Voltage reducer - loud pop and trips lithium cells

[demarcor]

So… just put 2 BigBattery eagles in my stock ‘06 precedent. Drove 8 miles in hilly terrain and lost only 1 bar on the meter! Very impressed so far.
Problem…
My voltage converter unit, when wired into the busbar that BigBattery provides, won’t allow me to power on the cells. I disconnected the reducer, and then both cells turned on, no problem. With both cells on, I attempted to connect the little ring terminals I crimped onto the reducer onto the busbar… and POP!!! Huge spark, trips both breakers. Everything appears hooked up correctly…. What the heck is going on??? It’s a 48 / 36v to 12v reducer off Amazon. Silvery looking box with fins. Headlights and radio wired to it.

Whaaaaat???

[Tom47]

The voltage reducers will spark when connected to a live circuit. But that doesn't account for yours tripping the breakers or not allowing the batteries to come on.

Offhand I'd say the reducer is defective. Take an ohm reading across the reducers 48 volt input wires. I'll bet they will read close to zero ohms.

[demarcor]

Yeah, not just a little spark… full blown lightning crazy… POW!!!

[CP241]

Did it work before you installed lithium batteries or is it a new purchase?

If it’s a new purchase I’d send it back and get another one. I have a cheapie from Amazon myself and have had no issues out of it at all. But cheap parts tend to have a high defect rate so it wouldn’t surprise me either if you got a bummer out of the box.

This is the one I have. It’s served me well the last couple years I’ve had this cart. SUPERNIGHT 120W Voltage Regulator Buck Converter 48V Step-Down to 12V 10A Waterproof Voltage Reducer for Golf Cart Power Module LED Strip Light https://a.co/d/f4QTKVq

[demarcor]

New purchase. Tested lights and radio off a single 12v in old lead acid set up. Both were good.

[CP241]

Double check to make sure you don’t have any of the wires mixed up. That’ll short out some stuff quick

But I’d guess bad converter out of the box. Just return it to Amazon and get another one

[Shanky]

Is it a 4 wire or 5 wire converter? If it is a 5 wire, make sure you did not assume the key wire was 48 neg in. That would cause a short. It is often between the 48v input positive and the 48v input negative. Also, the pos input should be fused.

[WalterM6]

Having a radio brings up this question. Your not trying to run a 30A circuit with a 10A converter are you?

[demarcor]

It’s just a bad voltage converter. 4 wire. Another one coming from Amazon on Tuesday. The radio is this hilarious little tiny unit. A pair of 2 inch speakers and the receiver all in one! It’s unbelievably good for the size. $29 … LOL! Obviously not a sound bar, but louder than we’ll ever need. I had it working off of a 12 V battery already before the conversion. Thanks…. Hopeful on the next reducer.

[CP241]

Hey I use a little klipsch gig Bluetooth speaker. More than loud enough for anything we’ll ever need (actually the little thing absolutely rocks) and I installed a usb charging port in case it dies. But I like the BT speaker because it doesn’t pull from the pack.