February 15 2020 – Steven Ramsden
Here at Stag we wanted to touch on a subject that is on every Sur-Ron owners mind right now, especially as some warranties are starting to run out. We get at least one but sometimes 3-4 calls a day asking which controller upgrade/battery upgrade we recommend. This is how we see it.
We see all sorts of fantastic claims, 60, 70 and even 80 mph videos. So, in the interests of trying to bring some honesty to back an industry that is suffering a lot of BS as it grows, we as a Sur-Ron Community need to challenge the manufacturers and retailers of controllers and batteries to test properly and to show facts.
Always the first question asked, “how fast will it go”. Sure, we do need some kind of benchmark but I am yet to see one of the big Japanese Manufacturers quoting MX bikes in terms of top speed. That fact aside guys if you want to put out a top speed please let’s do it properly. A speed test is both directions, one after the other and an average of the 2 recorded speeds. USE A GPS SPEEDO AT LEAST PLEASE!!
This is the big one. It is very hard to pin this down as there are no standardised measurements and so many variables. I have been out with 3 other riders all on identical bikes doing the same route, I came back with 12% others were 20%, 31% and 40%. Yes I am a fat b’stard but no heavier than the rider on the 31% bike so it was more down to riding style. The industry needs a standard and as a community I think we would welcome any suggestions but for now, let’s try to talk the same language. The average Sur-Ron rider is 70-80kgs, the most common use would be forest trail (at least here in the UK), elevation should be as level as possible although you may go up a hill you still return to your start. The fact is the harder you ride or faster you go the faster you will drain the battery because it’s simple physics, so what should the standard be? Max 30mph? Average 25mph?
This is the most concerning. The bottom line is a battery’s energy is finite, the more you use the quicker it will finish. In the case of Sur-Ron the BMS limits the flow to protect the battery. This is where it gets interesting, after upgrading the controller and feeling disappointed with the results we hear “it’s the battery” so we have 2 options.
- Bypass the BMS limits. Guys who know what you are doing well done but please be careful posting user guides on how to do it, most people don’t know what they are doing, and it is dangerous. It is only a matter of time until we see an accident the BMS limits are there to protect you.
- New upgraded battery, all sorts of batteries on offer but has anyone stopped to question the safety of these batteries? Who is liable if you bought a dangerous battery from Facebook? I challenge battery makers to go through the correct process before someone gets hurt. Look up UL1642.
- Discharge test
- Charge-discharge cycling
- Temperature Measurements, Temperature cycling tests
- Short Circuit tests
- Crush test
- Impact test
- Humidity test
- Shock test
- Vibration test
- Drop test
- Low pressure (altitude simulation) test
- And More…
As a result of all of the above, Stag Motorcycles are still not confident in recommending any Sur-Ron controller or battery upgrades and further challenge those out there developing these upgrades to back up the development with proper testing and proper safety measures. We will continue to work with our customers to upgrade suspension, brakes and other accessories.