Need a good interface between battery and harness (48v.)

Some clear photos would help you get some appropriate answers.

For the 48V battery/controller connector mismatch you may want to cut those off and splice in a common connector like XT90 (w/ precharge resistor) or Anderson PP45.

Snip off the wires, use something more common. You could also connect Deans plug to controller. Be careful cutting the battery connector. Cut a single wire and attach new connector one at a time, so you don't have a short. Be careful not to touch the bare wires together!

What size/model battery and controller? That will impact what connector is best.

yah, 48v, 20Ah battery needs to wake up somehow. it needs a switch of some kind? i'm currently a deans plug male/female to bullet type male/female. I sure dont want to blow anything up. it came witha charger, but no I am going to purchase a component analyzer i saw on Ebay. I had it all hitched on the bike and had to dismantle the bike build after testing the motor cuz no juice to motor. Now Im back to square one. It seemed so straightforward before, now I'm unsure. I'm so glad for this forum.

So what's your question?

I like to use XT90 connectors from Hobbyking for the battery connection to the controller, for the phases I use 4mm bullet connectors from Hobbyking (H.K.) then usually for the throttle I just hard wire it in using a 40w or 60w harbor freight soldering iron with some standard electronics 60/40 solder and use electrical tape to seal it all up or if your feeling fancy, grab some heat shrink from H.F. or H.K. meanwhile, while your at the H.F. store grab an on-sale digital multi meter for $5 or $10, then when your at the Dollarama store, grab the red 9V batteries for a buck and even a razor blade, I've been known to strip the insulation off wires using such blades but correct wire strippers are preferred. Theres the big wire (low guage) strippers, for bigger, beefier wires, then there is the small wire high guage strippers for thinner wires.