High power RC motor and drive unit production
- Thread starter recumpence
- Start date
GGoodrum
1 MW
ozace said:
Adam! Ha, I wondered how long it would take for you to find your way over here.
Save all those a123 and emoli packs. :wink:
GGoodrum
1 MW
1clue said:
Matt, and some others here, are using 6s-5000mAh LiPo packs from HobbyCity (in HK...) and other such places. Using four of these, 2 in series and 2 in parallel will give you 12s2p and 10Ah. Each LiPo cell is 3.7V "nominal", which is what the voltage settles down to after the surface charge burns off in a few seconds. That means a 12s setup is really only 44.4V, not 48V. These cells need to be charged to 4.2V per cell, so fresh off the charger a 12s configuration will be at 50.4V. By comparison, SLA cells have a nominal voltage of 2V and a charge voltage of 2.40-2.45V, so a 24-cell SLA configuration will have a nominal voltage of 48.0V, and would get charged to 58.8V.
LiFePO4-based cells, like the powerful a123s, have a bit lower nominal voltage, at 3.3V, and get charged to about 3.65-3.70V. For charging purposes, 4 LiFePO4 cells can replace 6 SLAs, so a 16s LiFePO4 setup has an optimum charge voltage of 58.4V, which is about the same as a 48V SLA configuration. One big performance advantage of doing a "drop-in" LiFePO4 replacement in a system designed for SLAs is that the system has to be capable of handling the voltage of the pack right off the charger, so for a 48V SLA setup, that means 58.8V. Once under any sort of load, the voltage will quickly drop to the nominal voltage of 48V. A 16s LiFePO4 setup will also start out at 58V, or so, right off the charger, but the nominal voltage for a 16s setup is 52.8V, a full 4V higher than the 48V SLA nominal pack voltage. Anyway, there are lots of 48V SLA charging solutions, most of which will work for a 16s LiFePO4 setup.
One still unknown issue with using typical "HV" RC controllers is that most are designed to work with a max of 12s LiPo setups. In particular, the Castle Creations HV110 is the prefered unit for these ebike setups right now, but it is not clear to me, at least, how much higher than 50V they can handle. I know from my RC helicopter experience that a 15s a123 setup works just fine, but I'm not sure about 16s just yet. I plan on testing an HV85 I have this week, to see. A 15s pack gets charged to about 55V, so I know it is good to that point, but a few more volts, I'm just not sure about yet.
LiPo packs save weight over most LiFePO4 setups, and can supply tons of current. They are not exactly the safest solution though, as they can catch fire if overcharged, or over-discharged. With proper precautions, however, they can work quite well. Not sure about how long they will last, however. Not too long ago, even good LiPo packs would only last a year, or so, but now, I just don't know. We'll find out soon enough,I'm guessing, as several people here have been using them for awhile now.
Personally, on my own bikes, I only use a123-based packs. With these RC-based setups, I'm hoping to standardize all my setups for 16s configurations. I just finished building a new 16s5p 48V/11.5Ah a123 pack, using the good cells out of a bunch of reject DeWalt tool packs that I bought from Doc.
-- Gary
recumpence
1 GW
Hey OZ,
You found our secret hangout! So, how did you find us?
We are making parts for these guys too. :wink: The guys at RC groups have been wondering where we went. Well, here we are! A few others here such as Miles are on RC groups a bit as well. Ron Somersen (spelling?) is here as well.
Welcome!
So, can Gary and I set you up?
Clue,
I have a few packs to run. However, the recumbent is currently running 12S 10ah cells (yes that is 10,000 MAH). For those who don't know, RC stuff is rated in MAH. 1,000 mah is 1ah.
I like Hyperion chargers best. I know you are already familiar with the ins and outs of Lipo. If you want to go that route, I can help you out chosing cells.
I get 20 to 25 miles out of my 48 volt, 10ah pack if I stay at 20mph. I would say, if you bring your charger with you to recharge at work, I would go with at least 15ah (15,000 mah) 48 volt pack.
