Power Wise Plus to SB50

[thompra]

I purchases an older Western Golf Cart with an SB 50 power charging plug on it. It came with a Powerwise Plus Charger, also with an SB50 cable attached.

Batteries are sitting at 35v +, ohmed out the cables, checked for the battery voltage back at the charger etc., everything appears great, fuse good, cap good, diodes good, charger runs when relay is shorted between wires, but it wont turn on when plugged in. I'll also mention that I just swapped out with a new controller inside Powerwise Plus because I thought it was that...still will not turn on.

Am I missing a wiring change within the Powerwise to make it think there is a return from the cart more than the two battery wires already bringing back DCv to the charger?

[JohnnieB]

Welcome to BGW!

Is the third wire in the output cable connected to the Negative terminal in the SB-50?
If not, the charger won't turn on when plugged into cart.

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Measure between the small Red and Black wires connected to the control board.
You should get full battery pack voltage. (About 35V in your case)

You can connect the black wire from the control board to the center tap of the transformer instead of connecting it at the SB-50 plug.

Here is a manual for a PW/PW+ and an edited schematic showing where to connect the black wire inside the charger.

[thompra]

Thank you for the reply...I had read about that "3rd" wire in other posts and have looked high and low for that "return" wire. But...the cable coming out of the Powerwise Plus has only 2 wires, and the SB50 receptacle on the cart has only 2 wires out to the batteries... - and +.

My first thought is that there was a mod to the Powerwise Plus to not use or expect a 3rd wire....thinking maybe the original Powerwise Plus cable was swapped for an SB50 cable...I have no idea what I'm talking about, merely attempting to speak to what I've read.

Thank you again for the help!

[thompra]

Thank you...pulled the black wire off the heat sink (panel), attached to negative on transformer (center wire) and wala.....Thank you!

Will see how charging goes...batteries are at 8 amps right now.

[JohnnieB]

Sounds like whoever did the switch to a SB-50 plug, switched the entire output cable and never verified proper operation of the charger afterwards.

Glad to hear you got it going.

Normal operation for a PW+ charger is to put out upwards of 20A when first plugged in, then taper off as the battery pack's on-charge voltage climbs and shut off when the on-charge voltage reaches into the 44V to 46V range.