Question about Battery Tender....

[blk-betty]

Can a Battery Tender bring back a weak battery or does it just prolong the battery life.

Have an 06 Street Glide (mine) and an 06 Softail Deluxe (hers) that neither have been ridden all that much lately.  Hers because she got a new job and is traveling 80% of the time and mine because, well I bought an 08 Triumph Tiger 1050 and have been riding it more than the SG. 

I bought a Battery Tender about 3 years ago but never actually used it.  We use to ride 9-10 months out of the year and it typically rarely gets below freezing at night here and warms to 50-60 during the day, but this week and last week's cold spell has put us well into the 20s at night and highs in the upper 30s during the day.

I figured I'd break out the Tender and give each bike some juice but didn't know if it would really do much to an already weak battery.  Last time I ran her Softail (about 2 monts ago), the battery was weak but it started up Ok and seemed to charge after a 20 mile ride, it fired right up, not like it had after sitting so long. 

[Tsani]

A battery will drain on its own. So if there are no other issues than a lttle bit of time and lack of use, yes an tender can bring back a weak battery provided it is not too far gone. It would be be wise to keep the batteries on the Battery tender plus when they are not going to be used for say a week or more because there is a small drain even when the bike is not in use. On that Deluxe, check the tightness of the connections. I find mine loosen up regularly. Don't know about the SG, but it can't hurt to check em.

[Dennis The Menace]

Mark, yes it will.  I recharged my Ultra overnight one time after forgetting to turn off the power.  Completely dead, and fired right up 10 hours later.  Dont expect it to do much after only an hour or so, they are a very slow rate of charge.

Dennis

[Dennis The Menace]

My batt was down to 7.5 volts, so maybe that is why mine worked. Good info to know, Indy.

[IndyHarley]

Wow - my experience is that most batteries that are down to 8-9 volts (in a rest state) are usually defective at that point. Although it would not surprise me that there are other variables at work also, i.e. how long has the battery been in a low volt state for example.

[HotRock]

Yes, a battery tender will charge a dead battery.   Depending upon the amount of discharge how long it will take to bring it back to full charge.  That is, if the battery is in good condition and WILL return to full charge.   Batteries work and last longer if kept at full  charge.  Once the charge gets to a low level the plates begin to sulfate.  The more they sulfate, the more the overall battery deteriates.   Finally if left completely discharged for a longer period of time the plates short out from the sulfation or it is left in a condition that will not recharge at all.  We used to experiment with discharged batteries just to see how many we could bring back to life.  Some batteries would read zero volts and refuse to take a charge, but after a few days on charge it would slowly come back to life and start receiving some current.    Sometimes it would take a couple of weeks at a very low charge rate and we would have success.   However, I would not want to depend upon a battery in that condition for reliable starts in a Harley. 
Battery tenders are great for motorcycles and other seasonal vehicles.   Just put one on and leave it all winter.   Which reminds me, I better go to the garage and hook up my tender.     Batteries seem to have a mind of their own.

[truck]

Also know that AGM batteries are not as forgiving to being "dead" and brought back as flooded batteries are. It's in here somewhere. http://www.dekabatteries.com/assets/base/0139.pdf

[blk-betty]

Thanks for the good info.

I'm going to hook it up this weekend and hopefully will get another year or so more out of the stock 06 batteries in each bike.

By the way, this is what is taking my attention away from the Street Glide

[harleyjt]

Wow - my experience is that most batteries that are down to 8-9 volts (in a rest state) are usually defective at that point. Although it would not surprise me that there are other variables at work also, i.e. how long has the battery been in a low volt state for example.

 

If its down that low, it's junk from my experience.
jt

[blk-betty]

Wow - my experience is that most batteries that are down to 8-9 volts (in a rest state) are usually defective at that point. Although it would not surprise me that there are other variables at work also, i.e. how long has the battery been in a low volt state for example.

 


If its down that low, it's junk from my experience.
jt

Just checked the battery on the softail.  11.9 volts.  Lights work and electrical work fine, starter tuned it over very slowly 2 revolutions then stopped.

Hooked up the Tender and will see what happens.  According to the manual, 11.8 volts is fully discharged.