what do you need the sla for? D8? if so, then you also need a D8 power cable to go from your deck to the battery (6v>4pin xlr) they are about 30$ on the eco site, but you can always hack your walwart. the charger is about 40-45$ and then you need the battery to complete the system. and i believe lee said above he might have an extra. so there you go. if you want to make it easy, try to find a used eco system for sale in the yard sale.