Downsizing my Power Cables on a DS

[BobHyatt]

Originally Posted by Volt_Ampere

I am being factual. If you replace half of your cables with much larger conductors, you get half of the benefit of replacing all of them. It is misleading to say that one piece of smaller cable negates the benefit of upgrading to larger cables. Of course it is better to upgrade all of them.

This fails physics 101.

Suppose you have three sections of cable. The first is huge and actually has 0.000 ohms resistance (not possible, but hang in there for a minute). Second and third are exactly the same. That cable, at 48 volts, will carry as much current as the batteries can dump.

Now replace just 1" of that cable with a 1 ohm resistor. Now the MAX current you can flow through that cable is 48 amps (amps = volts / resistance).

It is the TOTAL resistance that limits current, not any sort of "average resistance" (which is meaningless in electrical circuits like this.) This is a common automobile problem. Good cables from battery to starter, and starter to ground, but ONE corroded connection will ruin that circuit and prevent starting. Even though 99%+ of the cable is ultra-low resistance.

[Hunter450]

Houston, we have a problem. I decided to pull the battery pack out of the cart to clean up the support rack and I found some cancer on the rack so a couple pieces of alum angle, a few gallons of baking soda solution, wire brushing and washing and I put the pack back in after about 2 weeks. Got the cables all connected up, flip the switch to Run, turn the key, set rocker switch for forward, push the pedal, hear the solenoid and the cart moves about an inch and the battery light comes on. So, I put it on charger, the charger is happy and turns itself off sometime during the night. Pull the charger cord and nothing....nada. I'm stumped on what could have happened during non use, the cart did run before I started this and BTW I did reset the OBC.

[Sergio]

Wow, I missed the post above yours (#11), but just a reminder for folks reading this thread, it would take 2,500ft of 6ga to measure 1Ω resistance, so that post is not realistic for the discussion of cable gauges impact on overall current.

Volt_Ampere comment quoted is "physics 101" accurate.

Now, what is the pack voltage and does the reverse buzzer work when you put the FNR in reverse?

[Hunter450]

Originally Posted by Sergio

Wow, I missed the post above yours (#11), but just a reminder for folks reading this thread, it would take 2,500ft of 6ga to measure 1Ω resistance, so that post is not realistic for the discussion of cable gauges impact on overall current.

Volt_Ampere comment quoted is "physics 101" accurate.

Now, what is the pack voltage and does the reverse buzzer work when you put the FNR in reverse?

Pack voltage 51.2 volts after 20 minutes of cool down. I have the reverse buzzer disconnected but can reconnect if needed.

[Hunter450]

1 hour after charger auto shut-off the pack voltage is 51.4 sitting idle.

[Sergio]

Pack voltage is good, the reverse buzzer working is the easiest way to check if the OBC is in controller lockout mode.

[Hunter450]

Originally Posted by Sergio

Pack voltage is good, the reverse buzzer working is the easiest way to check if the OBC is in controller lockout mode.

connected the buzzer up and it buzzed. Disconnected it again

[Sergio]

Does the solenoid get pack voltage on the small terminals when You press the pedal?

If not, check the continuity in the micro-switch inside the Multi-Step potentiometer (Blue to Green/White wires at the Multi-Step connector).

[Hunter450]

Originally Posted by Sergio

Does the solenoid get pack voltage on the small terminals when You press the pedal?

If not, check the continuity in the micro-switch inside the Multi-Step potentiometer (Blue to Green/White wires at the Multi-Step connector).

Pack voltage was 51.2v on LCD cart meter..... with key switch off:
Solenoid small terminal voltage was 48.4 volts (pedal up) on digital multimeter
Solenoid small terminal voltage was 48.4 volts (pedal down) on digital multimeter.

No continuity between blue wire and green/white wire on multi-step potentiometer. Nothing on.... nothing pressed.

[Sergio]

The voltage on the solenoid small posts should be taken with the Multi-Meter probes connected to each of the small posts.

The problem appears to be the micro-switch inside the Multi-Step.