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[scZero]

So this is interesting,  I'm registering 56 Volts at the battery however the contactor is a 48 volt rated contactor.  Why would the battery voltage be higher than the rating of the installed contactor?  Something tells me I'm going to be sending back this 48V 400AMP contactor for a 72V 400AMP contactor thats NOT made in CHINA!  I don't trust China with my dogfood nor will I trust them with my voltage requirments or abuse.

[nigezero]

Sc; I considered the same thing bug don't think its a huge issue because the voltage will slump a bit when load is applied. Also I reckon from experience that most  manufacturers who make DC gear realise that it's a nominal status that can + or minus on batteries and thirdly any one half decent then leaves 10-20% headroom. Of course, a shit product is a shit product ....

Whole the logic of going to 72 makes sense the Altrax document warned against straying too far from nominal because the contactor needs the right voltage to operate

[scZero]

Right, I need to see what type of voltage swing we have.  Nigel, did you say you have leads to the battery so you can monitor your voltage while the pack is in?  If so can you monitor the voltage, say what the voltage is at 100% SOC and say what it is around 10% SOC?  I believe the pack is at 58V at 100% SOC.

Here's the clip from the Alltrax site where it discusses the voltage rating of the contactor.  Sounds safer if its a higher rated contactor, it just won't engage.  However if its under rated and the battery voltage is higher it will arch and begin welding the contacts causing it to always be on.

"The coil voltage rating is important – use the
correct contactor voltage rating! Using 24 volts to
drive a 48 volt coil does not generate the required
force necessary to hold the contacts in place during
operation. Too much voltage will burn – or cook - the
coil wiring of which the contacts may not separate
when turned off. Contactor plunger binding or self
arcing will cause controller failure.
 Choosing the correct current rating of a contactor
is just as critical as choosing the right size wire for the
motor and battery connections. The carrying current is
determined by the size and plating of the contacts
inside of the contactor."

[nigezero]

So; I'm still learning about LiPo behaviour and more specially our vintage/chemistry. At rest to about 10% dod, I have measured as low as around 50v. Under charge 57 and a bit. However, I haven't measured under load, which is where droops would occur, but I'd guess at not lower than 50 ish. One thing I've learnt is they hold volts incredibly well them fall off a cliff. I've got close but not gone off the cliff. I'd guess the controller plays in here too, possibly lowering and lifting to keep voltage more constant for the motor?

It could be worth checking dr bass or others who know way more. Having said all that, so far my 48v norm circuit breakers are working fine....

[oregonrider89]

Here is a pic of the 2010 battery with the panel removed showing the MBB and the contactor with the  scorched wire.

[scZero]

My guess is that the resistance was so great on your contactor due to the pitting that it began melting your connector.  Mine only had 1600 miles, so yours would have to be over 6 times as worse.  Looks like Zero identified that your contactor was suspect, but curious why they didn't replace that first especially since it showed signs of failure due to heat that shouldn't be there.

I may call Alltrax and run the question I have of why there's a 48V contactor in the Zero and if the 72V contactor would drop its relay connection due to being over-rated.  Still looking around online and asking questions on this one to understand it better.   

Any idea where the serial connection / which wires are the serial lines on the MBB?   

Thanks for the pic / pdf.

[scZero]

I asked a question on the Tesla Forum regards to the contator and the what the rated voltage is and got this good explanation:

"You sound like you're confusing coil rating and contactor interrupter rating.

The coil voltage is the voltage passed through the electromagnetic coil, which has a dc resistance. Passing current through the coil will engage the contactor. Depending on the contactor application, 12V to 24V is pretty typical. The main reason is that most vehicles have a 12V or 24V bus - like Model S - so it's convenient to use that vs generating a specific voltage. A 48V coil is odd. Most coils however are perfectly capable of operating over 25~50% of rated voltage, as they can dissipate the extra power safely. For example most 12V relays will have an absolute do-not-exceed voltage of around 15 to 20V.

Going by the fact that they appear to be using a 48V coil, the Zero bike might not use a conventional 12V system and instead run everything (lights, computers, fans, etc.) off the unregulated DC bus, which is rather odd...

The other rating is the interrupting voltage. This is the highest voltage the contactor can safely interrupt and still meet lifespan expectations. The interrupting voltage should be higher than the pack voltage.

You also have to account for interrupting power, the maximum power the contactor can interrupt. (Power = Voltage x Current.) There are usually "several-time" ratings (for example, inverter failure, software must abort, high current flowing) as well as a typical rating; the average battery bus contactor will interrupt current when it is close to zero, because the inverter will have been shut down by then and the only current flowing is leakage/parasitics/quiescent draw from standby stuff.

Pitting on the contacts suggests the 2nd is not happening reliably so you are wearing out the contactor quickly."

So I looked at the contactor spec on the side of the one I pulled out of the Zero more closely, the contactor does say:

Coil: 48V DC
Contact: 48V DC 200A

So this implies that the coil which activates the contactor is indeed 48V which I would have thought as well to have been 12V.
Also the contactor interrupting voltage does appear to be 48V which is under the battery/pack voltage of 58V.

[scZero]

This may be the contactor that may suit our needs, but I think I'm going to give Curt a call at EVdrives before I make an order and get the full spec of this product to ensure its the right one.

http://www.evdrives.com/product_p/sol-sw200s.htm

Rated Current - 400 Amps
Voltage Coil Options – 12V, 24V, 36V, 48V, 64V, 72V & 96V
Rated Voltage of Contact Circuit - 6 to 80 Volts DC

So this appears to support the 48V coil which triggers the contactor and has a rating from 6 to 80 volts where the Zero's pack voltage sits at 58 volts.

