How to use variable AC/DC power supply

Hi, I bought a variable voltage variable amp power supply to use
charging my RC batteries:
http://shop.vendio.com/evan2002/item...628/index.html

I don't really understand it much though. First, should I never turn
it on if there is no load?

I will use it with either a nicd/nimh charger or a lipoly charger. In
either case, should I turn the voltage to 12 volts, and the amps to
the maximum (10), then turn on the charger? Should the charger be
hooked up and turned on with a battery connected to be charged, before
I turn on the power supply?

Thanks very much in advance for any guidance.

Jim

Thanks for the replies.

I bought this power supply for $300, because I have other uses for it,
such as in my laboratory at work. But in some applications, I will use
it to its max to charger very large battery packs for very large
planes. It is what other people who do what I do buy.

RC battery chargers do not come with power supplies.

This is the charger:

http://www.batteryjunction.com/temilibachwl.html

Thanks for any helpful replies.

CharlesBlackstone <(E-Mail Removed)> wrote in news:17fdbbc6-
094d-43c6-8636-(E-Mail Removed):

> Thanks for the replies.
>
> I bought this power supply for $300, because I have other uses for it,
> such as in my laboratory at work. But in some applications, I will use
> it to its max to charger very large battery packs for very large
> planes. It is what other people who do what I do buy.
>
> RC battery chargers do not come with power supplies.
>
> This is the charger:
>
> http://www.batteryjunction.com/temilibachwl.html
>
> Thanks for any helpful replies.
>
>

Your supply seems to have two kinds of limits.
Voltage and current.

This means that you can regulate the 'open circuit voltage'. You would want
to make sure that never exceeds your battery voltage by more than a few
percent.

The current regulation means you can regulate the 'short circuit current'.
You would want to make sure this never exceeds the safe charging current
for your battery (which should be something on the order of 10% of the
discharge current).

You should look up the charging conditions for your particular battery,
with nothing connected to the supply, set the open circuit voltage.
Then, with an amp meter (perhaps the supply has one built in), short the
output and set the current to less than the max charging current.

NOW, you can connect your battery to be charged.

Since you have a 'dumb charger', you will need to monitor the charging to
make sure you don't overcharge the battery.
If your voltage and current settings are correct, that shouldn't happen,
but .... it is better to be safe than sorry.

What you do NOT want to do with a TRUE current supply (one that could go to
any voltage) would be to open circuit it, because it would go to infinite
voltage.
What you do NOT want to do with a TRUE voltage supply (one that could go to
any current) would be to short the output because the current would be
infinite.
A supply that regulates BOTH, however, is limited in both and thus kind of
the best of both worlds.




--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+(E-Mail Removed) remove ch100-5 to avoid spam trap

On May 17, 6:29*pm, bz <bz+...@ch100-5.chem.lsu.edu> wrote:
> CharlesBlackstone <charlesblacksto...@hotmail.com> wrote in news:17fdbbc6-
> 094d-43c6-8636-04ad44536...@s50g2000hsb.googlegroups.com:
>
>
>
>
>
> > Thanks for the replies.
>
> > I bought this power supply for $300, because I have other uses for it,
> > such as in my laboratory at work. But in some applications, I will use
> > it to its max to charger very large battery packs for very large
> > planes. It is what other people who do what I do buy.
>
> > RC battery chargers do not come with power supplies.
>
> > This is the charger:
>
> >http://www.batteryjunction.com/temilibachwl.html
>
> > Thanks for any helpful replies.
>
> Your supply seems to have two kinds of limits.
> Voltage and current.
>
> This means that you can regulate the 'open circuit voltage'. You would want
> to make sure that never exceeds your battery voltage by more than a few
> percent.
>
> The current regulation means you can regulate the 'short circuit current'.
> You would want to make sure this never exceeds the safe charging current
> for your battery (which should be something on the order of 10% of the
> discharge current).
>
> You should look up the charging conditions for your particular battery,
> with nothing connected to the supply, set the open circuit voltage.
> Then, with an amp meter (perhaps the supply has one built in), short the
> output and set the current to less than the max charging current.
>
> NOW, you can connect your battery to be charged.
>
> Since you have a 'dumb charger', you will need to monitor the charging to
> make sure you don't overcharge the battery.
> If your voltage and current settings are correct, that shouldn't happen,
> but .... it is better to be safe than sorry.
>
> What you do NOT want to do with a TRUE current supply (one that could go to
> any voltage) would be to open circuit it, because it would go to infinite
> voltage.
> What you do NOT want to do with a TRUE voltage supply (one that could go to
> any current) would be to short the output because the current would be
> infinite.
> A supply that regulates BOTH, however, is limited in both and thus kind of
> the best of both worlds.
>
> --
> bz * * *73 de N5BZ k
>
> please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
> infinite set.
>
> bz+...@ch100-5.chem.lsu.edu * remove ch100-5 to avoid spam trap- Hide quoted text -
>
> - Show quoted text -

