Suzuki RMZ 250 EV Restomod

[Eastwood]

You have moved weight around in the chassis that it wasn't intended for so things change

Yeah for sure Although the way I have the battery configured, it’s somewhat a “similar” shape to the actual stock engine. I took this in consideration what you’re saying about the weight being moved around in the chassis and that’s how I end up with this battery shape.





On a sidenote, I actually revalved the bike this morning Lol., I couldn’t help myself it’s not much work. It only takes about 45 minutes to remove the cartridges and tweak the shims and reinstall.



But it definitely needed to be done as yesterday I did some more extensive testing and it’s still harsh over sharp squared objects, even with the compression clicker turn all the way out.
So after the re-valve this morning, it’s much more plush and less harsh over squared Sharp objects.
Tweaked the low speed and high speed, Nothing too dramatic. I’m sure I’ll end up doing more re-valving once I have the final bike weight.

Next, I need to order the new main springs as I’m only using about 70% of the stroke. The race sag as of now for the forks is only 20 mm which is way way too stiff
According to race tech the Rmz 250 vs 450 the front spring rate is almost identical for my body weight so I’m thinking after I add the extra 10 to 15 pounds with the new battery, It shouldn’t be too much of a dramatic difference since race Tech has the 250 and 450 at almost similar spring rates for my specs.
RMZ 250cc .40kg/mm
RMZ 450cc .41kg/mm

My stock springs are .47kg/mm

 

[j bjork]

I am also in the process of re-valving and changing spring rates. Both my pressure springs were broken

 

[Eastwood]

Laying the first welds

 

[Eastwood]

Just spot welded the 2ply/level



The temp of the welding pen after this block

 

[Eastwood]

Finished spot welding the 3rd ply/level. This block is the biggest of all 4 levels, took lots welds.
One last ply/level to spot weld.






Using this sheet metal break to bend the busbars.






Also using the break bend for the FR4 fiberboard. Simply scar the board on both sides with a utility knife, then use the bending break to separate the pieces.

 

[harrisonpatm]

Here's my concern, which may be unfounded. Obviously it's good that the busbars from cell to cell are solid copper and thick, good for high current. And it's good that the part that gets spotwelded is nickel, because you can't easily spot weld copper. So, don't get me wrong, this is a superior product compared to 3 layers of nickel. I'm wondering however, the current still has to go through a (very short) length of nickel before it reaches copper. So isn't there still going to be some excess resistance? At least compared to something like the copper-nickel sandwich method.

Obviously I'm nitpicking. Just wondering out loud about the busbars as a product. I'm sure they're better than what I can make!

 

[Eastwood]

So isn't there still going to be some excess resistance? At least compared to something like the copper-nickel sandwich method.

I would think there’s less resistance with these WELLGO busbars vs copper-nickel sandwich. The nickel strip is very short, so the current doesn’t have to travel very far through the higher resistance material, nickel. Also, the nickel material is actually a hybrid copper material. So the bottom side of the busbars on the nickel part is actually coated in copper, which then is welded directly to the cells.

Obviously I'm nitpicking. Just wondering out loud about the busbars as a product. I'm sure they're better than what I can make!

Yeah, that was my main decision with ordering these busbars, because this is way cleaner than anything I could’ve fabricated. Plus it’s much quicker to spot weld these premade busbars versus cutting hundreds of pieces of nickel strips and copper and doing the sandwich method.

 

[Eastwood]

Well baby steps but making progress. Had to pull the motor out to rework the motor mounts for battery clearance. Plus I cut off the top motor mount as you can see in the picture. Also made a bash guard for the bottom side of the battery. Or I guess you could call it a battery cradle although it’s meant to take impact since my battery is so wide, used 1/8” steel plate. No welding, used 5 rivets on each side that connects to some L brackets I made which bolts to the main motor mounts. There will be more added to this bash guard, This is just the very bottom plate.





Got the negative discharge busbars bent into shape.




I actually had to notch my brake bend so I can make Z shape bend in the busbar.




filed down these bolts for the lugs on the negative busbar to 1.8mm. Had to grind and file them down due to battery clearance.


