Battery chat

[911GP]

Hi,
The idea of leakproof gel batteries makes them appealing but a car battery shop has told me that such batteries are not designed for regular cars since they have low cranking amps. Has anyone tried Sonnenschein A512/40 gel batteries in their car?

If they are not suitable, I guess the normal sealed wet battery options are there (Bosch/Lion/Varta etc) but I have heard that they can leak. In such cases do they leak from the small vent hole or do they leak elsewhere?

Thanks
Gitesh

[Gary71]

I’ve had normal sealed Halfords batteries in my cars for years and never had a leak.

The only bad experience was with a very old Polo with a battery you could top up that leaked out of the top, but I think that was being overcharged as well. That leaked acid onto my feet!

[Lightweight_911]

.
Maybe not what you're asking but in the past I've used a lightweight Odyssey PC680 battery (which can be picked up easily with one hand) in several early 911's (& my 904) plus other non-Porsches.

However, in each case they had minimal electrical requirements (ie no electric windows, sunroof, etc) & were all fitted with lightweight high torque starter motors - never had any problems.

[911hillclimber]

Ditto Gary's comments.
Halford supplied Bosch Silver batteries have served me well in my 911 for decades..
Heavy though which might be good in the front of a 911?

[911GP]

Thanks guys.

Gary, Graham - I too have never had a battery leak on all the cars I have owned (including a VW Polo, my first car) but after the restoration costs I am extra protective and would like to consider all options.

Andy - that is helpful, thanks. The Odyssey battery I was looking at was a little too tall and would have to be mounted sideways. The PC680 looks good but I would still like to go for a regular size/capacity one.

Someone on ESR tells me he has been using the Sonnenschein A510 on their 911s since the early 90s without issue and they have lasted about 7 years each time. Apparently it is important that they don't fully discharge so a CTEK type battery maintainer is a must if the car isn't used regularly. The A510 is a pricey option though at about £140 each.

Gitesh

[Nine One One]

https://www.racingbatteries.co.uk/index ... ng-battery

[gridgway]

I thought that gel batteries were really good at cranking current but poorer at cranking voltage.

Thats what happened on my caterham when I changed from banner to odyssey. Great cranking, but poor starting. Measured the volts when starting after some advice. Not enough for the MBE ECU. Went back to the banner battery and it was fine.

Graham

[911GP]

Hi Graham,
The Odyssey batteries are AGM and do have a good cranking current. Only issue is that there doesn't seem to be a version that matches the regular size battery for early 911s. They are either smaller, like the one Andy mentions, or bigger and stick out of the battery box. I didn't know about the voltage issue so thanks for that. Note however that gel batteries are different to AGM.
Kind regards
Gitesh

[inaglasshouse]

Hi Gitesh,
I found that an Odyssey PC925 fits very nicely in the early 911 battery box. Trick: AGM batteries can be mounted in any orientation (except upside down).
Cheers, Richard.

[Magnum]

Gents

My roughly 3 week experience of the Odyssey PC680 which is unfeasibly small and light....is one of disbelieve!!

This is in a 3.2 with Motronic, mounted sideways and it has coped amazingly well. Very impressed!

PS - I suspect that Motronic would be more sensitive to voltage variations etc. than a carbureted vehicle?

[smallspeed]

I have the same battery in two of my cars - both BMW's, high compression (10.5+) and 3.0 and 3.2 litre capacities
I have a dodgy earth somewhere in one of my cars and if i leave it without turning the battery isolator off it will drain it in 24-48hrs (which is more an issue of my wiring than the battery). Done multiple restarts, plenty of testing circuits, short runs, etc and they both work perfectly!

If the size and shape is an issue, and the capacity is a concern, have you considered doing something like mounting two PC680's on their side, one above the other? You could flip one battery over and fit some neat / short bus-bars pos to pos and neg to neg under the screw-in terminals if that makes sense.. I'd also install a cartek flying lead connector thing at the same time, so you can charge and condition the batteries without fiddling around trying to clamp onto terminals

I'm not sure what size the stock 911 battery is, but I imagine a PC680 is less than 1/2 the size

[smallspeed]

Infact, if there's any interest in a "battery rack" like this, or an adapter to hold a PC680 or similar in the standard position, post up the model number or dimensions of the stock battery/batteries, and the size of the battery box
I can knock-up some quick CAD drawings, and am happy to provide either DXF's for people to get parts cut themselves, or a kit of laser cut parts for self-assembly.. ..both for suitable donations to macmillan

[gridgway]

I always come back to why? I can't see any material benefit to shoe-horning the wrong size battery in when the standard one does the job so well.

If you have removed all the carpets, sound deadening, A/C, spare bits, drilled holes in all conceivable places, fitted mag wheels, fibreglass panels and been on a 5/2 diet for 2 years, then maybe it's worthwhile! But otherwise why?

Graham

[Northy]

I always come back to why? I can't see any material benefit to shoe-horning the wrong size battery in when the standard one does the job so well.

If you have removed all the carpets, sound deadening, A/C, spare bits, drilled holes in all conceivable places, fitted mag wheels, fibreglass panels and been on a 5/2 diet for 2 years, then maybe it's worthwhile! But otherwise why?

Graham

To add lightness.

[Magnum]

I hear you Graham....

BUT for those of us who get a little carried away, the battery swap to a lightweight version (and there are lighter versions than the Odyssey PC680) represents a very significant weight saving at very little cost - it must be about the most cost effective, short of throwing things off the car.

By way of example swapping out the old twin batteries and replacing with an Odyssey PC680 is a saving of 16kgs (or about 35lbs). With the lighter, newer alternatives that goes up!

But to your point, I completely understand that it's not necessary and/or not important to the majority .

Cheers