12S is 44 volts nominal. However, I very rarely see less than 46 volts when I run my pack. However, I typically recharge after 10 miles or so (1/2 charge).
Matt
You found our secret hangout! So, how did you find us?
We are making parts for these guys too. :wink: The guys at RC groups have been wondering where we went. Well, here we are! A few others here such as Miles are on RC groups a bit as well. Ron Somersen (spelling?) is here as well.
Welcome!
So, can Gary and I set you up?
Clue,
I have a few packs to run. However, the recumbent is currently running 12S 10ah cells (yes that is 10,000 MAH). For those who don't know, RC stuff is rated in MAH. 1,000 mah is 1ah.
I like Hyperion chargers best. I know you are already familiar with the ins and outs of Lipo. If you want to go that route, I can help you out chosing cells.
I get 20 to 25 miles out of my 48 volt, 10ah pack if I stay at 20mph. I would say, if you bring your charger with you to recharge at work, I would go with at least 15ah (15,000 mah) 48 volt pack.
12S is 44 volts nominal. However, I very rarely see less than 46 volts when I run my pack. However, I typically recharge after 10 miles or so (1/2 charge).
Matt
recumpence
1 GW
Oh, hey, my anodized parts are finished. They are being shipped back to me today. I should have them in the next few days.
Gary, the main pulley for you is finished as well (for your drive #2). So, your drive number 2 will be done shortly (maybe tomorrow). I have your lengthened shaft and bearing tube done. If I can get your drive done tomorrow I will ship together. If not, I will ship individually.
D, Your drive is next!
Y, your drive and JRH drives will be done after that.
Life is good!
Matt
Gary, the main pulley for you is finished as well (for your drive #2). So, your drive number 2 will be done shortly (maybe tomorrow). I have your lengthened shaft and bearing tube done. If I can get your drive done tomorrow I will ship together. If not, I will ship individually.
D, Your drive is next!
Y, your drive and JRH drives will be done after that.
Life is good!
Matt
Hmm.
Thanks for the explanation. I guess I didn't see the second set of cells, I only saw 2 on his old bike.
One habit I have right now, and don't intend to stop any time soon, is to use a balancer every time I charge. If necessary, I'll plug one into each battery and leave it there permanently.
I'm going to need more energy than what Matt is using. I'm going a lot further than he says he gets battery life for, and I'm a lot bigger man too. And the possibility of every day use for most of the summer implies that the cells will be taking a beating simply from the number of cycles. Personally I think I'm looking at around 30 AH or more, and probably two separate packs in case one goes bad. I could put the dead one in a battery bunker and charge it super-slow in my garage, and then swap out the new one onto the bike. My goal is to never get close to the "zone of temptation" when the voltage starts to plummet. Also, the higher the AH rating the slower the cells think they're being discharged, and the more efficient the batteries become.
You guys know all that, I guess I'm just letting you know I've done at least some homework.
Since I don't know a price tag for the batteries yet, I may change my mind later. I still have to get an estimate for my version of the drive, too, and that may make a lot of difference.
Frankly I was considering LiPo rather than LiFePO4. I know about the charging characteristics and the dangers. I'm still open to people who know better and think they can convince me though
Thanks for the explanation. I guess I didn't see the second set of cells, I only saw 2 on his old bike.
One habit I have right now, and don't intend to stop any time soon, is to use a balancer every time I charge. If necessary, I'll plug one into each battery and leave it there permanently.
I'm going to need more energy than what Matt is using. I'm going a lot further than he says he gets battery life for, and I'm a lot bigger man too. And the possibility of every day use for most of the summer implies that the cells will be taking a beating simply from the number of cycles. Personally I think I'm looking at around 30 AH or more, and probably two separate packs in case one goes bad. I could put the dead one in a battery bunker and charge it super-slow in my garage, and then swap out the new one onto the bike. My goal is to never get close to the "zone of temptation" when the voltage starts to plummet. Also, the higher the AH rating the slower the cells think they're being discharged, and the more efficient the batteries become.
