My new build! 72v 2000w

[SweetTrade324]

Just finished building my first ebike, a 29” Schwinn Axum with a 2000w motor 45a controller and a 72v 19.2ah lg battery. Great acceleration and a to end of 43.3mph on gps. Any tips you can think of I’d gladly take. Thinking of coating the connections in ACF50 and wrapping it all in silicone sealing tape.

 

[m@Robertson]

I would do everything possible on the front of cable management. You'll hear from all builders who have been down this road multiple times that cable management is a bit of an art form for us. A very disproportionate amount of time is spent hiding stuff and making sure nothing can catch on them as you whiz around with the cables exposed.

look into 'split wire looms' on Amazon. Then check out the water bottle mount storage containers that are out there.

 

[J.R.]

Just finished building my first ebike, a 29” Schwinn Axum with a 2000w motor 45a controller and a 72v 19.2ah lg battery. Great acceleration and a to end of 43.3mph on gps. Any tips you can think of I’d gladly take. Thinking of coating the connections in ACF50 and wrapping it all in silicone sealing tape.

72 volts, 45 amps will deliver more than the 2000 watts the motor is rated for. You're near household space heater power and all those coiled wires will be handling a lot of heat.



I'm no expert though.

 

[SweetTrade324]

72 volts, 45 amps will deliver more than the 2000 watts the motor is rated for. You're near household space heater power and all those coiled wires will be handling a lot of heat.

View attachment 136742

I'm no expert though.

That’sa very good point I never considered. I will look into other options. I do only have it set to 30a though

 

[m@Robertson]

72 volts, 45 amps will deliver more than the 2000 watts the motor is rated for. You're near household space heater power and all those coiled wires will be handling a lot of heat.

Thats a good point. I hadn't done the math. A 72v battery charged to 100% is 84.0 volts. If the controller is pumping 45a that means 84*45=3780w.

Here's the thing though: You have a UPP battery. Now... UPP batteries are inexpensive and thats the only good thing you can say about them. They have a reputation for not being robust and tend to be touted for their cheap price and thats it. Long term, expect to have it underperform. Here's the thing: that casing is sized for their typical 48v/52v packs and I can say absolutely for sure that there is no way in hell that what I am seeing in that pic is a 72v pack that holds 19+ ah of capacity. There is simply not enough room for that in the case. You would not be the first person who got sold a bill of goods in this regard.

This is what UPP's 72v, 20ah pack looks like: A giant brick.

D034 72V 20Ah BMS60A waterproof Ebike battery for 0-3000W 750W 1000W 2000W 2500W 3000W Electric E-bike with 4A Charger【USA Stock】

Free tax , no custom value , and fast shipping with US Fedex ，3-5working days arrive 。 USA After-sales Service Center This Item ships from United States , Can ship to most US States , don't ship to Hawaii , Alaska

www.uppbattery.com

Their 52v, 20ah battery looks exactly like yours:

Triangle battery 52V 20AH for 0-1000Motor + Waterproof & Shockproof Case (BMS30A)/With fast charge 4A/USA stock/3-5working days arrive

Free tax , no custom value , and fast shipping with US Fedex ，3-5working days arrive 。 USA After-sales Service Center This Item ships from United States , Can ship to most US States , don't ship to Hawaii , Alaska .

www.uppbattery.com

I don't think there is any chance you have a 72v pack. Yours is either 48v or 52v. If you bought from a reseller, they hosed you. That 52v pack has a 30a BMS. Thats as much as it can take and frankly I would not want to press my luck by going max with a UPP battery given their history.

 

[Tom@WashDC]

Just finished building my first ebike, a 29” Schwinn Axum with a 2000w motor 45a controller and a 72v 19.2ah lg battery. Great acceleration and a to end of 43.3mph on gps. Any tips you can think of I’d gladly take. Thinking of coating the connections in ACF50 and wrapping it all in silicone sealing tape.

Save your money moving forward because if you love that bike, your gonna eventually want a full suspension electric mtb enduro!

 

[tomjasz]

Why?

 

[SweetTrade324]

Change the wie management setup.

 

[J.R.]

Change the wie management setup.

If all the coiled wires are now encased in those packs, it's actually worse. The amount of power the system can produce is higher than that of most of the systems on a car or motorcycle. I don't know the wire gauge you have, but it looks light. In addition the long wires coiled up creates more resistance, resistance means heat. Heavy gauge, shorter wire will handle the heat better.

I only mention out of concern. Ebike fires are becoming commonplace and your build is concerning. Appearance is way down the list of concerns.

 

[SweetTrade324]

If all the coiled wires are now encased in those packs, it's actually worse. The amount of power the system can produce is higher than that of most of the systems on a car or motorcycle. I don't know the wire gauge you have, but it looks light. In addition the long wires coiled up creates more resistance, resistance means heat. Heavy gauge, shorter wire will handle the heat better.

I only mention out of concern. Ebike fires are becoming commonplace and your build is concerning. Appearance is way down the list of concerns.

I appreciate the info. I didn’t think of that I was worried about protecting from water and cleaner look. I saw other threads that gave me this idea… but I guess with this amount of power it changes things.

 

[tomjasz]

72V UPP build. Careful! You really should link up with builders on endless_sphere or Luna before you burn the house down. A motor cycle on a bicycle frame. Yikes!

 

[SweetTrade324]

Thats a good point. I hadn't done the math. A 72v battery charged to 100% is 84.0 volts. If the controller is pumping 45a that means 84*45=3780w.

