I'm considering a DIY project of a jump start kit. I know it's commercially available but I thought it'd be fun to DIY and customize the way I want.
I guess the first order of business is to choose a battery. I have seen some people use lithium batteries and I'm a little skeptical whether they can provide the current as well as the finickiness of dealing with lithium batteries.
A more logical choice is a lead acid battery, which should be easier to deal with. I suppose a 5Ah or 7Ah battery, commonly used in UPS units, should be sufficient for an average sedan or SUV. I'm slightly worried about the battery terminals though. Are they able to handle the kind of current a starter draws? I know it's just a couple of seconds and cheap jump cables only use 14-AWG wires (if not thinner), which can only handle 20 Amps, and they seem to work OK.
Any thoughts and advices? Thanks.