Chevy Bolt EV Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
390 Posts
Discussion Starter #1
From what I understood, the Bolt will condition the drive battery when parked and hooked up to a charger station, when temperatures are very high or very low. That is all nice, as it is good for range and battery life, I guess. But has anybody witnessed this process?

When looking at the charge station while the car is hooked up with a full battery, does the car make the charger to switch between 'connected' state (state B) and 'charging' state (state C) every now and then, in order to draw power for battery conditioning? Or does the charger stay in 'charging' state all the time?

The reason for asking is this: I am thinking ahead about charging two vehicles from a single power source, that cannot support charging of both vehicles simultaneously. Ideally, you want to have some sort of load balancing going on, but I thought it would be easier / cheaper to do it in a timeshare fashion, where one car / charger (this would be the Bolt / Ampera) takes priority over the other (this would be my Outlander). I was thinking about using the L1 and L2 pins of the Bolt charger to drive a contactor with NC contacts, that cuts off the power of the other charger (or cut off its pilot pin). So, every time the Bolt charger goes from 'charging' state to 'connected' state, the Outlander charger would become active. And it will shut off when the Bolt charger goes back to 'charging' state.

But if the Bolt charger stays in 'charging' state all the time (or most of the time), that won't do much good :(

Any ideas, suggestions?
 

·
Registered
Joined
·
4,514 Posts
I seem to recall reading somewhere that Tesla makes a multi-station J1772 charger that will load share between two vehicles. If only one is charging it gets the full power flow, but if they're both charging then they both charge at a reduced rate. That sounds like exactly what you're looking for.
 

·
Registered
Joined
·
390 Posts
Discussion Starter #3
For sure. I guess, many load balancing solutions already exist. But still, wouldn't the same question still apply?
Apart from the fact I am not willing to pay commercial prices for load balancing solutions.
 

·
Registered
Joined
·
862 Posts
In order to provide power to the vehicle (for battery conditioning, cabin preconditioning, etc) the EVSE will switch into a "charging" state.

Clipper Creek (among others) offer EVSE's where multiple units can be installed on the same circuit. The communicate/coordinate so as not to overload the circuit rating.
https://store.clippercreek.com/featured/Share2-HCS-40-Bundle
 

·
Registered
Joined
·
390 Posts
Discussion Starter #5
In order to provide power to the vehicle (for battery conditioning, cabin preconditioning, etc) the EVSE will switch into a "charging" state.
Well true, but it is the car that tells the EVSE to go into "charging" state, by lowering the voltage on the pilot pin from 9 to 6 volts. So, the car is in control over state, hence my questions regarding the Bolt.

What a multi-EVSE does is change the PWM duty cycle (on each outlet) to tell (each) car how much power it can draw.

This would be real load balancing. Ideally, the EVSE should also measure how much power is actually drawn by each car: if you have 32 amps available and the EVSE tells the first it can charge with 16 amps, the second can charge with 16 as well. But when the first car uses only 10 amps out of the 16 it is allowed (for example because it's battery is near full), the second can use 22. The EVSE should adjust the duty cycle for the second car. Etc. Pretty much the same as how smart grid load aware EVSEs can respond to you turning on the oven.

Altogether quite complex. And expensive 'off the shelf'. Although less optimal, IMHO it would be much easier to respond to the state switches (as you can see the L1 and L2 pins becoming 'hot') then it would be to respond to changes in actual usage .....
 
1 - 7 of 7 Posts
Top