Hi All,

A good friend recently gave me some 12V 2.2A lead-acid batteries. It
occurred to me that I can use them to power my VX-5R HT while at home,
using the accessory port power adapter. I went to RS and bought an
accessory port, soldered up some power connectors, and connected the HT to
one of the batteries.

It works fine when receiving, and the HT charges its internal battery when
off. But if I try to transmit at 5W (and sometimes at 2.5W) the VX-5R's
"safety reset" triggers. According to the manual this happens when power
is interrupted. This doesn't happen at the two lowest power settings.

What is happening here? I don't know how this safety reset works "under
the hood", and I don't know a lot about lead-acid batteries. Is my power
really being interrupted and if so how can I remedy this? Or is the HT
just seeing a large voltage drop on transmit and assuming that power is
being interrupted, thus triggering the reset (I assume this can be
remedied by putting two of the batteries in parallel to get more current
capacity).

Some background information, when plugged in and monitoring, the HT's
voltage readout shows 11 volts, coming from an external power source. On
transmit at 5W the voltage drops to less than 9.5 volts, and the VX-5R
says that the power source is from the internal Li-Ion battery, and then
resets. I'm guessing that the voltage drop is caused by the battery's
inability to supply the needed current, and that the HT assumes that
certain voltage levels correspond to certain power sources.

The VX-5R draws about 1.9A at 5W output, but note that the lead-acid
batteries I have are old, and so are probably not able to output the full
2.2A.

Any help is appreciated.

Thanks!

-Josh, AE6IQ

--


Remove the reversed "nospam" in the address.

In article ,
Joshua G Senecal wrote:

A good friend recently gave me some 12V 2.2A lead-acid batteries. It
occurred to me that I can use them to power my VX-5R HT while at home,
using the accessory port power adapter. I went to RS and bought an
accessory port, soldered up some power connectors, and connected the HT to
one of the batteries.

It works fine when receiving, and the HT charges its internal battery when
off. But if I try to transmit at 5W (and sometimes at 2.5W) the VX-5R's
"safety reset" triggers. According to the manual this happens when power
is interrupted. This doesn't happen at the two lowest power settings.

What is happening here?

The batteries aren't able to provide the full (1.9-or-so) amperage, at
the voltage required by the VX-5. The voltage drops when you key up,
and the VX-5's safety disconnect shuts down the radio.

Some background information, when plugged in and monitoring, the HT's
voltage readout shows 11 volts, coming from an external power source. On
transmit at 5W the voltage drops to less than 9.5 volts, and the VX-5R
says that the power source is from the internal Li-Ion battery, and then
resets. I'm guessing that the voltage drop is caused by the battery's
inability to supply the needed current, and that the HT assumes that
certain voltage levels correspond to certain power sources.

A fully-charged gel cell in good condition ought to be delivering no
less than 12 volts. If you're only getting 11 volts when drawing only
the receive-monitor current, then the battery is either badly run
down, or old and dying. If they don't charge up well and hold 12
volts, then you may not be able to use them for transmitting... just
for receiving, or as a way of providing portable power for recharging
the VX-5's built-in battery pack. [The latter is how I use some old
gel cells I have - I charge 'em on my solar panels, then use them to
charge up the VX-5.]

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

The batteries aren't able to provide the full (1.9-or-so) amperage, at
the voltage required by the VX-5. The voltage drops when you key up,
and the VX-5's safety disconnect shuts down the radio.

So wiring two of the batteries in parallel (for extra current) would be a
good fix until I have the funds for some better batteries?

-Josh

--


Remove the reversed "nospam" in the address.

The batteries aren't able to provide the full (1.9-or-so) amperage, at
the voltage required by the VX-5. The voltage drops when you key up,
and the VX-5's safety disconnect shuts down the radio.

So wiring two of the batteries in parallel (for extra current) would be a
good fix until I have the funds for some better batteries?

That might help matters.

However, the low voltage that you are reading under light load
suggests to me that the battery you are using is either seriously
undercharged, or is dying (a shorted cell, or dried-out electrolyte).

First thing I'd do is check your battery-charging circuit. If you're
trying to charge them from a 12-volt regulated source, then this could
be the root of your problem... a "12-volt" gel cell won't accept a
useful amount of charge at this voltage. You'll need around 13.8
volts to slow/float-charge the battery, and perhaps 14.3 - 14.4 volts
(with an appropriate current limit) to fast-charge it.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Wed, 25 Feb 2004 22:48:04 -0000, Dave Platt wrote:

First thing I'd do is check your battery-charging circuit. If you're
trying to charge them from a 12-volt regulated source, then this could
be the root of your problem... a "12-volt" gel cell won't accept a
useful amount of charge at this voltage. You'll need around 13.8
volts to slow/float-charge the battery, and perhaps 14.3 - 14.4 volts
(with an appropriate current limit) to fast-charge it.

