stupid me, I pull into my garage, hit the kill switch, jump off my bike and head straight to bed. I was the end for a long as night of saving lives in the ED (or, so maybe I delt with a lot more BS then I did life saving). So I wake up in the lafter that after noon and head out to my bike to start her up and head into the ED for the night shift, only to find it stone cold dead. I forgot to turn off the ignition switch so the lights drained it to zero. I put my battery tender on it and left in while I was as work. When I came home I found that the tender was so hot that I could not handle it for more then 10 seconds without having to out it down.
Do other people experience smiler issues with the battery tender overheating? And is it ok to keep using it if so?

Sorry if this sounds crazy, I am an ambien and 2 beers deep into my sleep. Hope all is well out there in motorcycle land.

 

And I am trying to sort out if I am ok to leave it on the bike to charge as it is 9th ring of hell hot at this time. (its currently unplugged and off the bike to give it a rest)

 

The tender is not a battery charger per se, and will not recharge a totally dead battery. When your ignition is "ON", aren't your lights on as well? In any event, your bike is rapidly discharging, while the tender is working at 100% and cooking the transformer trying to keep up. It's sort of like shoveling against the tide.

Under normal circumstances, your tender only gets moderately warm, correct?

My tender is on 100% of the time while the bike is off, unless I'm waxing it!

 

HDRusty; Battery Tender is for maintaining...you need a charger. Not enough juice to turn-over = dead & no tender will get it back to operation anytime soon. Go to WalMart & get cheap Black & Decker charger...you'll be back in the saddle much quicker.

 

I was thinking that maybe I was asking a little to much from the tender. Of course I wont be able to ride until tomorrow so maybe Ill let the little thing cook for one more day and see if that gets me going. If not I fear it will be time to lay down some $$$ for an actual charger. Thanks for the input boys.

 

I recently had the opportunity to throughly review the Battery Tender’s manual after running down my battery while listing to the radio as I worked on my bike. Normally I have it plugged in but because I was working on the tranny I unplugged it because the cord was in the way.

There is nothing mentioned in the Battery Tender manual about the BT overheating. They do recommend to periodically check the battery to see if it is unusually warm. This is an indication that the battery may have a weak cell and that it could go into a thermal runaway condition.

My battery was too dead to start but was over 3 volts so it did charge:

If you try to charge a dead battery having a voltage below 3 Volts, the BATTERY TENDER® CHARGERS will not start to charge because an internal safety circuit prevents the battery chargers from generating any DC output voltage.

Other info on charging rates:

The Battery Tender® Junior charges at a rate of 0.75 Amps (0.75 Amp-Hours per hour). The Battery Tender® Plus charges at a rate of 1.25 Amps (1.25 Amp-Hours per hour). Therefore, a fully discharged 15 Amp-Hour battery will take approximately 16 hours or 9.6 hours respectively, to recharge to 80% capacity with a Battery Tender® Junior or a Plus. Some large automotive or marine, deep cycle type batteries may take several days to fully recharge.

 

I have 12 vehicles on the 1.5 amp Schumaker tender from Wallyworld. I have had used them to charge a fully discharged battery. It will take several days but they never over heat because they only go to 1.5 amp.

What amp is yours? Even if you have a charger all battery manufacturers recommend not charging over 1.5 amp/hr.

 

I'd advise against "cooking" it for another day, or you may do significant damage to your battery. Heed, the above advice and wait until you can get a proper battery charger and it all should be good after that.

 

And you're still awake?

 

Despite what some say, Battery Tender brand and most other battery maintainers are chargers as well as maintainers.

As mentioned above, the Junior model will charge at 0.75 amps and the Plus will charge at 1.25 amps. Once the battery is fully charged, it will switch to the maintenance mode which is usually a few milliamps unless you have something on the bike such as Lojack that draws more current.

I am not an expert in battery charging but everything I have read through the years indicate that one should use a charge rate of approximately C/10 (1/10th the battery capacity) to charge. That means a 1.25 amp charger would work well for a 12 amp/hour battery. It will charge a larger battery but will just take a little longer than if you used a C/10 charge rate. I used a 1.25 amp Battery Maintainer on the boat battery I used to start my racing kart years ago. Depending on how many starts I made, the battery would be recharged and switched to maintenance mode by the next day. I still use a Plus on a car I have that does not get driven every day.

As stated, if the battery in your bike is below a certain voltage (I believe it is the three volts mentioned), a Battery Tender brand charger/maintainer will not charge the battery for safety reasons. If your battery is that low, it may come back up some just by leaving it sit for a while. Most batteries will recover after a discharge with the amount of recovery determined by the battery itself and other variables.

The Tender you used probably got warm because it was working to capacity for a while trying to recharge the battery. You did not mention if you have the 0.75 amp Junior model or the 1.25 amp Plus model. The Plus model will obviously recharge your battery more quickly.

Be careful about using higher amperage chargers on small batteries such as in our motorcycles. You can damage them by over charging them or charging them at too high of a rate. That's part of the reason (as far as I know) why the Plus is only 1.25 amps as this is a safe level for most small motorcycle/ATV batteries.

You could probably use something like a five amp charger on your battery without any issues, but it will also recharge with the Battery Tender you have. I would not buy another charger unless you were in a big hurry to get the bike running again. It will be safer and probably better for the battery if you can bring it back with the lower amperage charger.

As I stated, I am not a battery charger expert but I have been messing with chargers for motorcycle batteries for a long time and have read a number of articles about how to best maintain them for longer life and in a safe manner.

Hope this helps.