Sur-Ron - New Mid drive Bike

Back in 2017 when Allex first posted this thread no one had heard of SurRon. Now 8 short years later they've taken over the eBike world, and second place is miles behind. There's something very endearing about these bikes that makes owners willing to spend amounts equal to the original price of the bike for upgrades. A whole cottage industry has sprung up around them. The aftermarket for SurRon rivals or surpasses every bike I can think of except Harley Davidson. Every bike manufacturer dreams of having a hit like this. It's hard to put a finger on exactly what mades them so desirable. Besides just being a well designed, and well thought out bike, I don't think it's any one thing, but it's a combination of many. The power and speed of course. The low initial cost for sure, but that doesn't last long as most owners know. I think the small physical size is way up on the list. That seems to allow SurRon's to ride on the streets, and city trails unregistered, and unlicensed all over America judging by all the videos, and that might be the biggest factor.
 
I recently had the BMS on my 2020(I think around there) LBX die, I looked online and a replacement BMS was 260$


plus shipping and tax, which seemed kind of absurd. So instead I bought this

BMS for $73 plus shipping and tax. It barely fits inside the stock battery compartment but with some squeezing it works just fine (my battery is a stock 32ah, idk about the new batteries with the upgraded capacity). There is only one problem with a new BMS, it does not talk to the Sur Ron controller the way the old one does, but apparently, it does not need to. The secondary plug NEEDS TO BE PLUGGED IN but does not need to be connected to a BMS on the inside. If the plug is not plugged in then the power is limited, but when it's plugged in it works exactly like normal but more powerful. I do not know why this is but I assume the bike has some way of identifying if it's plugged in to both plugs. Installing the new BMS took me about an hour and a half but I work on batteries a lot so I knew what I was doing, if you have any questions DM me on Reddit and I am happy to help you out. This new BMS also outputs more power (100 amps vs 90 amps), and you can customize everything: charging voltage cutoff, low voltage cutoff, power output, temperature cutoff, and you can monitor the state of charge and change these setting all via the phone app and provided Bluetooth dongle which you can leave plugged in inside the battery. I have purchased multiple BMSs from this company and they are all high quality and well built, there is no need to run them below spec, I have one that is going on 3 years of age and running at max amps on my 4kw ebike. Overall, if you have some battery skills and want to save close to $200 dollars, use this BMS instead of a replacement stock one. (The power is equivalent to a BMS bypassed Sur Ron but you get all the benefits of a BMS). I hope this helps some of y'all!




TLDR: New BMS has Bluetooth, more power, and more features, and is around 200$ cheaper then a replacement one
 
I assume the original state-of-charge meter won't work with the new BMS?

It would be nice to figure out what's going on with the secondary plug. It may just be a resistor across some pins that controls the limit setting.
 
JamesKHamilton said:
I recently had the BMS on my 2020(I think around there) LBX die, I looked online and a replacement BMS was 260$


plus shipping and tax, which seemed kind of absurd. So instead I bought this

BMS for $73 plus shipping and tax. It barely fits inside the stock battery compartment but with some squeezing it works just fine (my battery is a stock 32ah, idk about the new batteries with the upgraded capacity). There is only one problem with a new BMS, it does not talk to the Sur Ron controller the way the old one does, but apparently, it does not need to. The secondary plug NEEDS TO BE PLUGGED IN but does not need to be connected to a BMS on the inside. If the plug is not plugged in then the power is limited, but when it's plugged in it works exactly like normal but more powerful. I do not know why this is but I assume the bike has some way of identifying if it's plugged in to both plugs. Installing the new BMS took me about an hour and a half but I work on batteries a lot so I knew what I was doing, if you have any questions DM me on Reddit and I am happy to help you out. This new BMS also outputs more power (100 amps vs 90 amps), and you can customize everything: charging voltage cutoff, low voltage cutoff, power output, temperature cutoff, and you can monitor the state of charge and change these setting all via the phone app and provided Bluetooth dongle which you can leave plugged in inside the battery. I have purchased multiple BMSs from this company and they are all high quality and well built, there is no need to run them below spec, I have one that is going on 3 years of age and running at max amps on my 4kw ebike. Overall, if you have some battery skills and want to save close to $200 dollars, use this BMS instead of a replacement stock one. (The power is equivalent to a BMS bypassed Sur Ron but you get all the benefits of a BMS). I hope this helps some of y'all!