You guys know all that, I guess I'm just letting you know I've done at least some homework.
Since I don't know a price tag for the batteries yet, I may change my mind later. I still have to get an estimate for my version of the drive, too, and that may make a lot of difference.
Frankly I was considering LiPo rather than LiFePO4. I know about the charging characteristics and the dangers. I'm still open to people who know better and think they can convince me though
MitchJi
10 MW
Hi,
Exactly.
The Yellow sprocket should be fixed. It can't FW in the same direction as the pedal sprocket because it wouldn't drive the shaft. It could FW in the opposite direction but that is redundant because there is already a FW on the rear hub. I think the easiest way to do that is to use Surly (or equivalent) track cogs. They will screw onto the 1/2" same FW adaptors Matt is using. Jason who made the FW adaptors for Matt quoted me $20 each for a lot of 5 custom adaptors with the extra length required for the Cog/FW combination.
The large green sprocket (on the secondary shaft) should also FW.
If you mount the Track Cog and the FW adjacent on the same shaft and use a shoulder-less shaft (concealed set-screws) I don't think that will be a problem. The track cog will have most of the force and its only about 7mm thick. The Purple will only have the pedal force and its only about an extra 7mm further out on the shaft. Both sprockets might actually be closer to the base of the shaft than with the standard configuration (with shoulders).
1clue said:Just had an idea. Here's my understanding of how your drive goes together, and with my double sprocket on the end. (that's assuming I figure out how to post my totally inadequate image)
So that's the drive stretched out (please forgive my art skills, they are nonexistent) but consider this:
Hmm, I already discovered a problem. The yellow sprocket going to the wheel would not be a freewheel, it would be solid on the shaft. The second stage driven would be a freewheel. Right?
Exactly.
The Yellow sprocket should be fixed. It can't FW in the same direction as the pedal sprocket because it wouldn't drive the shaft. It could FW in the opposite direction but that is redundant because there is already a FW on the rear hub. I think the easiest way to do that is to use Surly (or equivalent) track cogs. They will screw onto the 1/2" same FW adaptors Matt is using. Jason who made the FW adaptors for Matt quoted me $20 each for a lot of 5 custom adaptors with the extra length required for the Cog/FW combination.
The large green sprocket (on the secondary shaft) should also FW.
1clue said:
If you mount the Track Cog and the FW adjacent on the same shaft and use a shoulder-less shaft (concealed set-screws) I don't think that will be a problem. The track cog will have most of the force and its only about 7mm thick. The Purple will only have the pedal force and its only about an extra 7mm further out on the shaft. Both sprockets might actually be closer to the base of the shaft than with the standard configuration (with shoulders).
AussieJester
1 TW
Matt..be a slight delay in me purchasing said drive/motor ESC Have decided to finish this trike AS IS and use it AS IS as my 'ute' (pickup) and build a tilting trike which i will use your drive unit on so no need to set aside one for me from your first run sincerely appologise for any inconvenience may have caused mate.
KiM
Apprentice Gangsta 8)
KiM
Apprentice Gangsta 8)
etard
100 kW
1clue,
If you are going Lipo, you might save yourself some dough and snatch some of these up:
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=6499
$57, 52 left and counting. Thank Luke (liveforphysics) if you buy them.
If you are going Lipo, you might save yourself some dough and snatch some of these up:
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=6499
$57, 52 left and counting. Thank Luke (liveforphysics) if you buy them.
j3tch1u
10 kW
GGoodrum said:
hey gary, that's a beautiful motor. i'm thinking of picking up one of those myself. did you order custom or stock kv? please let us know what kind of performance you get.
Hello everyone, this is stunning work! The bunch of you are doing an incredible job developing and networking this innovation. I have questions and contributions and registered so i could jump in.
