spencerledlow
Posts: 3
Joined: Sat Dec 05, 2020 9:03 am

Re: Inaccurate energy consumption calcs on trip computer???

Fri Dec 11, 2020 11:02 am

I wonder if the charging efficiency goes down as the car approaches 100% charge. I'll try to limit it to 80% and see if that makes a difference. Any opinions on charging to 100% on battery life?

notfred
Posts: 511
Joined: Thu May 07, 2015 2:28 pm

Re: Inaccurate energy consumption calcs on trip computer???

Fri Dec 11, 2020 11:47 am

Better for battery life to only charge to 80%.

ksoul2084
Posts: 145
Joined: Thu May 16, 2019 10:48 am

Re: Inaccurate energy consumption calcs on trip computer???

Fri Dec 11, 2020 1:57 pm

Yes, I believe the closer the battery-pack gets to "full" the higher the resistance, thus, more power lost to heat.

ksoul2084
Posts: 145
Joined: Thu May 16, 2019 10:48 am

Re: Inaccurate energy consumption calcs on trip computer???

Sun Dec 13, 2020 8:24 am

ksoul2084 wrote:
notfred wrote:In theory it should trip after 3 hours. In practice it almost certainly will not.

The breaker is measuring the current, it can't tell how hot any of the rest of the parts of the circuit is getting, If you have a brand new good quality socket with good contacts and good connections to it, you'll probably be OK. But any poor contacts any where on that circuit and it can cause a fire.


Okay, I will run some tests and check the wiring and plug.

Thanks for the heads-up.


Yesterday, while the car was charging in my unheated garage I took some temperature readings using an IR temp. gun. It started charging with 45% left in the battery, so was probably at 65% state of charge or so when I took the readings:

Ambient temp. in the garage = 3c.
120v Adapter Cord between wall socket and charger = 30c
Wall socket near plug = 31c
Breaker in electrical pane in basement = 34c
Wire leaving breaker in basement = 34c

These seem completely safe to me and far from being hot enough to melt anything. Thoughts?

notfred
Posts: 511
Joined: Thu May 07, 2015 2:28 pm

Re: Inaccurate energy consumption calcs on trip computer???

Mon Dec 14, 2020 3:51 pm

I checked while charging mine on a 240V 30A EVSE. After 1 hour my breaker is a similar temperature (there is a thermal element to breakers so this is expected), but everything else is at ambient to maybe 1C higher.

Right now you don't have anything that is hot enough to cause a fire, but you are running outside of specs and one slight imperfection away from a house fire that your insurance will not pay for as it is not CSA certified. That cord is 27C above ambient. It could get close to its limits in the summer and high ambient temperatures - with all the other corners that they have cut I'd be surprised if they used high temp cable. A couple of unplug/plug cycles on that socket could increase the resistance slightly and a dramatic increase in temps. I wouldn't risk it, but it's up to you.

IanL
Posts: 165
Joined: Tue Feb 18, 2020 12:57 pm
Location: Jersey, English Channel Islands

Re: Inaccurate energy consumption calcs on trip computer???

Tue Dec 15, 2020 12:25 am

As another data point:

While I was fitting my 240V 30A EVSE, I wanted to test the setup before I had wired it back to the breaker board (is that what it's called in the US? - here it's the consumer unit). The EVSE is switchable to 32, 16, 13 and 8A, so I supplied the setup via an extension cord from a domestic socket (designed for 13A), started at 8A and worked up to 16A. I don't have an IR thermometer (must get one!), but feeling the two plugs in my temporary supply chain, they were unpleasantly hot at 13A, let alone 16. Neither were new, but they looked in good shape, as did the sockets.

I think that reinforces Notfred's point.

Gordo
Posts: 8
Joined: Wed Nov 11, 2020 11:54 pm

Re: Inaccurate energy consumption calcs on trip computer???

Mon Mar 01, 2021 5:55 pm

It's the wiring in your walls you need to be most concerned about. But even at 12amps some outlets don't do well under continuous load, if they aren't quite up to spec...

Image
But on topic, I've had my meter at 3.1 or so for months when it suddenly started jumping around randomly. I reset it and it started again, then seemed to calm down and now it's around 3.3.

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