June 2021 – Tales On Two Wheels

Seeding BBSHD aftermarket controllers has gotten more complicated in 2021. The 2021 choices have seen BBSHD market gorilla Luna up their controller game. To take on start up ERT in the F.O.C category, Luna has recently beta tested their Ludi V2 BBSHD controller. Luna explicitly states to “use this controller in off road only situations”.

The gray wire is an antenna for VESC dashboard & upgrades via Bluetooth on Android device.

I installed a Luna Ludi V2 FOC controller on my Specialized Pitch BBSHD conversion that utilizes a 42T Eclipse and wears Schwalbe 27.5 Moto X tires. Prior to upgrading the controller, the Luna 860c display showed a little over 30 hrs of riding time. I ride the same 25mi route of asphalt with this bike. It’s powered by a Luna Dire Wolf 52v 21aH battery that contains 84 LG MJ-1 18650 cells configured 14s6p.

I love this bike! It’s nimble and has crazy long range via 21aH Dire Wolf. It’s even color matched!

My commuter routine is about 12 mi asphalt in AM. Charge at work to 80%. Then ride home same route. Without changing gearing between the stock BBSHD controller loaded with Karl’s Sauce Settings and the Luna Ludi V2 controller, I have gained about 8 mph top end speed and my battery consumption has remain the same or slightly decreased.

The only issue so far with the controller upgrade is that the battery indicator goes red during acceleration or hill climbs when below about 50v. Previously the stock controller with Karl’s settings at the same mph and same gear selection did not trip the battery icon to red on the Luna 860c display .

On average, I am consuming about 3v less of total battery upon arrival at work, which is the 12 mi mark, before charging the battery to 80% using the Luna battery charger. My transit time is about 45 minutes to work and is nearly all ghost pedaling.

I am basically maintaining the same speed covering the same distance arriving at the same time to work but using less battery. This is possible because I am using less wattage/requiring less PAS as observed on the display.

Best 1st build BBSHD platform is a Thud Buster seat post on a mechanical discs hard tail frame.

The efficiencies can not be attributable to becoming a better ebike rider; getting more efficient in gear selection, braking, running stop light etc. If anything, I have greatly decreased gear changes. I am staying in my most effective cassette gear of 24T, 3rd biggest cassette gear, and not downshifting to provide more leg drive. 24T provides maximum chain wrap with out stripping. The previous 25hr of bike time I stripped out the lower tooth gears to the point I can’t use them under BBSHD power or human only power; the chain just skips terrible in those smaller cogs due to not enough chain wrap and the cassette teeth being worn down.

How much did I pay? This was beta and I did pay my own $. This is not available stand alone from Luna right now. If you want the Luna Ludi V2 FOC controller you have to buy a Luna BBSHD bike. In the past I did buy a Luna Ludi V1 controller for over $200 and I did buy an ERT NXT BAC 855 BBSHD kit for over $500. This beta was somewhere in between.

Make double sure you have the phase wire spade connectors seated properly to the BBSHD.

Is the Luna Ludi V2 desirable? YES!!! At the very least you can extend the range of your current battery. You can get more top end out of your bike and using throttle only you can reach a higher mph.

It was very straight forward to install. I have previously removed BBSHD controllers. I am familiar with how the PAS clip and 6 halls/temp clip operate etc. After you get familiar with this, it took under 1 hour to remove the stock BBSHD controller and install the Luna Ludi V2. It took about 10 minutes to silicone/water proof the connections.

Pro Tip!! When connecting the 3 BBSHD phase connection spade connectors, make double sure the spade goes into the female socket …… Plus look at the 4 pin PAS and 6 PIN halls/temp connector on your V2. Hints can be found how to disconnect your stock controller by actuating the retainer clip of the connector. When you disconnect wiring looms do you generally just grab and yank??!! No. Look at what came with the kit and carefully disconnect the stock controller by actuating the retainer tangs!

2nd Pro Tip!! Elevate the bike. Hang your bike by the front wheel and try to get the BBSHD/bottom bracket as close to eye level as possible. I had the luxury of a ceiling hoist. But you can use your garage door track or a ceiling hook as well. This will make it much easier to remove the stock controller and install the upgrade after mkt controller. You have to water proof all connection in the BBSHD before screwing down the controller and this is much easier at eye level.

It’s a tight fit to get everything folded back properly and the controller fastened to the BBSHD.