Read the label on the gel-cell. 14.4 volts will cook the battery in
no time flat. I learned that the hard way several years ago.

My power panel uses two regulated power supplies (a 50 A unit and a
35 A unit) operating through an isolation diode block to float
charge the Size 31 (100+ AH) marine deep-cycle gel-cell. The 50A
supply is set to deliver 13.5 V to the battery bus by itself, and
the 35A supply is set to deliver 13.3 V by itself - so I can tell by
the digital voltmeter readout as well as the LED on-line indicators
if the big supply goes off-line and the small supply has picked up
the load. The steady-state load on the bus is 7A which goes up to
25A when all transmitters are firing.

In designing the panel it helped that both my wife and I are both
electrical engineers trained in power distribution and that she
spent a few years in large-scale UPS design. She did insist,
however, that the installation be done to UL and USCG 12-V marine
safety standards, not "hamshack haywire". Expensive but "right".

The installation will run for about four hours in UPS mode after
which various boxes drop off line when the voltage goes much below
11.8 V. My next investment is a small natural-gas-powered gen-set
to supply the 120 VAC for the chargers and the computer installation
when commercial power fails. I'd love to put the whole house on
standby power, but who has a 50 KW gen-set or better yet fuel cell
hanging around that needs a good home? ggg

--
73 de K2ASP - Phil Kane

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

On Wed, 25 Feb 2004 22:48:04 -0000, Dave Platt wrote:

First thing I'd do is check your battery-charging circuit. If you're
trying to charge them from a 12-volt regulated source, then this could
be the root of your problem... a "12-volt" gel cell won't accept a
useful amount of charge at this voltage. You'll need around 13.8
volts to slow/float-charge the battery, and perhaps 14.3 - 14.4 volts
(with an appropriate current limit) to fast-charge it.

Read the label on the gel-cell. 14.4 volts will cook the battery in
no time flat. I learned that the hard way several years ago.

Good point. 14.4 is appropriate for most flooded-cell lead-acid
batteries, but is hard on gel cells, and is definitely too much for
AGM/glassmat/spiral-cell batteries.

13.8 seems to be generally safe, and some folks feel that
float-charging should be done at 13.6 or below for certain types of
batteries.

My power panel uses two regulated power supplies (a 50 A unit and a
35 A unit) operating through an isolation diode block to float
charge the Size 31 (100+ AH) marine deep-cycle gel-cell. The 50A
supply is set to deliver 13.5 V to the battery bus by itself, and
the 35A supply is set to deliver 13.3 V by itself - so I can tell by
the digital voltmeter readout as well as the LED on-line indicators
if the big supply goes off-line and the small supply has picked up
the load. The steady-state load on the bus is 7A which goes up to
25A when all transmitters are firing.

That's definitely in the "Don't drop the screwdriver, George!" category!

In designing the panel it helped that both my wife and I are both
electrical engineers trained in power distribution and that she
spent a few years in large-scale UPS design. She did insist,
however, that the installation be done to UL and USCG 12-V marine
safety standards, not "hamshack haywire". Expensive but "right".

*very* nice!

The installation will run for about four hours in UPS mode after
which various boxes drop off line when the voltage goes much below
11.8 V. My next investment is a small natural-gas-powered gen-set
to supply the 120 VAC for the chargers and the computer installation
when commercial power fails. I'd love to put the whole house on
standby power, but who has a 50 KW gen-set or better yet fuel cell
hanging around that needs a good home? ggg

Pity they never did make cold-fusion generators work.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Wed, 25 Feb 2004 22:48:04 -0000, Dave Platt wrote:

First thing I'd do is check your battery-charging circuit. If you're
trying to charge them from a 12-volt regulated source, then this could
be the root of your problem... a "12-volt" gel cell won't accept a
useful amount of charge at this voltage. You'll need around 13.8
volts to slow/float-charge the battery, and perhaps 14.3 - 14.4 volts
(with an appropriate current limit) to fast-charge it.

Read the label on the gel-cell. 14.4 volts will cook the battery in
no time flat. I learned that the hard way several years ago.

