Vectrix fuse and motor controller bolt sizes

Are you going with more voltage too? Or are you going with 125 volt nominal? On my new project I have a place for two each GOULD Shawmut Amp-trap Cat. No. A70P 150 Type 4 fuses one on Negative of pack and one on center of pack. I calculated power and wanted to limit power to 15,000 Watts So 150 Amp fuse would blow at 18,750 Watt, What is nice it is a DC rated fuse. It is the safest fuse I can find. How heavy is your projected Lithium pack? Highest terminal voltage on controller? New charger? VX-1 charger is constant 11 Amp charger timed for 3 hours max by CPU then 3 amp equalization charge. LiFePO4 emulates Pb-acid and NiMH is like Ni-Cads and NiFe cells, all take constant current charging. That is why I ask about 200 Amp fuse.
I just removed the bolts from controller and going to Hardware store to find out. Are you talking of dual ended bolts to hold controller? One is coarse thread and one is finer. I just looked and there is a stop thread. Both sides are metric.
Rusty

I'm collecting bits for my vectrix lithium conversion and I'm looking for some specific detailed info.

While I'm in there, I'd like to fit a 200A fuse. will this one fit?

http://www.evworks.com.au/index.php?product=FUS-FWH-200B

Also need to buy crimp lugs to connect the battery cable to the controller. What thread size are the controller terminals?

Cheers

that one won't fit.

i recommend bypassing the fuse inside the controller (the battery can be wired directly to the output of the fuse as I have done on mine) and placing the fuse somewhere reasonably accessable.

tbh, i have been running without a fuse for a while now, but i don't recommend running without a fuse entirely.

Matt

Wow
Do you have plans for "failure" if something does go awry? I hope it works but deciding on what can go wrong is hard to figure out. Lithium cells are capable of four point something and can go as low as 2.5 or three point something? A large swing . Maybe it be best to go up 20% on fuse first from 125 stock Amp to 150 first? Since going too low on Lithium is bad so have CPU on VX-1 kick out on low voltage on scooter and charge up to 150 max of the bike? Just a thought. Do you know what the input MAX on controller is? I don't want to blow up 2007 VX-1 but don't mind trying to blow my rear wheel motor on my NEW wrecked VX-1 on an old controller actually a VFD really. I read Mik's articles on VisforVoltage and VX-1 motor can develop 20,000 watts peak so that is a lot of Amperes. I sure admire all the work every one on this site does and all the failures and dealing with learning curves. I have a spare charger but NO spare controllers so I don't know working voltage on caps and IGBTs or MOSFETs or what ever does the controlling. I would hazard to guess 200 WVDC is on controller since bike is capable of Regen. The only thing I hate is over voltage circuits using a crowbar circuit. It blows fuses and your Bussman fuse and my Gould fuse is one expensive puppy. What is reason for higher voltage? It will give faster acceleration and yes you will need a bigger fuse for it may just need more current.
Rusty

"What is reason for higher voltage? "

not really phased about the slightly higher voltage. the controller is current limiting, and I don't ride full throttle everywhere.

Plus, hibba has already run this configuration :)

I don't expect to see pack voltages above 153 or below 108V. People have seen 152 on stock packs, with the stock systems.

I've selected 42 lifepo4 cells because the combined ideal charge voltage almost perfectly matches the vectrix charger output voltage and the minimum discharge voltage almost perfectly matches the stock controllers cut out voltage. This makes the BMS cutoffs emergency limits only and I don't expect to see it fire under normal circumstances.

you make it sound so easy.

Sounds "Right" placing fuses in the middle of the pack.In the USA there is Underwriters Laboratory (U.L.) and for forklifts battery pack they call placing fuses on each pack and I did that on my truck too. I used 5 packs of Delphi eight volters making 144 volt pack and every group of batteries went into a Bussman ANN 500 fuse. When the fuses popped I went to Gould Semiconductor fuses of 600 Amps. It is a better fuse for DC circuits. BTW, I only popped two fuses with a 1200 amp controller of the ANN-500 type. So I am not a Pb foot. Not even on my 2007 VX-1. I made a ground fault meter for my truck based upon a Wheatstone bridge circuit and being that there is or "was" a set of 102 cells. It can be center tapped for my old circuit. So maybe a balanced bridge circuit might be nice for you to "Smoke test your new setup"? Call me or email me for more information on that invention if you like. I used it at first to see if any batteries were going south and some did till I got a balanced pack.
Rusty

Lithium cells are capable of four point something and can go as low as 2.5 or three point something? A large swing . Maybe it be best to go up 20% on fuse first from 125 stock Amp to 150 first? Since going too low on Lithium is bad so have CPU on VX-1 kick out on low voltage on scooter and charge up to 150 max of the bike? Just a thought. Do you know what the input MAX on controller is?

i don't know what the input max on the controller is, however, if you are using the stock charger to charge with, then it will always be below the controllers max voltage.

lithium cells only get to as high a voltage as you charge them to.
in practice, a LiFePO4 cell is fully charged once you get it above 3.4v (and current falls to 0.05C).

the controller has a low voltage limit of 108v, or for 44 cells = 2.46v average.

in practice the BMS can sound a buzzer when a cell goes below 2.5v.
just back off the accelerator to keep the buzzer off.
if we could reprogram the controller, you could use the good/bad signal from the cell modules as a feedback loop in place of pack level low voltage limit.

the controller has an input current limit of 275A.

the controllers IGBT's are 600v devices (not sure what the caps are - they will be the limiting factor)

there is no crowbar circuit in the vectrix.

the fuse sizing has more to do with the I^2T rating of the wiring. Thats what it is there to protect, nothing more.

If ever your fuse blows, either it was undersized for the job, or your controller is long dead (in this case long means a second or two ago).

the higher voltage does two things:
increases the speed at which max power point occurs (at present 108v = ~70kmh)
increases the power of max power point, if the controller is operating in battery current limit)

Matt

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i don't know what the input max on the controller is, however, if you are using the stock charger to charge with, then it will always be below the controllers max voltage.
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Matt

Don't forget there were several reports of Vectrix chargers NOT terminating charging as required. That could potentially cause some nasty fireworks!

I do not know if it is any worse with your prospective Li cells than with the stock NiMH cell, but at least the stock cells have a pressure valve to prevent explosions.

If you go with 42 cells, you are going to use Lithium charger? I thinks antiscab mentioned something about stock charger not getting up to enough voltage? They are two different technologies. One is constant current terminating voltage and the LiFePO4 is usually three stage constant voltage and current preset and going to a third step. With help of management system.
Unusual arrangement, 42 cells, so what charging technique are you go to use?
And another thing. How is scooter computer going to measure miles remaining? And "Charge time"? Maybe any other parameters?
Rusty

What will happen if / when the stock BMS decides to do an EQ charge with the Lithium pack you plan to install?

I imagine that it would fill the pack until the evworks bms detected a cell at 4.1V and turned off the power. I wonder if the charger would balk at excessive voltage or low current first?

I don't have an EQ program on my bike. I don't intend to either, unless the supplied current can be dropped to 600mA.

I think 1.5A is the lowest that the stock charger can provide, but I might be wrong.