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[Булгаков]

Hi all, I was riding my Zero and then suddenly notice I have no working headlight, turn signals, horn, running lights, backlight for the dash, accessory power, etc.

I didn't have tools with me to check fuses or anything, but looking at Burton's 2013 schematic, since all of those things are on different fuses, for them to all fail simultaneously seems to imply that the Dc-dc converter died.

I'll post more when I can confirm the problem, but have others had similar problems? Kind of a scary thing to have happen at night.

[clockfort]

I'm in a similar boat and have recently done all of the research related to this topic for you... 
It's a common issue.

There are two separate common issues related to the converter; one is that early zero bikes right after the switch to euro-required ABS can draw too much power from 12V DC-DC converter while it is actively engaging. The more likely cause if yours is failing now, and you weren't involved in a.... 'spirited braking scenario'... when it failed, is that its just known to be prone to failure over time and there are several other people who have had this part fail on them like myself.

https://zeromanual.com/index.php/Unofficial_Service_Manual#DC-DC_12V_converter

I bought the converter from thunderstruck as per the wiki and am currently done disassembling the bike enough to put the new one in (it's kind of in the dead center of the bike and underneath the mbb, crossbar, seat, and tank plastics, and is just annoying to get out in general) and I'm in the process of putting everything back together.

I can confirm that the the things you mentioned not working are definitely on differently fused 12V ciruits and its not an issue of loose fuses, etc, though if you want to be thorough before ordering a $220 part, you could do some wiggle tests on the connectors between the battery <- DC converter -> fusebox just to make sure the issue isn't there.
But given the prevalence of myself and others with this sort of issue, I wouldn't be surprised if it's the DC-DC converter itself.


Anyone who read this far in my reply: Do you know why the original Zero 12V DC-DC converter is covered in metal tape? surely it can't be for EMI reasons since its already in a metal case, and the unit already is already IP67 rated for water/environment intrusion; so, what gives?

[Булгаков]

Thanks clockfort for your reply. Mine is 2014, so no ABS.

Since you have already done the work, can I ask if the part is easy to obtain directly or from other vendors than through a zero dealer? The local zero dealer here has been awful and very slow to interact with them.

Good luck with your rebuild

[clockfort]

If you click through to the 'unofficial zero manual' section I linked, there's a link to http://www.thunderstruck-ev.com/sevcon-72-80v-dc-dc-en.html , who sell online a compatible sevcon dc-dc converter and they'll just ship it to you no questions asked and no hassle. It looks like they now only sell the newer 500W version; I believe it is a strictly compatible upgrade for your current 300W one, but I can't give you any guarantee more than my intuition and how I've seen it in my 2015 SR.

I've also had good remote (and in-person) interactions with the infamous-on-these-forums Los Angeles Zero dealer Hollywood Electrics, and I suspect if you asked them nicely over the phone they would also be happy to ship you any parts you need if your local dealer is awful. Though, as I noted above, it's not completely absurd to pay a surplus to someone else to perform this surgery, as its a pain in the butt.

[BrianTRice@gmail.com]

I wrote the DC-DC converter manual entry and performed a swap myself.

In my case, my converter was not covered in metal/Nashua tape. I believe the failure was due to road grime from construction zones splashing up in the rain onto the connector while I was traveling between San Francisco and Seattle last October. Rain alone usually doesn't cause electrical faults, but rain with dirt in it can.

Anyway, the converter failed about 4-5 months after that. I advise checking the seating of the pins within the connector as well as a basic seating test as clockfort recommends above.

The ABS on startup hypothesis is not a bad one, but it's difficult to tell with a long-term failure where the issue may be slow and wear the device down over time. Mine lasted 26000 miles or so.

I'm so glad the manual entry helped someone out. I concur that calling or emailing Hollywood Electrics is more successful than anyone seems to guess. They're very knowledgeable and willing to help out those with odd requests if you show you've done your homework or are willing to learn appreciatively.

[Булгаков]

Update: once I got home and had daylight and tools to do any troubleshooting,Thankfully it was very simple fix. Short answer: I burned out the high voltage 125v 4A ABC fuse who supplies power to the Dc-dc converter.

I did not see a fuse shown on Burton's schematic (for 2013) but when I start to troubleshoot the converter I noticed one and it was dead. I couldn't find a local replacement for the paper ABC fuse at 4A, but I did find 125v 5A glass AGC bussman fuses at AutoZone. Just to test, I bought a package and it worked! Now I need to order the correct fuse.

Thoughts: I do not have ABS on my bike (2014) and only other change was adding USB charging port as shown in the manual ( https://zeromanual.com/index.php/Common_Modifications#Accessory_Power ) and it has worked well for long time. However I did have two smartphones connected to the two USB charging ports, listed at 1A and 2.1A .

