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Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

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MaverickNH

Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

As mentioned in another thread, I'm running my shack on a UPS that is rated
1500va/900w. With my K3S/100 and other hardware plugged in on the same input
the UPS often max's out at 900W at < 100W on the K3S. Typically, the
baseline with K3S on RX is ~350W and it spikes over 900W with TX at 100W and
the UPS limits output. So it seems 100W isn't 100W.

I'm looking to switch in another UPS rated 2200VA/1320W, or 420W higher, for
use with the KPA500/KAT500 I just acquired from another forum member. so
from a 100W station to a 500W station. Might this work or is the increase in
watt TX not equal to the watt drawn?

BRET/N4SRN

--
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Don Wilhelm

Re: Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

Bret,

The power rating of a transmitter is the output power, not the input draw.

If the overall efficiency is something like 33% (quite likely), then the
input draw will 3 times the output power.
The efficiency of an RF output stage alone is typically about 50%, but
there are other circuits in the transmit section that must be added and
brings the overall efficiency of the transceiver down even more.
So yes, the input power required is about 3 times the output power.

A KPA500 running on 120 volts just about maxes out a 15 amp circuit, and
that is 1800 watts input. The K3 will need about 300 watts additional.
That means your UPS should be rated at least 2500 watts, but 3000 would
be more reasonable because it seems you have other gear in the ham
station that needs to be supported as well.

73,
Don W3FPR

On 8/30/2017 7:16 AM, MaverickNH wrote:

> As mentioned in another thread, I'm running my shack on a UPS that is rated
> 1500va/900w. With my K3S/100 and other hardware plugged in on the same input
> the UPS often max's out at 900W at < 100W on the K3S. Typically, the
> baseline with K3S on RX is ~350W and it spikes over 900W with TX at 100W and
> the UPS limits output. So it seems 100W isn't 100W.
>
> I'm looking to switch in another UPS rated 2200VA/1320W, or 420W higher, for
> use with the KPA500/KAT500 I just acquired from another forum member. so
> from a 100W station to a 500W station. Might this work or is the increase in
> watt TX not equal to the watt drawn?

KQ5S-Tom

Re: Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

In reply to this post by MaverickNH

Something is not right. If your UPS is showing 350 with the K3S at idle and over 900 on transmit that is a difference of close to 600. The K3S draws 17-22 amps at full key down and 100 watts. Assume 20 amps at 13.8V. That is only 276. You are showing double that.

---------
KQ5S-Tom

> On Aug 30, 2017, at 6:16 AM, MaverickNH <[hidden email]> wrote:
>
> As mentioned in another thread, I'm running my shack on a UPS that is rated
> 1500va/900w. With my K3S/100 and other hardware plugged in on the same input
> the UPS often max's out at 900W at < 100W on the K3S. Typically, the
> baseline with K3S on RX is ~350W and it spikes over 900W with TX at 100W and
> the UPS limits output. So it seems 100W isn't 100W.
>
> I'm looking to switch in another UPS rated 2200VA/1320W, or 420W higher, for
> use with the KPA500/KAT500 I just acquired from another forum member. so
> from a 100W station to a 500W station. Might this work or is the increase in
> watt TX not equal to the watt drawn?
>
> BRET/N4SRN
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
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jh3sif

Re: Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

In reply to this post by MaverickNH

100W of output power normally needs 200W of input power. My K3 (not S) with sub-RX and other options draws around 18A from DC13.8V power supply on RTTY. On CW or SSB, the DC current goes rapidly up and down according to the modulation.
I guess your UPS does not assume its output current going up and down rapidly, so its high current alarm is triggered by the rapidly changing output current.

73 de JH3SIF, Keith

> 2017/08/30 20:16、MaverickNH <[hidden email]> のメール：
>
> As mentioned in another thread, I'm running my shack on a UPS that is rated
> 1500va/900w. With my K3S/100 and other hardware plugged in on the same input
> the UPS often max's out at 900W at < 100W on the K3S. Typically, the
> baseline with K3S on RX is ~350W and it spikes over 900W with TX at 100W and
> the UPS limits output. So it seems 100W isn't 100W.
>
> I'm looking to switch in another UPS rated 2200VA/1320W, or 420W higher, for
> use with the KPA500/KAT500 I just acquired from another forum member. so
> from a 100W station to a 500W station. Might this work or is the increase in
> watt TX not equal to the watt drawn?
>
> BRET/N4SRN
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
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KQ5S-Tom

Re: Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

In reply to this post by Don Wilhelm

3000W at 120V is 25 amps. He had better have a dedicate circuit. I believe if I had to run a dedicated circuit I would run a 220 circuit for the amp and put everything else on the UPS.

