Boiling Battery

[OAP]

This is not strictly 7, as it happened yesterday on my Radical, but the problem is generic so I guess there will be some knowledgeable BC users who are able to give advice.

All the electrics failed, and when the car rolled to a stop there was a strong smell of battery acid. Investigation showed the battery swollen at the sides by a couple of inches, and hot fluid leaking out through the stretched seams. The engine is a ZZR1100 Kawasaki, and I think the starter and alternator are the same unit. I took the battery out this morning and it still gives a voltage reading (12.7v), so there must be a blown fuse somewhere in the wiring, which i will eventually find.

Question is, how could this happen? Is it likely that the alternator regulator has failed, and the battery has seriously over charged?

It is a tiny battery and I had to jump start the car yesterday morning in the cold, and it had been outside all night on the trailer, when it was below freezing.

Anyone any ideas?

[Paul Deslandes]

You were lucky it didn't let go 😳

 

It could be a faulty regulator or an internal short in the battery or the external wiring. The last could explain a blown fuse. You might have damaged the battery or the regulator when you jump started it although its unlikely.

 

I think I'd start by looking for a short circuit somewhere in the wiring and accessories. Then put in a new/another battery and check current drain with ignition 'off' and then 'on', then start up and immediately check the battery voltage. If its above 14.5 V then you have an alternator/regulator fault.

 

Paul

 

 

[David Lynch]

I had this happen on my Seven. In my case it was faulty alternator regulator overcharging the battery. It turned a Redtop 20 into a football and blew all the main lights. All hail Aerospace battery safety standards or could have been a lot worse !!!

 

EN Yorks 7's Flickr

[Ian B]

If the battery has boiled and swelled (and still has charge) then it's been overcharged (a lot) and I would strongly suspect the regulator.

The reason the electrics died is probably because the whole system will have been subjected to a higher voltage from the unregulated alternator and has probably (hopefully) blown one or several fuses - you'll need to check them all!

I wouldn't connect another battery to that regulator (for longer than 15 seconds), which should be long enough to start the car and check the regulator voltage.

 

---

Ian - Slightly Vider SVelte SuperVeloce model 😬 - Joint AR for North Kent - Area details and calendar here

[Gridgway]

The starter and alternator are definitely different units. Almost certainly a regulator problem.

Graham

[OAP]

Thanks for all these replies - they confirm my suspicion that the problem lies with the voltage regulator, but I don't know why it might have failed. Any ideas?

The alternator is a separate unit as Gridgway pointed out, and I see that the regulator is an integral part, so it looks as if I need to replace the whole thing. I'll get it off today and take it apart, but it might be easier just to buy a new unit from a breakers yard.

I can only find two fuses, one in the starter circuit and the other in the ignition circuit, and sadly both are intact, so I'm uncertain yet what other damage may have been caused. Any speculation? I guess I'll find out when I am able to connect another battery.

[Bob_Rich]

Hi

 

Dont know the vehicle but agree with the other posts that overcharging due to regulator fault in the alternator circuit is the problem you have. Could it be that vehicle has a back stop thermal cut-out that kicked out just before things got really nasty? by the time you took out the battery things had cooled down and it had reset.

 

hope U sort it OK best of luck

 

Bob

[Bob_Rich]

Hi again Just had another thought.

 

If there is a high current fault on some line when you try the battery again make the live (+ve connection assuming it is -ve earth) via a old head lamp bulb--this would limit the current to 7A or so. with ignition on, but engine not started, I guess you should only draw a modest current so this bulb would, or should, glow a little dim if it shot up to full light that may indicate a short

 

hope this helps best of luck

 

Bob

[hendrixswhitestrat]

Happened to me in my 7 a couple of months ago....

 

My 12 year old daughter spotted a "horrible guffy smell" and the battery was swollen and smoking when I stopped.

 

Turned out that the voltage regulator on the (then 3 month old) alternator from CC had failed and cooked my battery. CC paid for a new one.

 

M

[Geoff Wilcx]

I've still got a few spares lying around from my old Clubbie.

 

Drop me a line if you want me to look.....also got a few other odds and sods.

 

'08 Upgrade was a screaming DVA K05.

'09 Upgrade was a Radical

'10 Upgrade was even more Radical

www.geoffwilcoxphotography.co.uk

[OAP]

Hi Geoff, yhm.