Extreme XB-600
Andrew,
I rode the scooter for hours after doing this mod (taking turns riding my daughter and her friend) and the motor never got anything more than warm. That's not to say the controller won't fry later, but I don't care if it does. It's a crappy controller anyhow. If it does fry I'll get one of the crystalyte 72v 40a models and keep on scooting. Like I said though, we rode for hours at full throttle and didn't have any hint of a problem. Works like a charm.
Hey, that sounds like a great improvement. I'll be interested though to know the longterm effects. Now, I've read the "shunt" mod before...with the other scooters. But to keep me from running all over here to find and read those again. Can someone just basically explain exactly what that is doing to give more power. I'm not one of the more electically savy people on here so I need to know what a "shunt" is to begin with and what it does.
Thanks,
Gus
A shunt is a calibrated resistor. The voltage drop measured across a shunt can be used to determine the current flowing. The controller may measure current from an internal shunt to base its set limit on.
The voltage drop (V) in relation to current flow (I) and resistance (R) is given by: V=IR
So, we want to alter the controller current limit. How do we do it? Because it may not be so easy to adjust the controller logic, then we can alter the controller measurement of current flow or fool the controller. This can be done by recalibrating the shunt. The above equation tells how to do that. If we want to make the controller measure half of the real current, then we must half the voltage drop. If the resistance is halved, than the voltage drop will be half.
In simpler terms, decreasing the resistance of the shunt will make the controller think there is less current flowing, and increase the real current limit. The resistance can easily be lowered by adding wire to the shunt, using thicker wire, a shorter piece of wire, or even adding any conductive metal available (like zerogas did with a piece of a coat hanger).
If it has been determined that a current limit is not really needed to protect the motor or controller and not desirable, than just lower the resistance of the shunt by a lot using any means available. A precise adjustment would not be needed in this case.
However, if a precise adjustment is needed, then first measure the resistance of the shunt. Send a current flow measured by a digital multi meter or measured somehow accurately through the shunt, and measure the voltage across the shunt. Then cut pieces of wire to the length of the shunt and measure their resistance by using the same method. Use the equation for resistors in parallel to determine how much the added wire will change the resistance of the shunt. The equation is given here: Wikipedia - Resistor. Another method is to add wire to the shunt, then grind it down until the resistance of the shunt is at the desired level.
The change in current limit will be the reciprocal of the change in resistance. So if the resistance is 1/2 of what it was originally, then the current limit will be 2/1 or double. If the resistance is 1/3, then the current limit will be 3 times, ect.
Thanks Andrew for that very clear explanation. So as in the pic back on the EMax forum seems to show...Zerogas just soldered in the coat hanger wire from contact point to contact point where each "end" of the present "shunt" is soldered to the board...to create the same path with even less resistance by adding the coat hanger wire?
Gushar
Gushar,
That is exactly what I did. I cut a 1 and 1/2 inch piece of coathanger. drilled a hole 2mm in diameter in each contact point beside the existing shunts. and soldered it in. It's not exact, but I'm not worried about this controller. If it booms there are better ones available to purchase (crystalyte). I'm just trying to see what I can do on the cheap to make this scooter faster. Today I'll be adding a 5th battery to try and increase top speed. This will give me 60v. The FETs in the controller are only rated for 63v, so I don't want to try 72v just yet. They would fry for sure. If I'm careful with the throttle at 60v I think it should be ok. If not I'll have to order the crystalyte controller :D
Ok,
I'm stuck. i wired a 5th battery in the red wire coming from the battery pack, just before the fuse and when I turned on the scooter the voltage gauge showed in the red and the scooter would not run. I then tried wiring the battery between the fuse and controller, same thing. Does anyone know how to add another battery to the xb 600? I'd rather not have wires hanging out of the battery pack, but wiring under the seat to the hot wire isn't working. Should the 5th battery go to the controller's output wire? HELP!!!
