braille lightweight carbon battery

[alicrozier]

I had the carbon tat battery out of the Exige for charging so thought I'd post somepics:



6.8kg



Someone in the background can't resist a photo opportunity.



Tech specs:
http://braillebattery.com/index.php/batteries/b2015c/#

[robin]

Interesting. For the same weight (6.8Kg) you could get 1.2kWh out of Lithium Polymer cells vs. 20*12 = 0.36kWh out of this lead acid design.

I doubt you need 1,000A of cranking (if you did, then your 20Ah would last about one minute cranking before running flat. Assuming you really need something in the order of 250A cranking with maybe a 500A stall torque peak for the first 1 second then you could use 20C max/15C cont Lithium Polymer cells with 5Ah capacity ... you would need 4 in parallel to get the 500A peak/250A "continuous" rating; you would need 3 in series to get into the right ballpark for car battery voltages, so that's 12 cells at a weight of 0.1kg each = 1.2kg. Add a box to keep them in and some metal bus bars and a bit of electricery to make it all work - still well less than 2kg and easily fitting in the same footprint ...

In one offs it would be expensive, of course - maybe USD500 - but that's not a bad price for saving nearly 5kg of weight, as these things go (and actually, if you're starting with a normal car battery, it's perhaps 15kg of weight saved?).

Cheers,
Robin

[tut]

Pity about the cost Robin, otherwise you could start up a nice little sideline.

tut

[hiscot]

Robin that battery is rated at 1000 pluse amps not CCA it is pretty meaningless for starting a car measured at less than a 3 second burst hence pluse
i found this to be a good option
http://www.mx5parts.co.uk/product_info. ... cts_id/635
lighter smaller highly rated on mx5 forums and being a agm battery its has a very slow discharge when left
pity i cannot post a photo next to a std battery as for some reason my photos are too big on image shack ( i expected image shack to resized them )
and most of the photo gets cut off ( in preveiw)

[tut]

Only application though unless you are philthy rich is to cut down weight for competition.

Otherwise Dingbros 30 quidders do fine.

tut

[robin]

Absolutely tut - it would be crazy to do anything like this except for racers, but from Andy and Neil's season in the LOTRDC series I remember that losing 15kg was quite a big deal and could easily cost a lot of money.

Cheers,
Robin

[tut]

Actually 15 kg is a lot of saving and I would go for that even for road and track, but only at reasonable cost. Steve Butts would jump at it.

As you know I am a lover of MMC disks, and they save me 12 kg over steel for no extra cost, so that makes 27kg total, one unsprung weight and the other reducing pendulum weight. That is almost the weight of a full tank of fuel.

tut

[Corranga]

...and there's me with an ice scraper and some nice heavy duty jump leads in the car

[Edin430]

Mate.. That is a gorgeous cat.... More pics?

[tut]

Agreed. Can't beat lying in bed on a Sunday morning looking at a nice, warm, pussy.

Oh, you mean the one behind the battery?

tut

[Andy G]

the Atom had a watch battery in it, was even smaller than that thing, which was great, unless i forgot to plug in the trickle charger

PS. I'd keep your cat locked up if Tut comes to visit

[Edin430]

Agreed. Can't beat lying in bed on a Sunday morning looking at a nice, warm, pussy.

Oh, you mean the one behind the battery?

tut

On second thoughts..

[alicrozier]

Mate.. That is a gorgeous cat.... More pics?

http://www.scottishelises.com/phpbb/vie ... =9&t=19252 (pussy content)

[Sanjøy]

In the market for small battery as it looks like the one in the 340 has had its day and no longer holding a charge. Checked and the alternator is producing a decent current.

Not had the old one out to see what model Scotty put in but it is ~1.2 the size of normal. Any suggestions other than Alis £500 CF one ?!

SP

[Mikie711]

In the market for small battery as it looks like the one in the 340 has had its day and no longer holding a charge. Checked and the alternator is producing a decent current.

Not had the old one out to see what model Scotty put in but it is ~1.2 the size of normal. Any suggestions other than Alis £500 CF one ?!

SP

Not quite £500, more like £208 + vat

here

Or stuff the carbon in favour of the cheaper no weight option, same power and weight but £139 +vat

here