I started reading the E-motorcycle posts, looking interesting alt transportation vehicles. I'm in Milwaukee and sell scooters and motorcycles for a living. I tune and ride my hot rod Lambretta GP upwards of 5000 miles a year and have taken her coast to coast. My dad was a Master tool+die maker for the AMC/Chrysler/Snap-on plants in Kenosha and taught at GTC. For years I have been lucky enough to be around people who not only think of innovative solutions, but create thier own adaptations as well. People who customize at the drop of a hat. People who improve and recombine the availible tools.
So, if I'm up to speed, these high performance RC motors with low Kv provide good torque. The Lipo packs coupled with high powered controllers can dump voltage fast and efficiently. The reduction drive needs to be very sturdy to interface to the bike, yes?
Perhaps, the recent clamp design can be more universal if you make it larger, then offer several different size inserts made of machinable nylon. Or perhaps, V shaped nylon inserts for quick universal clamping. Consider also, that the mounts used for two stoke 50cc bicycle motors is similar...and those folks don't have a source for heavy duty universal frame mounting hardware any better than the local hardware store.
Since there are a number of different final/rear hub harware sets being discussed, you may want to consider adding what dirt bikers call swingarm sliders. They are nylon "bobbins" that protect they axle and chain in a drop. Motorcyclist also use frame, bar-end, and front hub sliders as well. These bikes are getting heavier and more complex and being pushed further than ever. Small bicycle scaled sliders would protect the investment even if the bike tips over while parked. They could likely be adopted by all the motored bicycle riders who "have a taste for speed". I think PA66 nylon in 1" diameter would work.
Personally I like vintage small motorcycles and am planning to build a Boardtracker bicycle that has concealed RC components. Batteries go in the gas tank, controller in the tool box, and drive mounted into the mudguard behind the seat post. Belt or chain to the rear wheel...I really can't decide yet. In the bigger picture, I have begun searching through manufacturers of mini-chopper, pocket rocket, and small motorcycle gas tanks and have some leads and contacts with importers. So, my angle here is to suggest that a 2 to 6 liter mini-chopper tank can carry the batteries, and perhaps controller, sensors, guages, cooling fans, charging port, frame mount and lock, etc... It would look cool and work for hub, RC, and rear DC motors. It could be a drop on upgrade for the millions of 24v and 36v bike already out there. Yes - No?
Let me know if I'm onto anything here. I'm not claiming to be the first to think of any of this.
Thanks, Peej
I started reading the E-motorcycle posts, looking interesting alt transportation vehicles. I'm in Milwaukee and sell scooters and motorcycles for a living. I tune and ride my hot rod Lambretta GP upwards of 5000 miles a year and have taken her coast to coast. My dad was a Master tool+die maker for the AMC/Chrysler/Snap-on plants in Kenosha and taught at GTC. For years I have been lucky enough to be around people who not only think of innovative solutions, but create thier own adaptations as well. People who customize at the drop of a hat. People who improve and recombine the availible tools.
So, if I'm up to speed, these high performance RC motors with low Kv provide good torque. The Lipo packs coupled with high powered controllers can dump voltage fast and efficiently. The reduction drive needs to be very sturdy to interface to the bike, yes?
Perhaps, the recent clamp design can be more universal if you make it larger, then offer several different size inserts made of machinable nylon. Or perhaps, V shaped nylon inserts for quick universal clamping. Consider also, that the mounts used for two stoke 50cc bicycle motors is similar...and those folks don't have a source for heavy duty universal frame mounting hardware any better than the local hardware store.
Since there are a number of different final/rear hub harware sets being discussed, you may want to consider adding what dirt bikers call swingarm sliders. They are nylon "bobbins" that protect they axle and chain in a drop. Motorcyclist also use frame, bar-end, and front hub sliders as well. These bikes are getting heavier and more complex and being pushed further than ever. Small bicycle scaled sliders would protect the investment even if the bike tips over while parked. They could likely be adopted by all the motored bicycle riders who "have a taste for speed". I think PA66 nylon in 1" diameter would work.