[nigezero]

That looks perfect,  and you would make a great contribution by being a gunea pig

[scZero]

Yes, I hope it works and glad to be the guinea pig...  Another plus is that the SW200 is made in England, NOT China.

I also forgot, I believe I have to pick up a new Coil Suppression Diode since I'm bumping up my rated amps from 200 to 400.  The 200Amp stocker had a 1Amp diode where I need to move up to a 3Amp diode for the 400Amp contactor.  Also I'm going to install a pre-charge resistor, that is suppose to take and lessen the wear and initial load of the contactor when its 1st turned on.  The Zero didn't have that, curious why they skipped it.  I'm guessing extra cost.  Also that may be the reason why that under-rated contactor ended up in there too.

http://www.alltraxinc.com/Products_Sys_Components

[scZero]

So I went with the SOL-400 Contactor since it was already ordered and delivered.  I don't think I could go any bigger and have it fit inside the battery case like the stock one.  I had to file the mounting holes of the contactor to make it fit and it just fit.  Closing the rear battery door has turned into a problem, a lead coming off the charger fuse hits the hot battery wire of the contactor.   Also one of the fuses has the same issue, coming closer to the metal surface of the contactor.  So I'm looking for more compact solutions in that area.  I cut a few zip-ties and had to re-route some wiring to make the door shut.  One thing to keep in mind when doing this.  *** Look for anywhere there could be a short ***  This means like the fuse / charger issue where an open hot lead will ground and short / spark.  Also look for any place where wires can rub over time and wear down to the bare wire causing a short.  If you see this re-route them and / or put a protective cover around it.  I put the lower allen bolts in the rear battery door and tilting it up, looking down from the top part and bottom part of the battery where you can see the wires / obstructions / and issues where the concerns may be.  I have to say take your time here!!!  Don't be in a rush at this part, its very important and also you don't want a fire, to get shocked or have it fail due to cutting corners or overlooking something that needs attention.

I picked up my parts to make a pre-charge resistor and put that on as well.  I may have found the reason why Zero didn't put one in there.  It will give the Zero a Vampire Drain which is 0.1 Amps with the key off.  Reason being is that there's no battery switch which would kill this current draw when the bike is sitting.  I calculated if my math is right that a 4.4kw pack fully topped off and unplug will last 15 days unplugged before it goes to 0% SOC. Which to me is rather fast.  Now I'm going to have to think the trade off now, if I want to protect my contactor / controller or not have it and eliminate the battery draining to nothing which may kill the battery where it can't be recovered.

I did find a serial com port to the little Zero computer box (mbb) inside the pack.  I'm going to run 4 wires from this serial line so I may access it and see if I'm able to modify some parameters to get more performance like on the 2011 DS which has been documented on this forum.

Hopefully I make some progress this weekend buttoning up things.

[scZero]

I'm throwing out all the fuses and putting circuit breakers that Nigel gave inside to the mod.  My fuse and fuse holders are fine but I'm running into issues of space where the fuse and contactor are meeting when closing the battery door.  Nigel put his breakers on the outside, I found a place along the top after cutting zip ties and re-routing some wires.  That way they stay away from water exposure which I didn't find my breakers to be isolated from.  I'm also trying to find a way to break the pre-charge resistor and have it enabled only on key-on from the ignition.  Have to see how much time I need to charge up the controller's caps but I think I have time since the bike does not activate until a few seconds after the green LED comes on the instrument panel.  Also going to have a hard wire lead connected directly to the pack so I can monitor its voltage and also use the pack as a power source in case of an emergency.  I really want to put this thing together but patience is key, do it right the first time, take the time to design it right and you'll have higher reliability and be happier with the results

[scZero]

Had time to put the bike together with the heavier duty contractor.  I also put a pre-charge resistor in, and had that turn on when the 12v circuits get fired up / turn on.  Otherwise there would be a vampire drain running across the pre-charge resistor.    Happy to say so far the glitch is gone.  Bike is very responsive, more than it was before.  I found the serial cable leads to tie into the MBB inside the battery pack, I soldered a longer wire so it can be accessed outside the bike via a laptop.  Will try to do some mods to the MBB code when I have a spare moment.  I put the battery back in the bike by myself, just laid the bike on the side and carefully slid it in.  If you do this you need to put some sort of padding on the inside of the frame or else it'll scratch when sliding the pack in.  I also removed the front fender which made the install way easier.  Will check back in after a few weeks of hard riding.  I have a pretty good feeling that the wicked glitch from the west is no-more!  I also removed the stock fuses and put in push-button breakers.  Good upgrade, but also I had too.  The larger contactor is of course bigger and the rear door didn't close with the stock breakers.  I installed the breakers on the rear panel and rerouted the wires.


Sorry about the pics, doesn't make sense making a 600kb restriction across your entire upload.  You loose the power of what the forum is to preserve, detail, now all my pics are grainy.  Anyways if anyone needs high res pics feel free to PM me.

[scZero]

More pics.

[scZero]

Feels like the bike has more power and a very consistent torque curve now.  Throttle is not touchy like it use to be and the throbbing pulses at 21-26mph are barely felt.  I use to have a huge bog on full throttle from 0-32mph then the torque curve significantly raised.  Off the line it rolls like usual but kicks in more after 5-10mph, increasingly pulling intensely into 60 mph and still pulling.  I haven't tested top speed yet.  I let a gas motorcycle rider take it for a spin today.  It was his 1st electric experience where he's still talking about how quick, fast and intense the electric bike is hours after the ride.  I think if he rode it like it was before he would have said something about its initial lag it give but it made him happy.   

I think there's less resistance going across the better equipped contractor points, so more electric juice pouring to the controller and then motor.  I also think that's why the reason for throttle responsiveness improving so drastically better.