Good point. 14.4 is appropriate for most flooded-cell lead-acid
batteries, but is hard on gel cells, and is definitely too much for
AGM/glassmat/spiral-cell batteries.

13.8 seems to be generally safe, and some folks feel that
float-charging should be done at 13.6 or below for certain types of
batteries.

My power panel uses two regulated power supplies (a 50 A unit and a
35 A unit) operating through an isolation diode block to float
charge the Size 31 (100+ AH) marine deep-cycle gel-cell. The 50A
supply is set to deliver 13.5 V to the battery bus by itself, and
the 35A supply is set to deliver 13.3 V by itself - so I can tell by
the digital voltmeter readout as well as the LED on-line indicators
if the big supply goes off-line and the small supply has picked up
the load. The steady-state load on the bus is 7A which goes up to
25A when all transmitters are firing.

That's definitely in the "Don't drop the screwdriver, George!" category!

In designing the panel it helped that both my wife and I are both
electrical engineers trained in power distribution and that she
spent a few years in large-scale UPS design. She did insist,
however, that the installation be done to UL and USCG 12-V marine
safety standards, not "hamshack haywire". Expensive but "right".

*very* nice!

The installation will run for about four hours in UPS mode after
which various boxes drop off line when the voltage goes much below
11.8 V. My next investment is a small natural-gas-powered gen-set
to supply the 120 VAC for the chargers and the computer installation
when commercial power fails. I'd love to put the whole house on
standby power, but who has a 50 KW gen-set or better yet fuel cell
hanging around that needs a good home? ggg

Pity they never did make cold-fusion generators work.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Wed, 25 Feb 2004 22:48:04 -0000, Dave Platt wrote:

First thing I'd do is check your battery-charging circuit. If you're
trying to charge them from a 12-volt regulated source, then this could
be the root of your problem... a "12-volt" gel cell won't accept a
useful amount of charge at this voltage. You'll need around 13.8
volts to slow/float-charge the battery, and perhaps 14.3 - 14.4 volts
(with an appropriate current limit) to fast-charge it.

Read the label on the gel-cell. 14.4 volts will cook the battery in
no time flat. I learned that the hard way several years ago.

My power panel uses two regulated power supplies (a 50 A unit and a
35 A unit) operating through an isolation diode block to float
charge the Size 31 (100+ AH) marine deep-cycle gel-cell. The 50A
supply is set to deliver 13.5 V to the battery bus by itself, and
the 35A supply is set to deliver 13.3 V by itself - so I can tell by
the digital voltmeter readout as well as the LED on-line indicators
if the big supply goes off-line and the small supply has picked up
the load. The steady-state load on the bus is 7A which goes up to
25A when all transmitters are firing.

In designing the panel it helped that both my wife and I are both
electrical engineers trained in power distribution and that she
spent a few years in large-scale UPS design. She did insist,
however, that the installation be done to UL and USCG 12-V marine
safety standards, not "hamshack haywire". Expensive but "right".

The installation will run for about four hours in UPS mode after
which various boxes drop off line when the voltage goes much below
11.8 V. My next investment is a small natural-gas-powered gen-set
to supply the 120 VAC for the chargers and the computer installation
when commercial power fails. I'd love to put the whole house on
standby power, but who has a 50 KW gen-set or better yet fuel cell
hanging around that needs a good home? ggg

--
73 de K2ASP - Phil Kane

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

The batteries aren't able to provide the full (1.9-or-so) amperage, at
the voltage required by the VX-5. The voltage drops when you key up,
and the VX-5's safety disconnect shuts down the radio.

So wiring two of the batteries in parallel (for extra current) would be a
good fix until I have the funds for some better batteries?

That might help matters.

However, the low voltage that you are reading under light load
suggests to me that the battery you are using is either seriously
undercharged, or is dying (a shorted cell, or dried-out electrolyte).

First thing I'd do is check your battery-charging circuit. If you're
trying to charge them from a 12-volt regulated source, then this could
be the root of your problem... a "12-volt" gel cell won't accept a
useful amount of charge at this voltage. You'll need around 13.8
volts to slow/float-charge the battery, and perhaps 14.3 - 14.4 volts
(with an appropriate current limit) to fast-charge it.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

The batteries aren't able to provide the full (1.9-or-so) amperage, at
the voltage required by the VX-5. The voltage drops when you key up,
and the VX-5's safety disconnect shuts down the radio.

So wiring two of the batteries in parallel (for extra current) would be a
good fix until I have the funds for some better batteries?

-Josh

--


Remove the reversed "nospam" in the address.