I couldn't wait, I wired the 5th battery in series with the pack and it worked!! I now have a 28mph scooter!! HAHAHAHAHA!! 28mph on flats and 25mph on hills. Now my xb 600 owns at 60 volts. :D I'll now have to ride for an hour or so and monitor the motor and controller. So far with 30 minutes of test riding the motor is still only warm. Perhaps later in the summer I'll rewire the scooter and get a good controller do a 72v version, but for now, I'm happy with just shy of 30 mph performance from a $740 scooter, a piece of coat hanger, and a $30 12v/12ah battery :) Oh, yeah. To do this I took the top of the battery pack and cut the black wire coming from the negative of the last battery. I then extended both these wires up through the seat pan through (2) 1/4" holes. Then I put a snap connect on each wire( 1 male and one female so I can disconnect the 5th battery and plug them together when charging). Then I put the corresponding snap connects on 2 more wires and ran them to the 5th battery which sits under the seat perfectly. I have a 2 amp trickle charger to charge the 5th battery and I unplug the snap connects and plug the extending wires from the pack into each other to charge the pack with the 48v charger that came with the scooter. I hope this answers some questions about the abilities of these chinese brushless hub motors and controllers. It seems if there is any weak link in these scooters it will be the controller, because the motor still doesn't get hot. I can hold my hand on it with no problem. Now, go "juice" your scooters!!!!!!!!!!!
The following is a precaution that you probably should take to protect the XB-600 from damage. First, you should either let the batteries rest for a while or turn on the scooter at 48V and cut the headlights on high for several seconds then power down before installing the fifth battery. This will dissipate or remove some surface charge thereby reducing total system voltage (drops to usually between 65 and 66V afterwards.) This will help you avoid trouble like going above the high voltage cut-off of the controller (if it exists it may cause you some delay waiting for voltage to drop off some), overstressing the DC-DC converter (max rating probably 60V), or risk blowing capacitors in the controller (usually rated up to 63V.) Once you ride a little ways the voltage will drop and you will be in the "safe" range. I used a Vector/Black&Decker 12V 2/4/6A charger for the spare battery. There is 12V 2/1A version of the charger that is too slow with questionable reliability that I would not recommend using.
Well, all is well so far. I'm recharging now. I must say, the extra speed does zap the batteries faster. LOL. I still will have plenty of range for my 6 mile trek to work, so all is good here in 28 mph xb 600 land :) I'll link some videos on youtube when I get charged up and it stops raining.
Congratulations on the mod. Could you also post some pics on here? Or even better could you start a thread for these mods and post the pics and repost the descriptions of what you did there? I know that may seem like asking alot but usually the folks who do these type mods and report them here are kind enough to do that for those of us who might want to do the same...cause you know that's alot of what this forum is all about...helping each other out when one person succeeds in making such a modification work.
Gushar
Gushar,
As soon as I get some more batteries for my camera and it stops raining here I will get some pics up. This was very easy to do. For the controller shunt mod you can see pics at the link above. It works the same way even though the shunts on the xb 600 controller are in the middle of the pcb. It takes about 30 minutes to do it. Soon I'll post pics of the battery wire routing etc.. for adding the 5th battery. Again, this is about another 30 minutes of work, so in 1-2 hours tops you can easily add 8- 10 mph to your xb 600. I would definitely recommend the shunt mod for better hill climbing ability even if you don't want to do the 60v mod like I did. Also, I want to test it a few more days so I can post some stats on range, speed with a full charge (my batteries were low when I did the 60v mod and still got to 28 mph :D). The main reason I want to wait to post pics and instructions is so I can make sure the scooter can take it before other people do it and burn up their scooters.
Thanks Zerogas. Yeah, I understand. I'm really interested to see what happens on the longterm as well. Like I've said recently on here, I'm basically satisfied with the xb600 as it is. However, I wouldn't mind having some better hill climbing. Also, a bit more speed on the flats would be nice too. Of course what you've reported is really a vast difference in performance. I can't imagine being able to go 25mph uphill or 28-29mph on the flats! That's about a 10mph difference for both and that's a huge difference when you're at those speeds. I've looked at the "shunt" mod several times on the other post. I guess I'm just trying to imagine exactly where the new shunt gets soldered and why you have to drill holes in the board. Is that to run the ends up through to solder on the other side?? Are those points at the same place, or directly beside where the existing shunt is soldered? Anyway, I appreciate your willing to take the risk here with this and that you've shared this info thus far with other xb600 owners. I wish we knew the exact maximum safe voltage range for the motor, controller and dc-dc converter, as well as max amps. Wonder if xtreme knows this??? and would share it? I'm beginning to wonder if in fact the speed, etc. was limited not because the components couldn't deliver it without failing/burning out...but rather to meet the federal e-bike definition in the US???
