Watch those battery tenders

[geekonabike]

I think the regulator circuit in my Battery Tender Jr is out.  The  LED stays on red (indicating "charging") all the time the battery is hooked up.  It does charge the battery, but my (analog but not real cheap) FET multimeter says 14V.  I started the bike to give the battery somewhere to let some of it off, and after a minute I turned it off and it was down to 13.8V.  I'm glad I didn't leave JR on all night.

It used to be OK, charging and then doing it's maintenance thing, and the LED so indicated.  I used it one whole winter on a 12V riding lawn mower's battery.  Not anymore.

I must have left the bike's parking lights on (turned key past "lock"?) for the last couple days.  Third time it's happened since I got the bike, I think.  Unless there's another leak that's doing it.  Anyhow I had to jump it.  Rode a couple miles, got new tags, and had to push start it though by then the battery would at least turn the engine a couple times.  By the time I got home it was more like 11.5V and could actually start the (warm) engine, so that's when I put on the Tender.  I already suspected the charger would keep charging so I pulled it off several hours later, when I took the higher reading.

Just curious, anyone else had this problem with this ubiquitous device?

--Mike D.

[werase643]

you think your charger is broke cause it is at 14V?

and this is bad cause the alt only charges at 13.8 V?

what Amperage is the JR charging at?


why would you want to float charge the battery continuously?

Note: when you charge a lead acid battery.... the lead sulfate in solution is returned to the lead and lead oxide plates....a by product is hydrogen gassing....the hydrogen comes from the water in the battery.  if you continue to charge a battery.... it will eventually "boil" dry
soooo
check fluid level in battery before recharging

yes I took a 1 week school (40Hr) on Batteries in the early 90's .....everything you don't care to know about batteries

[coll0412]

If it is a battery tender[/b[, then it works a little different than consently charging it.  It measures the voltage and/or the "c...." something(i cant remeber the word) but is a measure of how much sulfate has deposited it self on the plates. THe thing you want to watch is if holds a charge. Almost all batteries that don't have a bad cell(remeber each cell contributes 2.12V) will still maintain a high voltage, of about 12.72V.

  If you have deeply discharged your battery, it may be peremently damaged. The batteries used in cars as well as motorcycles are deemed a starter battery. The lead plates are thin and more plentyfull as to produce more surface area for the reaction of Pb+PbO2+2H2SO4→2PbSO4+2H2, as you can see the hydrogen gas is a product of the reaction, however, it is not always a gas and can be dissolved into the sulphuric acid. So if it is discharged slowly then it wont produce that much gas. If you charge it slowly, however, not to much of an issue. In your case you may have decreged the plates, by basically coating them with  lead sulfate, you may have to "burst charge" the battery to remove the deposits by basically boiling the acid next to the plates in hope it will remove the deposits.

You may have to take you battery in to have it checked, because my guess is that the charger is not bad but is unable to charge the battery because it is a bad battery.

Yeah....long post but I got rambling sorrry...

[geekonabike]

Well the charger is supposed to charge a battery, and once it's charged, go into some kind of maintenance cycle where it checks every so often and "tops it off."  So my battery was obviously fully charged at 14V, and the tender still showed red on the LED which means "this battery is not yet fully charged so I need to keep charging it."  I admit I'm not totally aware of the battery internals (and thanks for the explanation by the way), and so the battery to me is a "black box" in the sense that it charges, it discharges, depending upon the load or voltage applied to it.  I know that's simplistic, like saying I should be able to start a motorcycle and go.

Anyhow I would think that the Battery Tender Junior isn't stopping when the battery is fully charged, but rather overcharging it.  Hence my thought that the part of its circuitry that tells it the battery is fully charged could be fried.

OTOH it occured to me later that there may be an alternative explanation, in that I (DOH) didn't actually disconnect the battery from the bike when I put the charger on it.  Maybe something in parallel with the battery is causing the tender's LED to stay red.  Hmmm.....

Sorry if I missed something obvious.

--Mike D.

PS:  If it weren't so cold I'd check in my garage, but my memory is the JR does somewhere in the 750-900 milliamps range.

PPS:  Thanks for the reminder to check the fluid level before charging.

[geekonabike]

If it is a battery tender[/b[, then it works a little different than consently charging it.  It measures the voltage and/or the "c...." something(i cant remeber the word) but is a measure of how much sulfate has deposited it self on the plates. THe thing you want to watch is if holds a charge. Almost all batteries that don't have a bad cell(remeber each cell contributes 2.12V) will still maintain a high voltage, of about 12.72V.

  If you have deeply discharged your battery, it may be peremently damaged. The batteries used in cars as well as motorcycles are deemed a starter battery. The lead plates are thin and more plentyfull as to produce more surface area for the reaction of Pb+PbO2+2H2SO4→2PbSO4+2H2, as you can see the hydrogen gas is a product of the reaction, however, it is not always a gas and can be dissolved into the sulphuric acid. So if it is discharged slowly then it wont produce that much gas. If you charge it slowly, however, not to much of an issue. In your case you may have decreged the plates, by basically coating them with  lead sulfate, you may have to "burst charge" the battery to remove the deposits by basically boiling the acid next to the plates in hope it will remove the deposits.

