Rechargeable Batts
When I read through the book and got to the servo setups, it recomended that I not use rechargeable batteries since they were 1.2v rather than 1.5v. Which kinda sucks because I purchased an additional 8 rechargable batteries so me and my kids could tinker with these guys and not worry about batteries as much.
Can these not be used at ALL? Are they going to mess up the servos for sure?
What do you recomend in place of these as far as rechargables? Can I get a RC type batt and charge kit to work with this?
Sorry for my ignorance. I just do not want to fry my chips nor my servos.
Can these not be used at ALL? Are they going to mess up the servos for sure?
What do you recomend in place of these as far as rechargables? Can I get a RC type batt and charge kit to work with this?
Sorry for my ignorance. I just do not want to fry my chips nor my servos.
Comments
When you say "When I read through the book and got to the servo setups, it recomended that I not use rechargeable batteries since they were 1.2v rather than 1.5v." I'm not sure which book you're speaking about, nor what they intended to imply, but please consider this.
Given some arbitrary target voltage, you can't use the same number of primary batteries (non-rechargables) in series as rechargables, since the base, individual cell voltages differ by .3 volts per cell. However, also consider this:
4 x 1.5 = 6.0
5 x 1.2 = 6.0
So, the addition of one more rechargable battery in a batttery "pack", over what is found in a non-rechargable batttery "pack", results in the same final voltage. Therein, there is little difference, voltage-wise, between those two battery "packs". "Packs" here is intended to imply multiple batteries connectied in series, so that they appear as one voltage source.
Regards,
Bruce Bates
Post Edited (Bruce Bates) : 9/3/2006 2:17:43 AM GMT
Thanks again for the help.
See, they just don't make battery holders that hold 5 cells (batteries.)· If you look around a little, you can find single-cell holders; so, with a "4" and a "1" you can make your own 5-cell arrangement.· There are 6-cell holders and, if you know what you are doing, you can jumper/short one of them (i.e. a cell slot) out and everything will be everything --·if a "6V" re-chargeable battery is your objective.
I'm not sure how much better I can get my point across than what I've already said, but I'll try. Generally speaking, in any and all cases, NOTHING will be damaged, but performance (from a number of viewpoints) will unneccessarily suffer, when full voltage is not supplied to a given electrical or electronic device on the supply side (where the initial source of power exists).
Here is what I offered before, and I'll now expand on it:
Primary battery pack: 4 cells x 1.5 VDC = 6.0 VDC total
Rechargable battery pack: 5 cells x 1.2 = 6.0 VDC total
The above represent EQUIVALENT sources of power, presuming the mA (ampacity) ratings of the batteries·are equal, which they may or may not be.
Now, try this on:
Goal: Primary battery pack: 4 cells x 1.5 VDC = 6.0 VDC total
A: Rechargable battery pack: 4 cells x 1.2 VDC = 4.8 VDC total
B: Rechargable battery pack: 5 cells x 1.2 VDC = 6.0 VDC total
Which of the above rechargable battery packs is MOST equivalent (from a voltage perspective) to·our "Goal" of 6.0 VDC?
In what ways does A: above represent a poor and unaacceptable substitute?
1. Initial voltage (4.8 VDC) far below the optimum voltage of (say) 6 VDC. This will yield poor performace in most cases, and overheating in some cases.
2. Shorter period (duration) until cut-off voltage occurs. All active or dynamic electrical and electrical components generally have three voltages specified:
Minimum Voltage (MinV), Typical Voltage (TypV), Maximum Voltage (MaxV)
Example:
Arbitrary and hypothetical motor specifications:
MinV - 4.0 VDC, TypV = 6.0 VDC, MaxV = 7.5 VDC
Explaination:
As a battery is used, the operating voltage diminishes. With non-rechargables (non-alkaline) this voltage curve can be rather sharp. With alkalines, this voltage curve becomes less steep, and longevity over time (time to hit cut-off voltage) is increased. With rechargables, this curve is not only less steep, but is actually "propped up" a bit. (Ref: Battery performance curves for various battery chemistries for·additioanl information).
Where you START (initial or starting voltage) very much determines how·SOON you will STOP (reach the cut-off voltage) of your electrical or electronic device. The longer time this takes, the better performance and longer duration you will get.
Now reflect on the total voltage shown above for the various battery packs and configurations.
Let's HOPE this didn't confuse you completely :-)
Regards,
Bruce Bates
your explanation actually answers other questions I had and was a great help. Thanks for your knowledge in this department.
They make singles, doubles, triples, quads, and sixes, though.
Voltage is force, so generally lower voltage will not harm anything.
The excessive force of over-voltage is what causes the damage as most devices are either designed to be or are self-protecting in a brown out state.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
You shoudn't have any problems. Good Luck!
Those almost have to be nickel cadmium (ni-cad) batteries based on the voltage you are reporting. The full-charge single cell voltage should be 1.25 VDC, NOT 1.20 VDC.
Regards,
Bruce Bates
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
<!--StartFragment -->
Bill
Bill
Thanks for all the help guys.