Experience is a great teacher, but it ain't cheap....

I've got a Group 22F battery on my Deere F725. New this summer. Somehow, the key got left in the "on" position a month ago and ran the battery dead. Mistake #1

I hooked the charger up, and noticed that it would not charge to completion. It's old, so I figured it was on the fritz, so didn't think much of it and just pulled it off and called it a day. A couple days later, I tried hooking my Battery Tender up to the battery but it would only blink red and wouldn't charge. After a bit of poking with my voltmeter and a shower of sparks when my ground terminal turned out to be hot, I realized that the polarity on my battery terminals was reversed.

After a bit of reading, it seems like that since the battery was fully discharged it is susceptible being charged into a state of reversed polarity if the charger leads are hooked up backwards. I'm not sure how I did it, but somehow I must have hooked the leads up backwards. That's my only guess as to how this happened. The garage is dark and I guess it highlights my need to break down and get bifocals.....

Anyway, from what I read I could try and fully discharge the battery again and force it back. But I also see that the battery is likely permanently damaged. Has anyone had any luck doing this? Or should I just buy another battery and chalk it up to another $70 in tuition paid to the school of experience?

Sorry if this is a dumb question but why not just hook the positive cable on the mower to the negative on the battery and put the negative on the tractor on the positive on the battery. Would that not work? If not I think your best bet is just buy a new battery.

 

Not a dumb question. I was wondering the same and made an edit about the same time you posted. My only concern is that I've read some comments saying that battery life is reduced significantly. I don't know, but if the battery is going to be iffy I'd rather just spend the $$ and be assured it will start.

 

Yeah I read that too on some other forums. I don't know it may be worth it just to spend the $$ and be done with it.

 

Most chargers have some sort of protection for reverse polarity, unless the battery was truly black flag dead. If it had much of any charge at all, I'm sure it would have tripped the breaker in the charger.

I'd check it with a multimeter and see what it says for polarity. The meter will display a minus sign when polarity is reversed. Then you'll know if it got charged in reverse or not.

 

It does show a negative reading on the multi meter, which changes to positive when I swap the leads to the opposite "incorrect" positions.

I've also hooked up a different battery charger with a polarity error light. It lights up when I hook it up the way it should be, and the light goes out when I reverse the leads. My old Schumacher charger I used originally doesn't have the light, and evidently didn't have a breaker or the battery was truly stone cold dead.

I'm 99.99999% positive the polarity is reversed.

 

But what about the 00.00001%! I think you're right it must have reversed polarity id see if it would start the mower like that for all we know it may be ok.

 

Just use a light bulb or some other load and run the battery dead dead then connect charger correctly and slow charge it for a day.

Walt Conner

 

Or since it's a new battery this summer, take it back to the place of purchase and use the prorated warranty.

 

This sounds like the best option. My experience with lead acid batteries is if they are run completely dead, the likely hood of them coming back to full capacity (being charged correctly) is 50/50. In your case, the reverse charging has probably damaged the internal plates. These batteries rely on a chemical process to produce voltage, reversing this process may have caused the plates to become plated.

 

I'd thought about the warranty, I just don't feel right about doing it since it was user induced damage. Call me crazy, I dunno.

 

:thThumbsU

 

I'd take the old battery out, throw it in the truck and head for the dealer. Take it in and 'fess up to what happened. They might decide to run it through warranty for you. If they don't you will likely need the old battery or pay a "core charge" on the new one. Up here (Canada) I am being charged a "core charge" if I don't have an old battery when I go in.

 

Drain it ,charge it,test it ,replace if nessesary.

 

if the battery has changed polarity this would make the starter turn backwards & not start the engine.. it will prolly just spin the starter.. now too u could damage the chargin system on the tractor too just by turnin on the key..

there is no doubt in my mind that u have damaged the battery.. it will not last long.. I suggest u get a new battery..

I'm also takin this time to inform u guys that it's time to vote in this tread below.. it's the machine of the month time for votin.. when u get there u'll notice that my Perky machine is in the vote.. this is not a demand u vote for mine.. u do have a choice to vote for the one u like.. I'm tryin to get people out to vote.. I'd love to see 500 people votin at least.. then we could call it the Indy500 votin race..

http://www.mytractorforum.com/174-mtf-contest-forum/1096273-machine-month-voting-thread-march.html

 

So to close this thread out, I ended up just buying a new battery. From what I've read on here from your comments and elsewhere, even if i can successfully pull off the discharge/re-charge with the proper polarity - the battery is internally damaged.

I just bit the bullet and turned it in. I didn't try the warranty route. The battery failed due to user stupidity, not a manufacturing defect. I know there's a 50/50 chance I could have pulled off a warranty claim anyway.

I'd like to say I have good Karma coming, but as I was screwing the battery hold down back on the bolt sheared off flush with the metal of the frame. I'm not sure I can get at it from below, so it looks like I'm going to have to get the extractor out. That's tonight's project.