---------
KQ5S-Tom

> On Aug 30, 2017, at 6:42 AM, Don Wilhelm <[hidden email]> wrote:
>
> Bret,
>
> The power rating of a transmitter is the output power, not the input draw.
>
> If the overall efficiency is something like 33% (quite likely), then the input draw will 3 times the output power.
> The efficiency of an RF output stage alone is typically about 50%, but there are other circuits in the transmit section that must be added and brings the overall efficiency of the transceiver down even more.
> So yes, the input power required is about 3 times the output power.
>
> A KPA500 running on 120 volts just about maxes out a 15 amp circuit, and that is 1800 watts input. The K3 will need about 300 watts additional.
> That means your UPS should be rated at least 2500 watts, but 3000 would be more reasonable because it seems you have other gear in the ham station that needs to be supported as well.
>
> 73,
> Don W3FPR
>
> On 8/30/2017 7:16 AM, MaverickNH wrote:
>> As mentioned in another thread, I'm running my shack on a UPS that is rated
>> 1500va/900w. With my K3S/100 and other hardware plugged in on the same input
>> the UPS often max's out at 900W at < 100W on the K3S. Typically, the
>> baseline with K3S on RX is ~350W and it spikes over 900W with TX at 100W and
>> the UPS limits output. So it seems 100W isn't 100W.
>> I'm looking to switch in another UPS rated 2200VA/1320W, or 420W higher, for
>> use with the KPA500/KAT500 I just acquired from another forum member. so
>> from a 100W station to a 500W station. Might this work or is the increase in
>> watt TX not equal to the watt drawn?
> ______________________________________________________________
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Don Wilhelm

Re: Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

Tom,

That 3000 watts I mentioned is for everything in the station.
The KPA500 alone needs 120 volts at about 13 amps, maybe peaking to
something greater.

73,
Don W3FPR

On 8/30/2017 8:16 AM, KQ5S-Tom wrote:
> 3000W at 120V is 25 amps. He had better have a dedicate circuit. I believe if I had to run a dedicated circuit I would run a 220 circuit for the amp and put everything else on the UPS.
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Bob McGraw - K4TAX

Re: Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

In reply to this post by KQ5S-Tom

Tom, Bret et al;

I agree with you ........... something is not right.    I see my K3S
draws about 1.2 amps DC on receive. at 1.38 volts that's about 17
watts. If my supply is only 50% efficient, that's 35 watts.   I can't
understand where the 350 watts would be used unless other equipment is
being used.   And I agree that transmit is 20 amps at 13.8 volts or 276
watts. Again with a supply that is 50% efficient, that is only 550
watts or so. Certainly no where near the "over 900 W".

Perhaps the computer, monitor, lamp, printer and other ancillary
equipment is part of the load on the UPS. It is more likely the
inductive load on the UPS is creating an issue with the power output
indication. Although that doesn't explain the UPS shut down or fold
back in power.    One other issue regarding the UPS, is the output Pure
Sine Wave, Modified Sine Wave or Square Wave? This may have a
significant impact on its function with various types of loads.

One way to evaluate the indication of the UPS output is to use an
incandescent bulb of 150 to 300 watts. They are resistive and
reasonably accurate with regard to power consumption. Don't use any of
the bulbs which are "equivalent" rated ones.   I use this method as a
load when I've had to repair any of my DC to AC inverters.

73
Bob, K4TAX

On 8/30/2017 6:50 AM, KQ5S-Tom wrote:

> Something is not right. If your UPS is showing 350 with the K3S at idle and over 900 on transmit that is a difference of close to 600. The K3S draws 17-22 amps at full key down and 100 watts. Assume 20 amps at 13.8V. That is only 276. You are showing double that.
>
> ---------
> KQ5S-Tom
>
>
>
>
>> On Aug 30, 2017, at 6:16 AM, MaverickNH <[hidden email]> wrote:
>>
>> As mentioned in another thread, I'm running my shack on a UPS that is rated
>> 1500va/900w. With my K3S/100 and other hardware plugged in on the same input
>> the UPS often max's out at 900W at < 100W on the K3S. Typically, the
>> baseline with K3S on RX is ~350W and it spikes over 900W with TX at 100W and
>> the UPS limits output. So it seems 100W isn't 100W.
>>
>> I'm looking to switch in another UPS rated 2200VA/1320W, or 420W higher, for
>> use with the KPA500/KAT500 I just acquired from another forum member. so
>> from a 100W station to a 500W station. Might this work or is the increase in
>> watt TX not equal to the watt drawn?
>>
>> BRET/N4SRN
>>
>>
>>
>> --