Then I accidentally put my hand of the bolt right after using the grinder on it lol… Well that burned

 

[amberwolf]

Then I accidentally put my hand of the bolt right after using the grinder on it lol… Well that burned

Don't worry, no one else here has EVER done anything like that before.

 

[Eastwood]

Almost got the negative discharge busbar finished. These three 1/0awg will come out of the battery case through one hole and crimped into one large lug, then bolted to the main 4/0 AWG discharge wire. Will make more sense as I post progress pics. I don’t think could’ve built a more difficult battery especially this being my very first battery build


Thinking of using some red Loctite on those lug bolts coming off the busbar


As you can see in the picture, the 3 negative discharge wires will come out of the battery case and run down between the motor mounts. Will heat shrink all 3 wires together with marine grade heat shrink.

 

[Eastwood]

Got the controller mounted. Used 1/8” aluminum and painted black satin. mounting brackets were made by hand and used a file to profile the metal.





Before painted


Fabricated and installed two metal plates that serve as the battery cradle. The very bottom one connected to the frame is 1/8 inch steel. Should be able to take a hard impact as it’s somewhat of a skid plate for the battery. The metal plate on top of the motor is aluminum to keep the weight down. On both plates, I made a rubber gasket/spacer so that the battery can sit flush on the mounts to avoid sitting on the screws and rivets. Also, the rubber will help with vibration.



Finished the bottom of the battery case, this part has been very time consuming!! The thin battery case just serves as the waterproof barrier there will be an additional shield around the battery to take impacts. This part of the build is probably the most grueling process of any other projects I’ve ever done, it’s taking me a month to pretty much complete nothing


Also finished the bottom cell Block. As mentioned before, these three 1/0awg wires will be bolted directly to the main 4/0awg discharge wire. Same for both the - and +.







Applied DP420 epoxy, to the very outside edge of the cell spacers to reinforce. DP420 can be used as a structural support ,not just to bond objects together. I can now certainly see the advantage of 3-D printing your own cell spacers. These cheap spacers are so thin and are easily breakable

 

[speedy1984]

Great detail into the batteryGoing to be a solid pack.I would definitely turn the controller over though why there is still time.One forces air in the heatsink and two keep the crap off all the wiring loom.The placement is 100% the best place for weight distribution so great job.

 

[Eastwood]

Great detail into the batteryGoing to be a solid pack.I would definitely turn the controller over though why there is still time.One forces air in the heatsink and two keep the crap off all the wiring loom.The placement is 100% the best place for weight distribution so great job.

Thanks!
A lot of thought and effort that’s going into this battery build. Especially this being my first battery build, I’m trying to be overly safe and not rush.

I’ll probably keep the controller the orientation it is because there will be an enclosure that blocks any water from entering. That being said, I’ll be putting a fan on the controller for cooling. Although I might not even need a fan, considering I will only be using half of the rated specs of this controller, most of the time.

 

[Eastwood]

Time to upgrade the phase wires! The goal is to simply lower resistance, and also the phase wires being larger will act as a heat sink to pull the heat out of the motor through the wires. I’m not sure what gauge I will go with yet. The phase wires will be at least 50% bigger than what they are now. Maybe 1/0awg if I can fit it.

Here’s some pictures of the factory phase wires and connections.








So they soldered and crimped the phase wires. A decent connection at best


If you look closely you can actually see a little air gap at the top of the copper connector. they didn’t crimp it properly and or not enough solder



This plastic piece is what snaps into the motor and the wires go through it. Should be able to just drill this out to fit the larger wires and use silicone for sealing

 

[amberwolf]

When you put the new phase wires on, you can ditch the whole soldered section and just use a really good crimp with tube lugs like those. If it's crimped correctly, the solder won't have anywhere to go in it anyway, for the important connection bits.

Just make sure to remove the winding wire's insulation before doing the crimp, for the entire length that will be inside the actual crimped area.

If the solder has to hold the connection together, it could come loose in extreme overheating situations (very rare, but it's been done around here more than once in various motors).

