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Author Topic: 12V circuit goes down in cool weather, and is fine in warm weather  (Read 1117 times)

phildaniels

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Hi there, I have a 2015FX and the 12V system only works when temp is above 70F in the garage.  When it's warm, upon startup, all 12V items (headlights, indicator, horn and ABS) all work fine.  But, if the nighttime temp goes cold, and the garage temp is ~60F or less, then the 12V stuff doesn't turn on.  (Interestingly, the dashboard display always works) So something is intermittent with the 12VDC device circuit. 

Any ideas, anyone?  What kind of fuses are used in this thing, or are they solid state relays which control the 12V?  How is the 12V created?  Is it a DC-DC converter off the battery voltage? 
Can anyone point me in the right direction?

Thanks,
Phil
New Hampshire
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corentinoger

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Re: 12V circuit goes down in cool weather, and is fine in warm weather
« Reply #1 on: May 19, 2016, 01:32:59 AM »

Hi Phil,

Sorry I can only give a tiny bit of answer.
On the electric vehicles I have worked on (Nissan &  Renault lineup of electric vehicles, the closest to a motorcycle being a Twizy), there is always a traditional 12V lead battery charged by a DC-DC converter from the main battery. A dead 12V battery will prevent starting even with full traction battery, since high voltage relays (and therefore DC-DC converter) keep the lithium battery isolated from the rest of the world until a complete self-test has been performed by the on-board control unit, a bit of a "catch-22" situation, but you can always jump start an electric car like you would with a gas one.

I don't know if it's the path chosen by Zero (and I'm interested if someone does know since I'm planning on buying a Zero)

Just found a post by someone that actually did it:
http://www.petergmcdermott.com/2015/02/02/jump-starting-my-electric-car/
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2015 Zero DS, formerly BMW F650GS(800cc), Honda Varadero 125, Yamaha YBR 125

MrDude_1

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Re: 12V circuit goes down in cool weather, and is fine in warm weather
« Reply #2 on: May 19, 2016, 02:13:56 AM »

Hi Phil,

Sorry I can only give a tiny bit of answer.
On the electric vehicles I have worked on (Nissan &  Renault lineup of electric vehicles, the closest to a motorcycle being a Twizy), there is always a traditional 12V lead battery charged by a DC-DC converter from the main battery. A dead 12V battery will prevent starting even with full traction battery, since high voltage relays (and therefore DC-DC converter) keep the lithium battery isolated from the rest of the world until a complete self-test has been performed by the on-board control unit, a bit of a "catch-22" situation, but you can always jump start an electric car like you would with a gas one.

I don't know if it's the path chosen by Zero (and I'm interested if someone does know since I'm planning on buying a Zero)

Just found a post by someone that actually did it:
http://www.petergmcdermott.com/2015/02/02/jump-starting-my-electric-car/

The zero does NOT use a lead-acid battery. The 12v output for lights and accessories is really just a DC-DC power supply that runs off the main battery whenever the key is on.
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Doug S

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Re: 12V circuit goes down in cool weather, and is fine in warm weather
« Reply #3 on: May 19, 2016, 04:33:12 AM »

I'm an EE, but I haven't studied Burton's wiring diagram, so I don't really know how Zero wires things up (Burton's diagram is for the S, anyhow). But I'll add a few thoughts.

At least on the S, Zero does use a DC-DC convertor, made by Sevcon, which also makes the motor controller. Clearly all the stuff you're describing would be powered by the DC-DC convertor, but I'd be very surprised if the dash isn't, as well. That would lead me to believe the DC-DC convertor is not causing the problem.

What you're describing sounds to me more like a flaky connection somewhere. Fuses don't show a lot of pathological behavior, but connectors sure do. I can't tell you how many times I've seen intermittent behavior and managed to track it down to a connector pin not fully seated, usually making contact but not always. The temperature dependence you're seeing seems to point the same way -- something expands a bit and makes contact, or shrinks a bit and loses contact.