Why did the high voltage fuse pop? I don't know.  The bike was at full charge, so 116v x 4a = 464 watts being drawn from my 300w DC-dc converter for fuse to pop. On 2014 model bike there are 12vdc fuses for headlight (10A), accessory (10A), flash/horn/brake light (10A), and gauge/running lights (5A).
I did not measure actual normal running amps for lights/gauge/etc , but excluding accessory port, theoretically (10+10+5A) x 13.5V = 337.5 watts possibly drawn from the 300W charger without popping the low voltage fuses and no accessories connected. If the USB charging ports were actually supplying only a Max of (2.1 + 1A) x 13.5v = 41.85w then the total rises to 379.5 watts, or if the accessory port maxed out at an additional 10A without popping low voltage fuse, then another 135watts brings total to 472.5watts from the 300watt charger .
I know this is ridiculous analysis because these loads should be less than max fused amperage and/or not be simultaneous, but since none of my low voltage fuses popped but everything works after replacing the high voltage fuse, I assume it may be possible in worst case scenario.

Also, I checked all low voltage wiring+connectors for shorts or worn out insulation and all is ok.

Maybe it is just a random occurrence and I should just forget about it and bring fuses and tools with me when driving. However if the Dc-dc converter does fail I would probably like to upgrade to the 500watt for replacement with appropriate high voltage fuse. Or use lower fuse limit for accessory power.

Clockfort, I didn't read that the converter you sent a link to is ok with 116vdc input instead of only 72-80v input. Did I misread?

Thoughts?

[clockfort]

Thankfully it was very simple fix. Short answer: I burned out the high voltage 125v 4A ABC fuse who supplies power to the Dc-dc converter.

  Happy for you and more than a little jealous that you didn't have to completely take your bike apart to fix your problem

Clockfort, I didn't read that the converter you sent a link to is ok with 116vdc input instead of only 72-80v input. Did I misread?

Thoughts?

I thought the same thing; I did confirm by unwrapping my original one that it is indeed the 80V part listed on the wiki, and I can confirm that it works now that I've finally finished reassembling my bike. (See attached image for side-by-side comparison of the one I grabbed out of my 2015SR and the replacement that the wiki recommended)


Oddly, sevcon even make a 96V DCDC converter; unfortunately, the sevcon "data sheets" available even if you sacrifice an email address and firstborn child to sevcon are incredibly light on actual data. Notably, I'm not sure Sevcon makes a 96V 500W DCDC converter; I can't find anyone selling a sevcon 96V one more than 300W, and the datasheet just says to enquire with your 'sevcon dealer' to find out which combinations of input voltages are available with which output wattages. 
The data sheets also do not specify min/max input tolerances nor % efficiency at various input voltages.
I'd find it possible that sevcon's converters could be mostly the same with regards to absolute input tolerances and just tweaked for efficiency peaking at different median voltages, but I don't have any data to prove that.

[Булгаков]

Wow! Interesting. Thank you for confirming!

And yes, I feel lucky that I did not have such big headache. I hope your luck improves

[ray336]

I have the 2016 zero FSX. My 12 volt system works intermittently. I checked the input voltage to the dc dc converter and there was voltage. I wasn't sure how to check voltage on the signal wire. After a lot of research, I finally shelled out the big bucks to get order me a new dc-dc converter. Oddly the dc-dc converters from the factory are rated for a minimum of 80 volts when the batteries provide a constant 105 volts to the converter. There is no documentation for the max input voltage and if the voltage fluctuates, and reaches the max rated voltage, it will destroy the converter. I guess that is the function of the 125v fuse. To make sure the converter doesn't get fried.

Like clockfort mentioned, there weren't any 96V 500W converters available. Only 96V 300W ones. The only reason I can think of for Zero to use the 80V ones is that if your battery runs really low any the voltage drops below 90V, you wont have the 12V supply. Maybe they are trying to match the minimum battery voltage with the converter.

Hopefully Zero custom orders a 96V 500W converters soon to replace the current ones.

[Crissa]

Minimum is minimum.  It has nothing to do with maximum.

At the minimum, it stops providing the right conversion.

-Crissa

[ESokoloff]

................
Oddly the dc-dc converters from the factory are rated for a minimum of 80 volts when the batteries provide a constant 105 volts to the converter. There is no documentation for the max input voltage and if the voltage fluctuates, and reaches the max rated voltage, it will destroy the converter. I guess that is the function of the 125v fuse. To make sure the converter doesn't get fried.
..............

You are mistaken if you think that the purpose of the fuse is to protect against over voltage conditions.
Fuses protect against over current conditions.