XB-600 "Shunt Mod" instructions

Well, add another one to the club. I got my extra controller in and couldn't resist doing the mod and popping it in my wife's scooter to try it out.

Many thanks to hyperob's excellent tutorial, here are the pertinent details:

The mod went absolutely as advertised, hyperob's instructions were right on. The only points I would make are:

Use a decent-size soldering iron, 30 watts or more. You DON'T want cold solder joints in your EV controller.

Now's the time to go buy that drill press you've been wanting. I'd be very reluctant to try this with a hand drill!

The clearance on the bottom of the board is very small. Don't make your soldering any bulkier than necessary and CHECK to make sure it doesn't touch the case when you put it back in.

The above point about discharging the caps is a good one. Capacitors this size can kill you. And make sure and remove the battery cable; better safe than sorry.

On to the pictures!

Yeah, these are quite obviously used parts:

Here's my shunt mod, the smallest coat hanger wire I could find, solder on the bottom only:

Oh, the results? I rode it only a block so as not to drain the batteries while I have no charger, but there's a quite dramatic difference in pickup. I can't wait to give it a full test.

And while I'm posting pics, here are a couple of the inside of my toasted power supply:

[CROCODILE_DUNDEE]Now THAT'S a capacitor![/CROCODILE_DUNDEE]

They've "placed the order" for the new charger but I haven't received a ship notice yet. Anyone have an opinion on how bad it is to leave this battery half-charged for a week? I'm wondering if I should dig into it and charge each battery individually with another charger.

Congrats, I think you will like the better pulling power.

Do you know what fried in your charger?

Congrats, I think you will like the better pulling power.

Do you know what fried in your charger?

Yes, I think it was this power transistor (I think that's what it is):

Anyone have a source for these or a matching component? I might try to repair it.

While I'm at it, one more note about the shunt mod. Spend the three bucks at Radio Shack and give yours a nice paper thin layer of heat sink grease on the back of the mosfets before you put it back together.

Well, this was so unexpected I had to post about it - I got the replacement power supply TODAY, delivered Priority Mail! I think X-Treme gets a lot of deserved flack but credit where credit is due - they expedited my power supply and my batteries will be fine. I did gently suggest in the original report that too much time taken over this request would damage the batteries, maybe that helped.

In any case score one for them.

I've been fairly surprised with them recently. They got me replacement parts for my kickstand and and turn signals very quickly. Although, they did send me two right hand turn signals when I needed 1 left and 1 right. However, the replacement is en route. I think a lot of X-treme's problems with service were from a year or so ago. Though, I'd still keep a wary eye on them.

hopefully they change the sticker on the charger . Mine came with ... " Suitable for ...12Ah batteries .Could not get intended specs or anything else from them.

OK, one last report on my shunt mod... I have a little over a 3 mile commute to work (one way). I have been taking the XB in the mornings, coming home for lunch, and taking my Vego back in the afternoons, just because the XB's struggling up those final hills worried me that it wouldn't make the trip twice.

After the shunt mod, what a difference. I can EASILY make the entire round trip twice a day, with power to spare! Of course it had the range all that time, but the pokiness up the final hills made me unwilling to try it. With the shunt mod, I get a steady 20 mph up the steepest hills on my commute. The side benefit of the added acceleration is no small thing either; really makes you feel a lot more confident at intersections.

I made the entire round trip twice in a row yesterday, and immediately after I got back home, the hub motor wasn't any warmer than it ever is.

So in short, if anyone was on the fence about this mod, I highly recommend it. It totally removes that slight "disappointment factor" I had when twisting the grip!

MopedBrainy,

My charger, which works fine for me, is rated at 130 VA (Volt * Amps), that is about a 2.5 Amp charger. If your new charger is rated similarly, then it should work, regardless of the fact that it says it is for 12 Amp batteries. However, if it is rated at, for example 60 VA then that would be 1.25 Amps, and would take roughly twice as long to charge the 20 Amp batteries in your XB-600.

If it really is designed for 12 Amp batteries, then you might want to consider returning the charger for the right one.

