madanglian

Sorry to resurrect an old thread but if anyone, like me, has much the same problem, this may help: 1. If the battery seems completely dead, it is worth opening it up at the plug end and checking the fuse, which is a standard "euro" style fuse (as fitted to loads of cars) and if it needs replacement, you should be able to get one from Halfords or similar. 2. It's very difficult (I'm trying not to say impossible) to get a straight swap off-the-peg li-ion battery pack that will fit inside the case, because of the way the cells are arranged. There seems to be 30 cells (18650s presumably) arranged in 3 (wired in parallel) blocks of 10. Each block of 10 is arranged in a 3-4-3 "stretched-hexagon" shape, wired in series to give 36-37v. So the cells themselves run length-ways in the case. All of the off-the-peg li-ion packs are assembled so that the cells would be oriented across the case, and since the cells themselves are 65 mm long, the packs are usually around 70 by 40 mm - too big to fit in the case which has an internal diameter of 73 mm. Writing this now, I'm wondering if the cells in the later "bottle" style packs have the same configuration as the X-6/X-24 pack. But if you want to renew the original Powabyke battery pack, the only option AFAIK is to take it to a re-cell specialist. The simpler option to me seems to get a rear rack mounted battery which I've seen for £229 (including rack) for a 10 Ah unit, much more than the 4.4 Ah OEM one. This may be the route I end up going down.

I've been trying to get hold of a charger for my Carrera Sparc for nearly 2 months now. Every time I order one, the sellers in question umm and ahh for 1 - 2 weeks, then refund my money cause they can't get one. Is it because SRAM have stopped making them, or are the sellers copping out when they find out how much they have to pay the importer?

Well we do still have the International Automotive Research Centre ..... there's an irony there which I hadn't spotted before

Don't think many politicians would dare say that these days, what with oil starting to run out, costs of running and maintaining a car, and road congestion. In the early 90s I had a colleague at work (in Coventry) whose wife worked at Heathrow Airport - they lived roughly mid way between the 2, and both had a 90-minute commute. I thought they were nutters at the time, but road congestion is twice as bad these days and there are still people doing that kind of commute. These days I'm working at the University of Warwick and having moaned for the last couple of years about their apparent declaration of war on car use, I am about to rediscover, at the age of 52, the joys of commuting on two wheels

I actually got it from here in the end

Thanks for that. It definitely says "16.8v 2005>" on the website I have now ordered it from, and the cells in my battery pack have a label on saying they're NiMH. I see nearly all the places that had it advertised at £60 or less have upped the price in the last few days. Wouldn't be surprised if I get a phone call tomorrow quoting T&Cs, especially the one about "prices subject to change without .... " etc.

Another question, do all the Sparc chargers have the 3-pin square connector? One or two places (eg here) show it as a round plug.

Yes, it is NiMH. I thought the price was partly because at 16.8v it's a bit of an odd voltage. There are lots of chargers for batteries which are nominally 12v for instance. I see the correct charger can do a full charge in 4 or 5 hours, so it must be going at around 0.3C (2.5 amps) and use a temperature sensor (third pin on charger?) to tell it when to stop.

Hi everybody, just got a Carrera Sparc off ebay. No charger, hope it hasn't been nicked ....... Had lots of fun charging the battery using a laptop PSU, a bunch of 10w resistors and a multimeter Now I know it works, I will be investing in a proper NRAM Sparc charger soon - £ 60 From Halfords £ 98 :eek: