LOL you guys really amaze me - you're so afraid to admit when someone is right you would rather twist the facts around to suit your agenda even at the risk of saving someones home or life. It amazes me a Public Forum would accept the responsibility to mask my thread which will avoid a potential danger!
Just to clear the air here's a quote from Farasis from this very same forum and further backed by Zero's new unattended charging policy:
"In the event of the BMS and the MBB not responding and the contactor is welded and the charger some how outputs more than 117.6V then yes there is a risk of fire. This is probably why Zero ask you to check on it every 72 hours to make sure the bike is still responding and the BMS is still alive."
Be Safe - Mike Mas
Ok so you are quoting me.
Here is the post he is referring to:
http://electricmotorcycleforum.com/boards/index.php?topic=6583.45
I don't care for arguing how people interpret things but I do care about people using the Farasis name. What I said in the post were my words as an individual sharing my limited knowledge. I don't represent Farasis and no one on this forum represents Farasis.
About the lighting thing. If your house has a big enough surge from lighting it could destroy the on board charger, but it shouldn't do anything to the BMS. The charger is an isolated power supply with suppressors on the input so if the surge if big enough the suppressors will fail short. Then your breaker should fail after that. The BMS and the rest of the bike is completely isolated from the charger so I don't see a current path there. This is why some people on this forum reports their charger is dead but the bike is fine and there wasn't any fire and most of the time Zero replaces the onboard charger for them. I can't think of any technical way the BMS would be affected. Let me know if someone has an answer to that.
Wontuan - thanks for your reply - sorry you got dragged into this but a user quoted your reply, so I responded, however you might want to clarify your last post on your position with Farasis and Zero because when Brian asked you; " Not to pry, but how do you know Farasis' practices and accident statistics?"
Your reply was:
"I guess I should have mentioned that I work for Farasis designing BMS and a bunch of the Zero engineers are my good friends."
I really don't see what is left to debate here or why there is so much aggression towards me. I'm just a rider like you guys who discovered an error in unattended charging and put up a post with my safety concerns then followed it up with a report to Zero. Evidently my concerns were valid since Zero's reply was:
"For planned long-term storage (more than 30 days), we recommend draining the power pack to a 60% state of charge, and leaving the charger unplugged. The key change is we are dropping the guideline/requirement that you must or should keep it plugged in all the time."
Zero's revised procedure is the same I outlined in my now "Closed Thread" so why do a select group of guys find fault with the issue and continue attacking me. I am publicly asking the administrators to "Re-open" my Safety thread to avoid it from disappearing from the view of newcomers who visit the forum who are not aware of this potential dangerous charging procedure. Why would this forum want to mask something that can be an dangerous to riders? There is nothing in the thread that violates Forum rules so please re-open my thread!
Mike Mas
Mike,
I am ok with people quoting me, even saying "an employee of Farasis said ..", but the things I comment on are from my knowledge and perspective. I do not represent Farasis what so ever. Just like everyone else I could be wrong. You are more then welcome to quote me, just don't say it was Farasis that confirmed anything. This goes for everyone on this forum, do not quote me or anyone else and say that Farasis said it. If Farasis has something to say they will inform their customers.
You are correct that Zero did revised their recommendation. This is to help users increase their battery life cycles. I do see that there has been some aggression going on and I think it is because you insist that there is a risk of fire. Which people view as a false claim. I believe that people do agree with you that leaving the bike plugged in isn't great for the battery cycle life, they just don't agree that there is any fire risk and that Zero changed the recommendation due to a risk of fire. If you truly believe there is a fire risk then try to form a compelling argument with information to back it up. For example if you think a lighting surge can cause damage to the BMS then ask others if they know what kind of surge suppression Zero has on the bike or if the bike is complete isolated from the AC outlet. I encourage you and everyone else to express concerns but also try formulate technical reasons to backup your concerns. Having a good discussion is what forums are about.
With that being said let me provide some information on some assumptions that have been made.
1. BMS not responding
If the BMS doesn't response the contactor will open because they are normally open contactors. While failed BMS have been reported, it is more likely the AFE chips drained some cells or won't close the contactors. The BMS was design to fail in a safe state.
2. MBB not responding
I have never heard of this happening, but who knows.
3. the contactor is welded
Contactor doesn't just weld when they are closed, they weld during closing event. The common way for a contactor to weld is if there is no pre-charging systems and the contactor closes and there is an arc across the contactors and it melts the copper and welds it shut. This happens on high voltage closing events, not opening or already closed.
https://support.industry.siemens.com/cs/document/22979862/reasons-for-contact-welding-in-contactors?dti=0&lc=en-WW4. the charger some how outputs more than 117.6V
I have no idea how this will happen. The charger is an isolated AC to DC charger with surge protection on the AC input and DC output. The BMS can tolerate high voltage so even a high spike the BMS won't care at all. Each cell has voltage clamps across them to limit the voltage on each cell. Also each cell can tolerate a spike on them, its sustained over-voltage that is bad.
If I have provide any incorrect information please let me know.
Again, I think conversations like this should be welcomed but lets keep it a conversation instead of a back and forth name calling thread.