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Battery Charger Voltage High?

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RLVZ

Battery Charger Voltage High?

Hi Guys,

I'm operating from a portable location and using a 12-volt automobile
battery with my K3. To keep the battery charged I'm using a Schumacher 15-Amp
Charger/Maintainer that automatically switches to "Trickle Charge" when the
battery is charged. My concern is that when the charger is connected the
battery voltage is peaking at 16.0 volts. The K3 manual says "maximum
voltage is 15 volts".

Do I need to be concerned about powering the K3 with 16.0 volts?

Thanks,

Dick- K9OM
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Christoffer Knutsen

Re: Battery Charger Voltage High?

Hello

Yes, you should be concerned. Battery chargers are different from PSUs as
they can easily create a high voltage peak which will destroy any
equipment hooked up to it. I highly recommend not to use the battery when
it is on the charger.

73 from LA3CTA, Christoffer

På Thu, 26 May 2011 19:58:34 +0200, skrev <[hidden email]>:

> Hi Guys,
> I'm operating from a portable location and using a 12-volt automobile
> battery with my K3. To keep the battery charged I'm using a Schumacher
> 15-Amp
> Charger/Maintainer that automatically switches to "Trickle Charge" when
> the
> battery is charged. My concern is that when the charger is connected
> the
> battery voltage is peaking at 16.0 volts. The K3 manual says "maximum
> voltage is 15 volts".
> Do I need to be concerned about powering the K3 with 16.0 volts?
> Thanks,
> Dick- K9OM
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html

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n7ws

Re: Battery Charger Voltage High?

In reply to this post by RLVZ

A "trickle charge" should not be 16V. How are you measuring this?

--- On Thu, 5/26/11, [hidden email] <[hidden email]> wrote:

> From: [hidden email] <[hidden email]>
> Subject: [Elecraft] Battery Charger Voltage High?
> To: [hidden email]
> Date: Thursday, May 26, 2011, 11:58 AM
> Hi Guys,
>
> I'm operating from a portable location and using a
> 12-volt automobile
> battery with my K3. To keep the battery charged I'm
> using a Schumacher 15-Amp
> Charger/Maintainer that automatically switches to
> "Trickle Charge" when the
> battery is charged. My concern is that when the
> charger is connected the
> battery voltage is peaking at 16.0 volts. The K3
> manual says "maximum
> voltage is 15 volts".
>
> Do I need to be concerned about powering the K3 with
> 16.0 volts?
>
> Thanks,
>
> Dick- K9OM
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

N5GE

Re: Battery Charger Voltage High?

In reply to this post by RLVZ

If the spec sheet on the K3 say's 15V max, then the voltage is too high, no
matter where the voltage comes from...

73,
Tom
Amateur Radio Operator N5GE

On Thu, 26 May 2011 13:58:34 EDT, [hidden email] wrote:

>Hi Guys,
>
>I'm operating from a portable location and using a 12-volt automobile
>battery with my K3. To keep the battery charged I'm using a Schumacher 15-Amp
>Charger/Maintainer that automatically switches to "Trickle Charge" when the
>battery is charged. My concern is that when the charger is connected the
>battery voltage is peaking at 16.0 volts. The K3 manual says "maximum
>voltage is 15 volts".
>
>Do I need to be concerned about powering the K3 with 16.0 volts?
>
>Thanks,
>
>Dick- K9OM
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:[hidden email]
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html

Amateur Radio Operator N5GE

RLVZ

Battery Charger Voltage High?

In reply to this post by RLVZ

It's measuring 15.7 volts in "Trickle Charge" on the K3 front panel
display and on Battery Charger's digital readout. When it's charging in either
the 10 or 15-amp mode then the voltage on both units goes to 16.0 volts.

Dick- K9OM

In a message dated 5/26/2011 1:08:48 P.M. Central Daylight Time,
[hidden email] writes:

A "trickle charge" should not be 16V. How are you measuring this?

