in those months. Last year I sailed it from June 10 to Aug 15. Better than nothing but I live right near it.
Sorry, had to get that off my chest,

Hope you make it home eventually.
Re: Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 8:12 am
by Highlander
Jim
Any small trickle battery charger with auto shut-off will do it will charge the battery when needed & turn on or off as necc, my mac19 has this set-up in my shop I always say to myself remember to switch it over to the other batt. every three months but it usually goes 5 months Ah just had a brain fart it was nov. when I switched them over last so I guess I'll do it today , but the batts are usualy OK
Jim , I see in your pic you have a battery sitting on one of your aft berth cushions "man " thats a no no "corrosives " will eat up your cushions in no-time !
Wish you all the best with your next asignment !
J
Re: Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 8:22 am
by c130king
J,
The batteries are in the battery compartment. They were only sitting up there for a few minutes before I installed them...took the opportunity to snap a photo.
So something like a 10/6/2 Amp automatic charger for around $50 from an auto parts store will do the trick? Do you charge flat batteries back up on the low 2 Amp setting?
Thanks,
Jim
Re: Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 8:45 am
by Highlander
Jim
The batt. charger I have in the mac19 is a 10amp I beleive would have to check it but its completely auto pd about $15 for it over 35yrs ago
deep cycle batts are not hurt by a fast charge ! if you buy a small cheap batt. charger like mine you will know if the batt. is low as soon as you hook it up if its charges at 10amps its low if at 2amps its good & will drop off to 0 amps when fully charged & kick in when necc, thecharger I have does not have a on/off switch so I have to hook up the charger first to the batt then plug it into the hydro !
J
Re: Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 12:48 pm
by Retcoastie
Jim,
A deep cycle charger should not be a concern for you. I have two and the directions for both say you can use the regular or the deep cycle setting after a deep cycle battery had been in service for six months or more. My big, fancy Xantrex does not even have a deep cycle setting.
Ken
Re: Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 1:00 pm
by c130king
John, Ken,
Sounds good. Just one more thing to add to my list of things I need to/want to buy for my boat.
Cheers,
Jim
Sailing on König
Re: Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 2:14 pm
by waternwaves
get yourself a lead acid battery desulfator...
a device that impresses a high frequency high voltage signal on the battery plates, typically in conjuction with a charger. these can recover even heavily sulfated batteries. YOu can pick them up on ebay. typically you will only need it once a year or so, as long as the batteries are not discharged over about 50% say 10.8V. The only problem is that these devices cannot be left on the battery, they are used to recover highy sulfated/deeply discharged batteries.
Re: Restoring or Recharging Dead Batteries
Posted: Sun May 09, 2010 2:37 pm
by DaveB
Other sulutions is take your batteries to Battery Plus or a Local Auto Zone or advance Auto and have them do a condition ck on batteries, Batteries plus will do a long term de sulfation to bring the batteries up to a close to normal charge if batteries can handle the charge and plates not ruined.
If batteries have sulfated to a no return or just sulfated to a point of ...get a new one.
Long periods of being under charge will sulfate the battery to useless.
It's a matter how long they were subject to 12.2 -12.4 volts or less (50% discharge)in a wet cell deep cycle battery.
10.5 volts is a total discharge in a wet cell deep cycle and never get those batteries below 12.2 volts or you will shorten the life battery in under a year.
Dave
waternwaves wrote:get yourself a lead acid battery desulfator...
a device that impresses a high frequency high voltage signal on the battery plates, typically in conjuction with a charger. these can recover even heavily sulfated batteries. YOu can pick them up on ebay. typically you will only need it once a year or so, as long as the batteries are not discharged over about 50% say 10.8V. The only problem is that these devices cannot be left on the battery, they are used to recover highy sulfated/deeply discharged batteries.