Battery upgrade for Cycloctricty Stealth 1000w
- Thread starter Andy Bluenoes
- Start date
I know the overall feeling is that my battery is okay, but I thought I would post these results hopefully to confirm it...
Start voltage was 54.4
14.5 mile commute, took 56 minutes. Its a pretty flat journey along part dirt track, canal path and a couple of miles on average condition roads.
A lot less wind than there has been of late, but the cycle path was still quite wed and muddy in places. Ice spiker tyres on still, running at 60psi
My weight is around 80kg, bike around 25 and my bag probably 4 or 5 on my back.
Bike was set on high power, and I would say power assist level 1 for 25%, level 2 for 60% and level 3 for 15% of the journey. Don't recall using the throttle.
Felt like there was a bit of juice left when I got here, as it quite often does the almost empty fuel tank thing.....you know when you're car has enough fuel in the tank for another mile, if you are going down hill and the fuel is at the right end of the tank? Weird that, but it does seem to happen.
Voltage now when I am about to charge it is 49.1
Dont know if this is expected, but it shows 4 volts when not switched on, both before the ride and after.
When it has drained on the odd occasion when I get here, it takes 3 hours or so to charge....
Many thanks
Hi Andy,
Your battery is OK. The range of battery voltage is 10V (from full to empty), you use roughly 53% of your 12AH capacity for 15 miles, 19.3WH per mile. That's normal for a direct drive motor.
It is unpleasant to ride on a more than half empty battery when you may be pressed for time but I am pretty sure you can squeeze 3 more miles out of it without needing to buy a new battery.
Your battery is OK. The range of battery voltage is 10V (from full to empty), you use roughly 53% of your 12AH capacity for 15 miles, 19.3WH per mile. That's normal for a direct drive motor.
It is unpleasant to ride on a more than half empty battery when you may be pressed for time but I am pretty sure you can squeeze 3 more miles out of it without needing to buy a new battery.
Thats good to know, thanks very much...it has confused me a bit though...if its used 53%...doesnt that mean I could get another 47% out of it?
yes, but you have to reduce the current draw to avoid low voltage cutout.
That means go slow.
The last 15%-20% will almost be unusable on a high current controller.
That means go slow.
The last 15%-20% will almost be unusable on a high current controller.
As the voltage goes down peak power available goes down too assisting you less. Simples.
A real world example, my battery at assistance level 5 and me just turning the pedals so not adding (m)any man Watts:
41.5 x 15 Amps = 622.5 Watts
36.5 x 15 Amps = 547.5 Watts
A difference of top end power of 75 Watts - that is roughly the Watts needed to compensate for the extra weight of the motor and battery on the bike.
A real world example, my battery at assistance level 5 and me just turning the pedals so not adding (m)any man Watts:
41.5 x 15 Amps = 622.5 Watts
36.5 x 15 Amps = 547.5 Watts
A difference of top end power of 75 Watts - that is roughly the Watts needed to compensate for the extra weight of the motor and battery on the bike.
D
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No, not go slow, go as fast as yo can on level one. The faster you go, the higher the efficiency.
You could try switching your controller over to speed control rather than current control. It's in the settings, so look in the manual how to do it. You could run on level 1 all the time then. It would be interesting to see the difference in efficiency. My prediction is that it would be more efficient.
You could try switching your controller over to speed control rather than current control. It's in the settings, so look in the manual how to do it. You could run on level 1 all the time then. It would be interesting to see the difference in efficiency. My prediction is that it would be more efficient.
Don't you mean pedaling harder on level one?
Should increase in air resistance more than eat away increase in motor yield?
Now i really am getting confused....Im pretty good with mechanical stuff. can even rebuild a car engine, but when it comes to electrics, I am at a loss. Ill have a google later, see if i can get my head round it all, appreciate the advice though 
Stick a WATT meter between your battery and controller and you will see what the amps/watts are doing in relation to your speed on different power levels.Now i really am getting confused....Im pretty good with mechanical stuff. can even rebuild a car engine, but when it comes to electrics, I am at a loss. Ill have a google later, see if i can get my head round it all, appreciate the advice though
http://www.ebay.co.uk/itm/DC-LCD-Monitor-Energy-Volt-Watt-Meter-RC-Battery-Power-Analyzer-60V-100A-UK-/252242300442?hash=item3abad00e1a:g:SrsAAOSwa~BYTkKu
Sorry to drag this up again, but after reading another thread about battery levels, it looks like a voltage drop of 1 volt is 10% of capacity gone....in which case, why dont these LCD's have a half decent "range left" display on them? It cant be that hard surely?
Maybe there is a way to DIY one.
All this has helped me though, I think im riding my bike in a different way now, and getting more out of it, but still not killing myself on the way to work. Ive been using it on level 1 assist for most of the journey now, 2 in a few places, and knowing I should have a burst of speed left at the end of the journey if I want it. And I can still do it in jsut under an hour which is my target really.
that is because the voltage also sags when the controller pulls more current. You will see the battery level on the LCD losing a bar or two when you climb a hill.
If you stop the bike for a minute to let the battery recover then the LCD shows pretty much the remaining capacity.
If you stop the bike for a minute to let the battery recover then the LCD shows pretty much the remaining capacity.
Im sure I read somewhere that the stealth meter for some reason doesnt show that...it shows how much drain you are putting on the battery based on your current load.....which is totally pointless really.
My old greenedge CS2 was much better at indicating what was left, and did work like you say.
My old greenedge CS2 was much better at indicating what was left, and did work like you say.
I have an excellent new power meter APP on my nexus 7 tablet and even that isn't capable of calculating what I have left in the battery (LiPo 3.8 V, 3950 mAh) despite it being a rather powerful little computer. Using a tablet doesn't involve head winds, hills, road condition... so you can imagine the added difficulty involved in calculating remaining range.
Experience and a Watt meter are the best tools to guess how much further you can go on a charge. My 20 month old Li-ion battery is completely unpredictable because it sags so much now. On the other hand my LiPo battery doesn't sag on the hills so it is very easy to guess how many km are left in it just from reading the remaining volts on the LCD.
Experience and a Watt meter are the best tools to guess how much further you can go on a charge. My 20 month old Li-ion battery is completely unpredictable because it sags so much now. On the other hand my LiPo battery doesn't sag on the hills so it is very easy to guess how many km are left in it just from reading the remaining volts on the LCD.
Perhaps I'm getting confused, but I thought Andy said he could only just about get to work on a single charge - he mentioned taking the charger to work.
In other words, his range is 15 miles, which equates to 39wh per mile.
Surely that's very high, suggesting the battery has nowhere near its theoretical capacity of 48v x 12ah = 576wh.
Yes, its a 15 mile run, I charge every day when i get to work. Occasionally I have ran out of juice on the way in and had to do all the work for the last mile.
In his earlier posts, he said he rides at arounnd 17-20mph. You can extrapolate that he pulls about 400W from his battery, or 8.3A,
8.3A * 0.3 Ohms internal resistance for this type of battery = 2.5V voltage sag. That means that he can't really use the last 25% reserve at that sort of speed. His trip uses 53%, he has 22% charge at easy going voltage before he hits the bottom 25%. He said he could do 3 more miles, I reckon he can do so about 6.5 miles rather than 3.
After that, he'll have to reduce assist level and pedal more.
Commuters on this sort of distance would do a lot better on a lightweight, light assist, rear hub bike like the Karoo.