AC voltage adjuster - how to do cheaply
 

On Sun, 23 Nov 2003 16:43:03 -0800, Panama wrote:

I have a 40 amp battery charger that has a 5 position switch to select
the battery charging voltage. Works great. Allows steps from about
13.2 to 17 volts. Prob done by a multi-tap transformer?

Trouble is - AC voltages in Mexico can be as high as 128-130 VAC and
other places can be as low as 105 VAC. The charger reacts by changing
the battery charging voltage up or down - a little but enough to vary
the DC amps that get to the batteries. I'm not going to replace the
charger.

I'm looking for a cheap variac/scr/triac something gizmo that I can
wire into the AC line to the charger and make the effective voltage
(RMS value?) go up or down by +/- 10% or so. The AC in is about max 9
amps. It could even be a big wired wound variable resistor I suppose.
Then I can set the AC line voltage to what my genset puts out and use
the charger at it's max 40 amps all the time.

Any ideas or products. Preferably cheap and never needs replacement
like the 27 years old charger.

(No I'm really not going to replace the charger.)

Seems like I answered this in another newsgroup, but if you missed it...

There are two types of auto-regulating transformers. The old kind uses a
swinging core. As the voltage varies, the core moves in and out to provide
a more or less constant voltage. I say "more or less" as they can seldom
act fast enough to block transients, those very short term spikes which can
damage electronic gear.

The second type are called "ferro-resonant" transformers. They work by
driving the core into saturation and operate in parallel with a
non-polarized capacitor to ensure that the output voltage always remains
the same. They offer a few advantages, the best being that they do not
transfer voltage transients (spikes).

Both are rated in volt-amps and both are available on the surplus market.

Good luck
--

Larry
email is rapp at lmr dot com

AC voltage adjuster - how to do cheaply
 

Panama wrote:

I have a 40 amp battery charger that has a 5 position switch to select
the battery charging voltage. Works great. Allows steps from about
13.2 to 17 volts. Prob done by a multi-tap transformer?

Trouble is - AC voltages in Mexico can be as high as 128-130 VAC and
other places can be as low as 105 VAC. The charger reacts by changing
the battery charging voltage up or down - a little but enough to vary
the DC amps that get to the batteries. I'm not going to replace the
charger.

I'm looking for a cheap variac/scr/triac something gizmo that I can
wire into the AC line to the charger and make the effective voltage
(RMS value?) go up or down by +/- 10% or so. The AC in is about max 9
amps. It could even be a big wired wound variable resistor I suppose.
Then I can set the AC line voltage to what my genset puts out and use
the charger at it's max 40 amps all the time.

Any ideas or products. Preferably cheap and never needs replacement
like the 27 years old charger.

(No I'm really not going to replace the charger.)

The specified/allowed 'Voltage variation' plus/minus varies (pun
intended!) a little from country to country and region to region.
E.g. North America, Europe, etc.
In some places it may be plus and minus ten (10) per cent. In
another area it may be, say, minus 6% to plus 10%. If in Mexico
the voltage is occasionally up to 128/130 on a supply that is
supposed to be 117/120 volts; that's around 9% to 11% high. i.e.
acceptable? If you are monitoring it anyway why worry? Is in
danger of burning out. i so tap it down to the next lower
ampere/voltage output setting?
Or am I missing something?

AC voltage adjuster - how to do cheaply
 

Terry wrote:

The specified/allowed 'Voltage variation' plus/minus varies (pun
intended!) a little from country to country and region to region.
E.g. North America, Europe, etc.
In some places it may be plus and minus ten (10) per cent. In
another area it may be, say, minus 6% to plus 10%. If in Mexico
the voltage is occasionally up to 128/130 on a supply that is
supposed to be 117/120 volts; that's around 9% to 11% high. i.e.
acceptable? If you are monitoring it anyway why worry? Is in
danger of burning out. i so tap it down to the next lower
ampere/voltage output setting?
Or am I missing something?