TLDR: New BMS has Bluetooth, more power, and more features, and is around 200$ cheaper then a replacement one
Click to expand...
Thanks for the write up. Why did you chose this BMS vs a Ant or something more popular? Looking at changing the stock BMS on my batteries for something with more amps as I don't like the idea of a bypassed battery.

Some probing of the stock BMS should tell you if something is jumped inside or if there is a resistors to tell the controller it's plugged in.
 
Has anyone else tried a different BMS with the stock battery?
 
Allex said:
ANy will do I use different depending on the cells. mostly i Use 20s 300A version though. The thin one.
Click to expand...
And they all fit in the stock case? I'm looking to replace my BMS vs doing a bypass on my stock battery
 
Quinc said:
what swing arm is that and how do you like it?
Click to expand...
It's the Ebmx swing arm & I love it. It makes this bike so much more stable at speed, I only ride off road. Also it still wheelies very easily but its much more controllable and less prone to flip over backwards. Very noticeable when you climb steep hills or going over deep dirt bike size whoops. Bigger whoops still cause it to bottom out occasionally but nothing like before.
 
They get seized and crushed by the police in the UK. Too many are used for drug transportation by county lines dealers.

www.yorkshireeveningpost.co.uk

Leeds police seize electric dirt bike and issue warning over dangerous usage

Police have seized an electric dirt bike in Leeds and issued a warning about the dangerous and inappropriate use of them.
www.yorkshireeveningpost.co.uk www.yorkshireeveningpost.co.uk

www.gazette-news.co.uk

Electric vehicles being used illegally and 'without consideration' seized by police

Essex Police's Tendring team confiscated the vehicles
www.gazette-news.co.uk www.gazette-news.co.uk
 
Theodore Voltaire said:
Back in 2017 when Allex first posted this thread no one had heard of SurRon. Now 8 short years later they've taken over the eBike world, and second place is miles behind. There's something very endearing about these bikes that makes owners willing to spend amounts equal to the original price of the bike for upgrades. A whole cottage industry has sprung up around them. The aftermarket for SurRon rivals or surpasses every bike I can think of except Harley Davidson. Every bike manufacturer dreams of having a hit like this. It's hard to put a finger on exactly what mades them so desirable. Besides just being a well designed, and well thought out bike, I don't think it's any one thing, but it's a combination of many. The power and speed of course. The low initial cost for sure, but that doesn't last long as most owners know. I think the small physical size is way up on the list. That seems to allow SurRon's to ride on the streets, and city trails unregistered, and unlicensed all over America judging by all the videos, and that might be the biggest factor.
Click to expand...
There was no competition. Theres a good number of small to medium mid drive dirt bike/ down hill bike hybrids now just a matter of if they take off or not and can meet shipping demands.

Plus sur ron is over priced now due to market share. Only thing worse of a buy in it's class is the Rawrrr mantis which is slower, has less range has worse suspension and costs more. All the other new sur ron rivals look good and I hope they do well.

Forum also had more engagement back then. No one covers new electric vehicles here anymore. Threads to bring attention to new dirtbikes, scooters, motorcycles coming to market die or get 2 replies when there used to be 100 page threads for junk ebay electric grom clones. The facebook page was also a bad idea.
 
