Battery voltage mystery

[awolfinsheepsclothes]

Goran
Tell us more about the new battery?
Dave

[Goran]

Thanks, so the VCDS is not voltage at battery terminals.

Here is more info about the lithium battery. Its put together by a company called Voltphreaks, and used in motorsport. Also a few people on the M5board have been using them for a few years.

Nominal voltage is 13.3V, fully charge it should be 14.4V, it is made up of 4 cells in series, 3.6V max each.

Weight is 4.9kg for the 59Ah version. Supposedly it will reduce the charging load on the alternator because it holds higher voltage than a Lead Acid battery (12.2V 50% discharged), so in theory it will release a miniscule amount of horsepower.

The other main advantage appart from weight is that it has a low-voltage cut off, preserving enough charge to start the car when you come back to it even if you left the headlights on, etc. Also it has a built in on-off button.
Apparently it should last 5-10 years, although to be honest my original Audi Lead Acid 95Ah battery in my previous S8 lasted 7 years before it no longer held a charge.

I managed to get the 59Ah model they just discontinued at a discount, "only" £880 shipped. I guess you have to be really serious about performance to spend this kind of money. Probably not worth it and not noticable, but now I started this weight loss madness I feel I have to see it through to the end

http://www.voltphreaks.com/technology.php

[ainarssems]

You could buy 60 of these and make one yourself :

http://www.ebay.co.uk/itm/UltraFire-...item51b3097a81

[awolfinsheepsclothes]

Nice piece of kit I'd proberly buy one if I had the spare cash and everything else that needs doing was done. the price didn't really surprise me to be honest they are a lot more in demon tweeks! I think you need carbon bucket seats,carbon propshaft and polycarbonate windows next
Cheers Dave
Ps and a full titainium or inconel exhaust!

[Goran]

Originally Posted by ainarssems

You could buy 60 of these and make one yourself :

http://www.ebay.co.uk/itm/UltraFire-...item51b3097a81

Thats a great idea! thanks for the link. The charging circuitry would have been a problem for me I dont know how to build electronics (beyond the odd resistor or zener diode).
Now I paid the (hopefully) one-off cost for the electronics, its good to know I can replace the actual batteries for only £60.

Originally Posted by awolfinsheepsclothes

Nice piece of kit I'd proberly buy one if I had the spare cash and everything else that needs doing was done. the price didn't really surprise me to be honest they are a lot more in demon tweeks! I think you need carbon bucket seats,carbon propshaft and polycarbonate windows next
Cheers Dave
Ps and a full titainium or inconel exhaust!

I was thinking about the titanium exaust too but I think it would cost close to £3000 if I went somewhere professional like Primary Designs. Its just too much for me at the moment.
I think for now I will have to satisfy myself with just chopping out the mid and rear boxes and replacing with some long cherry bombs / silencers (whatever they are called). For the sound as much as for the weight reduction.
Oh and for the seats I have 2 very comfy Audi TT seats lined up, 22kg each, and same rail spacing as D2 seats.

[awolfinsheepsclothes]

What does the std battery weigh in at? 23kg ish ?
22kg for your seats! I thought you would have gone for the 3.5kg each carbon buckets! How much weight have you shaved of your car so far?
Cheers dave

[Goran]

My stock 110ah battery weight 25kg.
I did consider bucket seats, but I was a bit worried about comfort and the lack of adjustment. Also they would really change the look of the car. The TT seats look very similar to the D2 recaros and should fit the interior perfectly. I agree 22kg is a bit heavy, but at least I will save 12kg compared to the 34kg recaros in there now.
If only someone thought to do fully adjustable recaros with a titanium or carbon frame, then we could have best of both worlds.

The service book weight was 1789kg, I shaved of 10kg with the lighter 18" alloys, and the Supersport tyres (-2kg per wheel).
I notice the previous owner removed the TV reciever, CD changer, etc, so thats another -2. But I added a foot pump, so thats probably +2.
I'm going to delay putting the battery in until the seats are ready, and put them in together, that should be -44kg in one go. I want to do it all in one go to hopefully be able to feel the difference. Also I'm hoping the rear box and middle box weigh close to 20kg together, so that should be another nice chunk.
According to my local MOT place, the middle box has rusted through so it has to come out anyway.