Terry writes further.
Transformers tend to be heavy (if this is of any concern on an
average boat?). A 'lighter' way than an auto transformer or
tapped transformer which carries the whole load (which is
apparently of the the order 40 amps x 12 volts = approx. 480
watts; that's about 500 VA) is to use a smaller transformer with
a low voltage output.
For example lets assume a suitable transformer of 120 volts input
with ten volts output. That small transformer is connected in
such a way that it's output 'opposes' the too high voltage coming
from the shore supply; viz. 128 volts minus the approx. ten volts
of the smaller transformer is; 128 - 10 = 118 volts (almost spot
on!).
You have to know what you are doing but it can and has been done.
The small transformer in the example given will only have handle
about 10/120 of the total power = less than one tenth of the
total wattage and can thus be more compact, cheaper and lighter.
But it must be done safely and connected the proper way with
appropriate fusing.
Cheers.

AC voltage adjuster - how to do cheaply
 

yeh, you're missing something. I pull into marina 1 in town 1 - AC -
105V - charger puts out say 14.3 V - go to marina 2 in town 2 - AC is
114 V - charger puts out 14.4 V - now go to marina 3 in town 3 - AC is
130 V - charger puts out 14.7 V . So my genset puts out 120 V and the
charger does 14.5 V - all the 14 v voltages are regulated but
dependent on AC input voltage - I'd like to adjust the AC to the same
120 V no matter what town/marina I'm in - then I get the same
charging. The AC voltages are constant in each town but vary from town
to town.


On Sun, 30 Nov 2003 21:33:42 -0330, Terry
wrote:

Panama wrote:

I have a 40 amp battery charger that has a 5 position switch to select
the battery charging voltage. Works great. Allows steps from about
13.2 to 17 volts. Prob done by a multi-tap transformer?

Trouble is - AC voltages in Mexico can be as high as 128-130 VAC and
other places can be as low as 105 VAC. The charger reacts by changing
the battery charging voltage up or down - a little but enough to vary
the DC amps that get to the batteries. I'm not going to replace the
charger.

I'm looking for a cheap variac/scr/triac something gizmo that I can
wire into the AC line to the charger and make the effective voltage
(RMS value?) go up or down by +/- 10% or so. The AC in is about max 9
amps. It could even be a big wired wound variable resistor I suppose.
Then I can set the AC line voltage to what my genset puts out and use
the charger at it's max 40 amps all the time.

Any ideas or products. Preferably cheap and never needs replacement
like the 27 years old charger.

(No I'm really not going to replace the charger.)

The specified/allowed 'Voltage variation' plus/minus varies (pun
intended!) a little from country to country and region to region.
E.g. North America, Europe, etc.
In some places it may be plus and minus ten (10) per cent. In
another area it may be, say, minus 6% to plus 10%. If in Mexico
the voltage is occasionally up to 128/130 on a supply that is
supposed to be 117/120 volts; that's around 9% to 11% high. i.e.
acceptable? If you are monitoring it anyway why worry? Is in
danger of burning out. i so tap it down to the next lower
ampere/voltage output setting?
Or am I missing something?

AC voltage adjuster - how to do cheaply
 

"Panama" wrote in message
...
yeh, you're missing something. I pull into marina 1 in town 1 -
AC -
105V - charger puts out say 14.3 V - go to marina 2 in town
2 - AC is
114 V - charger puts out 14.4 V - now go to marina 3 in town
3 - AC is
130 V - charger puts out 14.7 V . So my genset puts out 120 V
and the
charger does 14.5 V - all the 14 v voltages are regulated but
dependent on AC input voltage - I'd like to adjust the AC to
the same
120 V no matter what town/marina I'm in - then I get the same
charging. The AC voltages are constant in each town but vary
from town
to town.


I think we went through this before. It is not cheap, but take a
look at:

http://www.sola-hevi-duty.com/produc...ning/Index.htm

Leanne

AC voltage adjuster - how to do cheaply
 

On Fri, 05 Dec 2003 22:07:27 -0800, Panama
wrote:

yeh, you're missing something. I pull into marina 1 in town 1 - AC -
105V - charger puts out say 14.3 V - go to marina 2 in town 2 - AC is
114 V - charger puts out 14.4 V - now go to marina 3 in town 3 - AC is
130 V - charger puts out 14.7 V . So my genset puts out 120 V and the
charger does 14.5 V - all the 14 v voltages are regulated but
dependent on AC input voltage - I'd like to adjust the AC to the same
120 V no matter what town/marina I'm in - then I get the same
charging. The AC voltages are constant in each town but vary from town
to town.

