Wednesday, October 21, 2015

Radio interference by Leaf or Chademo or ?

I sometimes listen to AM radio. While most of it's junk, there's a show called "Tim Conway Jr. Show" on KFI 640AM. One of their programs is called "What the hell did Jesse Jackson say?" where callers hear a snippet of some speech by Jesse Jackson and try to guess what he said. It is HILARIOUS! No, I don't think it's racist, although I wish he'd have other hard to understand figures, such as "George Bush" specials; I mean, it's NU-CLEAR, not NU-QULAR.

I was listening to this show one night while fast charging, and the radio went bonkers all of a sudden. It was not static, but some sort of buzzing (PWM?) that completely wiped out the reception. I didn't know what it was at the time. Oh well, back to audiobook.

In another time, as I was pulling into charge with the AM radio playing with Leaf already charging, I noticed that buzzing got worse as I got closer. Then it dawned on me; it's Leaf charging. Over the next few weeks, I observed that interference was not only from Chademo only charger (Nissan made?), but dualhead ABB charger as well when Leaf was plugged in.

So the culprits for the interference could be any combination of the following: Chademo standard; Chademo chargers (Nissan and ABB); Leaf

Unfortunately, this will come across as Leaf bashing, but that's not the case. If I encounter other EV and I remember to test the AM radio, I would. But these days, it seems only EV using fast chargers are Leaf. If you happen to see EV charging, please try to test the AM radio.

More unfortunately, BMW i3 in US does not come with AM radio (supposedly, EU version does), so they can't test it. I3 drivers are missing out on a very entertaining show!

By the way, please don't go complaining to some government agency if you find interference. If you'd like to complain, you can put comments below or contact the companies. I'm hoping the industry will fix itself if there's a problem rather than involving the big brother.

Edit Nov. 9 2015

As I was waiting to charge next to a Leaf (getting Leafracked; >90%, slower than molasses in Arctic winter) and a SoulEV, both using ABB chargers, I was able to listen to the AM radio. This was in LA where the station is based, and there was no interference! It seems the interference problem is not universal, and strong AM signal could result in no discernible interference from Leaf.

But in San Diego, the radio is clear as in LA. The signal may be weaker, but the AGC (automatic gain control) of the radio would compensate. If there is much stronger interfering source, such as charger and/or Leaf, it would wipe out the signal. Unless there is a way to determine RSSI (received signal strength indicator), it would be difficult to know when the interference would be so bad as to wipe out the radio. I suppose I could get some Ferrite loop and make crude spectrum analyzer and ...

NO NO NO. I am not getting involved, despite how tempting the dark side may be!

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