Thanks again and I'll look forward to seeing just how you did things.
Gushar
Sorry Gus,
I should have been more clear on the shunt mod. You have to drill (2) 2mm holes so you can solder the tips of the coat hanger on the other side. There isn't alot of room on the pcb to do it, so I drilled my holes directly beside the existing shunts ends. This mod alone will give you 20 mph up hills. It's easier to do than you might think, and it works like a charm. I would do this mod no matter what. When my 72v controller comes in I plan to do the shunt mod on it also. Look out! My xb 600 is gonna hit the 40's !!! I'm looking into a 2000 watt motor for a 72v mod, so stay tuned. Gas can kiss my ass! LOL
Thanks Zerogas for the clarification. I'm thinking as well it was critical on the other shunt mod post about the size (diameter) of the coat hanger wire...realizing this or that coat hanger may be different in diameter??? Have to read that other post again.
What did you think about the one post talking about the max voltage of the dc-dc converter...and bleeding off some voltage with the headlight? Seems if that's a problem it would be better to try and find a converter that will take higher voltages.
Can't wait to see a video of your xb600 tooling along at warp speed! :-)
Gushar
Oh, thought of something else I was curious about. I haven't even opened up the battery box on mine so I don't even know what size wires they use in the battery string and into and out of it??? I know on my previous small cheapy scoots 24v, 36v, it was pretty small wire. And how do they have the battery connections made? Again on those small scoots I had there were spade connectors. And btw, when you wrote "snap connectors" do you mean those that just "clip and cut into" the wire and you can add another wire or join two wires with them? Cause that's what I know as "snap connectors." But they're not made to continuously be opened and closed????
And I'm thinking as well why not just get a suitable replacement charger for a 60 volt bat pack rather than charging separately. Sorry for all the questions...just got me curious about those connectors, etc.
Gushar,
Take it from someone who has done the 60V upgrade from 48V for a long time on a similar scooter and experienced a burned out DC-DC converter as well as blown capacitors in the controller. Bleeding off some of the extra voltage before connecting the fifth battery takes only a few seconds and will likely save you money on replacement parts/gas to return to an ICE and time disassembling and reassembling the scooter. Also finding a DC-DC converter that will handle the extra voltage is not easy. Most solutions are pretty expensive (~$200) or will need to be custom made yourself (will need to output 10 amps.) If you are planning on trying to use a 60V charger instead of a 48V and a 12V charger, you will expose the electrical components of the scooter with up to 75V which is a bad idea as this is over the max voltage for the capacitors and DC-DC converter as well as equal to the max voltage that the FETs will handle (usually 75V for a 48V scooter's controller.) You should consider getting a spare DC-DC converter and/or controller just in case. Alternatively, you could just upgrade the capacitors and FETs in the controller first for a long-term solution.
It would also be advisable to find out where the DC-DC converter taps off the pack. Then, run those wires to the original 48v section of the pack (I know this is not possible with the way zerogas did the wiring). If doing this, you must charge the extra battery separately so it remains in balance. This will save the DC-DC converter, and this is the way EVT owners did 60v mods with the EVT scooters.
Hi again,
Gus, by snap connectors I'm referring to the spade type that have a male and a female which can be plugged into each other. I used these on the wires from the 5th battery and from the battery pack for quick disconnects and to plug the 48v pack back together for charging. I charge the 5th battery separately with a $28 shumacker charger from Wal-Mart. My previous post of 28mph was wrong. Apparently my 5th battery was almost dead when I bought it. With a full charge I'm getting 30 mph and 27- 28 mph on hills. As for the dc converter, If it fries I'll get a better converter or run the 12v system off of the 5th battery (crude way of getting 12v with no converter LOL). You definitely need to open your battery pack.... I found 2 of the cables in the pack were loose, so I tightened them up while I was in there. As for the gauge of the wire in the pack, it seems to be 10ga. wire. It's pretty small stuff. When I do the 72v conversion ( with a 72v controller and better dc- dc converter of course) I'll rewire the whole scooter, including the battery cables. All the wires seem to be undersized on these scooters. If all goes well to work and back tomorrow on my xb 600, I'll get some pics up on here. I keep forgetting to buy batteries for my camera!! LOL Oh, also, I wouldn't worry too much about the diameter of the coat hanger for the shunt mod. Anything has to be better than what's in the controller already. If you encounter any hills.. at all... ever... you should really start your mods with the shunt mod just for better hill climbing ability. Good Luck and happy Modding!
