A question about voltage levels

[Newbuggyboy]

This evening I went ahead and tested this again with the 36V RXV solenoid. The diode and resistor are a little bit awkward, because the rxv solenoid is not flat, but they are the new ones i purchased. I wanted to keep the old diode and resistor intact to verify/review/return to service.

Key off same as above zero voltage at both small terminals. One large terminal (the one connected to pack + ) had pack voltage. The other large terminal (the one which goes to controller ) had pack -3v.

You do dangerous things when you don't have your jack stands or an assistant. Big Chief "Just because were dumb ***** don't me you can be too. So don't do any of this at home." Key on volt meter shows nothing different. Lightly press and release accelerator, hear the click. Hold meter leads with one hand and lightly press and release accelerator, here the click. Voltage on the small leads go to pack voltage. Large terminal to controller slightly rising.

Again tonight I remove the power in because I'm not sure what is what. It almost seems like that pack -3v is traveling across the large leads, reduced by the resistor.

[handtools]

I think what you are seeing is normal.

[Newbuggyboy]

Originally Posted by handtools

I think what you are seeing is normal.

Ok, but am I going to burn up my motor, other things? What happens when I charge the battery pack?

[JohnnieB]

Originally Posted by Newbuggyboy

This evening I went ahead and tested this again with the 36V RXV solenoid. The diode and resistor are a little bit awkward, because the rxv solenoid is not flat, but they are the new ones i purchased. I wanted to keep the old diode and resistor intact to verify/review/return to service.

Key off same as above zero voltage at both small terminals. One large terminal (the one connected to pack + ) had pack voltage. The other large terminal (the one which goes to controller ) had pack -3v.

You do dangerous things when you don't have your jack stands or an assistant. Big Chief "Just because were dumb ***** don't me you can be too. So don't do any of this at home." Key on volt meter shows nothing different. Lightly press and release accelerator, hear the click. Hold meter leads with one hand and lightly press and release accelerator, here the click. Voltage on the small leads go to pack voltage. Large terminal to controller slightly rising.

Again tonight I remove the power in because I'm not sure what is what. It almost seems like that pack -3v is traveling across the large leads, reduced by the resistor.

That is exactly what is happening and it is completely normal.

Effectively, you have two resistors connected in series between B+ and B-. The one you can see (pre-charge resistor) is between the two large terminals on the solenoid and connects the battery pack's main B+ terminal to the B+ terminal on the controller. The other resistor (bleeder resistor on the filter capacitors) is inside the controller and connects the controller's B+ terminal to the controller's B- terminal, which is directly connected to the battery pack's main B- terminal, completing the series circuit.

They is only a few milliamps flowing and they do not pass through the motor or anything else other than the what is described in the preceding paragraph.

The reason this circuit exists is to prolong the lifespan of the solenoid's contacts. If the miniscule amount of current flow bothers you, take the precharge resistor off the solenoid, it is not needed for the cart to operate. The net results will probably be the solenoid will only last two or three years instead of twenty or thirty.

[Newbuggyboy]

Thanks. I let you know in twenty years about that prediction! I will offer a +/- 15% margin of error.