You may have to take you battery in to have it checked, because my guess is that the charger is not bad but is unable to charge the battery because it is a bad battery.

Yeah....long post but I got rambling sorrry...

Thanks for that explanation too.  Sorry I couldn't read your post before my second post got posted.  (There's a tongue twister waiting to be born there.)  This is the third time this has happened, that I came out to find the battery croaked, I guess because I must have left the key in the parking-lights position (full counter-clockwise).  The other times I jumped it and/or charged the battery and was fine for months, so I'm not convinced I did damage to the battery, but of course I'll have to wait and see.  Neat that there isn't an aspect of the bike's operation that isn't fully understood by someone on the forum.

Even if the battery is toast, in the greater scheme they are cheap, and having a new one in there (not bought by the previous owner) will mean a little added confidence.

Best regards,
Mike D.

[MarkB]

You didn't say how long you left the Battery Tender Jr on the battery while waiting for the red light to go out and for the green light to go on.  It may take it quite a while to declare victory and the battery will charge more slowly if it is cold.  14 volts at the terminals should not hurt the battery even if applied for a couple days.

Here's a link to a good general tutorial on battery charging and the tradeoffs in techniques:
http://www.batteryuniversity.com/partone-13.htm

This link describes the algorithms used by the various Battery Tender products:
http://batterytender.com/battery_basics.php

And this shows the typical charge cycle for the Battery Tender Jr:
http://batterytender.com/includes/languages/english/resources/Product_Info_BT_Junior.pdf

In short, I think you're worrying about nothing.  Put the Battery Tender on and let it do its thing.  If the light doesn't go green in a day or so, try pulling the battery and charging it somewhere warmer than your garage. If that doesn't work, then we have something to talk about.

[geekonabike]

You didn't say how long you left the Battery Tender Jr on the battery while waiting for the red light to go out and for the green light to go on.  It may take it quite a while to declare victory and the battery will charge more slowly if it is cold.  14 volts at the terminals should not hurt the battery even if applied for a couple days.
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In short, I think you're worrying about nothing.  Put the Battery Tender on and let it do its thing.  If the light doesn't go green in a day or so, try pulling the battery and charging it somewhere warmer than your garage. If that doesn't work, then we have something to talk about.

Thanks for the links.  The last one indicates that it will charge it up to 14.45V before going into mainenance mode.  OK, I guess I didn't wait long enough.  I freaked when I saw the battery was up to 14V.

If I get a chance, I'll take the battery out and put the tender on it, in the middle of the garage floor (I know that's cold but I'd prefer to keep it out of the house) for a week.

One other thing that had me worried an earlier time I was getting this behavior was that the tender was getting rather hot, even when the battery was pushing these higher voltages.  But I should give the little guy more credit I guess.

SORRY BATTERY TENDER GUYS.  I should not ASSUME (Makes an ass out of me).

--MIke D.

[geekonabike]

You didn't say how long you left the Battery Tender Jr on the battery while waiting for the red light to go out and for the green light to go on.  It may take it quite a while to declare victory and the battery will charge more slowly if it is cold.  14 volts at the terminals should not hurt the battery even if applied for a couple days.

Sorry.  It was on about six hours.

Got up to ride, battery dead.  Used car battery to start the bike.  Rode two miles, did an errand, battery could turn the starter a couple turns (figured that would be the case).  Push started.  Got home (another two miles).  Batery read about 11.8V, and could start the bike fine, though by then the bike was quite warm.  That's when I put the tender on for about six hours, and the voltage was at 14V.

Just to clarify.  --Mike D.

[MarkB]

If you keep the bike in the garage and you don't want to bring the battery in the house, I don't think there's any real advantage to taking the battery out of the bike to charge it.  I'm assuming that you haven't added any accessories that would load the battery with the key switch turned off.

If you haven't done so already, now would be a good time to check the fluid level in the battery and top off with distilled water if necessary.  You didn't mention how long the bike sat for the battery to discharge, but it may be that your battery is on its way out.  Batteries lose a lot of their starting capacity when it's cold and the engine will be harder to start under those conditions, so if the battery is getting weak, now is when you would notice.

[coll0412]

Another good test to see if you have a draw is to first get a hold of a ammeter, most mulit meters have them built in, just make sure it can  do more than 500ma. What you want to disconnect the negative battery terminal,turn the ingnition to off, place the negative(black) lead to the negative terminal and the red lead from the meter to the negtive battery cable terminal. This in effect makes to the current have to go threw the multimeter. If you measure a drain of more than 35ma then you need to locate the drain, if you measure alot(ie 300+ ma) then you basically have a large short. If you don'tl notice a large drain you may have to investigate your charging system.