Luna has posted a firmware update. Using the VESC app, my nephew flashed the controller wirelessly using his Android phone and the blue tooth connection via the small antenna sticking out of the controller case. The flash upgrade included a pseudo-motor idle function that helps keep the chain semi-tight when letting off the throttle, helping to reduce chain slap. The amount of idle is increased by increasing the PAS level.

Performance into a 15MPH wind flat ground 55v at full sag during these observations.

Throttle only in PAS 5 and the biggest cassette gear of 34T gives 25MPH at 800 Watts; over 30+MPH at 1200 Watts. Full throttle made the LUNA Dire Wolf battery icon go red so I did not hold it there long but it was very fast acceleration and speed.

PAS 5 ghost pedaling and the biggest cassette gear of 34T gives 16.5MPH at 500 Watts; 24T gives 22.5MPH at 500 Watts.

In PAS the speed controller would stick to a MPH level and increase or decrease the Watts to maintain that speed; almost like a governor.

The BBSHD never got too hot to hold your hand on the motor or the controller. The motor never got hotter than 110 F.

Overall the Luna Ludi V2 is very good. It’s $ well spent even if just considering the battery range extension. If you are looking to scooter throttle only you won’t be disappointed in acceleration and top speed. As a PAS ghost peddler, it does not seem that different from the stock Bafang controller loaded up with Karl’s Sauce Settings. VESC app analytics dashboard looks cool but I don’t have an Android device nor the time to play around with those features. Luna warns not to change parameters on the controller without considering the consequences and locked out some of the most dangerous ones to the motor and rider.

P.S. At the time of publishing another field weakened BBSHD after market controller has burst on the scene. Enthusiasts of ASI BAC 855 have banded together via Discord collaboration to present a potential product challenge to Luna Ludi V2. The High Voltage team of Captain Codswallop, Mike and Greg bring a formidable grass roots business plan. I’ve done business with Captain on 3D printing for ebike items and was blown away at the exceptional level of quality and customer service. Captain told me High Voltage is “…new to the market but are providing a high quality product that customers are very happy with…focus…on customer service and quality. We are looking to expand to other motors in the near future.”

The High Voltage brand graphic to look for on authentic products:

In BBSHD Programming for the Pedaling Cyclist, I laid out what my preferred settings were for my ebikes. I have settled upon them after a fair bit of tinkering over time. Since that was published, I have made some refinements.

I’m going to skip all the background I went into before. None of those details have changed. I’ll just note what I have done, and what it seems to accomplish.

Remember, There is no one perfect suite of settings for the Bafang BBSxx series of motors. Most likely, your perfect setup will take a bit from here and a piece from there to give you exactly what you want. Use what you see here as a basis for your own experimentation.

In fact, I don’t even have a single flavor I stick to as you will see below.

The Basic Screen

From then to now, I changed nothing on this screen, and I’m only showing it here to give you a complete settings reference in one place.

Figure 1: My standard Basic screen settings

The Pedal Assist Screen

There are several changes here, all geared to toning things down and making behavior more gentle. I have two versions of this screen in play on different bikes. The first is the more general-use, but the things I get from Version 2 could be very desirable on any bike.

I can’t say enough that there is no one best choice of settings for your BBSxx motor.

Version 1

This config change is just here to show a couple of settings and discuss what they do.

BEFORE on the left. AFTER on the right

Pedal Sensor Type

Some motors come programmed with BB-Sensor-32, others with DoubleSignal-24. Depending on who you ask, BBSHD motors have 24 sensor signals per rotation, which seems to indicate DoubleSignal24 is the proper setting. I have tried them both and can tell no difference from one to the other.

Start Current

This has been reduced to 4 from 6. Start Current dictates how much juice goes to the PAS system when it initiates. A lower number means a lesser ‘jerk’ on the drivetrain as the PAS system engages. This is a percentage number, so we are going from 6% to 4%. Restated, that is from ‘gentle’ to ‘more gentle’. Still, as small of a change as is indicated by the numbers, its effect is noticeable.

Start Degree

This has been increased from 4 all the way up to 10. Start Degree is the number of signal points that are crossed (as you turn the crankarms) before pedal assist engages. A full rotation of the crankarms equals 24 signals, so I have kicked up the pedal assist engagement from a 1/6 turn to almost a half-turn.