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Guy, K2AV

Re: Battery Charger Voltage High?

In reply to this post by N5GE

This sounds like too small a battery for the given charger. Or too
large a charger for the battery.

On Thu, May 26, 2011 at 2:21 PM, <[hidden email]> wrote:

>
> If the spec sheet on the K3 say's 15V max, then the voltage is too high, no
> matter where the voltage comes from...
>
> 73,
> Tom
> Amateur Radio Operator N5GE
>
>
> On Thu, 26 May 2011 13:58:34 EDT, [hidden email] wrote:
>
>>Hi Guys,
>>
>>I'm operating from a portable location and using a 12-volt automobile
>>battery with my K3. To keep the battery charged I'm using a Schumacher 15-Amp
>>Charger/Maintainer that automatically switches to "Trickle Charge" when the
>>battery is charged. My concern is that when the charger is connected the
>>battery voltage is peaking at 16.0 volts. The K3 manual says "maximum
>>voltage is 15 volts".
>>
>>Do I need to be concerned about powering the K3 with 16.0 volts?
>>
>>Thanks,
>>
>>Dick- K9OM
>>______________________________________________________________
>>Elecraft mailing list
>>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>Help: http://mailman.qth.net/mmfaq.htm
>>Post: mailto:[hidden email]
>>
>>This list hosted by: http://www.qsl.net
>>Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

Don Wilhelm-4

Re: Battery Charger Voltage High?

In reply to this post by RLVZ

Dick,

Yes, 16 volts is too high. There is a 15 volt zener diode right at the
DC input of the K3 which should limit the voltage to the K3 at 15 volts
(or until that zener diode is damaged).

The charger may be dropping into the bulk charge output rather than
staying in the trickle charge state.
You may be better off with a simple trickle charger than a 2 or 3 state
battery charger.

73,
Don W3FPR

On 5/26/2011 1:58 PM, [hidden email] wrote:

Fred Townsend

Re: Battery Charger Voltage High?

In reply to this post by RLVZ

Something smells... is that your rig burning. Seriously, a battery will act as a
voltage clamp unless it is open.

Power supplies make good battery chargers but the converse is not true. Chargers
do not contain filter caps so the voltage can spike, particularly if the battery
is disconnected.

Invest in a good power supply. It will pay many dividends. While you are at
it... it sounds like your battery is shot too.
73
de Fred, AE6QL

________________________________
From: "[hidden email]" <[hidden email]>
To: [hidden email]; [hidden email]
Sent: Thu, May 26, 2011 11:21:58 AM
Subject: [Elecraft] Battery Charger Voltage High?

It's measuring 15.7 volts in "Trickle Charge" on the K3 front panel
display and on Battery Charger's digital readout. When it's charging in either

the 10 or 15-amp mode then the voltage on both units goes to 16.0 volts.

Dick- K9OM

In a message dated 5/26/2011 1:08:48 P.M. Central Daylight Time,
[hidden email] writes:

A "trickle charge" should not be 16V. How are you measuring this?

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John Huggins, kx4o

Re: Battery Charger Voltage High?

In reply to this post by Don Wilhelm-4

Keep in mind automotive power busses can and do have steady state voltages
over 15V and even 16V when you include allowable ripple. Power busses are
a terrible terrible place.

Assuming the K3 designers' had in mind a car's electrical system, the
choice of the BZW50-15 (in the QRP version) puts the effective clamping
voltage above 16.6 volts and even then it is a gradual rise in clamping
action vs. voltage. Then if you take away the 1/2 volt or so drop from
the reverse protection, the net bus voltage inside can be more than 16V
steady state and even higher for brief surges. Yuck. Clearly the
designers' know about real-life DC power busses and designed the rest of
the radio to take the abuse with some margin and rely on that clamp diode
to blow the fuse should things get hopelessly ridiculous on the power
source.

So the good news is the K3 should be able to take the smack in the face
from what I assume is a PWM style battery charger when in trickle mode.