What is the voltage and current that is specified to charge the
batteries that you are planning to charge????

"Dave Plowman (News)" <(E-Mail Removed)> wrote in
news:(E-Mail Removed):

> In article <Xns9AA1BC2E27A24WQAHBGMXSZHVspammote@130.39.198.1 39>,
> bz <bz+(E-Mail Removed)> wrote:
>> This means that you can regulate the 'open circuit voltage'. You would
>> want to make sure that never exceeds your battery voltage by more than
>> a few percent.
>
> IMHO the charge voltage is pretty irrelevant. It's the current that
> matters.

I agree that the current IS the most relevant parameter.

The voltage is relevant if there is a cell that is failing or if you want
to safely charge different kinds of batteries and avoid overcharging.

There is no harm to limiting the voltage.






--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+(E-Mail Removed) remove ch100-5 to avoid spam trap

On Sat, 17 May 2008 18:45:15 +0100, Dave Plowman (News) wrote:

> In article
> <ee259986-a06e-40fb-b75d-(E-Mail Removed)>,
> CharlesBlackstone <(E-Mail Removed)> wrote:
>> Hi, I bought a variable voltage variable amp power supply to use
>> charging my RC batteries:
>> http://shop.vendio.com/evan2002/item...628/index.html
>
>> I don't really understand it much though. First, should I never turn it
>> on if there is no load?
>
>> I will use it with either a nicd/nimh charger or a lipoly charger. In
>> either case, should I turn the voltage to 12 volts, and the amps to the
>> maximum (10), then turn on the charger? Should the charger be hooked up
>> and turned on with a battery connected to be charged, before I turn on
>> the power supply?
>
>> Thanks very much in advance for any guidance.
>
> Seems to be a very expensive way to buy a battery charger. A bench power
> supply like this is designed to provide clean stable DC for electronics
> use - which you pay dearly for. Nor will it monitor the battery
> condition and adjust the charge to suit.

OK, this is what you do. You will need a diode with at least a one ampere
rating. Connect the cathode, that is the lead that is next to the band
around the body, to the positive binding post. If your batter is rated
at, say 12 volts, get a 12volt auto lamp rated at one amp, like one for
the tail light. Hook it to the remaining lead of the diode. Now set the
voltage on power supply to 13.6 volts. Next connect the positive terminal
of the battery to the free lead of the lamp. Connect the negative lead to
the negative binding post.

If the battery is not charged at all, the lamp will glow brightly as the
current flows into the battery. It should dim over time as the battery
charges up. If it doesn't, then the battery may be dead. If you have a
voltmeter, check the voltage of the battery every now and then. If it
reaches 13 volts or so, it will be fairly charged.

If it is a 6 volt battery, get a 6 volt, 1 amp lamp, and set the power
supply to 7.2 volts.