Just my thoughts,

Tom

sbmguy, I don't suppose you took any pictures of your XB500 controller while you had it open, did you? I would be interested, as I just bought a new controller for my XB500, which I intend to do the shunt mod on.
My idea, for all those who are interested, is to remove one of the two shunts, and replace it with a different shunt of lower resistance. I thought I would pull one of them out, take it to a metrology lab (I have a friend who works at one), and measure the resistance. Then I could figure out how long a piece of coat hanger wire I would need to increase the current limit by 25 - 30%.
When I do my mod, I'm going to first measure the peak current going to the motor before the mod going up a steep hill. Then after the mod, I'll measure it again, and if it's more than 30% more, i'll file off some of the metal from my shunt until the current is limited to what I feel is safe. My XB500 comes with a 25 amp fuse, so i'm sure I don't want to exceed that, but we'll see what happens.

I'm quite interested to see what you get. I measured the resistance across the shunt when I modded mine a bit back and I believe it was .7-.8 ohms. My meter could only resolve to 100 milliohms and I'm not too sure what the error % is. After the mod it was at .6-.7 ohms. I also went very conservative on my mod (very few hills) in that I used a small paper clip (small diameter) but made it the normal length. I also had issues with my 35W iron heating the clip so I think the solder joint was a bit cold which certainly doesn't help the resistance any. The result is that I've kind of got a shunt mod, but with less worry. Acceleration and hill climbing are better, but not superb, but I also seem to get well over 20 miles per charge.

So, all this sort of beg the question... is there something more, um, 'precise' than a paperclip that we all could use to optimize how this is put together?

Very expensive shunt wire? Or you can try to measure the resistance of a piece of coat hanger/paper clip and adjust the length accordingly to get the desired resistance.

Well I just got finished using a paper clip to do the shunt mod to my Luyuan E-Bike and it worked perfectly. I now have a lot of torque. Before my E-Bike would slowly get up to speed from a dead stop. Now it is faster from a dead stop then most cars. I am now very happy. I am fine with the 35KMH top speed. But the slow take of performance was very disappointing. Now that that has been solved I am very happy now. Even though my E-Bike is not a XB-600 the description of the shunt mod was exactly the same except where the shunt was located inside my Luyuan 48V 25A Speed Controller.

Thanks,
Ken Finch

Question, how much will this affect my range? If I keep a eye on the built in Ammeter and keep the current draw lower (say 10A or so) will my range still be good. I wanted the extra torque for only those times at rush hour in the morning and in the evening to and from work on Victoria Park and Sheppard Road area in Toronto, Ontario, Canada. All othe times I will use the throttle to keep the current lower. Or is there a way to add a switch to enable/disable the shunt mod?

Ken Finch

On an XB-600, it will effect range only to the degree you use full throttle up hills. In other words, if you have to use full throttle up hills, it will probably double the current that the motor draws. If you are not going up a hill, and are for example driving on the flat, then the shunt mod has no effect on battery life, because it doesn't make the scooter go any faster. The top speed is identical on a flat road. Of course if you are really heavy, (I'm about 230, so heavier than me) then the range may drop some because the motor can't achieve full speed.

So basically, yes there will be an effect, but it depends on how you drive it,

Tom

OK my E-Bike has a Ammeter on it that shows the Amps drawn when driving and Amps added when the Regenerative Braking is working. So the Ammeter has a green area, yellow and red area on it for the Amps drawn. If I keep it in the green area then my range will not be affected that much. I do noticed when I accelerate heavily the Battery level meter goes down for a few seconds then when the speed levels off the battery level meter builds back up to full power again.

Ken Finch

hyperob,

Yah, it is probably unrealistic to think anyone could have extra torque available and not use it. So your estimate of 30% decrease in range is as good as any,

Tom
P.S. I received the 60 volt charger, and the extra batter today. Post at the link (probably on the second page).

http://visforvoltage.org/forum/3534-30-mph-xtreme-xb-600-60v-modification-instructions

Ok thanks all for the info, I am happy with the mod and it is a keeper. The range reducing effect is fine, as I charge my E-Bike whenever possible.

