Hi, I'm new and still trying to wade through all the stuff I need to meet my requirements.
I have a recumbent (a SWB TW Bent USS) that I would really like to use for my short (2 miles each way) commute to work. Unfortunately I pulled a thigh muscle badly (whilst paramotoring.......) and now find that sustained hill climbing is a real problem on the bent (bent riders here will know how hard hills are on the quads). My commute includes a long, (but quite gentle) grade on the way in that is enough to slow me down to below a safe speed in traffic. The fact that I am in my mid-fifties and not as fit as I'd like also has a bearing on my poor performance! Some power assist on the hill is my main aim, not all-electric power, as my intention is to use the commute to get fit as well as avoid doing short journeys in my Prius hybrid.
My chosen solution is a X'lyte 405 in the 20" front wheel, mated to a 35A controller. I already have a small stock of 12V 4.5A/Hr SLAs (with a 60A max discharge rate), so the initial plan is to use 4 of these as a test bed.
As far as control goes, I'd like to go pedelec, but hill starts on a bent are always challenging, so the option for a power start would be useful. I've ordered a thumb throttle, but plan to build a combined pedelec/throttle system. This should be easy enough, as it looks like the X'lyte controller just needs a 0 - 5V (or thereabouts) power control signal. If I put a cadence sensor on the bike and build a unit to mix the throttle and cadence outputs, such that the throttle can override the cadence sensor if required, then I think I should have what I want. I have a background in instrumentation design so this seems easy enough to do.
I've looked at bike power requirements and reckon that I need an average electrical input of about 200W for my commute, perhaps more on the way in but less on the way home. I believe that I will need about 80 to 90 W/Hrs of usable battery capacity for the two way journey. My 48V, 4.5A/Hr pack would give me a theoretical 216 W/Hrs, but I'm guessing that it's not sensible to use more than about 60% to 70% of theoretical capacity on SLAs. If my estimates are reasonable (any views?) then my SLAs might be OK as a permanent solution, although I might be inclined to invest in some lighter NiMH, or even perhaps Li Ion, batteries if it all works OK.
I'd appreciate any feedback on my proposed build - feel free to tell me I've got it all wrong!
I've also been playing with building some high power LED lights, using some ideas gleaned from the thread in "Technical". Being an electronics bod, I've opted to drive the LED's properly from a constant current supply to ensure reliability, which is easy enough. So far I'm impressed with the brightness, particularly for the reflector mounted rear array - they are so bright that it hurts your eyes to look straight at them. The combined current draw from the front and rear lights is less than 40mA from my 48V battery, so should have virtually no effect on range. I'll try and take some pics when they're finished and tested properly.
Jeremy
I have a recumbent (a SWB TW Bent USS) that I would really like to use for my short (2 miles each way) commute to work. Unfortunately I pulled a thigh muscle badly (whilst paramotoring.......) and now find that sustained hill climbing is a real problem on the bent (bent riders here will know how hard hills are on the quads). My commute includes a long, (but quite gentle) grade on the way in that is enough to slow me down to below a safe speed in traffic. The fact that I am in my mid-fifties and not as fit as I'd like also has a bearing on my poor performance! Some power assist on the hill is my main aim, not all-electric power, as my intention is to use the commute to get fit as well as avoid doing short journeys in my Prius hybrid.
My chosen solution is a X'lyte 405 in the 20" front wheel, mated to a 35A controller. I already have a small stock of 12V 4.5A/Hr SLAs (with a 60A max discharge rate), so the initial plan is to use 4 of these as a test bed.
As far as control goes, I'd like to go pedelec, but hill starts on a bent are always challenging, so the option for a power start would be useful. I've ordered a thumb throttle, but plan to build a combined pedelec/throttle system. This should be easy enough, as it looks like the X'lyte controller just needs a 0 - 5V (or thereabouts) power control signal. If I put a cadence sensor on the bike and build a unit to mix the throttle and cadence outputs, such that the throttle can override the cadence sensor if required, then I think I should have what I want. I have a background in instrumentation design so this seems easy enough to do.
I've looked at bike power requirements and reckon that I need an average electrical input of about 200W for my commute, perhaps more on the way in but less on the way home. I believe that I will need about 80 to 90 W/Hrs of usable battery capacity for the two way journey. My 48V, 4.5A/Hr pack would give me a theoretical 216 W/Hrs, but I'm guessing that it's not sensible to use more than about 60% to 70% of theoretical capacity on SLAs. If my estimates are reasonable (any views?) then my SLAs might be OK as a permanent solution, although I might be inclined to invest in some lighter NiMH, or even perhaps Li Ion, batteries if it all works OK.
I'd appreciate any feedback on my proposed build - feel free to tell me I've got it all wrong!
I've also been playing with building some high power LED lights, using some ideas gleaned from the thread in "Technical". Being an electronics bod, I've opted to drive the LED's properly from a constant current supply to ensure reliability, which is easy enough. So far I'm impressed with the brightness, particularly for the reflector mounted rear array - they are so bright that it hurts your eyes to look straight at them. The combined current draw from the front and rear lights is less than 40mA from my 48V battery, so should have virtually no effect on range. I'll try and take some pics when they're finished and tested properly.
Jeremy