If it ever did get that hot then even if it didn't come loose, the solder could dribble off the connection from vibration, and end up as bits being ground up in the motor. Unlikely to cause an electrical issue, but would cause some mechanical wear.


While you're doing it, you could also add a separate hole in the casing as far away from the phase wires as possible for the sensor cable, with it's own separate grommet, and route them all internally as far from the phase wires as you can. This may help prevent induced noise on the signal, ground, or power lines, which can cause motor/controller timing issues under high loads. While it wouldn't be worth opening a motor just to do this unless there already was a problem, it doesn't hurt to do it preventively while you've already got it open.

If you do end up having the problem anyway, more extreme measures for reducing this kind of noise issue include RF shielding over the sensor cable and wires for as much of their length as possible, grounding this only at the controller end, and then various passive or active electronics measures if it's really bad.

 

[Eastwood]

When you put the new phase wires on, you can ditch the whole soldered section and just use a really good crimp with tube lugs like those. If it's crimped correctly, the solder won't have anywhere to go in it anyway, for the important connection bits.

I’m glad you brought that up as I had planned to just cut off the soldered section and crimp to new section as there’s enough length. I wasn’t 100% sure it was good to do this but I figure it was fine. So I’m glad you brought this up
I did this on my last motor as well, QS205.

Just make sure to remove the winding wire's insulation before doing the crimp, for the entire length that will be inside the actual crimped area.

Looks like QS already stripped that whole section. I can tell by the color difference. But I’ll go over it one more time to make sure all of that protective layer is stripped off. Maybe I’ll use a scotch bright pad, it seems that that would cover more surface area of the wires since it’s flexible.

If the solder has to hold the connection together, it could come loose in extreme overheating situations (very rare, but it's been done around here more than once in various motors).

If it ever did get that hot then even if it didn't come loose, the solder could dribble off the connection from vibration, and end up as bits being ground up in the motor. Unlikely to cause an electrical issue, but would cause some mechanical wear.

Yeah, for sure no solder with higher power. I remember hearing live for physics talking about this a couple of years back and that’s one of the reasons I’m not using solder on my battery build as well.

While you're doing it, you could also add a separate hole in the casing as far away from the phase wires as possible for the sensor cable, with it's own separate grommet, and route them all internally as far from the phase wires as you can. This may help prevent induced noise on the signal, ground, or power lines, which can cause motor/controller timing issues under high loads. While it wouldn't be worth opening a motor just to do this unless there already was a problem, it doesn't hurt to do it preventively while you've already got it open.

Very good point, sir! I hadn’t thought about this, but I will do that

If you do end up having the problem anyway, more extreme measures for reducing this kind of noise issue include RF shielding over the sensor cable and wires for as much of their length as possible, grounding this only at the controller end, and then various passive or active electronics measures if it's really bad.

I’ll use some RF shielding as well, thanks for the tip!

 

[Eastwood]

@amberwolf
I might try this Shielding Wire Mesh for the signal wires. Amazon.com

Since I have the motor open, will install a second temperature sensor that I can connect directly to a small temperature gauge. The motor already has a temp sensor installed that functions with the controller. Would be convenient to have a second temp sensor connected to a separate display.

Need to sand and repaint the side cover since I scratched it up pretty bad from dropping the bike on some rocks. Well more like gouges not scratches.

It’s funny how one thing leads to another, right
Just planned on upgrading the phase wires and now I have created a longer list of tasks to complete
But it’ll be worth it in the end

Oh and I decided to go with 1/0awg for the phase wires. From measuring there about 50% bigger than the stock wires so that should help.

 

[amberwolf]

The shielding linked will probably work fine as long as you can fit all your wires in it. (iv'e sometimes repurposed the shield off of old cable-TV coax cable, though it takes some effort to get it off undamaged--harder the longer the cable is, but not really difficult).

If youre temperature range allows you to use an LM35 sensor, you can connect it to a simple voltmeter; it's output is scaled 10 mV/degree C so it's directly readable that way as degrees (just ignore the decimal point).