KQ5S-Tom

Re: Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

In reply to this post by Don Wilhelm

Understood but I believe he is talking about running everything in the shack off the UPS so if he buys a 2500-3000 UPS he will need a dedicated circuit unless he already has one. No telling what else is on the circuit in the shack if it is not dedicated.

Not sure what the intent is of running the amp off of a UPS. You will not get much operating time, matter of minutes, so maybe it is for surge protection.
———
Tom

> On Aug 30, 2017, at 7:28 AM, Don Wilhelm <[hidden email]> wrote:
>
> Tom,
>
> That 3000 watts I mentioned is for everything in the station.
> The KPA500 alone needs 120 volts at about 13 amps, maybe peaking to something greater.
>
> 73,
> Don W3FPR
>
> On 8/30/2017 8:16 AM, KQ5S-Tom wrote:
>> 3000W at 120V is 25 amps. He had better have a dedicate circuit. I believe if I had to run a dedicated circuit I would run a 220 circuit for the amp and put everything else on the UPS.
> ______________________________________________________________
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KQ5S-Tom

Re: Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

In reply to this post by Bob McGraw - K4TAX

Hi Bob,
I did not consider the efficiency of the power supply. The 600W was the difference between his shack load with the receiver in standby and in full transmit. So as you state, if the power supply is only 50% efficient, then 276W times 2 would be close to the 600W difference.
———
Tom

> On Aug 30, 2017, at 7:33 AM, Bob McGraw K4TAX <[hidden email]> wrote:
>
> Tom, Bret et al;
>
> I agree with you ........... something is not right. I see my K3S draws about 1.2 amps DC on receive. at 1.38 volts that's about 17 watts. If my supply is only 50% efficient, that's 35 watts. I can't understand where the 350 watts would be used unless other equipment is being used. And I agree that transmit is 20 amps at 13.8 volts or 276 watts. Again with a supply that is 50% efficient, that is only 550 watts or so. Certainly no where near the "over 900 W".
>
> Perhaps the computer, monitor, lamp, printer and other ancillary equipment is part of the load on the UPS. It is more likely the inductive load on the UPS is creating an issue with the power output indication. Although that doesn't explain the UPS shut down or fold back in power. One other issue regarding the UPS, is the output Pure Sine Wave, Modified Sine Wave or Square Wave? This may have a significant impact on its function with various types of loads.
>
> One way to evaluate the indication of the UPS output is to use an incandescent bulb of 150 to 300 watts. They are resistive and reasonably accurate with regard to power consumption. Don't use any of the bulbs which are "equivalent" rated ones. I use this method as a load when I've had to repair any of my DC to AC inverters.
>
> 73
> Bob, K4TAX
>
>
> On 8/30/2017 6:50 AM, KQ5S-Tom wrote:
>> Something is not right. If your UPS is showing 350 with the K3S at idle and over 900 on transmit that is a difference of close to 600. The K3S draws 17-22 amps at full key down and 100 watts. Assume 20 amps at 13.8V. That is only 276. You are showing double that.
>>
>> ---------
>> KQ5S-Tom
>>
>>
>>
>>
>>> On Aug 30, 2017, at 6:16 AM, MaverickNH <[hidden email]> wrote:
>>>
>>> As mentioned in another thread, I'm running my shack on a UPS that is rated
>>> 1500va/900w. With my K3S/100 and other hardware plugged in on the same input
>>> the UPS often max's out at 900W at < 100W on the K3S. Typically, the
>>> baseline with K3S on RX is ~350W and it spikes over 900W with TX at 100W and
>>> the UPS limits output. So it seems 100W isn't 100W.
>>>
>>> I'm looking to switch in another UPS rated 2200VA/1320W, or 420W higher, for
>>> use with the KPA500/KAT500 I just acquired from another forum member. so
>>> from a 100W station to a 500W station. Might this work or is the increase in
>>> watt TX not equal to the watt drawn?
>>>
>>> BRET/N4SRN
>>>
>>>
>>>
>>> --
>
>
> ______________________________________________________________
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> Message delivered to [hidden email]

Larry (K8UT)

Re: Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

Put the radio and other shack items on the 2.2kw UPs. Buy a separate 220
volt UPS for the amplifier.

