48v Throttle from Kelly

[kwheels]

Hey everyone,
I've recently gotten my KDS48200 running on my newest project, but have a question about the 48v throttle with battery indicator from kelly
http://www.newkellycontroller.com/product_info.php?cPath=36&products_id=647
i believe its a wuxing throttle


Does anyone know the voltage at which its lights cut out? It doesn't seem to actually show amount of battery left like i was expecting, but rather weather im driving economically or not. If i just cruise slowly and dont accelerate hard, the green light typically stays on, but if I floor it, especially from a stop, all lights but red turn off.


anyone have any imput to this? or at least know at what voltage the lights are cutting off?

 

[John in CR]

You're seeing the results of voltage sag. When you draw higher current like on acceleration the voltage of your pack drops. What kind of batteries and AH are you running?

 

[kwheels]

4S1P 12V 12AH SLA's @ 48v, 55.5 freshly charged.
No readings for when the batts are low
I knew there would be voltage sag, and with my old controller/throttle, it would do the same thing, but it would also give a much better idea of what kind of battery life is left.

as it is now, when my batteries are dead[enough that the controller hits the lvc and 'lurches' as it stops pushing] all 3 lights are still on. at that point, any throttle will drop the green light, and then the LVC kicks in.

is this just the peukert effect kicking in at the extreme, or just how the throttle lights were designed?

 

[John in CR]

Those LED battery gauges are fairly easy to tune with resistors. I had to do it once when I used a different pack voltage than the design voltage. I just used a cheap little variable potentiometer to determine my target resistances.

 

[kwheels]

thats sweet...have any more info on it? does one pot tune all of them, and you just hook it up to the yellow wire and tone it down?

 

[John in CR]

thats sweet...have any more info on it? does one pot tune all of them, and you just hook it up to the yellow wire and tone it down?

I only needed one resistor on the main wire, but mine were spread nicely between the highest and lowest LED. It sounds like yours may lack proper spacing and might need an extra resistor or two. I wouldn't leave the pot in line if you're actually using it as a battery gauge. A better cheap alternative is to pick up a multimeter for under $10 to install on your bike until you upgrade to something like a Cycle Analyst. Actual voltage is worlds better than a few LEDs.