2017 i3 REx battery readings versus Juice Box Pro 40

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fbt12

Well-known member
Joined
Oct 28, 2019
Messages
50
Bought a 2017 i3 with CPO used (Halloween) and installed a JuiceBox Pro 40 soon after.

Last night i charged it (set to 11pm to 7am charging time on JBP). Took about 4 hours to add 28.32 kWh to the battery. The i3 display shows 100% charge with a (estimated) 127 miles range on battery.

On the JuiceBox Pro website (using my account info) it shows that the current state of charge is 79% for 77 miles versus a 100% charge of 97 miles range.

So....how do i translate these 2 different sets of data?

Thanx for any clues.
 
I have a Juicebox Pro 40 as well. I don't believe the Juicebox can access the battery state of charge information from the car. The Juicebox website / app only shows how much energy the charger has provided to the car during the most recent charging session. I use the EnelX app on my phone. It displays charging information as added charge, added range, added energy and miles added.
 
ALso note that the EVSE knows how much energy passed through it to the vehicle, but the ACV-DCV conversion isn't perfect...you'll always put more Kw into the car than is actually stored in it. The efficiency differs some based on the input voltage, with 240vac more efficient than using 120vac. Don't remember the efficiency numbers, but both were in the 90-percent range, 240vac being the more efficient source. ANd, depending on environmental conditions, it might use some for either heating or cooling the batteries.
 
sterfry said:
I don't believe the Juicebox can access the battery state of charge information from the car. The Juicebox website / app only shows how much energy the charger has provided to the car during the most recent charging session.

I can corroborate this. The juicebox doesn't collect any info from the car and doesn't know your state of charge when you plugged in, it just saw 28kwh flow past its meter and juicebox compares that to published info on the battery capacity and efficiency of the i3.

To reiterate the other points mentioned, the juicebox also doesn't know where that electricity is going; it may be to the battery, it may be lost due to inefficiencies, or it may be used for battery temp reasons. Comparing my juicebox meter to the i3's data suggests a typical charge efficiency of 85~90% of the electricity going into the battery but if the car activates battery cooling or heating and it can easily use a kwh or more just for that.
 
3pete said:
Comparing my juicebox meter to the i3's data suggests a typical charge efficiency of 85~90% of the electricity going into the battery but if the car activates battery cooling or heating and it can easily use a kwh or more just for that.
The Idaho National Laboratory measured the i3's charging efficiency at 7.2 kW to be 93.8% which is pretty good.

As you stated, the EVSE has no way to determine an EV battery pack's charge level because the J1772 charging protocol does not include transmitting charge level information to an EVSE unlike the DC fast charging protocol.
 
Thanx for feedback. Helps me understand my new computer with new os that just happens to have wheels.
 
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