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[Keith]

Here's a detailed explanation of how to get backup power from a Zero motorcycle. I've shown most of these pieces in other posts but here's everything you need to know in one place. There's a video that I posted on the Facebook Zero Motorcycles Owners Group that shows it all working, you can see it and download it here https://drive.google.com/file/d/1N4gv07_ggUlECXyOvBImH_AHT9HtKKzL/view?usp=sharing. Actually it shows several different things, I'll describe each one separately .

But first some reality checks. Electricity is dangerous. Don't mess with it if you don't know the basics and understand the risks. I know a lot and I still got some surprises in learning about this specialized application. Next, be aware of the limitations. There are only so many kW hours in the Zero batteries, it won't run your whole house for very long. And of course you can damage your batteries by discharging them too far. Maybe the BMS will prevent that, maybe not. And if you drain all the charge from your bike, you can't use it to go get gas for your generator to recharge it. I'm not going to cover charging here except to mention that of course solar or a generator can be used if the grid is down. But you can get power silently at night from your Zero, here's how.

First and foremost you need an inverter. Well actually you don't if you can use DC power. Regular light bulbs, heaters without fans, universal motors and many chargers will run on DC. The tricky part is that switching and protecting DC circuits is more difficult than AC because it will arc, a lot, watch this . So special breakers, switches and relays are needed for DC. With solar installations becoming common these parts are readily available, but they are not the same as those used for AC.

I bought this inverter https://www.ebay.com/itm/2500W-Off-Grid-Pure-Sine-Wave-Power-Inverter-Solar-inverter-CE-EMC-Certified-/232508158041
Credit to Doctorbass for finding it, the 90-120 volt DC input voltage range needed for Zero power is not common. Mine came direct from China. There was a 15% upcharge for the high voltage version but it was still under $300. But you need to specify the voltage and outlet type to get the right one. This thread has the discussion that inspired me to try it, which I did http://electricmotorcycleforum.com/boards/index.php?topic=7415.0. The Reliable Electric inverter works well, is inexpensive, was delivered quickly and does what they say it will.

The next hurdle is connecting to the bike or power packs. I'm doing both but I had to get to know the Anderson connectors first. These are used in the pack adapter and Y cable you can buy from Zero, but you will need to make your own connections to the bike and inverter. http://www.zeromotorcycles.com/shop/index.php?main_page=product_info&cPath=15_5&products_id=186&zenid=ebfqhfimtda5domiq436amllc0  http://www.zeromotorcycles.com/shop/index.php?main_page=product_info&cPath=15_5&products_id=196&zenid=ebfqhfimtda5domiq436amllc0 

The external charge port on the bike and the Y cable use the Anderson SBS 75X connector. The housing is https://www.mouser.com/search/ProductDetail.aspx?r=879-SBS75XBRN I used these pins for the main contacts https://www.mouser.com/search/ProductDetail.aspx?r=879-1339G3-BK These are for 10-12 gauge wire, heavy enough for short distance runs of the level of current my 2500W inverter can use. A larger inverter might need the 8ga or even 6ga pins. You might also need the smaller pins that are used in the Y cable for the enable signal. More about that later but essentially you will need to connect these if you want to get power from packs off the bike as the video shows. The males pin will send an enable to the pack https://www.mouser.com/search/ProductDetail.aspx?r=879-PM16P1620S30 I also use the female pins to receive the enable from external chargers https://www.mouser.com/search/ProductDetail.aspx?r=879-PM16S1620S32

The Anderson pins need to be crimped or soldered. They can be inserted without special tools. Removing the large pins can be done with a small screw driver, google it. But removing the enable pins is difficult and requires a special tool https://www.mouser.com/search/ProductDetail.aspx?r=879-PM1003G1 I crimp the large pins with a bench vise, crude but effective.

