Error light on battery tender

[pozo_izquierdo]

What do you battery experts say?
My OEM gel battery had drained over the week when I left the ignition key in the middle position and forgot to plug the tender to mains. (The socket was hooked all the time.)

OK I thought, I just plug the mains and the BMW battery tender will take care of charging. But heck no! The red error light comes on on the tender.

Does this mean that the battery is totally gone or should I try to charge it with less sophisticated charger that does not have all the fancy leds and just tries to pump some juice in the battery...?

The OEM battery just turned two years.

Thanks for the comments in advance

[jzeiler]

Ari,

Most likely you have "trashed" the battery. They don't recover well from a full drain. The tender will not bring it back to life or work until the terminal voltage is up around 10 - 11 volts. If you have another type of charger or jumper cables from one of your cages, try that to get it back up to where the tender will work. Just don't leave it unattended for the recovery on the other charger. It may come back but it most likely won't last the riding season.

[pozo_izquierdo]

Ari,

Most likely you have "trashed" the battery. They don't recover well from a full drain. The tender will not bring it back to life or work until the terminal voltage is up around 10 - 11 volts. If you have another type of charger or jumper cables from one of your cages, try that to get it back up to where the tender will work. Just don't leave it unattended for the recovery on the other charger. It may come back but it most likely won't last the riding season.

Thank John,

this is what I suspected. The tender is OK as I tested it on my lawn mower battery and the appropriate charging leds turn on.

My bike battery has been on battery tender on and off of the non-riding past 5,5 months and occasionally I have stressed it with testing all my add-on farkles but I have never managed to totally drain it except this past week when I forgot to plug the tender in mains.

So, I will try with a conventional charger just to see if the voltage goes up and if this battery turns out to be dead I'll look for the Odyssey 680 model that seems to be recommended by many.

Regards

[TMH]

I agree that the Battery Tender needs to see a minimum voltage before it will begin to trickle charge. I can't fully agree that you have likely trashed the battery. This will be very dependent upon the condition of the battery before this event. If you have generally kept it topped up for the 2 years you have had it, it could be in good shape, and will weather this event O.K.

On the other hand, going to an Odyssey will never be a bad thing. But you might be able to have some more quality time with your current battery before you have to spring for the Odyssey. Anyone local to you have a battery load tester? Get your current battery initially charged, then topped up with the Battery Tender. Then it should be ready for a load test, which will tell you the real story on its current condition. Most auto repair shops have one.

Tom

[wcarter]

Last weekend (away from home and the Tender) I managed to drain my battery dead flat. No power whatsoever when I turned the key.

I jumped it off, and drove it highway speeds for over four hours, which seemed to charge it up nicely. I've kept it on the Tender since returning home, and it seems to "top off" the same as it did before the drain. I have not had the battery load tested, however.

[messenger13]

...and then I hooked it up to my 2-amp car charger and it's been fine ever since. The Battery Tender is back to working as normal too.

[jzeiler]

The best way to find out if the battery will recover is to monitor the specific gravity of the electrolyte. I just have not figured a way to do it on the Gel and AGM batteries.

I just didn't want to give Ari false hope for a full recovery and have him be disappointed. Some batteries do recover and live a useful life. Others continue to self drain and leave you stranded (I know only too well) when you least expect it.

[pozo_izquierdo]

Thanks to all for your comments and advise.:)

I charged the battery with a regular battery charger for some 3 hours until the voltage went up to the level that the battery tender was able to take over.
At least the charging seems to take place so now I just have to watch how the battery behaves after I get riding.

So far no hope for riding for another week or two as the winter seems to hold on tight...On the other hand, some farkle projects are still ongoing so the bike is pretty naked.:p

Best regards