Here's the thing though: You have a UPP battery. Now... UPP batteries are inexpensive and thats the only good thing you can say about them. They have a reputation for not being robust and tend to be touted for their cheap price and thats it. Long term, expect to have it underperform. Here's the thing: that casing is sized for their typical 48v/52v packs and I can say absolutely for sure that there is no way in hell that what I am seeing in that pic is a 72v pack that holds 19+ ah of capacity. There is simply not enough room for that in the case. You would not be the first person who got sold a bill of goods in this regard.

This is what UPP's 72v, 20ah pack looks like: A giant brick.

D034 72V 20Ah BMS60A waterproof Ebike battery for 0-3000W 750W 1000W 2000W 2500W 3000W Electric E-bike with 4A Charger【USA Stock】

Free tax , no custom value , and fast shipping with US Fedex ，3-5working days arrive 。 USA After-sales Service Center This Item ships from United States , Can ship to most US States , don't ship to Hawaii , Alaska

www.uppbattery.com

Their 52v, 20ah battery looks exactly like yours:

Triangle battery 52V 20AH for 0-1000Motor + Waterproof & Shockproof Case (BMS30A)/With fast charge 4A/USA stock/3-5working days arrive

Free tax , no custom value , and fast shipping with US Fedex ，3-5working days arrive 。 USA After-sales Service Center This Item ships from United States , Can ship to most US States , don't ship to Hawaii , Alaska .

www.uppbattery.com

I don't think there is any chance you have a 72v pack. Yours is either 48v or 52v. If you bought from a reseller, they hosed you. That 52v pack has a 30a BMS. Thats as much as it can take and frankly I would not want to press my luck by going max with a UPP battery given their history.

I appreciate insght. It does read 72v on the read out and the controller is set to 72v so I assume it is 72 but I am thinking I got hosed on the size. I have the controller set to 30a if that helps at all? Maybe I’ll lower it to 25 though. Any extra insight would be helpful. Will this battery get me though the next 8-12 months? Or would I be better trying to return or sell it and getting a new one…????

 

[tomjasz]

Your charger is 84v? As far as hosed goes it’s probably generic batteries and steel connectors. Not a good mix. UPP has gotten quite a market share. Just remember you have no protection or methods to hold them responsible. Step back. Link with fellas on endless sphere. Some of the old timers. Amberwolf, neptronix, guys who have a long history of doing and watching high power builds.

Reread m@robertsons post. Got a multimeter? Don’t trust a 35cent UPP readout.

Things get hot FAST!

Slow down.

 

[tomjasz]

You’re getting good advice. I remember only to well how exciting my first 35mph build was. I thank dieties I didn’t burn down my shop. As others have pointed out 72v is an entirely different cuppa.

 

[SweetTrade324]

Thanks! Already joined endless sphere and asked for help! I appreciate everyone!

 

[m@Robertson]

I appreciate insght. It does read 72v on the read out and the controller is set to 72v so I assume it is 72 but I am thinking I got hosed on the size. I have the controller set to 30a if that helps at all? Maybe I’ll lower it to 25 though. Any extra insight would be helpful. Will this battery get me though the next 8-12 months? Or would I be better trying to return or sell it and getting a new one…????

Honestly if you got BS'd on X, then I would expect potential for more BS on Y and Z. You won't know what those letters stand for until they jump up and bite you. Potentially very hard.

The reason I said I would not want to exceed 30a is because the reputation of UPP is not exactly sterling if you have been around the online DIY community for awhile. If a 52v battery typically has a 30a BMS, and your controller is set to 30a, then you are running it right at the redline with zero amps of fudge. By that I mean if you have a motor whose controller has a *peak* setting of 30a, then you want the BMS to be capable of handling more than that on its *continuous* setting. That way if your controller's momentary peak goes on for longer than your BMS' understanding of what 'momentary' is (and perhaps the BMS and the controller don't exactly agree on the voltage level), the BMS will not pop and need a reset (meaning you ride the bike home unpowered, and do a BMS reset, which occurs when you plug the pack into a charger).

Here's a real example: I had a 2wd bike once that had two motors that had peak controller values of 25a front and 30a rear. So in theory I can only peak at 55a total. I had a battery with a BMS whose peak value was 90a and continuous was 60a (and guess what... later on I found out the vendor who built this custom pack for me had used UPP as their pack manufacturer). So, close to home I decide to stress-test the new system and nail both throttles going up a mild hill. The hill will keep the motor amp outputs at their peak for an extended period. 3/4 of the way up, the bike shuts completely down. The controller had decided it needed max power for a period long enough for the BMS to decide we had crossed from 'peak' to 'continuous' and shifted to the lower output level limit. When that happened, what is likely a sloppy / cheap BMS tripped at a lower value than should have been possible (55a popped a 60a BMS).

So yeah, probably a good idea to drop to 25a on your controller. But still I would not trust a pack from that supplier.

 

[SweetTrade324]

Thank you everyone! Especially m@robertson!

 

[SweetTrade324]

So I added fender, 4 piston hydraulic shimano in the front, line pulling hydraulic by Juni Tech m1 by Area 13 to the back. I cleaned up the wires and added ukc1 color display. Running very well. I keep it at 25-30 but she will do well over 40 with torque to spare. Thanks again to everyone who helped and sent me to endlesssphere for more help!

 

[SweetTrade324]

That's what I was thinking.
If it was 19.2Ah, it usually means it's powered by 3200mah in parallel.
And it's a 72V, so 20S6P, which is 120 cells.
There is no way 120 cells would fit in that triangle casing.

I have since found out it is 80 cells… 20*4. 4800mah cells. But still claiming 19.2 which i I even know Is not what it is. Any idea on how much I may actually have?

 

[PedalUma]

Once upon a time, I thought more was better. I even put a 58-t chainring on a bike.