Once you are connected you might want to know how much power you are using and how much is left in the battery. EDIT I DO NOT RECOMMEND THIS METER!! NOT RELIABLE AT 116V details in post below. I like the DROK DC meter shown in the video. It is inexpensive, accurate and flexible. I made a neat package with the meter, connectors, a switch and battery that does everything I want without a messy tangle of wires. Pictures and schematic are attached. It measures everything, volts, amps, watts, watthours, time etc., in either direction, charge or discharge. There are two versions, a 30amp and a 100 amp current shunt. I bought both but ended up using the 100amp without the relay available here https://www.amazon.com/DROK-Multimeter-Charge-Discharge-Electricity-Overvoltage/dp/B01M5CWR2P/ref=sr_1_3?ie=UTF8&qid=1512684063&sr=8-3&keywords=drok+dc+multimeter The meter isn't essential but it is very convenient.

With inverter and connectors you can do what I show in the video. First, I connect the inverter to the bike external charge port directly. Turning the key on closes the contactor. Note that there must not be a load connected when the key is turned on. The bike will precharge before closing and that will fail if there is a load, so the inverter should be unloaded or off first. After the click, the inverter can be turned on and then loaded, by a heater in the video. The inverter recommends turning the load off before switching off the inverter, probably to prevent arcing. That is also good advice for the bike contactor, that is turn off the load, then the inverter and then the bike so that there is no current when the contactor opens.

At about 50 seconds the video shows the DC meter connected between the bike and the inverter with the heater load. The meter's current shunt can be connected in either direction and that affects the polarity. I have it so that discharge shows as negative current although DROK calls that CHG in red. At 1:05 the video shows the meter while charging with two DeltaQ's and a Y cable. That shows a positive current of 17 amps, 2kW, and DIS in green. I may decide to reverse the polarity to make better use of the battery capacity readings. It is all explained in this pdf https://images-na.ssl-images-amazon.com/images/I/C1KogaBOhLS.pdf

While connecting to the bike is the simplest way, it has drawbacks. Leaving the key on is the only way I know to close the contactor. If there is no rider input, the bike will open the contactor after one hour. So you burn headlights and have to keep it going by doing something at least every hour. This is an unsolved problem, unless you have the modular packs.

Next, the video shows how to use the packs off the bike with an inverter. You need an enable signal to get the pack to close the contactor. I discovered how to do that in this thread http://electricmotorcycleforum.com/boards/index.php?topic=7116.msg59032#msg59032 With a pack adapter the connection is simple as shown in the meter schematic. It is just a battery connected to a male pin on the SBS 75X in either the P1 or P2 position. This simulates the enable signal from an external charger. It is best done using a 10k resistor so that current is limited. I've seen the Trikester version on Burton's wiring diagram that uses a 100k resistor to the 100v to do this but I haven't tried that. The voltage is not critical, I've used two or three AAA batteries to get 3-4.5 volts and am now using a 3.7v lithium coin battery in the meter package that I built. I have a switch so that the enable signal can pass through from a charger or come from the 10k resistor battery circuit as needed for discharging.

There are some quirks with the enable logic with packs off the bike. Same as when connecting to the bike, it is best to have no load current when closing or opening the contactor. However, if the pack is not fully charged it expects current flow soon after closing the contactor. If no load is turned on, the contactor will open after a short time. So in the video, I switch on the battery enable signal and then turn on the inverter and heater, that keeps the contactor closed. A fully charged pack will stay closed with no load and removing the load is OK once the contactor has decided to stay closed.

That ends the video and concludes my explanation of how to get power from your Zero. You have to give that power back of course, and then you have a Tesla wall, energy storage for later use. There are many ways to do this but I chose a simple and relatively inexpensive approach. I hope this information is useful, but of course I make no guarantees, it might not work for you, and lots of things can go very wrong!

[Keith]

A few more pictures of the meter package. It made me very happy to figure out how to do this in a neat unit rather than a kludge of dangling wires. It's a very handy way to see what's happening. And it can be wireless so the meter can remote from the power and inverter.

[Keith]

  I'm not so happy with the DROK meter now, just blew up another one. It sometimes doesn't like sudden applied voltage, like pack contactor closing with no load connected or plugging by itself into aux port while contactor is closed. Bang, spark, smoke, dead. Not sure what I'll do about it...

