| Author | Message | ||
     Thunderclap |
i bought a battery tender, but do not have electricity in my shed, so i removed my battery, hooked up the battery tender but its still blinking red. it is connected properly. then i read if the batteries charge is to low it wont charge. is it dead for good? or can i some how jump it? | ||
| Leroysch |
Not familiar with battery tenders but here's how I troubleshoot my battery...same process for cars and tractors, too. 1. Measure open-circuit voltage of battery at the battery posts. Is it 12V-ish or more? If no, go to step 2. If yes, go to step 2 anyway. 2. Hook up a battery charger to the battery, set it to the low charge rate if adjustable, then check if you are getting any charging current. For example, my battery charger has a low 2 amp rate and a meter to show what the charging current is. If the battery is "low", you should get pretty close to the max. charging current which will be indicated on the meter of the charger, if so equipped. If it doesn't show anything, odds are pretty good the battery is toast. If you don't have any way to verify the charging current...after letting the battery "charge" put it back in vehicle and try to start it. Be sure to clean the battery cables as mentioned below. If the voltage tanks, battery didn't take a charge. Also, if the voltage tanks when you turn on the ignition due to your lights coming on...the conclusion would be the same. 3. If the battery takes a charge but still won't work in-vehicle, be sure to clean the connections to the battery posts. I had cases where no alarming signs of visible corrosion were observable, but still was getting a pretty big voltage drop across the connection. Cleaned up the connections and I was good to go. 3. If you replace the battery, be sure you put your meter across the battery outputs and verify you're getting a charging voltage...something greater than the open-circuit voltage of the battery..13.6-ish volts or more. This will help verify the initial diagnosis and ensure a bum voltage regulator or alternator isn't the problem. As you can tell, I'm not one to trust idiot lights! | ||
| Sparky |
A Battery Tender will not charge a dead battery. The battery has to have a certain minimum voltage before attempting to charge with a Battery Tender. However, if you can temporarily jumper the dead battery with a good battery while the Tender is connected to the dead battery, you should be able to trick the Tender into starting its charge. Connecting to a good battery has to be done very carefully because you don't want sparks around the batteries. The best way to do this is to connect the positive terminals with one jumper cable then connect the negative cable to the dead battery negative post but leave the other end of the cable loose for now. Note: do not have the car engine running because there is more than enough capacity in the car battery for this task. When the Tender is connected to the dead battery and plugged in ready to go, hold the loose jumper cable clamp for a second or two onto a part of the car frame that's clean and not close to the car battery. Here it will spark relatively harmlessly as current pumps into the dead battery with hopefully enough juice to get the Battery Tender to start charging. Be careful though, the cable clamp you're holding may get hot, so wrap a glove or something around it and don't leave it clamped on. So the idea is to be connected to the good battery only long enough for the Battery Tender to start charging. When its green light comes on, remove the loose negative cable clamp from the car frame and hopefully it will continue to charge. When it does, then remove both jumper cables, negative first, without disturbing the Tender's cable connections. | ||
| Brother_in_buells |
Take a 12v bulb with two wires (home made voltage detector)and clamp one wire on + and one wire on - and put it on the battery charger. if it,s good the light starts glowing. Let it so for some 20 minutes and check then if it,s started charging the battery. when it is started charging the battery remove the light and let it charge till it,s full Good luck! | ||
| Sparky |
Thunderclap has a Battery Tender. Those don't start charging unless it sees a certain minimum voltage out of the battery it's connected to. You can put a 12V bulb across a Battery Tender by itself and nothing will happen. The preceding is not how a normal battery charger operates however. So, Brother, what you are saying would work with a normal charger but not with a Battery Tender (unless they've changed the way Bat Tenders operate since I last bought one) which is what Thunderclap has. | ||
| Fahren |
Sparky, are you talking about the Tender Junior or the Tender Plus? I have the former; would your trick work with that? | ||
| Sparky |
I'm most familiar with the Harley Davidson SuperSmart and Global Battery Charger, both made by Deltran. I'd imagine the JR & Plus work the same way regarding charging a dead battery but I don't know for sure. Deltran's website doesn't specifically say that their Tenders will charge a dead battery. All I know is that if you connect a VOM set to read DC volts to the Battery Tender output leads and turn on the Tender with no battery connected, the VOM will read 0 VDC. A "dumb" charger would be outputting approx 15 VDC open circuit. Their Tenders are "Smart" chargers. That can only mean we have to "outsmart" the damn things to do what we think we want them to do, LOL!  |