Other battery voltages will take other values for the lamp. If you have a
7.2 battery, put a 6 volt and a 1.5 volt lamp in series. Set the voltage
to 9 volts on the power supply.

What does the lamp do for you? It limits the current inrush to a
discharged battery and gives you a rough idea of the state of charge of
the battery.

The diode prevents a mistake where the voltage on the battery is higher
than that set at your power supply. You don't want the battery to be
pushing current into your power supply.

Experiment and have fun!

Al

"Dave Plowman (News)" <(E-Mail Removed)> wrote in
news:(E-Mail Removed):

> In article <Xns9AA1BC2E27A24WQAHBGMXSZHVspammote@130.39.198.1 39>,
> bz <bz+(E-Mail Removed)> wrote:
>> This means that you can regulate the 'open circuit voltage'. You would
>> want to make sure that never exceeds your battery voltage by more than
>> a few percent.
>
> IMHO the charge voltage is pretty irrelevant. It's the current that
> matters.
>

Here is a current regulator that can be used for 0-2A with supplies that
don't have current regulation built in.
http://kd1jv.qrpradio.com/vps/voclps.HTM





--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+(E-Mail Removed) remove ch100-5 to avoid spam trap

On May 19, 10:07*am, bz <bz+...@ch100-5.chem.lsu.edu> wrote:
> "Dave Plowman (News)" <d...@davenoise.co.uk> wrote innews:(E-Mail Removed):
>
> > In article <Xns9AA1BC2E27A24WQAHBGMXSZHVspamm...@130.39.198.1 39>,
> > * *bz <bz+...@ch100-5.chem.lsu.edu> wrote:
> >> This means that you can regulate the 'open circuit voltage'. You would
> >> want to make sure that never exceeds your battery voltage by more than
> >> a few percent.
>
> > IMHO the charge voltage is pretty irrelevant. It's the current that
> > matters.
>
> Here is a current regulator that can be used for 0-2A with supplies that
> don't have current regulation built in.http://kd1jv.qrpradio.com/vps/voclps.HTM
>
> --
> bz
>
> please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
> infinite set.
>
> bz+...@ch100-5.chem.lsu.edu * remove ch100-5 to avoid spam trap

Hey thanks everyone for all the great answers. I have been busy and
not returned (and I thought the thread had sort of faded away).

bz, what is the purpose of regulating the current, when the power
supply can supply current from 0 to 10 amps (or if I parallel the two
PS in it, 20 amps)?

Al, thanks. When people charge batteries directly with these PSs they
do use a diode. I may do that eventually but for the moment am using
the PS to power pretty smart chargers. In that situation your idea of
having the bulb in circuit is brilliant, it's a way to monitor charge
status. Cool.

Mike, this is down the road, and why I got this monster:
http://www.youtube.com/watch?v=bSfTx4csNsw
Thats' 44 volts he's putting in those batteries starting at 10 amps,
and as you can see it just takes a few minutes to replenish a pack
that holds 2300 mah. The objective is to charge a pack in the same
amount of time it will keep your plane in the air, so with a couple
batteries and the Mastech PS, you can fly all day. People either use a
Honda generator/inverter or a couple deep cycle marine batteries with
an inverter. This is not a cheap hobby. Probably more than you wanted
to know but.....

Thanks to your help I set the voltage at a little over 12 (since I
dont' have a diode between charger and PS), put the amps at max,
turned the PS on, connected it to the charger which was already
connected to the battery, and the charger nicely started pulse
charging the nimh transmitter pack. I'm so new to this stuff I was
afraid to turn the Mastech on which I just got. All is good now.

Wow, this is a great group and lot's of nice folks, I'll come back for
help and let you know how my learning curve goes.


