Leaking battery during Autocross & Trackday
 

I don't know if it's something wrong with my car... Or if I'm just really unlucky with car batteries.

I've had the battery of my 2013 BRZ leak twice within the passed 3 months. Had the first battery replaced under warrany after it leaked during autocross and when I had it checked with those fancy tools you clamp onto the battery, I was told the charging system was fine...

The replacement I got leaked 3 months after out the vent hole during a trackday. (Maintenance free battery)

While on the track I plugged in an obd2 reader and was monitoring voltage during a track and if I remember correctly, it never went above 14.5 or (14.2 I think) which is supposedly normal. Had my eyes on the track.
It seems to only happen at high rpm high load scenarios as it didn't leak on the way home from the track, but would always leak when I would go out for a lap on the track... I taped a piece of tissue over the vent hole to confirm that the battery was leaking out of there.

Now I'm thinking; if this is still an issue with the alternator even after having it previously checked and nothing is wrong, OR it is the sensor with the plug on the Negative battery terminal as it is supposed to monitor the battery (?). I'm not completely sure, but I'm stumped right now. not sure also if it's the brand of battery I'm using or if I got a bad battery? But c'mon 2x within 3 months!?! ��

It's the second time I will be having to clean and paint my engine bay because of the battery fluids leaking and rusting out the car :/

Anyone have an idea what may be wrong?

Here's some pictures

I was told the charging system was fine during the first replacement. (Car is on and was even asked to rev it before the picture was taken)
https://ibb.co/y6H7Zxz
https://ibb.co/y6H7Zxz

Picture of the battery leaking during trackday
https://ibb.co/Cb6FkcH
https://ibb.co/Cb6FkcH

If you don't have a sealed battery, chances it's just getting a lot of heat during track use and/or sloshing around, causing the fluid to come out the vent hole(s).


Try switching to a sealed AGM? They do vent gas, but shouldn't have much mobile fluid

Maybe your car doesn't like a maintenance free battery?

If you had a conventional battery and you were sure it wasn't being overcharged, I'd suggest you draw down the battery fluid to just above the plates.

That's the thing; I'm not completely sure 😥, I was told the charging system was fine when I had the previous battery replaced under warranty 3 months ago, and the obd2 didn't read that it was overcharging above 14.5 volts on the track last week (even if it still leaked)

If the problem only comes out on track or autocoss (hasn't leaked on mountain roads and on the expressway)
I can only find out if it's not the batteries fault when it already leaked again.

If I get an AGM battery to make sure it doesn't leak and it really was a charging system issue that the car didn't detect. I would've just wasted a perfectly good battery too 😵
Is there other ways to find the issue? I'm trying to find more information about the sensor plug on the negative battery terminal to see if that has something to do with it? But I haven't heard of that part failing on anyone else's car.

Well, its easy enough to check to see how much electricity is being sent to the battery from the alternator. Just start the car and while its running check the reading with a volt meter across the battery terminals. It ought to read about 13 + a few of a volt.

I checked with Bubba and he said that if the battery only leaks at the track, just soak a wash towel with baking soda and water solution, let it dry then lay it over the battery and duct tape it in place just before the race. After the race, take it off and THROW IT AWAY - DO NOT give it back to whoever does the wash in your household. ALSO, after you take it off, if it is wet DO NOT wipe your hands on your pants - :eyebulge:

About the "sensor plug", I know nothing about that, I don't think my 2013 FRS has one of those.

I'll ring up ol @soundman98 for you, he knows a lot about moving electrons - :thumbsup:

Thank you, keep me posted :)

Here the picture of the voltage reading with one of those battery checkers saying it's 14.25 volts with the accessories on. https://ibb.co/y6H7Zxz
Do you think there is an underlying cause of the battery leaking on track or it may just be another bad battery?

I actually did something simmilar to that to finish my trackday last week. I duct taped a wad of tissues on the vent hole where the Battery was leaking and would replace it after doing a few laps since it would come back soaking wet ��

Edit: here's the picture of the sensor plug on the negative battery terminal https://ibb.co/nnq0GXb

It's probably just sloshing out of the vents.

Check the side of the battery, some makers stick a little bag with a plug and L fitting to install a vent tube for interior mounting, if you've got them, install the plug and use the L fitting to install a vent tube that goes higher or make a U path to contain the splashes.

If you don't have them, you might ask a parts store if they have any left over.

Or go gel cell or agm

As I mentioned before, since it is a conventual battery, you might try drawing down the fluid so that the plates are just barely covered. That may keep the fluid from sloshing out - :iono:

I had this on my car, swapped to a light weight battery and no more problems.


Remember, tracking brings lots of heat into the engine bay, and you are spending most of your time with the RPMS well above normal which may cause some overcharging. Plus you are seeing more than normal g forces which will bring fluid to places it shouldn't normally be for more than a quick second.

I can't draw out the water on mine sadly, it's one of those "maintenance free" batteries.

Oh, it's nice to see I'm not the only one!

Like in one of the replies reccomening a Gel or AGM battery, will this solve the issue aswell?

I don't think a lightweight battery would be the best for me since the car sits for weeks and sometimes gets used for a whole week.

My car sits all the time too, I have a plug in battery tender on it. The factory sized/replacement battery I had didn't last too long either.

I think a less expensive alternate to AGM would be an Optima battery. We use them in race boats all the time. An other far less elegant solution would be a battery with a drain line, dump it out under the car or in a can.

intentionally adding something to drain leaky fluids on the track sounds like a bad idea to me.