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Minimum charge rate when using the 120 VAC charge cord?

Posted: Tue Sep 04, 2018 6:49 pm
by Gasbuggy
What is the minimum charging rate when using the 120 VAC charging cord?
Can the limiting resistor in the charging cord be switched to a different value to allow a somewhat lower minimum charging rate?
This question assumes one has a limited number of Solar Panels and a relatively small DC to AC inverter for charging the Bolt.

Re: Minimum charge rate when using the 120 VAC charge cord?

Posted: Tue Sep 04, 2018 9:59 pm
by DucRider
Gasbuggy wrote:What is the minimum charging rate when using the 120 VAC charging cord?
Can the limiting resistor in the charging cord be switched to a different value to allow a somewhat lower minimum charging rate?
This question assumes one has a limited number of Solar Panels and a relatively small DC to AC inverter for charging the Bolt.

Are you talking about modifying the EVSE to "advertise" a lower rate to the charger in the Bolt by changing the pilot signal?
The PWM duty cycle of the 1 kHz CP signal indicates the maximum allowed mains current. The SAE defines the ampacity value to be derived by a formula based on the 1 ms full cycle (of the 1 kHz signal) with the maximum continuous ampere rating being 0.6 A per 10 µs (with the lowest 100 µs giving 6 A and the highest 800 µs giving 48 A)

Pretty sure any lower value will not be recognized by the Bolt and charging will not be initiated.

Re: Minimum charge rate when using the 120 VAC charge cord?

Posted: Wed Sep 05, 2018 12:11 am
by SparkE
Gasbuggy wrote:What is the minimum charging rate when using the 120 VAC charging cord?


8A : this is setable in the Bolt (only for 120V charging) and 8A is the default (if it hasn't been changed). I believe that the stock EVSE advertises 12A, but it is the CAR that determines what the charging rate will be (while never exceeding the max rate advertised by the EVSE). So if you can find an EVSE that you can set to a lower rate (the EVSE itself - there are some that allow user selectable rates) then you can get a lower charging rate.

Re: Minimum charge rate when using the 120 VAC charge cord?

Posted: Thu Sep 06, 2018 12:38 am
by Gasbuggy
DucRider wrote:
Gasbuggy wrote:What is the minimum charging rate when using the 120 VAC charging cord?
Can the limiting resistor in the charging cord be switched to a different value to allow a somewhat lower minimum charging rate?
This question assumes one has a limited number of Solar Panels and a relatively small DC to AC inverter for charging the Bolt.

Are you talking about modifying the EVSE to "advertise" a lower rate to the charger in the Bolt by changing the pilot signal?
The PWM duty cycle of the 1 kHz CP signal indicates the maximum allowed mains current. The SAE defines the ampacity value to be derived by a formula based on the 1 ms full cycle (of the 1 kHz signal) with the maximum continuous ampere rating being 0.6 A per 10 µs (with the lowest 100 µs giving 6 A and the highest 800 µs giving 48 A)

Pretty sure any lower value will not be recognized by the Bolt and charging will not be initiated.


* Thank you Gary and SparkE for your prompt responses. I now understand the default charging current, with the 120 VAC charging cord, is set to 8A. I believed that the 1 kHz pilot signal PWM duty cycle setting resistor, that determines that default current, is mounted in the 'extension cord' connector that plugs into the Bolt. I was wondering if an alternate resistor could be switched in that would allow charging at the minimum 6A rate. If the pilot signal duty cycle could be selected for the 6A charge rate, from the Bolt control panel, that would be the best option.

Vern