Found a decent dc- dc converter 72v to 12v for under $150. A little pricey, but more digging may result in a better deal. http://www.powerstream.com/dc-dc.htm
Wow...that is so much more speed...and getting almost as much speed on hills as on flats! Thanks again for the additional info. Also wondered if getting the original batt to match the others might help hold the range a bit since it is 20ah if I recall correctly??? But man I am really impressed with what these mods have done. I do want to wait a bit since you've become the "test" for these mods...and see if anything happens with the motor/controller in the next couple of months. Hopefully both are capable of the voltage/amp increase with no real degradation to the components.
Keep us posted and I'll sure be looking for those pics on here!
Gushar
I rode my xb 600 to work today for some real testing. It performed beautifully, except that a co-worker rode it and laid it down :( . Still, fresh off the chargers it runs 30mph exactly, but after a few miles the top speed is more like 28-29mph and 26-27mph on hills. As for the long term, my 72v controller should be in any day and after the shunt mod and another battery we'll see how tough this motor really is. For a 600 watt motor it's got alot of grunt. The bottleneck on these scooters really seems to be the controller. X-treme could offer alot more scooter if they wanted to. i guess everything is limited for reliabilty. I'm looking into a 2000 watt motor in case this one gets melted from 72v LOL.
Hi guys,
I finally got off my scooter and took some pics. I started a new thread showing how I did the 60v mod on my xb 600. Here is the link http://visforvoltage.org/forum/3534-30-mph-xtreme-xb-600-60v-modification-instructions
Thanks for all the help and advice you guys have given me. When my 72v controller gets here, I guess I'll have to make a new thread again! LOL
Here is the link to the youtube video of my speedometer showing 29mph. I had ridden the scooter for awhile so speed had dropped from 30mph to 28-29mph. It happens, but oh well, it's still so fun to ride. Notice how fast it gets to 29mph!! The shunt mod makes it accelerate so fast! http://www.youtube.com/watch?v=N2Sr590DSgw
Let me know what you think.
Found 72v dc-dc converters here for $35 dollars shipped. I have one on order :D http://www.power-factor-1st.com/shop/dc-dc-converter/on-board/sd-15.html
72v chargers...Hmmmm. http://www.evdeals.com/72Vchargers.htm
How are you going to increase the DC-DC converter's max amps up to the 10 amps that the stock converter could deliver (like high beams on, braking with turn signal on)? Also the 72V charger is only rated at 1.2 amps which would take a very long time to charge up. Have you found a 72V charger for a reasonable price that could charge faster? I am watching your progress and potential move up to 72V as I am sitting at 60V on a similar scooter already.
I'm still looking around at prices and options. That soneil charger is the only 72v charger i've found so far. I don't mind slow charging, it's better for the batteries and I charge at night and while I'm at work, so speed charging isn't a big deal for me. As far as the amps on the dc-dc converter.... for $35 I'll try it and see what happens. It's a lot cheaper than the $150 I found on another site. :D
I bought it off the web from Extreme. Had I known you were 3.5 hours away I'd have been up to see you. We should talk some time. I am thinking about a dealership here. Don't know how many 600s you have sold but I can tell you that they are as advertised .
Thanks for your information, James.
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zerogas, that's a huge boost in performance. Is the controller getting hot, or burning? Can you take some pictures? I'm not too surprised that the controller was the bottleneck, but that's a lot more than I thought.
Just go easy on the motor at first and feel the motor at 2 minute intervals on a long ride. The motor may gradually get very hot, so don't expect it to be fine if it is cool after a few minutes of riding. It is difficult to know at which point the motor is reaching its critical temperature from the outer casing temperature, but at least you can compare to how it felt before. Once it gets very hot to the touch, than it may be approaching or at its designed safe operating temperature.
If there's some way you can get a temperature reading of the windings themselves than that would give a much better indication. The winding insulation will break down when the temperature gets too high and the motor will fry, so that is the critical point.
KZ750 Motorcycle Conversion
900 watt scooter
Pic from http://www.electricmotorbike.org/