72v 37MPH xtreme xb 508!!!
My first upgrade was the 72 volt and Shunt mod on my controller, described on zerogas's great xb 600 thread here. Many thanks to all the contributors there! Turns out it's a pretty simple matter of replacing the mosfets and caps with 100 volt versions of the same parts. Then all that's left is to attach the wire that comes from the key switch to a 48 volt tap point from your battery pack, and not the 72 volt wire coming from your controller. richardb has put together a great website detailing his mods,
http://www.bergerweb.net - on his xb 500 including specifics on what size and gauge wire to use for the shunt mod, as well as a nice schematic. The result of those 2 mods increased my speed from 21mph to 28mph, and improved the hill climbing ability a lot! I then rode my XB every day to work for well over a year, even on 106-107 deg. days, and the performance was rock solid and the motor always only got slightly warm to the touch, never a problem. Other 72 volt mod riders here report the same performance. I recommend this mod to all XB owners. If you are not good with a soldering iron, I suggest you pick up a 72 volt controller ready
My second upgrade recently was picking up an 800 watt 48 volt motor with controller I found on Deputydaves' 700li thread that fits XB's nicely. I noticed the speed at 48 volts on this new one was about the same as my old 550 watt motor running at 72 volts, but the torque on this new one was much better! I couldn't WAIT to get this one up to 72 volts also!! So the upgrade parts finally arrived and this last weekend I put them in. Then went for a test spin and top speed is now 37MPH!! The torque taking off from the line and going
up hills is amazing! It momentarily pulls 33 amps accelerating or going up hills and drops down to 22 amps on a level road. I have attached pics showing the new motor (looks stock huh) and the 2 extra batteries in the seat compartment.
*Note on axle washers: In order to be able to use the correct amount of washers on the axle to be able to tighten the wheel on the forks without binding as I was having problems with, it turned out I needed about a 1/4 inch more space between the forks in order to do so. In asking around a friend loaned me his 10 ton hydraulic "puller" (it's more a spreader really) he uses for car body repair to spread the forks. Sounds big but its actually a small unit about 2 feet long and about 4 inches wide. But plenty strong to spread those steel forks!
Many thanks to the creator of V is for Voltage and all the participants sharing tips here! I am no electronics expert, but there are many on here helping those of us out who are electronically challenged. Take a bow, this success is yours as well!!
The new motor still looks pretty stock.
Extra batteries for 72 volts stored in the seat compartment.
Actually the 2nd upgrade I did (and the biggest bang for the buck) was put on some different tires. You can see from this picture the comparison between the stock tire and the new one shows about 3 times the extra thickness of tread, which ended the flat tire problems I was having, and really improved the feel of the ride overall. Also the tread extends up the side of the tire, improving the cornering ability greatly.
zerogas discovered these, cheng shin brand for $14 ea!
http://www.bikebandit.com/tires/c/a642336a4a8a634806 Select the 90/90 - 12 option. They are for 12" rims. They replace the "16 x 3.00" tires that come stock on XB's perfectly. XB-500, 508, 600 and 700li owners who have tried them, so far all swear by them, including myself.
My latest project is replacing the little round amber reflectors on the sides of my front fairing with LED side marker lights for trailers. I came across them by accident and noticed they seemed to be about the same size. A side by side comparison turned out they were indeed a perfect fit...
... so I used a standard hole saw to drill out the new hole needed, then notched out the tabs on the ends of the hole using this template I traced from the back of the unit.
Here is the end result:
I wired the pigtail connectors on the back to the running lights circuit. Anything to help make drivers see us is a good thing. I'll turn it on and take a pic when I have the rest of my light mods complete.
Great post! Thanks for the update and the pics.
Are you in Phoenix? (Where else does it get 106-107 degrees on a routine basis) I am in Phoenix and ride my 700li to work almost every day. I installed the Cheng Chin tires almost a year ago, and the ride improvement was impressive. After 16 months of riding and almost 3000 miles, my range seems to have dropped a bit, to 18 miles per charge. I am 6'2", 225, and often ride in 100+ degree weather, so the bike is working hard no doubt. But I am considering the voltage upgrade that you did. I would also like to upgrade my LIMN04 to LIFEPO4, which I believe will require a new charger. Anyway, thanks for the update!
