Left grip heaters on overnight, now battery won't charge

[ZuluHour]

Alright, so like a dork I thought I turned my grip heaters off and left the bike for the evening.  The next day I go to turn the bike on and nothing, battery is completely drained.  Gauges don't light up and the fuel pump doesn't prime.  Realized then my grip heater switch was on - doh!

This is on a 2002 RC51 with the cheapy $20 cycle gear grip heaters.  They're wired straight to the battery so I took the easy route - feel free to flame on for my laziness.  They're coming off the bike when I sell it in the spring - but I digress.

Threw the Battery Tender Jr. onto the SAE leads and let it charge for a couple of hours.  Came back and just barely getting a click and flash of light on the gauges.  Let it charge overnight and now the bike starts and runs on its own, but I figured the battery would have been fully charged by now.  The LED on the BTJr is still solid red, so less than 80% full iirc.  The BTJr was also really hot.  Should I leave the BT on for another day and see if I can get a full charge?  The battery is only 1.5 years old and is the OEM style Yuasa.  

[Dan K]

Battery Tender (I believe) has a circuit that will tell you if the battery won't take a proper charge. If it's charging, leave it on there until it flashes green, then turns green.

 -Dan

[sleazy rider]

Get a regular battery charger on it.  Battery Tenders are for maintaining a charge in a fully charged battery.

[bomber]

Get a regular battery charger on it.  Battery Tenders are for maintaining a charge in a fully charged battery.

^this right here . . . . .

[Carbonero]

It's also possible that your battery had been deep-cycled previously and is now toast. That happens; your average car/bike battery is not designed to be deep cycled.

[ZuluHour]

Get a regular battery charger on it.  Battery Tenders are for maintaining a charge in a fully charged battery.

First I've heard of that.  Is there a reason the BT won't charge the a dead battery properly?

Did a little research on the Deltran website.  Turns out they have a ballpark estimation for battery charging: (Battery Ah/Charger current = hours).  So 11Ah/.75A = 14.667 hours for a fully depleted battery.  That gets it to about 80%. They go on to say to roughly double that for the last 20%.  So I'm looking at around 28-29 hours of charge time.

No wonder it's not there yet.

[maddjack]

Yep Leave it on , it brings back to full charge.

[GRN]

^this right here . . . . .

Yup, BTDT, and if you don't have a regular charger, jump start it and go ride it like you stole it for an hour (with as little draw being used as possible). If it won't restart when you get home, it's toast.

[Dan K]

The 'Battery Tender' he's talking about is a combo charger / float charger once full.  It should charge the battery fine, assuming the battery can take a charge.  My Battery Tender brand charger also tells me by certain code (flashing red?) when the battery is toast/can't take a charge.

If you want to use a regular charger, that is NOT for leaving on after the battery is charged, go ahead, but if you leave it on too long that in itself can toast your battery.

I'd just put the Battery Tender Jr. on, leave it on, and leave it on some more until it either is fully charged or it tells you the battery is toast.

- Dan

[bomber]

Yup, BTDT, and if you don't have a regular charger, jump start it and go ride it like you stole it for an hour (with as little draw being used as possible). If it won't restart when you get home, it's toast.

and you'll have had an entertaining ride . . . . .

BONUS!

[sfalexi]

And go spend a few bucks on a relay, positap, and zip tie!  Lol.

I've had got a few direct to the battery switches, but usually to charging ports for cellphones while I'm commuting.

Lesson learned.  I doubt you'll be the last.  Bring the battery to auto part store and ask them if its still working and they'll charge it up to see if it'll hold a charge.

Alexi

[veefer800canuck]

Some float style battery maintainers won't recharge a battery that's totally flat.

Try a 2amp straight-rate charger, one that puts out 2A continuously without a float mode.

Use it for about 6 hours max so you don't damage your battery by leaving it on overnight.

[JonS]

The instructions for my cheap hand warmers said to tap into the headlight power. Easy to do and no worries about leaving then on.

[veefer800canuck]

Well, did the battery come back, or is it FUBAR???

[ZuluHour]

Forgot to reply, battery charged to full the evening of my last post. Ive been riding a few days since and zero issues so far!

[bomber]

Great news, Zulu --

On a different note, everytime I see your handle, I hear Sam and Dave in my head . . . .this is a good thing, so, thanks for that!

[02Tac]

First I've heard of that.  Is there a reason the BT won't charge the a dead battery properly?

Did a little research on the Deltran website.  Turns out they have a ballpark estimation for battery charging: (Battery Ah/Charger current = hours).  So 11Ah/.75A = 14.667 hours for a fully depleted battery.  That gets it to about 80%. They go on to say to roughly double that for the last 20%.  So I'm looking at around 28-29 hours of charge time.

No wonder it's not there yet.

It is not that it will not charge it properly, it is just not the right charger for the job.  As you saw from the heat level, you were really working the charger.