Personally I like vintage small motorcycles and am planning to build a Boardtracker bicycle that has concealed RC components. Batteries go in the gas tank, controller in the tool box, and drive mounted into the mudguard behind the seat post. Belt or chain to the rear wheel...I really can't decide yet. In the bigger picture, I have begun searching through manufacturers of mini-chopper, pocket rocket, and small motorcycle gas tanks and have some leads and contacts with importers. So, my angle here is to suggest that a 2 to 6 liter mini-chopper tank can carry the batteries, and perhaps controller, sensors, guages, cooling fans, charging port, frame mount and lock, etc... It would look cool and work for hub, RC, and rear DC motors. It could be a drop on upgrade for the millions of 24v and 36v bike already out there. Yes - No?
Let me know if I'm onto anything here. I'm not claiming to be the first to think of any of this.
Thanks, Peej
recumpence
1 GW
Hmm, sounds interesting! We need pictures of your project when you get it running. I think you are on the right track on this. Untimately, RC type motors are the future for light weight, high performance setups.
I really have nothing to add to your comments. I think you are right on track.
Gary,
Your drive #2 shipped today along with the longer bearing tube and shaft (the #2 drive has the longer shaft and tube also. So, both of your drives will be setup this way).
I got my black anodized parts back today also. Very nice!
I will try to complete one drive per day to complete the pending orders.
Matt
I really have nothing to add to your comments. I think you are right on track.
Gary,
Your drive #2 shipped today along with the longer bearing tube and shaft (the #2 drive has the longer shaft and tube also. So, both of your drives will be setup this way).
I got my black anodized parts back today also. Very nice!
I will try to complete one drive per day to complete the pending orders.
Matt
Ypedal
100 TW
would love to see picture of anodize.. !! 8)
recumpence
1 GW
Patience, Daniel-san.
I will post pics when I can.
Oh, I also dropped off the frame clamp design with Dave. He will quote me on it shortly.
Matt
I will post pics when I can.
Oh, I also dropped off the frame clamp design with Dave. He will quote me on it shortly.
Matt
GGoodrum
1 MW
recumpence said:
That's perfect, thanks.
For those doing setups that use the crank, you might want to also request the longer shaft (5"?) and bearing tube. Assuming the drive is centered in the frame the distance from the center to the sprocket chain line for the bikes I have on hand ranges from about 1-1/2" to about 2-1/2 inches, depending on which "position" the drive sprocket/chainwheel is in.
-- Gary
Matt,
How many drives have you sold so far? Have you decided to serialize them? Is there a name for this drive? If you could even make a CNC program to carve your name and a serial number in there, that would be great.
Having done a little bit of research, I am admittedly confused about batteries again.
It seems that there is an industry for scooter batteries, but they are huge. It also seems that everyone is using LiFePO4 cells, when I would have thought they were small enough to use LiPo effectively. It also seems that the LiFe batteries are even more expensive than the LiPo ones are. Do scooter packs tend to have a battery management system inside?
I just noticed that this site has a section on that. I'm going to go do more research on a non-RC site.
How many drives have you sold so far? Have you decided to serialize them? Is there a name for this drive? If you could even make a CNC program to carve your name and a serial number in there, that would be great.
Having done a little bit of research, I am admittedly confused about batteries again.
It seems that there is an industry for scooter batteries, but they are huge. It also seems that everyone is using LiFePO4 cells, when I would have thought they were small enough to use LiPo effectively. It also seems that the LiFe batteries are even more expensive than the LiPo ones are. Do scooter packs tend to have a battery management system inside?
I just noticed that this site has a section on that. I'm going to go do more research on a non-RC site.
recumpence
1 GW
Gary,
Making the bearing tubes and shafts longer is easy. However, I designed the drive to be 4 inches wide for crank arm clearance. Most bike have 5 inches or less between the crank arms.
Clue,
I considered serialing them. But, I have not on this run. Maybe that can begin with the next run? Hmm, that would make unserialed drives more valuable?
