Why only 9kW charging rate on 9.6kW charger?

[ForumLeech]

I’m using a 240V 40A (9.6kW) charger I bought from OpenEVSE in December 2017 and it always charges my car at 9.0kW instead of the 9.6kW the car and this charger are rated for. I already verified the charger’s settings are not the bottle neck and my garage temperature is about 10°C/50°F. I have heard that an EV’s computer will negotiate a lower charging rate when the battery is too cold but this isn’t extremely cold weather and the 9.0kW number has never changed over varying temperatures and multiple charging cycles. What are other people seeing for maximum kW of charging?

OpenEVSE Advanced Charger:

NEMA 14-50 outlet:

One meter of 4.1mm thick (6 gauge) copper wire from outlet to main house electrical panel.

2014 B250e:

 

[GlennD]

I charge my B250E at 40A and 245VAC with a DIY OpenEVSE. It has a Barbouri ver 4.2 board. I have no problem charging at 40A with a Quick Charge Power J1772 cable. I do not use the internal meter since it is not as accurate as my external meter. I only use the internal meter on my never used carry along EVSE. So far it is just along for the ride. I do not like the fact that the voltage is fixed and not measured. My external meter gives me volts, current, watts, and watt hours.

I also used it at 32A until I changed the cable. I had a 24Ft 32A cable for my eGolf and I used it for a while.

Every version uses the same firmware so it may just be measurement error. I currently use firmware ver 3.11.4 which when I last looked was the production version. In any event it works for me.

 

[GlennD]

If you have a programmer like the USBASP you can tweak the settings for the current coil. Lincomatic considers it calibrated if it is within 1A but with the source you can set it exactly. You can also set your 240V level.

The unsupported programmers are less than $5 on eBay. Chris sells the same thing with support for $20 shipped. You can get the drivers from his site but it is nice to support him and $20 certainly will not break the bank. The firmware is available at github under lincomatic.

 

[ForumLeech]

Problem solved. I needed to calibrate the charger to report more accurately. Method:

Visit charger’s web interface > System tab > Developer mode > RAPI tab > RAPI command > $SA 220 0

Change the 220 value up or down until 40A is reported.

 

[GlennD]

The RAPI commands obviously work but I tend to ignore them. I am more a basic unit with an external power meter person. I just want a simple unit that works.

 

[JeffRay]

So I went to my other garage with a Clipper Creek charger and plugged in. Only getting 2.4 KwH currently. Have scheduled a service appointment for a warranty fix on my new 2017 as it is likely a software problem.

 

[GlennD]

Clipper Creek models indicate the size of the required circuit. A 16A EVSE would have a model ending in 20. A full 40A EVSE would end in 50.

Most cars excluding Tesla based cars are happy with an EVSE ending in 40 for a 32A max EVSE. My VW eGolf charged at 30A from my 40A EVSE. It ignored the extra and took what it wanted. My B250E takes all 40A. That, the RAV4EV and Tesla's are the only high power cars.

 

[GlennD]

I still do not have my car back after 2 months but as I recall you could set the car for less than max. I always use the maximum.

So far I have spent $40 on gas for the service loaner.

 

[GlennD]

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I charge at home at 40A and 240V. Most commercial EVSE's run from a wye at 208VAC. That allows 120VAC at the wall outlets. In addition most commercial EVSE's are 30A.

208AC at 30A is just over 6K so that is normal for most non home EVSE's. There are a few 40A EVSE's around but they are few. Both Mercedes dealers that I have used only had 30A units running at 208VAC.

The car is J1772 compliant and it will set itself to match the available current.