-larry (K8UT)
-----Original Message-----
From: KQ5S-Tom
Sent: Wednesday, August 30, 2017 8:44 AM
To: Elecraft
Subject: Re: [Elecraft] Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

Hi Bob,
I did not consider the efficiency of the power supply. The 600W was the
difference between his shack load with the receiver in standby and in full
transmit. So as you state, if the power supply is only 50% efficient, then
276W times 2 would be close to the 600W difference.
———
Tom

> On Aug 30, 2017, at 7:33 AM, Bob McGraw K4TAX <[hidden email]> wrote:
>
> Tom, Bret et al;
>
> I agree with you ........... something is not right. I see my K3S draws
> about 1.2 amps DC on receive. at 1.38 volts that's about 17 watts. If my
> supply is only 50% efficient, that's 35 watts. I can't understand where
> the 350 watts would be used unless other equipment is being used. And I
> agree that transmit is 20 amps at 13.8 volts or 276 watts. Again with a
> supply that is 50% efficient, that is only 550 watts or so. Certainly no
> where near the "over 900 W".
>
> Perhaps the computer, monitor, lamp, printer and other ancillary
> equipment is part of the load on the UPS. It is more likely the inductive
> load on the UPS is creating an issue with the power output indication.
> Although that doesn't explain the UPS shut down or fold back in power.
> One other issue regarding the UPS, is the output Pure Sine Wave, Modified
> Sine Wave or Square Wave? This may have a significant impact on its
> function with various types of loads.
>
> One way to evaluate the indication of the UPS output is to use an
> incandescent bulb of 150 to 300 watts. They are resistive and reasonably
> accurate with regard to power consumption. Don't use any of the bulbs
> which are "equivalent" rated ones. I use this method as a load when I've
> had to repair any of my DC to AC inverters.
>
> 73
> Bob, K4TAX
>
>
> On 8/30/2017 6:50 AM, KQ5S-Tom wrote:
>> Something is not right. If your UPS is showing 350 with the K3S at idle
>> and over 900 on transmit that is a difference of close to 600. The K3S
>> draws 17-22 amps at full key down and 100 watts. Assume 20 amps at
>> 13.8V. That is only 276. You are showing double that.
>>
>> ---------
>> KQ5S-Tom
>>
>>
>>
>>
>>> On Aug 30, 2017, at 6:16 AM, MaverickNH <[hidden email]> wrote:
>>>
>>> As mentioned in another thread, I'm running my shack on a UPS that is
>>> rated
>>> 1500va/900w. With my K3S/100 and other hardware plugged in on the same
>>> input
>>> the UPS often max's out at 900W at < 100W on the K3S. Typically, the
>>> baseline with K3S on RX is ~350W and it spikes over 900W with TX at 100W
>>> and
>>> the UPS limits output. So it seems 100W isn't 100W.
>>>
>>> I'm looking to switch in another UPS rated 2200VA/1320W, or 420W higher,
>>> for
>>> use with the KPA500/KAT500 I just acquired from another forum member. so
>>> from a 100W station to a 500W station. Might this work or is the
>>> increase in
>>> watt TX not equal to the watt drawn?
>>>
>>> BRET/N4SRN
>>>
>>>
>>>
>>> --
>
>
> ______________________________________________________________
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Elecraft mailing list

Re: Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

In reply to this post by Don Wilhelm

> A KPA500 running on 120 volts just about maxes out a 15 amp circuit, and
that is 1800 watts input.

I would think this depends on the mode you operate in?

For Field Day, I operated my KPA500 (SSB only) with a 1000 watt inverter,
without any issues the whole weekend.

http://www.xantrex.com/power-products/power-inverters/prowatt-sw.aspx

Barthold

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Don Wilhelm
Sent: Wednesday, August 30, 2017 5:43 AM
To: MaverickNH; [hidden email]
Subject: Re: [Elecraft] Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

Bret,

The power rating of a transmitter is the output power, not the input draw.

If the overall efficiency is something like 33% (quite likely), then the
input draw will 3 times the output power.
The efficiency of an RF output stage alone is typically about 50%, but there
are other circuits in the transmit section that must be added and brings the
overall efficiency of the transceiver down even more.
So yes, the input power required is about 3 times the output power.