Ken Finch

OK, I received my extra XB-500 controller. It's quite different from the XB-600. There are only 6 MosFets, and the Shunt is a single loop at one end of the board. I was going to try to pull the shunt out of the board and measure it's resistance, but even with a 100 Watt soldering gun, I was unable to suck enough of the solder away to loosen the shunt wire, so rather than take a chance on damaging the board, I left it in place.
For my modification, I used a 3 inch length of a coat hanger, which I measured as being 0.076" diameter. Considering that About 1/4 inch of each end was in contact with the circuit board, that means that about 2.5 inches of steel wire constitutes my shunt. The wire thickness corresponds to about 12.5 gage wire, which has a resistance of 10.61 ohms/1000 feet, or 0.000884 ohms/inch. My shunt is therefore about 0.0022 ohms. Once I had the modded controller installed, I tried my bike on a hill which I haven't been able to climb in the past, I would stall, and have to walk the bike up the steepest part (about 40 feet). With the mod installed, I climbed the hill and my speed dropped to 8 mph. Soon, I'll be posting a thread on my mod with pictures, for all who are interested in making their XB-500 a usable bike.

In a previous post, someone noted that they thought their shunt measured about 0.7 ohms. Mine, with only a single loop, measured the same as shorting the two leads of my meter together... about 0.1 ohm. This is probably just measuring the resistance of my leads and their connection to the shunt.

Win32forth, Thank you on the advice. X-treme avoided to release to me the intended rate output and alleged the replacement charger was the appropriate for the xb-600 and that was the only one they had.In any case ,after some thinker the stock charger is back in use and since among my usable batteries there are 8 12v 12Ah -it was a blessing in disguise .

hi i just tried it on a veloteq commuter.do not know how to up pics but I did not feel comfortable drilling board so i just dropped a bead on soder on each shunt (there are 2).Tried it out seems faster on takeoff will try it on hill later today.

well tried it really not much difference but... my drain on my batteries seems more than before.strange.Maybe I' try to find a small enough drill bit but my shunt are really close together not much room to work.

Janeffto,

I don't know anything about your Veloteq, but here is how I modified the shunt on my XB-600.
Before:

After:

Notice that the shunts are very close together, and I just added a heavy wire across the existing shunts.

Warning, This method of modification could cause your controller to apply too much current to the motor, and may blow the fuse, or even destroy the controller, so you are on your own if anything goes wrong. I chose to buy a second controller to modify (cost $65), just in case I destroyed the controller.

Tom

I've been riding at 60 volts with the shunt mod for a couple of weeks with no problem at all, and then yesterday popped the 30 amp fuse. Perhaps a slightly larger fuse is called for with the shunt mod? Any opinions?

Luckily where I work there is a full electronics R&D lab! They got me up and running in no time.

I would say no, to a larger fuse. What were the conditions when the fuse blew? Full charge? Going uphill? Full throttle? Was it the original fuse? (mine blew before any mods once). I'm at 60v and with shunt mod for about three weeks and no problem with the 30A fuse, knock on wood, fingers crossed, salt over shoulder and avoiding black cats.

My original fuse blades looked corroded and probably were the reason the current went high enough to blow it last December. That was going uphill, full throttle, lights on and full charge. Made it about 50 feet out of driveway. Didn't have a 30A fuse so put a 20A fuse in and rode for a week with no problems and then replaced it with a 30A. Now I carry spares.

I would take a wait and see approach, and carry a spare.

My two cents worth isn't what it used to be due to inflation. :(

Happy scooting,
JamesS

O.K. here is a picture of my controller and board


sorry about quality taken with my phone.
if any body else has info on this controller let me know.I rather put a shunt in so I can add an extra battery as with the wire maybe to much current is going through.
Any input is helpful and if you need more info on bike let me know.BY the way as you can see in picture controller is 750w and motor is 500w.
peace out.

Janeffto

I would be a bit concerned about adding another battery to your scooter. From the pics your controller doesn't seem to have a heat sink for the MosFets. Did you have to remove the 12 screws from them to get the case open? I can't imagine them not having a heat sink, but its not shown. Take the number off of one and google it. You should be able to find out the voltage rating and can go from there.

Happy scooting,
JamesS

well I found a smaller drilbit and added a coathanger in the middle if the 2 shunts.Did not blow up anything when I turned the bike on. Will test it futher later.I have six screws on he side of the case that I had to remove that had the heat sinks on it.Wish me luck!!!

I need a kind soul to do the XB-500 mod for me. Any takers?