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I hooked up my new Plugshare charger with WiFi. I noticed that every 2 hours it does a quick charge again. Would this be just topping up the battery?

2017-03-27 00.34.29.jpg
 

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Battery conditioning .. probably. This happens all the time (depending on external factors) but if the car is plugged in, it tries to use grid power. To the best of my knowledge, Time Of Use settings do not seem to have any affect on this type of usage.
 

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If it is anything like lead acid batteries, then this is called a float state of charge.

With LA, the entire battery bank bus is charged first with a bulk charge, then an absorbtion charge to top up the final 20%. Once the battery hits 100%, the charger "floats" the battery voltage just around the voltage set point, with minimal amps.

With lithiums, I understand it is each cell that is individually charged, but I imagine that implies each individual cell then goes through bulk-absorb-float cycle.0


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Most likely caused by the thermo management keeping the battery warm/cool depending on outside temp. This is affected by time of rate setting and should not happen during peak time if you have that set up.
 

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It runs the DC-DC converter for a while every so often, and tops the battery up, because while it is plugged in there are 12V systems running. Basically, no, I don't believe it is charging or conditioning the traction battery, it is charging the 12V system.

That's why the recommendation is to leave it plugged in while you are away. The car monitors all its own systems, and might even provide active heating and cooling if necessary.

I've seen this on mine too, of course, it is what it is meant to do. But I have not noticed it to be so frequent as your graph. It might be prudent to check the health of your 12V battery, though I am not suggesting there is anything wrong with it, just that I would not have expected so many 12V charge events.

In the case of heating, you will see excursions over a kW and probably all the way to 3kW. It is possible what you are showing is short runs of the AC, which only uses 500W or so at minimum operating power. But I wouldn't expect you are experiencing 24hr heat requiring that just yet in the year, wherever you are. I imagine it would need to be over 30C for this to be repetitive traction battery cooling events.
 

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Does Plugshare, or any other tracking system, have an approximate charge per hour on this top off? I manually track my charging costs and always wonder how much this trickle charging affects my total estimates. Also, is there difference between G1 and G2? Thank you.
 

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From what I know, the Volt will constantly be conditioning the traction battery between charges. If you're near the car during those times, you'll hear your Volt's coolant pumps and possibly radiator fans running.

I do not believe that it charges the 12V battery during those times. Most EV's only do that when traction battery is engaged: When it's charging or being used.

What EVSE are you using? I've been looking for a good one that has WiFi and doesn't cost $500. (Edit: Oh, is that a Charge point EVSE. That's what the app looks like.)
 

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I do not believe that it charges the 12V battery during those times.
If that's true, then why doesn't the 12V battery go flat if the 12V system is burning something like 100~200W all the time, to power the BMS?


Or do you 'believe' that all the BMS and control electronics are working at 400V?

Think about it! Pretty obvious it is topping up the 12V system.
 

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If that's true, then why doesn't the 12V battery go flat if the 12V system is burning something like 100~200W all the time, to power the BMS?


Or do you 'believe' that all the BMS and control electronics are working at 400V?

Think about it! Pretty obvious it is topping up the 12V system.
If the HV battery is engaged during the conditioning, it is not long enough to charge the 12V battery. I've read many times about Volt's having dead 12V batteries while plugged in.
 

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Battery cooling

+1

Last summer, I was out in the garage doing stuff when the car A/C started by itself. It had been plugged in for about 26 hours, and long since finished charging. My guess at the time was battery cooling. The temperature was in the mid to high-90s.
 

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+1

Last summer, I was out in the garage doing stuff when the car A/C started by itself. It had been plugged in for about 26 hours, and long since finished charging. My guess at the time was battery cooling. The temperature was in the mid to high-90s.
I've seen the same thing plenty of times, as my garage regularly stays over 100F all day during the summer (South-facing doors with direct sunlight). The MyGreenVolt app will show temps for HV battery pack (as well as engine, transmission, and electric motor) and it's very rare that the HV pack would ever be more than 80F, even after hard driving and L2 charging. The Volt's HV pack thermal management system does a great job at keeping that pack between 60F and 80F.
 
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