waternwaves wrote:get yourself a lead acid battery desulfator...
He indicated that he has a Bateryminder. These devices claim that they use the pulsed high frequency desulfator, so he should be OK there.
One trick that I have used for "flat" batteries, those that will not accept a charge: Parallel up a good battery with the bad one and a charger. Often times a completely flat battery will not charge because it is showing a no load condition to the charger. By paralleling a good battery, it will bleed some charge to the bad one and often times recover it at a slow rate. When the bad battery is above about 10.5v, it should charge on it's own and with the use of a desulfator, may return to good service.
One tip on the BatteryMinder's... you MUST check the water in the batteries at least every two months. The BatteryMinder will keep already-charged batteries nicely floated, but there's a cost - the water will be depleted over time. Indeed, I forgot to water my batteries over one winter and opened up the boat in the spring to find them virtually *dry* - it took over 1.5 gallons of water to re-fill the two batteries! (Yes, GALLONS!)
I specifically do not recommend the batteryminder because it combines desulfating and trickle charging. Testing shows that this does not extend battery life over separating the two function. Maximum battery life is obtained by use of separate devices. I have 13 year old batteries with intermittent use that still discharge to 95% of their rated capacity. IF you use a trickle charger, put it on a cycle timer so that it does not run continuously. say 3 hours a day. Your batteries will thankyou. Better yet, put a small load on the batteries with a second cycle timer. and you will only need to desulphate every 3 to 5 years. Water use will also decrease significantly
With proper tending, nuclear power stations achieve 20 year lead acid and lead calcium battery life 20+ years.
Do you guys think my batteries will be in bad shape after sitting unused for over 7 months? They were manufactured in May 2009 so they won't be very old when I finally get back to them.
How long does a battery need to sit unused before it becomes "bad"?
c130king wrote:Do you guys think my batteries will be in bad shape after sitting unused for over 7 months? They were manufactured in May 2009 so they won't be very old when I finally get back to them.
How long does a battery need to sit unused before it becomes "bad"?
Thanks,
Jim
Lead acid batteries will last a long time if taken care of. It is not a issue of how long they have sat but have they stayed charged.
If yo do not discharge past 50% or high current discharge/recharge they will just about last forever.
waternwaves wrote:I specifically do not recommend the batteryminder because it combines desulfating and trickle charging. Testing shows that this does not extend battery life over separating the two function. Maximum battery life is obtained by use of separate devices. I have 13 year old batteries with intermittent use that still discharge to 95% of their rated capacity. IF you use a trickle charger, put it on a cycle timer so that it does not run continuously. say 3 hours a day. Your batteries will thank you. Better yet, put a small load on the batteries with a second cycle timer. and you will only need to desulphate every 3 to 5 years. Water use will also decrease significantly.
OK, I'll accept you know more than I do about this... but if this is the case, how come somebody hasn't made a device that does just exactly that? i.e., you plug it in, connect it to your battery, and it automatically cycles every 3-4 hours between trickle charging and applying a load? Seems pretty simple to make.
grady wrote: Lead acid batteries will last a long time if taken care of. It is not a issue of how long they have sat but have they stayed charged.
If yo do not discharge past 50% or high current discharge/recharge they will just about last forever.
But mine are NOT being "taken care of" right now and they will have sat for 7+ months without being touched. I don't live near my boat and have no family nearby to help me out. They are just about 1 year old right now. In July/August, when I finally get back to them, they will be 15 months old.
Will a 15 month old battery go bad if sitting unused/untouched for over 7 months? There is ZERO load on the battery...they are not hooked up to anything. Is this "bad" for the battery? How fast will a battery sitting unused and not hooked up to anything go flat? Is this sulfidation issue a problem in this case or does that take longer? Batteries are in the boat in Jacksonville, FL.
Once I get back I will take care of them and expect they will last me a long, long time. But for now I am trying to find out if they have likely gone bad and can they be recovered and how. Or I can trade them in and start fresh with new ones.
waternwaves wrote:I specifically do not recommend the batteryminder because it combines desulfating and trickle charging. Testing shows that this does not extend battery life over separating the two function. Maximum battery life is obtained by use of separate devices. I have 13 year old batteries with intermittent use that still discharge to 95% of their rated capacity. IF you use a trickle charger, put it on a cycle timer so that it does not run continuously. say 3 hours a day. Your batteries will thank you. Better yet, put a small load on the batteries with a second cycle timer. and you will only need to desulphate every 3 to 5 years. Water use will also decrease significantly.
OK, I'll accept you know more than I do about this... but if this is the case, how come somebody hasn't made a device that does just exactly that? i.e., you plug it in, connect it to your battery, and it automatically cycles every 3-4 hours between trickle charging and applying a load? Seems pretty simple to make.
Trickle charging and Float charging are two different things. A trickle charge will boil and dry out your battery. A true float charge should not. Not every battery is the same and the float charge voltage does change with temperature.
Jim - ive seen estimtes for self discharge rates from 1-10% per month. I suspect 10% per month is way high though.
I would put them on the charger when you return for a couple days, let them sit a week, and they see how much charge they took by testing the specific gravity. My guess is they will have reduced capacity but work ok.
Do you mean a "big" charger...or the Battery Minder? I think I will buy a "big" charger from somewhere and use that and see what happens. Worst case is I blow up the batteries, make a big mess in my garage, ruin the paint on my car from splashed battery acid, and then spend $150 on two new batteries...
Thanks to all for all the comments/recommendations. Now I just need to get back.
Sears 4-6 amp charger - maybe 30 bucks or so. Also useful at home for prolonging life of car batteries (up here in the frozen North, an old battery will die only in winter, so if you can make it to spring, you get another 6 months free...
I was thinking a 6 Amp car charger - thats about 1.4kW hours per day, so after 2 days (each battery) you will pretty much have put whatever charge you can back into them.
Okay.. so is the boat in Florida? If so you don't have cold freezing temps to kill the batteries. Just normal sitting around without being charged discharge right?
I wouldn't sweat it. 7 months, most of which are mild climates doesn't seem like a battery killing environment. Get back, charge 'em up and see what happens I say. If they are totally run down, maybe take some of the wise words above. But if it were me, I'd put them on a slow charge for a couple of days and see what gives.
IMHO, cool and dry is better than warm and humid for battery storage. I could be wrong.
RussMT wrote:So many great battery experts with good advice.
Okay.. so is the boat in Florida? If so you don't have cold freezing temps to kill the batteries. Just normal sitting around without being charged discharge right?
I wouldn't sweat it. 7 months, most of which are mild climates doesn't seem like a battery killing environment. Get back, charge 'em up and see what happens I say. If they are totally run down, maybe take some of the wise words above. But if it were me, I'd put them on a slow charge for a couple of days and see what gives.
