Is there by any chance a way of jump starting/charging a Spider battery using connection points under the bonnet rather than on the battery please? The battery being in the passenger compartment is a real pain!
Also, is it essential to disconnect the battery when charging it please?
Nope, no easy way of jump starting from under the bonnet. I looked into this some years ago 'cos, as you know, some cars with batteries in the boot/under seats etc, have connection points for this under the bonnet, sadly not so in the 916 cars.
For a quick get you going thing I bought a cigar lighter to cigar lighter fast charger unit, I had to use it twice last week and will say that it worked very well, 10 minutes charge was enough to start the engine. These are advertised as " Jump Starters ", even the instructions infer that this is what they are. No way, use as a charger only.
Of course the real answer is to replace a dodgy battery. Mine let me down twice last week, it now resides in the great Bad Battery Billet in the Sky. A car with a flat battery is a pain in the ..... If you are having trouble bite the bullet and get a new one.
P.S. I have owned the car almost four years and SAW the battery for the FIRST time last week, no complaints from me !