WARNING DON'T BUY THE DROK METER - EE explanation follows (I'm buying one more, see later posts)

Also sold by Vanjing, this meter has great features and is really cheap but it blows up at the Zero battery full SOC voltage and I know why. There is a work around if you really want the features, but the price is more than doubled.  It can be used if you choose the 3W jumper setting and use an external power supply, either a 10-30V wall wart or a DC-DC converter like this one http://www.mouser.com/ds/2/75/SPEC-ECLB40W-110-V11-1114358.pdf User manual here explains hookup with external supply ("three wire") but doesn't say why you should use it https://images-na.ssl-images-amazon.com/images/I/C1KogaBOhLS.pdf

The meter has a linear voltage regulator to reduce the 120V down to 10-30V for the 5V convertor it uses, but that is the weak link. I've had two of these self destruct, in the same way, with fully charged pack voltage suddenly applied. I'm pretty sure the MJE340 transistor goes into second breakdown if the applied voltage is high and the filter capacitor is fully discharged. It might survive that a few times but then it won't and many components go up in smoke. If the meter is connected to the bike with key off, the precharge brings it up slowly and that should be fine. But closing the contactor off bike or connecting to the bike with the contactor already closed: BANG, dead meter. So don't use it, or use it only with an external supply. Too bad, it really is a nice meter...

[Keith]

While connecting to the bike is the simplest way, it has drawbacks. Leaving the key on is the only way I know to close the contactor. If there is no rider input, the bike will open the contactor after one hour. So you burn headlights and have to keep it going by doing something at least every hour. This is an unsolved problem, unless you have the modular packs.

Looking at the problem of closing the contactor with packs on the bike (keeping it closed while stealing power) I have a new finding. The enable line used by the pack adapter to connect the external charger is pin three of the pack. That pin is NOT CONNECTED on the bike. So there is a special pin on the pack just for the no CAN bus charging enable signal that I hacked. Wonder if that pin exists on the non modular bikes. Also wonder if you connect a 10k 5V pull up to it with the packs in the bike would that work?

[Keith]

I am buying another DC power meter, this time I won't blow it up!  https://www.amazon.com/review/ROJAZVXMUEDBC/ref=pe_1098610_137716200_cm_rv_eml_rv0_rv I'm going to use a nice little DC-DC converter with it so it runs cool and stays happy. There aren't many converters for the Zero voltage range but this one is perfect. https://www.mouser.com/search/ProductDetail.aspx?r=418-EC6AW-110S12 Stay tuned, I'm going to use this meter as a charge controller, you can set the stop voltage and control the external charger with a very simple setup.

[Keith]

IMPORTANT ADVICE - MUST READ IF YOU ARE GOING TO DO THIS
I've learned that the nice inverter I have includes a VERY LARGE input capacitor, about 2.5 millifarads. That stores a lot of energy (17 joules) and it means you will probably damage your contactor if you don't take a few extra steps. The inrush current if you close the contactor with a large capacitor load is limited only by the wire and ESR (probably many hundreds of amps), it will burn the contacts that create the circuit when they close. This damage can be prevented with a simple precharge circuit and some care in sequence. I'm using a 4.7k 5W resistor. That part can handle the full pack voltage indefinitely. It gets only slightly warm when used in series with the inverter input to charge the capacitor. About one minute after closing the contactor, the inverter will be almost fully charged through the resistor (time constant is 12 seconds) and you can then short the precharge resistor with a switch. I'm using a 20A light switch for that. The inverter can then deliver power to the AC load. Your contactor will thank you!

It's also recommended NOT to use the inverter power switch or the contactor to turn OFF the power. Instead, turn off the AC load, then turn off the inverter, then open the contactor. Turning off high DC current causes arcing as I mentioned in the first post. Using the right sequence to power down avoids that. So precharge, then close contactor and then connect load to power up. Disconnect AC first to power down. I'll make a circuit drawing and maybe a fun video with some sparks later.

[MrDude_1]

Sounds like you enjoy playing with the same fun stuff I do.
What I would add to this is a simple MOSFET controlled switch so that the inverter (or other load) can precharge safely then turn on automatically.
something like this:
https://endless-sphere.com/forums/viewtopic.php?f=3&t=40142&start=100

The more foolproof you can make it, the better... because even the best of us make mistakes in connection order.

