https://www.amazon.com/gp/product/B004FGWY54/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Charge both my 4s 2200 packs and one 3s 5000 pacj weekly; been holding up for 6 months no prob.
This is the charger I'm planning on getting. https://www.amazon.com/gp/aw/d/B004FGWY54/ref=ox_sc_act_image_4?ie=UTF8&psc=1&smid=A3IAN4VN1Q26HU
I have zip ties, wire, soldering irons, heat shrink and everything else.