Last edited:
Hello everyone. I just registered on this website. My name is Pedro and I live in Barcelona, Spain. I have a Sur-ron LB and I am very happy with her, but I only have about 35 km of range. I've replaced the original battery cells with newer ones, now having 50 Ah instead of 32. I've not changed the original controller. But a inconvenience has appeared. The original BMS of the battery is not capable of correctly managing the increase in capacity. Seeing that I cannot take advantage of the original BMS of the battery, I am looking for one aftermarket BMS compatible with the new cells and also with the original controller. Do any of you know of a BMS that works correctly? Thanks in advance. Regards, Pedro
 
Petrus69 said:
The original BMS of the battery is not capable of correctly managing the increase in capacity. Seeing that I cannot take advantage of the original BMS of the battery,
Click to expand...
Normally the BMS doesn't monitor capacity directly and limit usage based on that, it only monitors the individual cell groups and limits based on their voltages. If yours does, perhaps you can post the info that shows this, and the model / brand of BMS, so we can see if there is a setup software for it that can alter it's settings.

If you are not seeing the greater capacity from the new battery (which should also take significantly more space than the original to get a 5/3 increase in capacity), it usually means something is wrong with one or more cell groups, so they drop in voltage before they should and the BMS shuts off output to prevent damage to them.
 
If you don't connect the signal wires from the battery, the bike will still run, it just won't go into Eco mode when the pack gets low or hot.
Their BMS was custom made and I am not aware of any way to reprogram it. I have seen people modify the shunts on the BMS to allow higher current. If you did this mod with the right resistors, you could recalibrate the coulometer to match the new capacity of your cells and the SOC meter would be close to accurate and the low battery safety features should work.
 
fechter said:
If you don't connect the signal wires from the battery, the bike will still run, it just won't go into Eco mode when the pack gets low or hot.
Their BMS was custom made and I am not aware of any way to reprogram it. I have seen people modify the shunts on the BMS to allow higher current. If you did this mod with the right resistors, you could recalibrate the coulometer to match the new capacity of your cells and the SOC meter would be close to accurate and the low battery safety features should work.
Click to expand...
coulometer? Whats with this word and usage? Why all of the sudden peeps starting to use a coulometer instead of a wattmeter?
"Coulometry determines the amount of matter transformed during an electrolysis reaction by measuring the amount of electricity (in coulombs)" We are not doing the above right, we are actually measuring Amps and Volts, so why this coulometer where the unit is "coulombs"
 
Allex said:
coulometer? Whats with this word and usage? Why all of the sudden peeps starting to use a coulometer instead of a wattmeter?
Click to expand...

Because quite a few ads for them are using that term in addition to or instead of wattmeter (for the same item), particularly for the ones that use remote shunts unlike the typical RC Wattmeters we commonly think of in this usage. If we use the term too, then it makes it easier for those reading our posts to find them to buy them to do the testing/etc with (since we can never make those advertising them use correct terminology).

And the wattmeters *are* effectively counting coulombs, just displaying it as Ah or Wh after some math (and hence, the "wattmeters" are also effectively coulometers).

None of the terms used for these things actually describe their functions accurately and completely....

Also, there are multiple BMS chips out there that do specifically do coulomb-counting.
 
coulometer = amp-hour meter. It's how the battery SOC bar graph gets its information.
Either way, by changing the shunt resistance, the amp reading going to the chip will be changed.
 
Thank you for your reply. I haven't explained in enough detail my problem. With the original cells (32 Ah) the autonomy was about 40 km. When I had traveled about 32 km (the battery display indicating a capacity of 20%) the eco mode started and stayed until the end. Everything was normal. But with the new cells (50 Ah), the eco mode kicks in when I have also traveled 32 or 34 km (?) (the display also indicates 20% capacity), although this time the eco mode is more powerful than with 32 Ah . If I keep riding, at approximately 40 km the display indicates 0% charge but I can still ride... about 20 km more while the display is saying 0%!! (?). 40+20= about 60 km. If I park the motorcycle with a 10% charge p. ex., one day later the indicator shows a charge of 32 or 35% (?!).

Making a by-pass in the shunt (it is a solution that works in many electric vehicles), the result is even worse.

I do not know what is happening. The BMS and controller are the original ones from Light Bee.
 
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