Electronics > Electronics
3.7 v lipoly powering micro servo? bad idea?
mklrobo:
:) Hello!
I think I am begining to see a target of interest.
The ampere/hour of the battery will be of interest to you, in relation
to the amount of work desired, and the motor that is consuming the amperage.
Batteries Plus+ may have a good direction of what you would require.
I would base the load on the servos, doing what you want them to do for
a specified amount of time. (not forever) OR, the opposite, acquire the
amps of the servos moving, and convert that to ampere hours. The ampere
hours will determine how long you can run the servos.
The process will help you navigate the limitations of the batteries
that are avaliable, VS. time worked. What do you think? 8)
dmehling:
--- Quote from: bdeuell on February 09, 2015, 03:56:52 PM ---as 4.8 v is listed as the low end of the range I would not count on it working at a lower voltage.
You could also contact the manufacturer/retailer but they will probably give the same response. If you want to know for sure buy it and try it out they don't cost too much. Likely you will find that it doesn't work (or if you're lucky turns but has very little power). Remember there is a control circuit inside a hobby servo that requires power as well.
If you only have to power 2 small servos you could look for a boost converter that can handle the current. this would let you run the servos within their specified range and would maintain constant performance across the battery life. Remember that batteries decrease in voltage as they are drained, your servo system needs to work with a range of input voltages.
--- End quote ---
Are you sure it would not be possible? I just googled 3.7 v servo again, and found several sites and discussion forums of others who have used 4.8 v servos with 3.7 v batteries. They suggest that it may not be the ideal, but is workable with light loads. I have found some of the smallest servos I can find, and they will perform very light duty actions for very brief amounts of time. The servos should encounter very little resistance. So I should at least try it out. I was just wanting additional confirmation of what I had read elsewhere.
I would certainly consider using a boost converter as you suggested. If I was doing that, how would I know when the voltage is falling? I intend to put all of the electronics for my project inside of an enclosure, except the servos. Is there some way I could have the voltage voltage be checked internally and then have an LED light up if it goes to low?
dmehling:
What do you think Mklrobo about this issue of 3.7 v lithium polymer battery to power light usage of a sub micro servo 4.8v?
I would really like to use just a single battery, and preferably not use the heavier NiCd or NiMH battery packs.
dmehling:
--- Quote from: mklrobo on February 09, 2015, 04:28:34 PM --- :) Hello!
I think I am begining to see a target of interest.
The ampere/hour of the battery will be of interest to you, in relation
to the amount of work desired, and the motor that is consuming the amperage.
Batteries Plus+ may have a good direction of what you would require.
I would base the load on the servos, doing what you want them to do for
a specified amount of time. (not forever) OR, the opposite, acquire the
amps of the servos moving, and convert that to ampere hours. The ampere
hours will determine how long you can run the servos.
The process will help you navigate the limitations of the batteries
that are avaliable, VS. time worked. What do you think? 8)
--- End quote ---
Forgot to mention something else. Based on my very preliminary estimates I am thinking that a 300-1200 mah battery should give me enough power for at least 20 or 30 hours. I will only be running a servo for perhaps half a second every couple of minutes.
bdeuell:
--- Quote from: dmehling on February 09, 2015, 04:45:57 PM ---Are you sure it would not be possible? ... They suggest that it may not be the ideal, but is workable with light loads.
--- End quote ---
see earlier post:
--- Quote from: bdeuell on February 09, 2015, 03:56:52 PM ---If you want to know for sure buy it and try it out they don't cost too much. ... if you're lucky turns but has very little power
--- End quote ---
if you are engineering a design and want to use something outside if its specified operating parameters you can: A) request additional information about the product, B) conduct your own tests to determine the performance of the product, C) take an educated guess based on previous experience, or D) build it blindly and hope it works (not really engineering or recommended by me). Unfortunately i do not have experience undervolting servos to that degree and cannot offer you direct advice on option C. keep in mind you already have very small servos so your torque is already small without undervolting the servo (not to say it won't work just a caution). Also it doesn't really matter how short of a time you need the torque 1s - 10s the torque you can deliver is the same.
--- Quote from: dmehling on February 09, 2015, 04:45:57 PM ---I would certainly consider using a boost converter as you suggested. If I was doing that, how would I know when the voltage is falling? I intend to put all of the electronics for my project inside of an enclosure, except the servos. Is there some way I could have the voltage voltage be checked internally and then have an LED light up if it goes to low?
--- End quote ---
the battery voltage will continue to decrease as it is used (a datasheet would show this discharge curve). there are many ways to monitor a batteries voltage two common methods are to use an analog input pin on a microcontroller or a comparator circuit that uses a reference voltage to determine when the battery is below a threshold.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version