SE automatic battery topup

[adam quantrill]

I've realised with the SX (SE body) that the battery seems to top itself up, presumably when it rains water lands on the top of the battery via the slats in the bonnet and leaks in through the filler caps.

At least it saves a job.... if only the petrol tank would fill itself too... (not with water though ;^)

[grahamw48]

Ah yes, and it sits in its own little swimming pool.

Daft design really, but I'm sure a little fabricated water splash feature could direct the H2O somewhere more acceptable...or a drain hole.

[Wedg1e]

The risk is that enough water will short the terminals out and you'll get a gradual discharge.

[adam quantrill]

Yeah but being rain water it'll electrolyse and disappear.

I thinl the main problem is if the sulphuric gets too diluted over time. Seems to be OK so far after 2-odd years though.

[Barkychoc]

I don't know if it applies on the wedge (sorry I'm a gatecrasher on this forum) but the problem with a battery getting rainwater on / in the cells is if it overflows - as its then dilute sulphuric acid and if you have a metal battery tray it rapidly dissolves

[gsx600]

No metal battery tray, just fibreglass

I was thinking of sticking a rubber / plastic channel down both sides of the wings, as drain hole did not help. And trying to keep the footwell dry

[Wedg1e]

adam quantrill said:

Yeah but being rain water it'll electrolyse and disappear.

I thinl the main problem is if the sulphuric gets too diluted over time. Seems to be OK so far after 2-odd years though.

Many (and I do mean many) years ago, my cousin had a Fiat something-or-other on which the heated rear screen didn't work. He brought it round for my dad to look at and the old fella went through the electrics like a dose of salts but for the life of him couldn't fathom why the fuse for the rear screen heater kept blowing.
He was talking me through it when he opened the tailgate and a trickle of water emerged from the rubber around the glass and dripped onto me.
The penny dropped: condensation on the inside of the screen had been drawn around the rubber by capillary action and was acted as a shorting loop across the screen heater (an extra filament, if you will).
We peeled back the rubber, dried out the water and normal service was resumed. Until the next time the window misted up...
That fuse was something like 15A and the heater drew about 8A IIRC; the damp was passing more than 7A so imagine what it could do in the few inches between the battery posts

[adam quantrill]

You would need a continuous unbroken line of water (like in your example of the rubber seal). Don't forget that the battery posts are in depressions so it would be highly unlikely that the water would stay unbroken for very long, unless you live in Wales where it's permanently under water ;^)

[Wedg1e]

adam quantrill said:

You would need a continuous unbroken line of water (like in your example of the rubber seal). Don't forget that the battery posts are in depressions so it would be highly unlikely that the water would stay unbroken for very long, unless you live in Wales where it's permanently under water ;^)

Fair point. About Wales, that is