Brammo Owners Forum

Yes, you can use the onboard charger and the portable charger at the same time and the extra amps will show on the instrument screen as normal. I replaced the 16 amp J1772 port with a 32 amp one and ran a 2.5mm2 cable to a plug near the Anderson plug so when I'm charging at a public charging station I plug in the bike and then I have 220v to plug in the extra charger up to 3000 watts. The public chargers here in the US are mostly 6.6 KW or more so I can charge at 6K

I think what you are seeing is the battery heaters which draw about 300 watts. If the temp is less than about 60F they will come on, even when you are riding. You should be getting a warning on the dash that says something like batteries too cold. This is normal opperation. Lithium cells should not be charged at less than about 40F so the bike is protecting the cells. Be happy you have battery heaters built into the bike. In cold weather it is good to plug in for 20 minutes or so even if you don't need more charge just to warm the cells up to minimise voltage sag.  also, if you just hop on and go when it's cold the heaters come on running off the batteries and draw 300 watts trying to warm the batteries and you will get a power cut back until the cells have warmed up.

I agree that the best range would be attained at the most efficient motor rpm but how do we determine which rpm is the most efficient? Then there is the efficiency of the transmission itself as a variable. I am no engineer but I made a fair attempt to research gear drive efficiency and there are many variables there as to the number of gear engagements, the relative diameters of the gears and the load on the drive. Lightly loaded drives are less efficient than more heavily loaded ones and a small gear driving a large one is less efficient than two gears of the same size so every time you shift to a different ratio and a different load you are changing the efficiency of the transmission. I would imagine the motor efficiency at a given rpm also changes based on the load placed on it. So many variables ! So being a practical person I did some simple tests. These were done on 3 consecutive days at an ambient temp of 60 F. I charged the bike overnight and then before starting the ride I topped up till the amps went to zero. I tried to keep the same speeds and to accelerate from stops just staying with traffic. The loop I chose is 60 miles with everything from 35 mph suburban roads with stoplights to 60 mph highway and half on the flat and half on hilly rural roads. I checked the % left at the halfway mark and the finish. I recorded the results but don't have that here at home. All runs were done in sport mode for max regen. The first run was in 5th gear, then 4th gear and lastly in 3rd gear. No shifting, just left it in the same gear all the way. Fourth and fifth gears used exactly the same % of battery! That surprised me. Third gear was the least efficient. I didn't try second because you can't do 60 mph .Starting out in fifth the throttle response is pretty dead. Horrible I would say so that is out and it did nothing to improve range. Fourth was the winner, the bike is perfectly drivable in traffic and as the speed increases the power is decent. There is probably a way to drive always keeping the motor at it's optimal rpm for the given load but even if you could figure it out it would probably be impractical. So when I am just in touring mode and want max range I drive in fourth sport. When I am not going for max range I just go as fast and accelerate as hard as I want in the gear that is appropriate. Sometimes I take 200 plus mile rides and I want the maximum range to cut down on charging times. I carry an extra 2000 watt portable charger to help speed things up at the level 2 EVSEs. I test rode an Energica Eva today. I was impressed. They have come out with an 18.6 K nominal battery and DC fast charging is standard but only a 3.3 K onboard charger. That is a bike you could actually tour on.

Great video! Looking at the Brammo wiring diagram it appears that the logic cable is the only connection the batteries have to the bike except for the plus and minus battery cables. What would happen if you unplugged the original pack logic cable and just plugged in the other pack logic cable? You might already know this but there are a couple of different screens on the instrument display that you can access by holding down the two buttons at the same time. The first screen gives batt voltage and high and low cell voltages plus a few more things and a little indicator that shows the balancing between the 7 modules. So you can't see individual cell voltages but all other cells would be in between those two values so good enough. It would give you some idea of what the health of the second pack is like and you could use the balance function.  You could even possibly figure a way to switch back and forth.

When I talk about efficiency I mean longer range at a steady highway speed. I did several tests on a 60 mile loop with speeds from 35 to 60 mph in different gears and I definitely got farther in 4th than in third. I think when Brammo recommends 5000 rpm they are talking more about power than range efficiency. Using higher gears automatically reduces the amps you can draw while accelerating, kind of an automatic ECO mode that you can change on the fly. If you are driving for performance then you will want lower gears but you will pay with amp hours used, but you will have fun! 

Hi All
It's been 90 degrees here in Portland OR and riding on rural highways I can get one mile per 1% on the battery % meter !

It will be interesting to know what the bike does with two sets of CAN signals from two battery packs. Keep us posted and I would love to see some pics of your trike conversion! Thanks for posting, this is interesting stuff.