A KPA500 running on 120 volts just about maxes out a 15 amp circuit, and
that is 1800 watts input. The K3 will need about 300 watts additional.
That means your UPS should be rated at least 2500 watts, but 3000 would be
more reasonable because it seems you have other gear in the ham station that
needs to be supported as well.

73,
Don W3FPR

On 8/30/2017 7:16 AM, MaverickNH wrote:
> As mentioned in another thread, I'm running my shack on a UPS that is
> rated 1500va/900w. With my K3S/100 and other hardware plugged in on
> the same input the UPS often max's out at 900W at < 100W on the K3S.
> Typically, the baseline with K3S on RX is ~350W and it spikes over
> 900W with TX at 100W and the UPS limits output. So it seems 100W isn't
100W.
>
> I'm looking to switch in another UPS rated 2200VA/1320W, or 420W
> higher, for use with the KPA500/KAT500 I just acquired from another
> forum member. so from a 100W station to a 500W station. Might this
> work or is the increase in watt TX not equal to the watt drawn?
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Jim Brown-10

UPS Can Be a Noise Source

In reply to this post by MaverickNH

A UPS consists of a DC power supply that charges a battery, and a DC-AC
inverter to convert the battery voltage to 120VAC. Both operations can
be noisy. The DC power supply is probably a swtich mode, and the
inverter is a square wave generator that is shaped to resemble a sine wave.

Most UPS units operate in standby mode -- until power fails, the SMPS is
charging the battery, but the inverter is not operating, and the
equipment is connected to the power line. When power fails, the inverter
starts operating.

A FAR better way to provide UPS for radio gear is a 12V deep discharge
lead acid battery or 14.4V LiFePO4 that is float charged by a suitable
power supply. And as has been discussed several times, LiFePO4 batteries
have the major advantage that their operating voltage stays above 13V
for most of their discharge curve, while lead-acid batteries are below
12V for most of their discharge curve. This system is as quiet as the
power supply used to float-charge the battery.

With either battery type, care must be taken to not overcharge the battery.

73, Jim K9YC

On 8/30/2017 4:16 AM, MaverickNH wrote:
> I'm looking to switch in another UPS rated 2200VA/1320W, or 420W higher, for
> use with the KPA500/KAT500 I just acquired from another forum member.

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Mike Maloney

Re: Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

In reply to this post by Don Wilhelm

Oh my! The KPA500 is more efficient than you give it credit. Since few have instruments to measure ac input parameters, will volunteer actual measurement figures.At 650W output into 50 ohm load, highest VA recorded was at 14.1 MHz at 1166. Watts 974 with a pf of 0.83 or 83%. AC input amps 10.3. Awesome!
73,Mike AC5P

On Wednesday, August 30, 2017 7:28 AM, Don Wilhelm <[hidden email]> wrote:

Tom,

That 3000 watts I mentioned is for everything in the station.
The KPA500 alone needs 120 volts at about 13 amps, maybe peaking to
something greater.

73,
Don W3FPR

On 8/30/2017 8:16 AM, KQ5S-Tom wrote:
> 3000W at 120V is 25 amps. He had better have a dedicate circuit. I believe if I had to run a dedicated circuit I would run a 220 circuit for the amp and put everything else on the UPS.
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Phil Kane-2

Re: Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

On 8/30/2017 10:56 AM, Mike Maloney wrote:

> At 650W output into 50 ohm load, highest VA recorded was at 14.1 MHz
> at 1166. Watts 974 with a pf of 0.83 or 83%. AC input amps 10.3.
> Awesome!

I don't have a KPA500 (but I do have a KPA100). If it is running as a
true linear amplifier (Class A) maximum theoretical efficiency is 50%.
I'll let the designer(s) thereof kick that around. What do I know - I'm
just a (lowly) EE (with 60 years' experience). :)

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

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
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MaverickNH

Re: Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

In reply to this post by MaverickNH

Thanks all - I've got some good ideas to try!

Bret/N4SRN

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Lynn W. Taylor, WB6UUT-2

Re: UPS Can Be a Noise Source

In reply to this post by Jim Brown-10

I'm going to add that nearly every UPS made is meant to bridge the time
between when the power goes out, and the (automatic) generator starts.