I think first thing I'd do is go through and inspect all the connectors leading to the controls that aren't working, including disconnecting them and seeing if any of the pins don't look fully seated. Work the connector a few times to make sure it isn't hanging up on anything, and the connector shells are fully mating. I'd also throw some dielectric grease in there while you're at it.

If that doesn't work...well, since Burton hasn't made a wiring diagram for the SFX, and I doubt anybody else has one either, I'd just take it to the dealer.
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There's no better alarm clock than sunlight on asphalt.

FirstZeroFinland

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Re: 12V circuit goes down in cool weather, and is fine in warm weather
« Reply #4 on: May 19, 2016, 12:32:16 PM »

I think high voltage fuse holders are not the best available.  Spring under the fuse is heating up on charger fuse when charging. I put some copper wire on spring there to help conductivity and now it is better. 

(English is not my native language)
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Kocho

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Re: 12V circuit goes down in cool weather, and is fine in warm weather
« Reply #5 on: May 19, 2016, 08:19:36 PM »

I am not sure if the display is wired to the same DC-DC converter or not. If it is, then as you say - likely a flaky connection somewhere. But if it is wired independently, I wonder if it could be a faulty temp. sensor somewhere, indicating it is sub-freezing when it is just cool, and the bike thinks it needs to protect itself and shuts off most things except the display?

I doubt such consistent behavior would be due to a loose connection - too repeatable, plus it would be happening due to vibrations too, if it was just a connection issue.

Hi there, I have a 2015FX and the 12V system only works when temp is above 70F in the garage.  When it's warm, upon startup, all 12V items (headlights, indicator, horn and ABS) all work fine.  But, if the nighttime temp goes cold, and the garage temp is ~60F or less, then the 12V stuff doesn't turn on.  (Interestingly, the dashboard display always works) So something is intermittent with the 12VDC device circuit. 

Any ideas, anyone?  What kind of fuses are used in this thing, or are they solid state relays which control the 12V?  How is the 12V created?  Is it a DC-DC converter off the battery voltage? 
Can anyone point me in the right direction?

Thanks,
Phil
New Hampshire
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'15 Zero SR

hein

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Re: 12V circuit goes down in cool weather, and is fine in warm weather
« Reply #6 on: May 19, 2016, 08:51:40 PM »

I live in NH as well, and fortunately have not have had lot-temp 12V issues.
There have been plenty of low-temps around to verify... In the beginning of this week the mornings started out in the low 40s.

I have had issues with the main battery refusing to charge when too soon, when temps drop under 40, but above freezing.
Not that I think freezing temps (32 F, 0 C)  is relevant for the Zero batteries, just lower is important.

Why can the bike not just limit charging (and driving) currents a bit (even down to say 20%) when temps are low until the charging/driving warms up the battery a bit and then increase the amps, making the temp come up faster and so on until into safe max load range?

This is my biggest annoyance with the bike.
I got to the office one day in near freezing temps, and the bike refused to charge.
I needed that charge to get home at the speeds I prefer.

Hein


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phildaniels

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Re: 12V circuit goes down in cool weather, and is fine in warm weather
« Reply #7 on: June 29, 2016, 01:33:41 AM »

Now it's summertime, and the 12V is always gone. Lost it for good last week.  It was intermittent even on hot days and then it went out completely.  No lights, horn, ABS pump or indicator lights.  Dash still works but is not backlit.  I checked the 12V fuse panel and all fuses are fine, and so none of the 12V fuses are receiving voltage.

Why the dash still works is beyond me, it must be powered of 5V somewhere else?  Maybe there is a 12V conversion and another 5V conversion...Or - maybe the Sevcon power supply has 2 outputs...12V and 5V and the 12V is bad...

Calling dealer now, unless anyone has ideas.

Where is this DC-DC converter on a 2015 FX 5.7? 
Thanks!
Phil
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