LM35 data sheet, product information and support | TI.com

TI’s LM35 is a 1C high voltage analog temperature sensor, 10 mV/C. Find parameters, ordering and quality information

www.ti.com

If you use a thermistor, remember there are many variations of resistance and of "response curves" within a resistance class, as well as PTC and NTC types. You'd either pick a measurement/display device and then use the thermistor it's compatible with, or you pick a thermistor and then find a display/measurement device that can read that specific one.

 

[Eastwood]

So I picked up these 2/0awg Butt connectors for the phase connections.
BUT I will not be using them in the traditional sense of a “butt connection”. The problem with a butt connection is there’s actually an air gap between the two wires where they meet inside the connector which equals more resistance, a.k.a. more heat.

So I cut the butt connector in half and will overlap the phase winding with the phase wire so once it’s crimped, it will be one solid piece of copper with no gaps.


After being cut


The new connections will be much beefier


Here’s a comparison with the old phase wire



Here’s a picture of the cross-section of the factory phase connection. As you can see, it’s not the best connection because there’s still gaps between some of the strands of wires.

 

[amberwolf]

Yeah, that's probably why they soldered it--their crimper wasn't good enough.

 

[Eastwood]

Got the new phase wires crimped to the phase winding. Still need to heat shrink with marine grade heat shrink.



Crazy the sleeve connector look like this before crimping
I simply overlapped the wires and crimped multiple times on each connection. The connection should be a nice solid piece of copper with no air gaps.



As you can see from the picture, crimped these with so much force it actually made the connector longer lol


I will install these air/pressure valves on the motor. The material used inside the pressure valves is gore-tex. This filter/fabric is breathable, but water cannot enter through the material. The vents are rated to be submerged up to 90 minutes before leaking, which is perfect for a dirtbike in wet conditions, especially on the East Coast.




Found this really convenient temperature display that actually has two temperature sensors. One will be for the motor and the other one will be for the controller. I really like the fact that it has two sensors so I don’t need to install a second temperature display on the bike.



Will use this blower fan for the motor. The air will flow over the top of the motor and between the battery case. Will have to fabricate some type of shield to keep mud off the blower. This little blower kicks out so serious airflow. Plan to connect the blower to a small thermostat and same with the controller.

Looks like it pulls about 4 watts

 

[MDG]

Yo man, this is next level. Cool seeing the QS motor opened up! I just jumped to your last page but why are you upgrading the phase wires exactly? I’ll go back to the start in the morning, currently tired and lazy haha

 

[Eastwood]

Yo man, this is next level. Cool seeing the QS motor opened up! I just jumped to your last page but why are you upgrading the phase wires exactly? I’ll go back to the start in the morning, currently tired and lazy haha

Thanks!
Larger wires to lower resistance and the large phase wires also act as a heat sink, pulling heat out the motor through the wires.

I wanted to try the QS180 but this being a trail bike keeping it light is important so I just went with the qs138. So that being said, I’m trying to maximize efficiency with the smaller motor to help with heat buildup. With the larger wires and the blower fan should be able to keep the motor temperatures down.

 

[MDG]

Thanks!
Larger wires to lower resistance and the large phase wires also act as a heat sink, pulling heat out the motor through the wires.

I wanted to try the QS180 but this being a trail bike keeping it light is important so I just went with the qs138. So that being said, I’m trying to maximize efficiency with the smaller motor to help with heat buildup. With the larger wires and the blower fan should be able to keep the motor temperatures down.

Make perfect sense! Love it all, I’ll be following along with this for sure. My next project is a KLR250 SuperMoto Scrambler build so it’ll be in similar size as yours

 

[Eastwood]

Finished the phase connections. Stripped off the rubber insulation and used quality heat shrink.




Before heat shrinking the wires, I put a small piece of heat shrink directly over the connection to help cover any sharp edges





This parts finished
Now I need to install the grommet that I have drilled out to fit the large wires. Probably will drill a separate hole in the motor casing for the halls sensor wires to exit.


Well that’s good the side plate cover still fits
Definitely a tight fit with those thick wires.
As you can see, the side plate cover has been sanded down and ready for paint. As mentioned, I scratched up the side plate cover really bad dropping the bike on a rocky section of some Enduro trails.