This can come in handy when I am at a stop light, but I stopped several car lengths back from the actual intersection. I can then stay in the saddle, balanced, and slowly turn the crankarms a bit at a time to maintain my balance and crawl forward. If I do it right, the light turns green before I reach the edge of the intersection, whereupon I can start pedaling in earnest to move forward, without having to dismount (and then re-mount) the bike.

NOTE: This technique only works when you are on flat ground.

Current Decay

This is set to maximum now, meaning the system pretty much doesn’t want to cut back power as cadence increases; virtually disabling the cut-back feature from the Basic screen, which conserves power (if you can spin the crankarms superfast, you don’t need assist). This is a setting I will very likely continue to play with. If I set it to the minimum of 1, then the motor will aggressively reduce the provided power as cadence increases. A lower setting is much more in tune with the pedelec ‘philosophy’ which I usually stick to. So don’t be too surprised if you come back in a month and this text has been supplemented with talk of a different, much lower setting.

UPDATE: May 19 2023 – Its been a lot more than a month, and it turns out Current Decay is not well suited for hill country, where it is part of a suite of settings that cut power when cadence is high. Crawling up a hill in a granny gear – both on a hillside singletrack and on a city street – is not the time for a power cutback regardless of your cadence level. On flat ground, a Current Decay of 4 is indeed part of a cyclist-friendly exercise regimen where power gets cut as cadence increases.

Version 2

Version 2 is a riff on Version 1 above. Its what I use on my flat-land-bound 2wd/awd Bullitt cargo bike.

‘Before’ on the left is the Version 1 ‘After’ screen just above in Figure 2. On the right is Version 2

Start Current %

This value is reduced to two percent. Gentler is better for startup, with no real downside. One thing I have noticed, going down to 2% versus 4%: pedaling there is a slightly noticeable lag in performance; ever so slight. I’ll take that as it is a sign my motor settings are taking it very easy on my drivetrain, and this is part of why I have such long-lived chains and cassettes (3400 miles and counting on my Lizzard King’s original 11-speed chain as of May 2023).

Slow Start Mode

The slow start mode – the strength of the initial punch the motor gives out when it fires up – stays down at ‘3’. This is the lowest number that is agreed to be safe for the BBSHD controller based on other sources. This setting is part of keeping the BBSHD gentle on your drivetrain and eliminating wear and tear.

Start Degree

In Version 1 I have this set so that there needs to be just under a half rotation of the cranks before the slow-start of pedal assist engages. When all of the settings are taken in together, it typically means pedal assist doesn’t begin to be felt until the bike crosses a 5 mph speed (If I want assist earlier there is always throttle).

In Version 2, I have reduced this to a 1/6 turn of the crankarms. The idea with all of these settings put together is that assist from the rear motor starts faster – Remember, on this bike the BBSHD is supplemented by a front motor that starts almost instantly from a stop, so the BBSHD is not trying to haul a bike up from zero on its own. On such a big, heavy cargo bike, some assist from both wheels asap is a good thing. Net result is that with two motors, I can get a good result from pure pedal assist without having to resort to the battery-sucking throttle. I start pedaling and the bike safely glides forward even if its weighing 400+ lbs.

Current Decay

This is a full 180 from Version 1, where Current Decay is set to do as little as possible, meaning the motor is the least likely as it can be to pull power as your cadence increases. Here, it is at its next-most aggressive setting. In part this is informed by the fact that there is a front hub motor (running off the same common battery) that – if faced with a sudden power drop from the rear motor – will still provide forward assist, and in practice that means it will increase wattage as its workload increases. This is part 1 of 2 of this story, with Part 2 being …

Keep Current %

The amount of assist that is retained when Current Decay pulls power back has been reduced to 30%. So the two settings together make it more likely that, as cadence increases, power will be reduced, and the amount of power that will continue to flow has further been reduced by 25% from its previous (fairly low) value.

Got all that? Here’s what the rider feels: Not much. Despite my characterization of these changes as ‘aggressive’, which they are if you just look at the numbers onscreen, reality is the result is muted. We’re using a little less power, which we don’t miss much, and that is going to give us a bump in range. At 20-25 mph, pedaling strong at 60-70 rpm cadence, the BBSHD on flat ground is eating about 200-250w on the typical Assist Level 4 and 225-275w at Level 5. Thats pretty light (power consumption will be more on a bike with just the BBSHD for a motor!)

If you want to have the motor back off when you demonstrate you don’t need it (if you did you couldn’t spin your legs and the crankarms) the Keep Current and Current Decay settings are your go-to’s to reducing power consumption and increasing range.