No I am in Oregon, so getting temps that hot was a rare chance to see how it held up. I too am preparing to install 30 amp LiFePO4 batteries. After hunting around a bit, I found both a 24 and 48 volt model that will fit in my under seat storage and standard storage area. I would definitely go for the voltage upgrade, you will be very pleased. My primary motivation was to get better hill climbing ability. But also there are places where the bike lane abruptly ends and you are suddenly in with traffic. Now on these 35mph roads I am able to keep up with traffic, whereas before I was always a hindrance to traffic. And all this is legal up here too since the new ordinance now allows electric bikes to go 35mph. Let me know if you need any advice or have questions on doing the mod.
Here is part of the richardb schematic showing where to take the 48 volt tap from your 72 volt battery pack.
(The full version is available at his website.)
Note that he has installed a switch on the battery pack (I think for inspection purposes) so that he can ride at either voltage (48 or 72). I didn't bother with that switch because once you feel the improvement you can never go back.
In looking at the 2 wires coming from the controller to the ignition switch, you see one of them has a line drawn through the controller (Batt +48) to the wire marked R14 (positive terminal from your battery). If you measure those 2 with an ohm meter, you can determine which one of them is that wire, it shows a direct short to R14. THAT is the one you want to clip (as shown in the schematic with a small red x) and instead connect that wire from the ignition switch to your new 48 volt tap as shown, not to the wire coming from the controller (since it now has 72 volts). That way we avoid sending 72 volts up to the dash and the dc-dc converter, so everything up there is still at it's normal 48 volts.
Superb idea richardb, thanks for the simple solution! I have done this method with both controllers, works perfect.
UPDATE! *Important note* for connecting LiFePO4 battery packs in series!
While researching which batteries I am going to buy (a 48v and a 24v), I spotted this diagram on Ping's site:
Voltage rating of each diode = maximum voltage of the battery pack
Current rating of each diode = maximum current of the system (i.e. Max Peak current discharge of your batteries)
These are needed to protect your BMS(s). Glad I spotted that before I hook mine up.
You also will need one more if you have a regen controller:
Ping kindly responded to my query about this diode (since I have a regen controller) with the following:
"...The reason why we add the diode is that there’s no over-charge protection on the discharge wires, while regen power is usually going through the discharge wires. So, if a battery pack is right fully charged, and you ride the bike downhill for a period of time, the regen power will over-charge some cells. However, the diode can direct the regen power to the charge wires.
So, you can see that the diode is not a must if you understand why we add it.
You can turn off the regen function when the battery pack is fully charged, then when 10% or 20% power is used or there’s no long downhill way in front of you, you can turn on the regen function. If there’s a switch for regen function on the handle bar, it will be very easy to do that..."
Being an electronically challenged type, I love detailed explanations. Personally I am just going to spring for the diode ($7), and not worry about when I can use regen. I have not seen these warnings on any other vendor's site so far, so thought it a good idea to pass along no matter which LiFePO4 batteries you use.
This is a terrific thread...so full of useful information.
I plan on doing much the same thing.
Why the 48V + 24V?
Would it not be better to have two equal packs of 36V + 36V?
Good question, I considered that combination at first. But when I started shopping batteries I quickly found that with difficulty I could barely find a 24V model to fit in the under seat storage compartment, so no way I could squeeze a larger 36V in there (These are all 30AH models). Secondly, (and more important) I would then have no 48V tap point available in the battery pack to send up to the dash (which is what it expects) and the logic section of the controller. But most 48V models will fit fine in the floorboard compartment. Keep in mind that besides the battery pack, you need room for the BMS that is connected to it. When queried on the size of the BMS units, vendors uniformly replied "the size is 180x75mm". None offered the 3rd dimension for some reason. In looking at the pictures of the units and guestimating I would say about 1/2".
I have also just recently wired my 3rd controller in now (this one with regen, already 72V no mods needed) using the 48 volt tap point method. Worked perfect like the others. It keeps your DC-DC converter happy up front (which feeds your dash accessories and lights). Also it returns only 48V to the logic section of your controller (which has the smaller caps that we don't replace) via the ignition switch return wire (which we leave intact vs the other one that we clip).
Alternate source for XB rear wheel inner tubes - (X-treme was out of stock when I needed one)
Trying to find a 3.00-12 inner tube (which is the correct tube for your "3.00-16" stock XB tire) in my area for the rear wheel with the angle stem is impossible. Searching online is not much better. Even the source I eventually found on ebay didn't have the angle stem specified anywhere in the description, but the pic caught my eye:
$8 bucks each, always in stock, fast shipping.