Jim

On May 17, 11:45*am, "Dave Plowman (News)" <d...@davenoise.co.uk>
wrote:
> In article
> <ee259986-a06e-40fb-b75d-c91048ced...@27g2000hsf.googlegroups.com>,
> * *CharlesBlackstone <charlesblacksto...@hotmail.com> wrote:
>
> > Hi, I bought a variable voltage variable amp power supply to use
> > charging my RC batteries:
> >http://shop.vendio.com/evan2002/item...628/index.html
> > I don't really understand it much though. First, should I never turn
> > it on if there is no load?
> > I will use it with either a nicd/nimh charger or a lipoly charger. In
> > either case, should I turn the voltage to 12 volts, and the amps to
> > the maximum (10), then turn on the charger? Should the charger be
> > hooked up and turned on with a battery connected to be charged, before
> > I turn on the power supply?
> > Thanks very much in advance for any guidance.
>
> Seems to be a very expensive way to buy a battery charger. A bench power
> supply like this is designed to provide clean stable DC for electronics
> use - which you pay dearly for. Nor will it monitor the battery condition
> and adjust the charge to suit.
>
> --
> *Some people are only alive because it is illegal to kill.
>
> * * Dave Plowman * * * *d...@davenoise.co.uk * * * * * London SW
> * * * * * * * * * To e-mail, change noise into sound.

Hi Dave, I know what you mean by expensive, but this Chinese Mastech
switching triple power supply (30v10a cccv, 30v10a cccv, constant 5v)
cost less than $300. I looked up the price of a similar Agilent or
Tektronics PS and they were about 1500 percent of that.

Jim

CharlesBlackstone <(E-Mail Removed)> wrote in
news:f464e097-97ab-4366-87ab-(E-Mail Removed):

> On May 19, 10:07*am, bz <bz+...@ch100-5.chem.lsu.edu> wrote:
>> "Dave Plowman (News)" <d...@davenoise.co.uk> wrote
>> innews:4fa14a16d7dave@d
> avenoise.co.uk:
>>
>> > In article <Xns9AA1BC2E27A24WQAHBGMXSZHVspamm...@130.39.198.1 39>,
>> > * *bz <bz+...@ch100-5.chem.lsu.edu> wrote:
>> >> This means that you can regulate the 'open circuit voltage'. You
>> >> would want to make sure that never exceeds your battery voltage by
>> >> more than a few percent.
>>
>> > IMHO the charge voltage is pretty irrelevant. It's the current that
>> > matters.
>>
>> Here is a current regulator that can be used for 0-2A with supplies
>> that don't have current regulation built
>> in.http://kd1jv.qrpradio.com/vps/voclp
> s.HTM

>
> Hey thanks everyone for all the great answers. I have been busy and
> not returned (and I thought the thread had sort of faded away).
>
> bz, what is the purpose of regulating the current, when the power
> supply can supply current from 0 to 10 amps (or if I parallel the two
> PS in it, 20 amps)?

I was assuming directly charging batteries from a DC power supply.

If you have a supply that has an adjustable current regulator built in,
the cicuit I showed is not needed. I didn't look at the specs on YOUR
supply so I was just giving a link to a nice current regulator I had seen.
If you were charging batteries directly from a voltage regulated supply,
without any current regulation or limiting, you can damage your batteries.

.....

> Thanks to your help I set the voltage at a little over 12 (since I
> dont' have a diode between charger and PS), put the amps at max,

Check the specs for the batteries you are charging and be sure that you
never exceed the 'maximum charging current' ratings. Otherwise you will
damage your batteries and shorten their life.

I had a small battery blow up when I tried to recharge it.


> turned the PS on, connected it to the charger which was already
> connected to the battery, and the charger nicely started pulse
> charging the nimh transmitter pack.

You have a charger that is [I assume] designed for the batteries you are
using. Its job is to regulate the current flow so as to charge as fast as
possible without damage to the battery.


> I'm so new to this stuff I was
> afraid to turn the Mastech on which I just got. All is good now.
>
> Wow, this is a great group and lot's of nice folks, I'll come back for
> help and let you know how my learning curve goes.

Good luck and be careful.



--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+(E-Mail Removed) remove ch100-5 to avoid spam trap