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no i disagree with this answer. the HB is designed to be left on
normal charge indefinitely. the batts can get a little warm. if they
are hot then something is wrong, but a little warm is nothing to worry
about.
when fully charged and with no load it is not unusual to measure 10 to
11v on a nominal 9.6v pack.
re: adding a drop resistor in series with the servo pwr, it should not
be necessary, that is the purpose of the large 3 ampere drop diodes.
kevin, if you would, please add a load (10 ohm 5 watt resistor e.g.)
and let us know the measured voltage.
thanks,
fred
In your message you said:
> In lugnet.robotics.handyboard, Dr. Kevin Nickels writes:
> > I've got a pre-assembled Gleason Research HB with expansion board, and
> > have a
> > couple questions. We've left it plugged in (on normal charge mode) for
> > a week or so.
>
> Ouch. You don't want to do that too much or you will torch (may have
> torched) your NiCds. NiCds do NOT like to be overcharged, it causes a proble • m
> called Voltage depression that many mistakenly call "memory effect".
>
> [snip]
> > The HB seems to work just fine, but I'm concerned about hooking up my 6V
> > servo to a 10V sourse. I've yet to load the servo ports with a resistor
> > or something to see if that brings it down, but even with a 0.7v/diode
> > drop, we'd be significantly high.
>
> Servos will pull up to 300ma at high loads, so a drop resistor may not be wha • t
> you want to do. I have used hacked servos at up to 12V for 5+ minutes at a
> time with them only getting a bit warm. Are you measuring your voltage at th • e
> ports with the charger plugged in? This will raise that voltage a bit if you
> are. How many cells are in the battery pack? Regardless, hobby servos will
> happily chug along on as much as 7.2V for as long as you need them to. If yo • u
> are concerned, or are using expensive servos, just put a couple more diodes i • n
> the circuit, but make sure they can handle 300+ma loads, and remember that th • at
> voltage will most likely drop under load.
>
> have fun,
> DLC
>
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Message has 2 Replies:
 | | Re: Overcharged battery?
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| (...) I was guessing here - most chargers don't check for peak charge, since I didn't know if the Handiboard charger did or didn't... If the charger has a trickle charge of more than C/50 or C/100 then NiCds will be damaged eventually on a long-term (...) (25 years ago, 15-Mar-00, to lugnet.robotics.handyboard)
| | | Re: Overcharged battery?
|
| (...) OK, this is good to know. (...) Yes, *if* more drop is necessary, more rectifier diodes would be called for (i.e. relatively fixed voltage drop), not a series resistor (v=iR). (...) I didn't have any 5watt resistors handy, so I put a pretty (...) (25 years ago, 15-Mar-00, to lugnet.robotics.handyboard)
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Message is in Reply To:
| | Re: Overcharged battery?
|
| (...) Ouch. You don't want to do that too much or you will torch (may have torched) your NiCds. NiCds do NOT like to be overcharged, it causes a problem called Voltage depression that many mistakenly call "memory effect". [snip] (...) Servos will (...) (25 years ago, 15-Mar-00, to lugnet.robotics.handyboard)
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