However, I would not make a habit of it and heed others' advice about
staying within the 15V limit with a good DC power supply or charge with
the radio disconnected. It should have less electrical noise as a side
benefit.

John

> Dick,
>
> Yes, 16 volts is too high. There is a 15 volt zener diode right at the
> DC input of the K3 which should limit the voltage to the K3 at 15 volts
> (or until that zener diode is damaged).
>
> The charger may be dropping into the bulk charge output rather than
> staying in the trickle charge state.
> You may be better off with a simple trickle charger than a 2 or 3 state
> battery charger.
>
> 73,
> Don W3FPR
>
> On 5/26/2011 1:58 PM, [hidden email] wrote:
>> Hi Guys,
>>
>> I'm operating from a portable location and using a 12-volt automobile
>> battery with my K3. To keep the battery charged I'm using a Schumacher
>> 15-Amp
>> Charger/Maintainer that automatically switches to "Trickle Charge" when
>> the
>> battery is charged. My concern is that when the charger is connected
>> the
>> battery voltage is peaking at 16.0 volts. The K3 manual says "maximum
>> voltage is 15 volts".
>>
>> Do I need to be concerned about powering the K3 with 16.0 volts?
>>
>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>

Phil Kane-2

Re: Battery Charger Voltage High?

On 5/26/2011 1:43 PM, John Huggins, kx4o wrote:

> However, I would not make a habit of it and heed others' advice about
> staying within the 15V limit with a good DC power supply or charge with
> the radio disconnected. It should have less electrical noise as a side
> benefit.

Or use a smart-charger that is designed to float across a
battery used for communication with clean voltage and minimum
or no RFI. These are not cheap, but then again they are far
better for the application than the $69 Special at the auto
supply store. A high-current constant-voltage charger can cook
a battery (overcharge) in short order (we learn the hard way).

-- 73 de K2ASP - Phil Kane
Elecraft K2/100 s/n 5402

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w0ih

Re: Battery Charger Voltage High?

My question is, do you have a 12 volt battery in the circuit with the charger. Probably not, if the voltage is running at over 15 volts.

Chargers are made to run with a battery connected, which would drop the voltage to about 14.4 volts while charging, no higher.

Mike

n7ws

Re: Battery Charger Voltage High?

That's simply not true. There is a lot of information on the web about battery charging and care, particularly from manufacturers. Yet this thread and others about battery charging are full of, frankly, lousy information.

It's not unusual to do equalization charges on wet batteries at over 15V. Bulk charging does NOT apply excessive voltages as one commentator cannot be made to understand. And the myths go on.....

--- On Thu, 5/26/11, w0ih <[hidden email]> wrote:

> My question is, do you have a 12 volt
> battery in the circuit with the
> charger. Probably not, if the voltage is running at
> over 15 volts.
>
> Chargers are made to run with a battery connected, which
> would drop the
> voltage to about 14.4 volts while charging, no higher.
>
> Mike
>
> --

Don Wilhelm-4

Re: Battery Charger Voltage High?

Wes,

Oh, I do understand the UC3906 charge controller. Its bulk charge is a
constant current source, which means the voltage is not controlled
(except by the battery). Once the voltage reaches the V12 point, it
goes into an overvoltage charge until the current drops to a defined
rate, then it goes to the float voltage.

The various voltages and current states are determined by the choice of
resistors. If the battery has high resistance and does not want to take
a charge willingly, the charger will start out with the bulk charge and
almost immediately switch to the overcharge voltage, and may never go to
the float charge state.

So 16 volts is not an improbable situation, it all depends on the
battery condition and the resistors chosen by the designer of the charger.

73,
Don W3FPR

On 5/27/2011 5:03 AM, Wes Stewart wrote:
>
> It's not unusual to do equalization charges on wet batteries at over 15V. Bulk charging does NOT apply excessive voltages as one commentator cannot be made to understand. And the myths go on.....
>
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