LiFePO4 are much safer than LiPo. But, they are larger, lower C rating, and are expensive. LiPo are extremely light, powerful and high density. In my opinion, for those who are familiar with them, LiPo are the way to go. However, for a beginner that does not already understand them, I would steer them away from LiPo.
Matt
Making the bearing tubes and shafts longer is easy. However, I designed the drive to be 4 inches wide for crank arm clearance. Most bike have 5 inches or less between the crank arms.
Clue,
I considered serialing them. But, I have not on this run. Maybe that can begin with the next run? Hmm, that would make unserialed drives more valuable?
LiFePO4 are much safer than LiPo. But, they are larger, lower C rating, and are expensive. LiPo are extremely light, powerful and high density. In my opinion, for those who are familiar with them, LiPo are the way to go. However, for a beginner that does not already understand them, I would steer them away from LiPo.
Matt
MitchJi
10 MW
Hi Matt,
I have someone locally who can fabricate mounts but some people don't have that option. If you want to make mounts for buyers you could have them make a model of what they want in something like soft wood or rigid foam. They could email you digital photographs of the bike with the model mount and drive. You could suggest any changes you recommend and give them an estimate. They could send you the model and you could duplicate it in aluminum.
Question for Matt and David:
David's motor is going to have two machined end plates. Matt is machining a drive that will bolt to the front plate. Would it be more elegant and less expensive to combine forces and design and sell optional face plate(s) with some of the reduction unit integrated?
The faceplate(s) could have extension(s) for mounting the large pulley shaft, plus some stubs for attaching mount(s). There would need to be provision for the shaft to adjust for belt tension. For dual stage units there could be extension(s) on the opposite side of the motor for the secondary shaft.
I have someone locally who can fabricate mounts but some people don't have that option. If you want to make mounts for buyers you could have them make a model of what they want in something like soft wood or rigid foam. They could email you digital photographs of the bike with the model mount and drive. You could suggest any changes you recommend and give them an estimate. They could send you the model and you could duplicate it in aluminum.
Question for Matt and David:
David's motor is going to have two machined end plates. Matt is machining a drive that will bolt to the front plate. Would it be more elegant and less expensive to combine forces and design and sell optional face plate(s) with some of the reduction unit integrated?
The faceplate(s) could have extension(s) for mounting the large pulley shaft, plus some stubs for attaching mount(s). There would need to be provision for the shaft to adjust for belt tension. For dual stage units there could be extension(s) on the opposite side of the motor for the secondary shaft.
GGoodrum
1 MW
recumpence said:
I don't necessarily agree with all you comments here. LiFePO4 cells are definitely safer, and LiPos aren't for everybody, that much I will agree with, but not the rest. Ping packs are less expensive than any equivalent LiPo setup I've seen, including the lower-end "Zippys" from Hobby City. the Ping "duct tape" packs also use prismatic pouches, so they certainly aren't heavier, for equivalent capacities. Also included in the price of the Ping packs is a full BMS, so to really compare to LiPos, in terms of cost, you'd really need to add the cost of balancers.
As for performance, a123 cells match up with just about any LiPo I've ever used. They can handle 70A continuous, or 30C and up to 120A, for 10-20 seconds, which is 52C. That's a single cell. In typical ebike configurations, like 4p/9.2Ah, such a pack can handle 280A continuous, which is way more than any ebike application I'm aware would need. I have pulled over 100A out of a123 packs with very little voltage sag. In fact, the whole reason I ended up doing the LVC board in the first place is that I found it was too easy to run the packs down too far because the pack feels just as strong 10 seconds from the end as it does fresh off the charger.
-- Gary
Gary,
You're giving a compelling argument, and from your prior posts you don't seem like one to exaggerate.
Do you have any information site to back that up? I'm discovering that while I know a little bit about LiPo, I don't know a whole lot about some of these other chemistries.
I'm not stuck on LiPo, it's just what I know best.
Serial numbers: I want #6.
I am not a number, I am a FREE MAN!
