Onward / Precedent - Electrical changes for 72v?

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I'm preparing to switch from a ~48v LiOn pack to a ~72v one.

My motor / controller will be fine with the higher voltage, so no concerns there. The controller (Navitas) can also be programmed to continue to supply 48v to the solenoid coil, and I'm assuming the contacts in the solenoid (HD Albright 350A SPNO) should be OK with the higher voltage since it doesn't make / break contact under high current loads.

I had assumed most of the electrical system ran off the onboard DC-DC converter (which in my case is rated up to 96v DC input), But it appears that some of the onboard lighting, turn signals, horn etc... run on straight pack voltage (expecting 48v). I was under the impression these were 12v and were served by the OEM 48v>12v unit - I think the headlights are?

These (turn sigs, horn...) look like fairly low amp draw devices and maybe I should consider a 72v>48v DC-DC converter to power all devices in this category. For simplicity, is there a single place in the cart's wiring I can insert the converter? I.e is there an easy place I can "intercept" the pack voltage and insert the 72>48 unit, while still feeding the OEM 48+v>12 unit full pack voltage?

For those of you that are very familiar with the recent model Onwards / Precedents, what systems run on straight pack voltage and would be damaged with significantly more than 48v? Any other considerations I should be thinking about?

Any insight would be appreciated!

[Sergio]

Albright recommends a maximum of 48 switched or 60 uninterrupted voltage at the contacts if the contactor is not fitted with magnetic blowouts.

As far as I know Club Car has no accessories that run off pack voltage.

You either have a 48v->12v reducer or a cheap 16v->12v reducer installed for those.

Club Car engineers designed the Precedent/Onward to have the converter mounted up front and several sellers have the plug-and-play harness to connect the converter directly to the dash harness where it turns on/off with the key switch.

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Originally Posted by Sergio

Albright recommends a maximum of 48 switched or 60 uninterrupted voltage at the contacts if the contactor is not fitted with magnetic blowouts.

As far as I know Club Car has no accessories that run off pack voltage.

You either have a 48v->12v reducer or a cheap 16v->12v reducer installed for those.

Club Car engineers designed the Precedent/Onward to have the converter mounted up front and several sellers have the plug-and-play harness to connect the converter directly to the dash harness where it turns on/off with the key switch.

Thanks a lot for that information.

I thought the same - that the converter was powering all this, but looking at the wiring diagram it shows some 48v relays for turn signals etc and the reverse buzzer as 9-48v, so wanted to be certain that these circuits / devices were not getting pack voltage. Maybe those ratings are contact ratings and not coil voltage... The parts listing is attached.

So I think Albright may have a version of this solenoid that is for higher switching voltages - sounds like I'll need to change that out as I don't think the one I have has the mag. blowout feature you mention. Do you have a suggestion for a reliable solenoid that would be suitable?

My converter is factory, and is clearly marked as acceptable inputs being up to 90-something volts - can't remember w/out looking at the data plate. It has 2 input leads and is already from the factory connected using the higher of the 2 voltage selections. So I think I'm OK there.

[Sergio]

The "brake relay" is a 48v relay activated by the key switch, its only purpose is to turn OFF the 12v to the brake pedal when the key is OFF. It is not needed if your +12v converter already turns off with the key switch.

The buzzer is a +48v buzzer, the controller activates the negative side, they just happen to disclose the voltage input range that is possible.

The biggest issue with the Solenoid is the coil, as long as you can manipulate the PWM of the Solenoid driver to provide an average of 48v to the old solenoid it should be OK.

If the contacts later get damaged just buy the version with the magnetic blowouts, if you have a SW200, you can also order a new top cover with magnetic blowout fitted.

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Originally Posted by Sergio

The "brake relay" is a 48v relay activated by the key switch, its only purpose is to turn OFF the 12v to the brake pedal when the key is OFF. It is not needed if your +12v converter already turns off with the key switch.

The buzzer is a +48v buzzer, the controller activates the negative side, they just happen to disclose the voltage input range that is possible.

The biggest issue with the Solenoid is the coil, as long as you can manipulate the PWM of the Solenoid driver to provide an average of 48v to the old solenoid it should be OK.

If the contacts later get damaged just buy the version with the magnetic blowouts, if you have a SW200, you can also order a new top cover with magnetic blowout fitted.

I'm learning a lot here by what you're telling me - thanks - but I'm a little slow so... To be sure I understand all this:

1) The controller software has an input field for solenoid voltage (separate from the input field for Battery Voltage) - apparently the controller can reduce the voltage the coil sees (I guess by PWM?) so AFAIK I should be OK here in terms of coil voltage.

2) The cart's keyswitch switches pack voltage to:
A) The DC-DC12v converter (I do know this is happening for sure).
B) The brake relay that apparently isn't needed as you point out
C) Anything else?

3) I have the SW280 Albright, apparently no blowouts unfortunately - You feel like the contacts should be OK passing the pack voltage on to the controller? What would I expect if it fails, and what would likely be the cause of the failure, and under what conditions would you think (WOT, high current situations such as uphill or hard accel. etc...?) Would it likely fail in the closed or open position, or would you think it would be a slow degradation situation?

I have very little understanding of most of this, but I'm under the impression that the solenoid only connects or disconnects the load when there is almost no current (when you first touch the Go pedal it clicks, then clicks off after a pre-set idle time or when you go to Neutral.)

It seems like engaging or disengaging the contacts when there is a heavy load would be more difficult for the device and impact lifespan, but maybe there is significant wear (I know some heat, anyway) when you run the cart hard and the contacts are already engaged?

I'd change the solenoid if it should be done but of course would prefer not to if it should do the job with little chance of an issue.

Thanks for your take on it - very helpful.