My booster pack has failed me today for the last time https://www.canadiantire.ca/en/pdp/motomaster-eliminator-1000a-booster-pack-0111912p.html#srp the sla battery inside is as useless as can be, rather than replacing it with one that will fail in another year or two at the worst possible time i figure i'll replace it with some lithium ion ones. I have a hand ful of these laying around https://www.homedepot.ca/product/ridgid-18-volt-4-amp-hour-hyper-lithium-ion-battery/1000684121. What type of step down converter would i need to handle the ability to start a car? I'd imagine those 99 cent coin sized ones on ebay would fry instantly, any ideas?