You could use a variable autotransformer (one trade name is "Variac")
- cost US$200 - 300

However, despite your statement that you won't replace the charger, I
would strongly suggest installing a modern charger, such as the
Xantrex TrueCharge 40+ - they're around US$400, and have the advantage
that they are "install and forget" - they'll work from 90 to 135 volts
with no attention on your part, and will be much kinder to your
batteries than your old charger, even if you do remember to adjust the
Variac correctly.



--
Peter Bennett, VE7CEI
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

AC voltage adjuster - how to do cheaply
 

Let me explain why I won't install a new charger to solve this
irritation - it's not really a problem - a minor irritation.

I have 2 of these chargers - provides 80 amps of capacity and
redundancy (but never needed). They've been in use for 27 years -
since the boat was built - have never failed - never even hiccupped.
Not even the knob or meter has broken. I've had Heart and Trace
inverters (both bought by Xantrex) - fail - repairs cost more than
they were worth to repair. Not really junk - just not really good
stuff.

I've had my present Trojan 6V's for almost 7 years. Still fine. I had
Surette 8D's for 8 years before that. I treat stuff I own to
intellingent maintenance.

I don't need a "set and forget" boat - or items that break every 18
months. And lots of modern "marine" gear is really "marina" gear.



On Sat, 06 Dec 2003 11:42:33 -0800, Peter Bennett
wrote:

On Fri, 05 Dec 2003 22:07:27 -0800, Panama
wrote:


You could use a variable autotransformer (one trade name is "Variac")
- cost US$200 - 300

However, despite your statement that you won't replace the charger, I
would strongly suggest installing a modern charger, such as the
Xantrex TrueCharge 40+ - they're around US$400, and have the advantage
that they are "install and forget" - they'll work from 90 to 135 volts
with no attention on your part, and will be much kinder to your
batteries than your old charger, even if you do remember to adjust the
Variac correctly.

AC voltage adjuster - how to do cheaply
 

I guess you have answered your own question. A minor irritation
can be left as is. Spending several hundred dollars on a solution
is not money well spent it would seem. A 27 year old charger is
old technology that does not handle varying line voltage well.
If it ain't broke, don't fix it as they say. This kind of reminds me of
short story I read back in high school where a cup of tea was
sweetened with salt by mistake and the rest of they story dealt
with all the attempts to make the tea right. In the end they
tossed out the tea and brewed a new cup. Wish I could remember
the name of the story. Don't take Heart and Trace as the only
examples. StatPower (now Xantrex as well) and Ample Power
make great chargers.

Doug
s/v Callista

"Panama" wrote in message
...
Let me explain why I won't install a new charger to solve this
irritation - it's not really a problem - a minor irritation.

I have 2 of these chargers - provides 80 amps of capacity and
redundancy (but never needed). They've been in use for 27 years -
since the boat was built - have never failed - never even hiccupped.
Not even the knob or meter has broken. I've had Heart and Trace
inverters (both bought by Xantrex) - fail - repairs cost more than
they were worth to repair. Not really junk - just not really good
stuff.

I've had my present Trojan 6V's for almost 7 years. Still fine. I had
Surette 8D's for 8 years before that. I treat stuff I own to
intellingent maintenance.

I don't need a "set and forget" boat - or items that break every 18
months. And lots of modern "marine" gear is really "marina" gear.



On Sat, 06 Dec 2003 11:42:33 -0800, Peter Bennett
wrote:

On Fri, 05 Dec 2003 22:07:27 -0800, Panama
wrote:


You could use a variable autotransformer (one trade name is "Variac")
- cost US$200 - 300

However, despite your statement that you won't replace the charger, I
would strongly suggest installing a modern charger, such as the
Xantrex TrueCharge 40+ - they're around US$400, and have the advantage
that they are "install and forget" - they'll work from 90 to 135 volts
with no attention on your part, and will be much kinder to your
batteries than your old charger, even if you do remember to adjust the
Variac correctly.