Boiling battery - yikes

Post by **simonc** » Sat Nov 25, 2017 7:33 am

Hi guys, as you're aware, I had a new battery fitted about three or four weeks ago. When I was messing about one afternoon fettling the engine bay, I saw that the battery had 'sprayed' quite lot of fluid out and had left the obvious white deposit in the immediate area of the battery. Actually, it's quite a mess. Anyway, I asked Jason over the phone and he said that possibly the battery was boiling. I Googled 'boiling battery' and one or two sites said it's probably the voltage regulator that's kaput.
Just to wanted to confirm your thoughts, as I don't want to trust websites other than this one.
What do you think about it and what should I ask Jason to do? Your advice is most appreciated. Thanks, Si.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Sat Nov 25, 2017 1:30 pm

Yep, sounds like boiled battery
Two thoughts as to the cause...
Yes, could be the alternator regulator putting out incorrect voltage (easy to check/test) or... Someone forgot to remove the transit plugs from the battery meaning it had no vent (which causes over pressurising as it warms up in normal use).

There is of course a third possibility, which is that it was a jobby quality battery or it's a 6v battery rather than 12! (I cannot believe the latter could have happened though...?

)

Max · Post by **Max** » Sat Nov 25, 2017 3:26 pm

Also agree it does sound like a boiling battery. I had an Eunos roadster i bought to do up a few years ago and its main issue was the alternator regulator, i tested it and found it kicking out around 18v, this resulted in it blowing up most of the exterior lights and with the engine running you could hear the battery fizzing/cooking away, On that car i learnt the regulator couldn't be changed out so i put a whole new alternator in and the problem was solved, amazingly the battery survived and carried on going despite having vented some white residue, saved it just in time i guess.

When the Prelude one died it seemed to just stop putting out any voltage, i changed the regulator out for only £25 all in, it was pretty easy to do aside from getting the alternator bolted in and out of the car (which was fiddly as hell). I read the screws inside the alternator can get quote corroded and cause issues getting the regulator out but mine was ok.

Post by **simonc** » Mon Nov 27, 2017 6:06 am

Hi guys and thanks for the feedback. I went down to Jason's place today and he checked the battery with some kind of volt meter. He said it was okay. Then he opened the battery's 'chambers' to look for boiling but it didn't seem as it was.
Anyway, tomorrow he's taking it over to an electrical expert to give it a more thorough going-over.
Fingers crossed, I should have some firm news to share with you. Thanks again.

Post by **Vtecmec** » Mon Nov 27, 2017 5:17 pm

Also worth checking the alternator output for AC voltage, if the alternator rectifier is faulty it's what you'll get........

Post by **simonc** » Mon Nov 27, 2017 11:48 pm

Cheers fella. Another little bit of info to ask them to look at today. Ta.

Post by **simonc** » Sat Dec 02, 2017 12:16 am

wurlycorner wrote:There is of course a third possibility, which is that it was a jobby quality battery

That was it, Iain. It was a wonky battery. Jason's swapped it over for a sealed Varta one. Everything seems fine, so now I'll have to clean up all the white crap t'other left behind.
Thanks for the advice everyone, much appreciated.