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Boiling battery

The only thing that bothers me is your old battery tested "good' at the auto center and at the same time with it fully charged, you only had 12.4 volts out of it. I don't feel good about that because I was really expecting your battery to test bad..

You may want to test the output voltage of the regulator a few times just to be sure your charging voltage remains where it should be. (not higher than ~14.5).. Now that you have a known good battery you would not want to toast it.

Hope everything works out.
 
Hoople said:
The only thing that bothers me is your old battery tested "good' at the auto center and at the same time with it fully charged, you only had 12.4 volts out of it. I don't feel good about that because I was really expecting your battery to test bad..

You may want to test the output voltage of the regulator a few times just to be sure your charging voltage remains where it should be. (not higher than ~14.5).. Now that you have a known good battery you would not want to toast it.

Hope everything works out.
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Hoople you are right a fully charged battery should be a min. of 12.5 volts. i like to see them @ 12.75, but I knew this was a bad one< Jack
 
Nobody mentioned rectifier in this post, I believe its built into the reg on all harleys. The rect. changes the AC output to DC, if the first stage (diode) goes the bike it can still maintain a charge but the bat is getting some AC voltage and they don't like AC voltage. Just set your vom to AC volts and test anything more than trace voltage is hard on your battery, The smell test will usually tell your getting AC, either way I betting on a bad rect/VR
Good Luck
 
Big Rol said:
Nobody mentioned rectifier in this post, I believe its built into the reg on all harleys.
Good Luck
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Yes the rectifier is built into the regulator.
Yes it could be the regulator is still bad. Your right. Since the old battery tested Good, the reason for seeing 15 volts across the battery sure does point to the regulator. I was sure his battery had a bad cell but seems it did not. Time will tell...

Your correct, the less AC coming out of the regulator the better but seeing some AC voltage is normal. Ripple in the charging system is just that, AC that is superimposed on top of the DC. Naturally the less there is the better. The 3 phase stators reduced the AC ripple by a bunch. I bet the early level single phase charging systems have many volts of AC. As long as the AC value does not exceed the DC value, the battery just sees the AC as pulsating DC.
 
Ive seen stuck regulators and dead shorted batteries boil, cant think what else could be wrong here. Im am surprised after gharging and only seeing12.4 volts this battery is OK. If it over charged why would it have to be put back on a charger and only come up to 12.4 volts. Am I reading too much into this, Jack
 
Jack Klarich said:
Ive seen stuck regulators and dead shorted batteries boil, cant think what else could be wrong here. Im am surprised after gharging and only seeing12.4 volts this battery is OK. If it over charged why would it have to be put back on a charger and only come up to 12.4 volts. Am I reading too much into this, Jack
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Jack, I don't think your reading too deep into it. I have all the same questions. I don't know if this is the case but I would like to know exactly how the battery was tested. As far as I am concerned, there is really only 1 proper way (carbon pile) to test a lead acid battery and several wrong ways. I am hoping the battery was not really tested properly and it really had a bad cell. That would explain the reason for the boil out, the low battery voltage and even possibly the excessive high charging voltage. Now lets say a carbon pile tester was used. Then I want know what was the load in amps, how long was the load applied, and what was the terminal voltage along the way. I know I get carried away with wanting information, but without the facts the entire test is questionable. Sometimes shops don't have a carbon pile tester and they use these small hand held portable testers that use some formula to calculate battery condition. Or they do use a carbon pile tester but one that applies a Fixed load and is automated. Lets face it. They have to have simple "hook-up and go" testers so no training is needed and the customer can see spelled out results.

I will always go back to the good old fashion carbon pile load tester with load control. I actually can't remember a single time a carbon pile tester lied to me...
 
mlrc10 said:
Cranked the bike with a voltmeter on it and it fell to 9.4 volts.Pulled it and had it load tested.The guy said it was good,but it was only 12.25 volts but that should crank it.Since it was 1.5 years old I just decided to replace it.Charged it last night and rode it 18 miles to work.Pull the cover off and it was clean. Rode to lunch and 18 miles back home.Still good,so Hoople wins the prize I think.We are riding to Hammond this weekend (200 miles 1 way)to HOG Rally. If it (EDIT) out I'll have to get on wifes Honda LOL.So keep your fingers crossed.Thanks to everyone for the help.


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If he cleaned all connections, tested charging system properly and after he had the freshly charged battery it still drops to 9.4V definitely means bad battery...at least 1 or 2 cells are toast. New battery, and a few days or miles of checking that voltage is around 13.5-14V and I would trust it for your trip...ENJOY! :newsmile108:
 
Hoople said:
Jack, I don't think your reading too deep into it. I have all the same questions. I don't know if this is the case but I would like to know exactly how the battery was tested. As far as I am concerned, there is really only 1 proper way (carbon pile) to test a lead acid battery and several wrong ways. I am hoping the battery was not really tested properly and it really had a bad cell. That would explain the reason for the boil out, the low battery voltage and even possibly the excessive high charging voltage. Now lets say a carbon pile tester was used. Then I want know what was the load in amps, how long was the load applied, and what was the terminal voltage along the way. I know I get carried away with wanting information, but without the facts the entire test is questionable. Sometimes shops don't have a carbon pile tester and they use these small hand held portable testers that use some formula to calculate battery condition. Or they do use a carbon pile tester but one that applies a Fixed load and is automated. Lets face it. They have to have simple "hook-up and go" testers so no training is needed and the customer can see spelled out results.

I will always go back to the good old fashion carbon pile load tester with load control. I actually can't remember a single time a carbon pile tester lied to me...
Click to expand...

Same here I have a Sun Vat with a carbon pile, but first I like to check with a hydrometer if its not a sealed battery.If you have a bad cell it will show right away, nuff said. Thanks Jim, I thought I was crazy, wait I am LOL
 
Well guys just got back from Hammond a while ago. 600 plus miles this weekend with no problems.So I'm guessing its fixed,thanks for all the great input.
 
Excellent. Thanks for getting back. So it looks like a case of the "bad" battery that tests "good"!
 
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