If you don't have a generator, the UPS signals the computer(s) so that
they can shut down gracefully and turn the UPS off.

The (typically AGM lead-acid) batteries are sized for maybe 15 minutes,
which is way too fast. Drawing a lead-acid battery flat in 15 minutes
will kill it in only a few cycles.

What I did as part of my ISP was to remove the batteries from my UPSes
and replace 7 or 12Ah batteries with 100Ah batteries outside the case.

That didn't get me to the 10 hours for maximum battery life, but it got
me to 8 hours.....

Jim's suggestion also lets you size the battery to run all the gear for
more than a few minutes.

73 -- Lynn

On 8/30/2017 8:55 AM, Jim Brown wrote:

> A FAR better way to provide UPS for radio gear is a 12V deep discharge
> lead acid battery or 14.4V LiFePO4 that is float charged by a suitable
> power supply. And as has been discussed several times, LiFePO4 batteries
> have the major advantage that their operating voltage stays above 13V
> for most of their discharge curve, while lead-acid batteries are below
> 12V for most of their discharge curve. This system is as quiet as the
> power supply used to float-charge the battery.
>
> With either battery type, care must be taken to not overcharge the battery.
>
> 73, Jim K9YC

Tox

Re: UPS Can Be a Noise Source

There are also UPSes meant for extended runtimes that are a little less
brutal on the batteries. One Upon a Time, I had a couple racks of APC
SmartUPS 2000 units with daisychained batteries to give extended holdup to
a couple of racks of telecom and server hw. No clue how RF noisy those
units are, though.

On Thu, Aug 31, 2017 at 10:46 AM, Lynn W. Taylor, WB6UUT <
[hidden email]> wrote:

> I'm going to add that nearly every UPS made is meant to bridge the time
> between when the power goes out, and the (automatic) generator starts.
>
> If you don't have a generator, the UPS signals the computer(s) so that
> they can shut down gracefully and turn the UPS off.
>
> The (typically AGM lead-acid) batteries are sized for maybe 15 minutes,
> which is way too fast. Drawing a lead-acid battery flat in 15 minutes will
> kill it in only a few cycles.
>
> What I did as part of my ISP was to remove the batteries from my UPSes and
> replace 7 or 12Ah batteries with 100Ah batteries outside the case.
>
> That didn't get me to the 10 hours for maximum battery life, but it got me
> to 8 hours.....
>
> Jim's suggestion also lets you size the battery to run all the gear for
> more than a few minutes.
>
> 73 -- Lynn
>
> On 8/30/2017 8:55 AM, Jim Brown wrote:
>
>> A FAR better way to provide UPS for radio gear is a 12V deep discharge
>> lead acid battery or 14.4V LiFePO4 that is float charged by a suitable
>> power supply. And as has been discussed several times, LiFePO4 batteries
>> have the major advantage that their operating voltage stays above 13V for
>> most of their discharge curve, while lead-acid batteries are below 12V for
>> most of their discharge curve. This system is as quiet as the power supply
>> used to float-charge the battery.
>>
>> With either battery type, care must be taken to not overcharge the
>> battery.
>>
>> 73, Jim K9YC
>>
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Tox

Re: UPS Can Be a Noise Source

That said, for my own use, I've got a 100Ah LFP from Blackwood Innovations
for my ham hear; BioEnno has units all the way up to 300Ah for the
deep-of-pocker.

On Thu, Aug 31, 2017 at 11:35 AM, Tox <[hidden email]> wrote:

> There are also UPSes meant for extended runtimes that are a little less
> brutal on the batteries. One Upon a Time, I had a couple racks of APC
> SmartUPS 2000 units with daisychained batteries to give extended holdup to
> a couple of racks of telecom and server hw. No clue how RF noisy those
> units are, though.
>
> On Thu, Aug 31, 2017 at 10:46 AM, Lynn W. Taylor, WB6UUT <
> [hidden email]> wrote:
>
>> I'm going to add that nearly every UPS made is meant to bridge the time
>> between when the power goes out, and the (automatic) generator starts.
>>
>> If you don't have a generator, the UPS signals the computer(s) so that
>> they can shut down gracefully and turn the UPS off.
>>
>> The (typically AGM lead-acid) batteries are sized for maybe 15 minutes,
>> which is way too fast. Drawing a lead-acid battery flat in 15 minutes will
>> kill it in only a few cycles.
>>
>> What I did as part of my ISP was to remove the batteries from my UPSes
>> and replace 7 or 12Ah batteries with 100Ah batteries outside the case.
>>
>> That didn't get me to the 10 hours for maximum battery life, but it got
>> me to 8 hours.....
>>
>> Jim's suggestion also lets you size the battery to run all the gear for
>> more than a few minutes.
>>
>> 73 -- Lynn
>>
>> On 8/30/2017 8:55 AM, Jim Brown wrote:
>>
>>> A FAR better way to provide UPS for radio gear is a 12V deep discharge
>>> lead acid battery or 14.4V LiFePO4 that is float charged by a suitable
>>> power supply. And as has been discussed several times, LiFePO4 batteries
>>> have the major advantage that their operating voltage stays above 13V for
>>> most of their discharge curve, while lead-acid batteries are below 12V for
>>> most of their discharge curve. This system is as quiet as the power supply
>>> used to float-charge the battery.
>>>
>>> With either battery type, care must be taken to not overcharge the
>>> battery.
>>>
>>> 73, Jim K9YC
>>>
>> ______________________________________________________________
>> Elecraft mailing list
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>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
>>
>
>
>
> --
> Scott Small
>
>
>
>

Bob-270

Re: Wattage Draw - K3S/100 vs KPA500/KAT500 - for UPS

In reply to this post by Mike Maloney

Well maybe more shacks should have that capability. It is not expensive as here:

https://www.amazon.com/P3-P4400-Electricity-Usage-Monitor/dp/B00009MDBU/ref=sr_1_3?ie=UTF8&qid=1504119777&sr=8-3&keywords=power+meter

Certainly not lab grade but good as even just a shack line monitor or bench tool.

Another useful application, and I always have it on to monitor the output of the
backup generator. I can see output voltage and line freq. Seeing within a few
cycles of 60 lets me know that engine speed is being regulated correctly.

Disclaimer: Inadequate for future KPA1500 owners.

73,
Bob
K2TK ex KN2TKR (1956) & K2TKR

On 8/30/2017 1:56 PM, Mike Maloney wrote:

> Oh my! The KPA500 is more efficient than you give it credit. Since few have instruments to measure ac input parameters, will volunteer actual measurement figures.At 650W output into 50 ohm load, highest VA recorded was at 14.1 MHz at 1166. Watts 974 with a pf of 0.83 or 83%. AC input amps 10.3. Awesome!
> 73,Mike AC5P
>
> On Wednesday, August 30, 2017 7:28 AM, Don Wilhelm <[hidden email]> wrote:
>
>
> Tom,
>
> That 3000 watts I mentioned is for everything in the station.
> The KPA500 alone needs 120 volts at about 13 amps, maybe peaking to
> something greater.
>
> 73,
> Don W3FPR
>
> On 8/30/2017 8:16 AM, KQ5S-Tom wrote:
>> 3000W at 120V is 25 amps. He had better have a dedicate circuit. I believe if I had to run a dedicated circuit I would run a 220 circuit for the amp and put everything else on the UPS.

Jim Brown-10

Re: UPS Can Be a Noise Source

In reply to this post by Lynn W. Taylor, WB6UUT-2

Good observations, Lynn. A few more. First, I failed to observe that my
100Ah LiFePO4 battery runs ONLY my K3s. A big lead-acid from Costco runs
other 12V gear and LED lighting. I do NOT try to provide UPS for power
amps. If I need them, I'll fire up the big 240V generator.

Second, a local computer guru, AE6KS, has observed that most UPS mfrs
charge batteries at too fast a rate for good battery life. The objective
is to have the unit ready to do it all again if power drops, then
returns, then drops again. This intentional design goal kills batteries
pretty quickly.

Perhaps by accident, I found Cyber Power branded UPS units that 1) claim
an 8 hour charging rate and 2) FCC Part 15 Class B compliance for their
pseudo-sinewave units. I have two of them in my shack with a 160M
vertical only 25 ft away, and with good chokes on their wiring, can't
hear any noise when they're in standby mode. Haven't checked for noise
when they're inverting.

I use one to keep an ancient tower computer running, and the second one
to backup the 120V accessories -- rotator controllers and SteppIR
controller -- and the laptop PSU is plugged in there.

73, Jim K9YC

On 8/31/2017 10:46 AM, Lynn W. Taylor, WB6UUT wrote:
> Jim's suggestion also lets you size the battery to run all the gear
> for more than a few minutes.

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