Sorry for my bad english.
can i use vs=vl jumper and power vl 9v 1600mA bcoz i want to use only one battery.I don’t understand why you have to throw jumper away and connect it with two battery. 
And if i use 9v 1600mA.Is it too much?Thankyou
first off 9V on VS to power r/c servos is too much. as you want to connect VL=VS this implies you want 9V on both VS and VL. setting VS to 9V will damage many r/c hobby servos.
the reason removing the VL=VS jumper and using separate small 9V battery for VL is recommended is because when several servos are under a lot of load they can draw several amperes which tends to draw the battery voltage down. if they manage to draw the battery voltage below the minimum voltage required on the VL input it will reset the controller. thus the easiest solution is to use separate batteries for VS and VL so the micro never gets reset regardless of what degree of abuse the servos are suffering.
1.What’s about 1600mA.I read from the manual and it’s say that the maximum is 500mA.but i don’t understand that 500mA is VL or VS
2.I use only 4 servo.Do you think it will have reset problem or not?
- I am thinking some basics need to be explained… I’ll give it a shot.
The maximum current the VL input will draw is stated to be 500mA because the regualtor it connects to will only deliver up to 500mA before it shuts down. normally the current drawn by VL is much less, in fact unless you are powering sensors from the header with the ABCD inputs it is, as I recall, around 50mA.
Next up, your battery is rated 1600mAH, note the H in the units which stands for hours. mAH is an approximation of capacity © when the battery is discharged at a C/20 rate. The units of the 20 is hours so 1600mAH / 20H = 80mA. Now most of the time current is drawn at a much higher rate and experience allows people to make rough estimates on how much time a battery of a given capacity will deliver a specific current… the most common being to divide by 1H and say, in the case of your 1600mAH pack, you can draw 1600mA for 1H. This is also known as the 1C rate of discharge for the battery. A 2C rate would be 2 * C / 1H, equal to 3200mA in your example.
Ok so another thing infered from the 1600mAH is the batteries ability to deliver a specified current rate. This is very chemistry dependant and therefore experience again plays a role in knowing what to expect. In practice the higher C-rate you discharge a battery at the less of it’s capacity you actually get to use. Most batteries have a maximum C-rate specified in their data sheet… in fact some batteries use the C-rate as a much hyped selling point such as the LiPO packs used in r/c airplanes.
Beyond an understanding of what the 500mA specified for the VL input and the 1600mAH for you battery pack mean I hope you can see the two things have little to do with each other beyond helping to pick a battery with enough capacity to deliver an amount of current for so many hours (or minutes in some cases).
- an example using the information I provided above might help you see the point.
if we consider the worst case scenario of some fairly common servos you might see 3A peak drawn when they are stalled. So if you were to stall all 4 servos this could be 12A for a very short period of time. Using 1600mAH pack this would be a 7.5C rate for the battery. A couple of things happen when you start drawing large C rates from batteries. First is the batteries output voltage drops due to their internal resistance. This isn’t much… usually somewhere around 0.03 ohm for this sized NiMH cell. So right off the bat at 12A each cell drops 0.36V, and a string of 5 cells drops 1.8V, before we even consider the resistance of the connection between cells. Then there is and the wiring to the pack connector, from the connector to the switch, from the switch to the ssc-32 , and the actual connection at the ssc-32 VS or VL connector. Each of these connections adds 0.003 to 0.020 ohm or more and every one of them drops some voltage. What remains at the VL input is applied to the voltage regulator and if that gets as low as about 4.7V the ssc-32 will reset.
While the example considered the worst case current situation I’m sure you can see we didn’t even bother to add up all the other voltage drops so even at half or even a quarter of the load, i.e. one servo stalled, you run the risk of resetting the ssc-32.
So are you getting the idea of why the VL and VS terminals are provided on the SSC-32 and why it is so frequently recommended to use a small separate 9V battery to power VL? Powering just the ssc-32, that is no accessories on the 5V line, an alkaline 9V battery will last about 10Hr. They also make rechargable 9V batteries and those will run about 3 to 4 hr per charge depending on which brand/capacity you buy.
Short answer to 2, yes I think you will occasionally have reset problems powering VL and VS from a 6V (5-cell) 1600mAH pack with 4 servos.