[Keith]

Mistakes? Not me, I only uncover design weaknesses that are mistakes made by others!  And those mistakes blow up meters, make big sparks, pop fuses and do worse things that I won't mention.  That precharge circuit is interesting, I'll look into doing something similar with my setup, foolproof is best. Zero has done pretty well with achieving that but I've found some ways to get around their efforts. Deliberately of course. 

[MrDude_1]

Mistakes? Not me, I only uncover design weaknesses that are mistakes made by others!  And those mistakes blow up meters, make big sparks, pop fuses and do worse things that I won't mention.  That precharge circuit is interesting, I'll look into doing something similar with my setup, foolproof is best. Zero has done pretty well with achieving that but I've found some ways to get around their efforts. Deliberately of course. 

If you (or someone here) has a pinout of that module, it would be cool to see if it already had a precharge output you could use.... then just connect that via mosfet/resistor, wait until the voltage equalizes, then turn the contactor on. Even that is not foolproof is a load is placed on it while precharging.

[Keith]

That's a really interesting idea, it pretty much has to be that the bike precharge is done by circuitry in the modular pack. I've found that the Sevcon in my FX has about the same capacitance as my inverter. I measure 3mF across the aux connector so the amount of precharge needed by the bike is almost the same. Whether the MBB is or needs to be involved is the question. My wiring diagram has many clues, for example the brown and brown/white wires labeled system on in and out are likely involved but who knows who's in charge of those signals? The MBB watches the key switch so it wakes up the system, but the pack may only need a simple command to do the work. Not likely that CAN bus gets involved with basic startup. BMS logs clearly show the management of precharge and contactor operation. I was about to order parts to build my version of fechter's nice circuit, now I may need to reconsider...

https://zeromanual.com/index.php/Unofficial_Service_Manual#X-Platform_Schematic

[Keith]

I tried but could not hack the System On logic of the pack. Logic high on 'System On In' does pass through to 'System On Out' but the serial BMS reports system off even if the contactor is closed. Might be a handshake with the MBB, the bike on state of 'System On In' is low while 'System On Out' is high. CAN bus? Or just a handshake, maybe I'll borrow a scope. A simple jumper for the loop back leaves the second pack pins accessible to probes.

I'm working on a really nice precharge circuit, details soon, if/when it is working. Meanwhile i have a resistor and a light switch. I have one real world example of what I might use the inverter for if the power goes out. I have a wood pellet stove that makes great heat for cheap but it has a blower so it needs a little power. I could run it for days with my packs. It would be crazy to run a 5kW gas generator just for that.

I have a really nice new package for my DC meter now, much cleaner than the previous version. I'm waiting for a DC converter that is back ordered to finish it but it is working with wall wart power now. I'll post more pictures and applications for the meter when it is finished but it's really cool now that I know how NOT to blow it up. I'm going to use it to control my chargers as well as for discharge control.

[Keith]

I put my inrush control design on endless-sphere if anyone is curious and technical. I'll post it here after it is built and tested but it looks very promising. I really hope people are paying attention, inrush current will damage your contactor, it takes more than an enable signal to do this right.

https://endless-sphere.com/forums/viewtopic.php?f=3&t=40142&p=1350217#p1350217

[Shadow]

"it takes more than an enable signal to do this right."

Does this help at all for better safety to connect and disconnect another Zero bike's onboard charger input to the DC system voltage of a "power donor" bike?

[Keith]

I don't think so. Any connection or disconnection should be done with power off and contactors open. If a charger is designed to work from DC input there shouldn't be any inrush, the charger should control that when power comes on during the bike precharge.

[valnar]

I was just looking at buying a portable generator for home emergencies.  That took me to Generac, which then took me to inverter generators, the Goalzero Yeti's and back to here.

If using your Zero motorcycle as an emergency power source was easily possible, that would be a killer feature.  The highest Yeti is only 1.2kWh.
 Most of us keep our Zeros at 60%+ charge anyway.  Even if you didn't want to do the build from Keith, could you utilize the electronics from an existing Yeti for extra power in some way?  I love the possibilities.