You're giving a compelling argument, and from your prior posts you don't seem like one to exaggerate.
Do you have any information site to back that up? I'm discovering that while I know a little bit about LiPo, I don't know a whole lot about some of these other chemistries.
I'm not stuck on LiPo, it's just what I know best.
Serial numbers: I want #6.
I am not a number, I am a FREE MAN!
recumpence
1 GW
Oh no, here we go on the battery arguement!
Gary, you have me there on the cost. However, I have never seen a LiFe pack that is as light as a LiPo pack or as small. From my research, they are typically twice the weight and size of similar LiPo pack. My recumbent pack is 5 pounds exactly with wiring and it is a 48 volt, 10ah pack. Also, A123 cells can put out huge current, but they drop voltage further than good quality LiPo to do it. If I pull 10C out of my LiPo pack at full charge, I only lose 3 volts under load.
One thing I neglected to factor in (in my previous post) is charging. LiPo packs require an expensive charger to be charged safely. That dramatically increases innitial cost. The chargers are also large. So, they would typically not be carried with the bike. Whereas Ping packs typically use a small, lightweight charger that can be carried along easily. That, along with the safety factor, makes Ping packs and other LiFe packs more desireable than LiPo for the majority of riders.
I will repeat my warning on safety here..........
LiPo packs can be hazardous! I have had one explode when overcharged (bad charger). They are NOT for the beginner or the faint of heart. I have been running them for years, though, and am thoroughly familiar with their behaviour. That is why I run them.
Matt
Gary, you have me there on the cost. However, I have never seen a LiFe pack that is as light as a LiPo pack or as small. From my research, they are typically twice the weight and size of similar LiPo pack. My recumbent pack is 5 pounds exactly with wiring and it is a 48 volt, 10ah pack. Also, A123 cells can put out huge current, but they drop voltage further than good quality LiPo to do it. If I pull 10C out of my LiPo pack at full charge, I only lose 3 volts under load.
One thing I neglected to factor in (in my previous post) is charging. LiPo packs require an expensive charger to be charged safely. That dramatically increases innitial cost. The chargers are also large. So, they would typically not be carried with the bike. Whereas Ping packs typically use a small, lightweight charger that can be carried along easily. That, along with the safety factor, makes Ping packs and other LiFe packs more desireable than LiPo for the majority of riders.
I will repeat my warning on safety here..........
LiPo packs can be hazardous! I have had one explode when overcharged (bad charger). They are NOT for the beginner or the faint of heart. I have been running them for years, though, and am thoroughly familiar with their behaviour. That is why I run them.
Matt
scary stuff.FWIW i love my A123's performance, althoug i do have to have custom chargers, although i think that is because i know nothing and Steve makes them as user freindly for me as possible.
Matt, got any anodised pics? :lol: :lol: :lol: must be my turn now ? 8) give me a hit!!!
Cheers,
D
recumpence
1 GW
D,
I hope to finish your drive today if all goes well.
I will post pics of your completed drive as soon as I have it together.
I do not want to sound like I am saying Gary is wrong (other than the size and weight :wink: ). Gary is an expert on A123s. He ahs been running them longer than anyone I know. He is also more knowledgeable than I on charging. I just want to be clear that LiPo do have the highest power density per pound in the chemistries we are discussing here and the best discharge capability. They are dangerous, however, and cannot be fully discharged without cell damage. That being said, I would agree that A123 is a fantastic choice for the majority of users.
Matt
I hope to finish your drive today if all goes well.
I will post pics of your completed drive as soon as I have it together.
I do not want to sound like I am saying Gary is wrong (other than the size and weight :wink: ). Gary is an expert on A123s. He ahs been running them longer than anyone I know. He is also more knowledgeable than I on charging. I just want to be clear that LiPo do have the highest power density per pound in the chemistries we are discussing here and the best discharge capability. They are dangerous, however, and cannot be fully discharged without cell damage. That being said, I would agree that A123 is a fantastic choice for the majority of users.
Matt
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