Inverters and NiCd chargers
 

I use a 19.2 v Sears drill to raise the sail on my Nonsuch 26 and find
that the 75 watt 115 v charger does not function on the output of my
cheap square wave inverter. Would it work with a "modified square wave"?
Dick

Not likely. Your "cheap square wave inverter" is probably a "modified square
wave" as well. I haven't had much luck with the typical hand tool NiCd
chargers with these inverters.

David
"Richard Lane" wrote in message
. ..
I use a 19.2 v Sears drill to raise the sail on my Nonsuch 26 and find
that the 75 watt 115 v charger does not function on the output of my
cheap square wave inverter. Would it work with a "modified square wave"?
Dick

I recharge my Dewalt 14 volt batts with a modified sine wave inverter
all the time. Bottom line is that it depends... on the charger, and
on the inverter.

No two are alike.

David&Joan wrote:

Not likely. Your "cheap square wave inverter" is probably a "modified square
wave" as well. I haven't had much luck with the typical hand tool NiCd
chargers with these inverters.

David
"Richard Lane" wrote in message
. ..

I use a 19.2 v Sears drill to raise the sail on my Nonsuch 26 and find
that the 75 watt 115 v charger does not function on the output of my
cheap square wave inverter. Would it work with a "modified square wave"?
Dick



Thanks for your interest, I guess I'll have to wait till I have shore
power since "true sine wave" inverters cost more than the drill, Dick

Richard Lane wrote:
I use a 19.2 v Sears drill to raise the sail on my Nonsuch 26 and find
that the 75 watt 115 v charger does not function on the output of my
cheap square wave inverter. Would it work with a "modified square wave"?
Dick

Usually, the charger consists of a battery holder and a power brick that
goes into your 115/230v outlet. You could bypass the powerbrick if you
have a DC-DC converter (unstabilized, for this purpose) that supplies
the correct voltage. They're a few bucks if you need something = 12v.
12v is easy ;-) Unfortunately, 19.2 v 12v ... So maybe get a 7 to 9 v
drill is cheaper!

I use this to charge DC-powered non-12v small appliances that don't come
with their own "car adapter".

Kees

Kees Verruijt wrote:
Richard Lane wrote:
I use a 19.2 v Sears drill to raise the sail on my Nonsuch 26 and
find that the 75 watt 115 v charger does not function on the output
of my cheap square wave inverter. Would it work with a "modified
square wave"? Dick

Usually, the charger consists of a battery holder and a power brick
that goes into your 115/230v outlet. You could bypass the powerbrick
if you have a DC-DC converter (unstabilized, for this purpose) that
supplies the correct voltage. They're a few bucks if you need
something = 12v. 12v is easy ;-) Unfortunately, 19.2 v 12v ... So
maybe get a 7 to 9 v drill is cheaper!

I use this to charge DC-powered non-12v small appliances that don't
come with their own "car adapter".

Kees

I have a laptop 12v power supply with varyable output voltage up to 24v.
These should be as readily available in the US as they are here in UK. Try
an electronics shop such as Radio Shack.

Dennis.

Jack Erbes wrote:

Richard Lane wrote:

I use a 19.2 v Sears drill to raise the sail on my Nonsuch 26 and find
that the 75 watt 115 v charger does not function on the output of my
cheap square wave inverter. Would it work with a "modified square wave"?
Dick


I know a person that took a dead battery from a similar drill, opened
the battery case up and made themselves a simple adapter with a 10-12
cable that lets them clip onto a auto battery and run the drill off of
that. Those drills have DC motors and the voltage varies with the
speed, so it will work over a pretty wide voltage range. To get full
speed you would need to get up around the rated voltage (14.4, 19.2, etc.).

This adapter was made by cutting open the battery case, removing all the
dead/useless cells, soldering wires to the contacts, and "potting"
everything into place and reclosing the battery case with Liquid Nails
construction adhesive. It was more a tribute native cunning and
inventiveness than professional engineering but it works very well to
manipulate the leveling jacks on a RV.

Another option might be to check the output voltage from your 115V
charger and then look for a DC-DC adapter (for one of the older laptops
or something like that) with a similar output voltage and amperage rating.

I'm a little confused about how to do the latter method though. The
battery charger for my DeWalt 14.4V drill has an output voltage of 42V
as measured across the charging contacts. That is apparently DC, it
does not fluctuate any on my meter. The charged batteries are in the
13-14 Volt range. I think the 42V charger voltage is because the rated
voltage of all the cells (in series) totals a little less than 42V or
something like that. Maybe one of the electrical gurus here can explain
that.

Jack

Yes those are certainly other alternatives however going via the NiCad
battery and then recharging reduces the peak current demand of directly
running the drill from the house battery via a 12/19.2v dc-dc inverter.
In fact I am thinking of replacing the NiCad cells with NiMH cells when
the two packs lose their charge taking ability and so achieving
increased AH.
Dick

Richard Lane wrote:

I use a 19.2 v Sears drill to raise the sail on my Nonsuch 26 and find
that the 75 watt 115 v charger does not function on the output of my
cheap square wave inverter. Would it work with a "modified square wave"?
Dick

I know a person that took a dead battery from a similar drill, opened
the battery case up and made themselves a simple adapter with a 10-12
cable that lets them clip onto a auto battery and run the drill off of
that. Those drills have DC motors and the voltage varies with the
speed, so it will work over a pretty wide voltage range. To get full
speed you would need to get up around the rated voltage (14.4, 19.2,
etc.).

This adapter was made by cutting open the battery case, removing all the
dead/useless cells, soldering wires to the contacts, and "potting"
everything into place and reclosing the battery case with Liquid Nails
construction adhesive. It was more a tribute native cunning and
inventiveness than professional engineering but it works very well to
manipulate the leveling jacks on a RV.

Another option might be to check the output voltage from your 115V
charger and then look for a DC-DC adapter (for one of the older laptops
or something like that) with a similar output voltage and amperage rating.

I'm a little confused about how to do the latter method though. The
battery charger for my DeWalt 14.4V drill has an output voltage of 42V
as measured across the charging contacts. That is apparently DC, it
does not fluctuate any on my meter. The charged batteries are in the
13-14 Volt range. I think the 42V charger voltage is because the rated
voltage of all the cells (in series) totals a little less than 42V or
something like that. Maybe one of the electrical gurus here can explain
that.

Jack

--
Jack Erbes in Ellsworth, Maine, USA - jackerbes at adelphia dot net
(also receiving email at jacker at midmaine.com)

In my experience, with charging battery packs, the free standing charge
stations don't like inverters. Even my modified sine wave charger inverter
will overheat the internal components..

I'm told and have noted myself that the wall wart type seem to work fine.

If you still want to charge with a battery charge station, then be very
observant for overheating.


--
My experience and opinion, FWIW
--
Steve
s/v Good Intentions

Richard Lane wrote in
:

Yes those are certainly other alternatives however going via the NiCad
battery and then recharging reduces the peak current demand of directly
running the drill from the house battery via a 12/19.2v dc-dc inverter.
In fact I am thinking of replacing the NiCad cells with NiMH cells when
the two packs lose their charge taking ability and so achieving
increased AH.
Dick



I took my dead B&D battery pack to Batteries Plus (www.batteriesplus.com)
and instructed the kid to replace the cheap ni-cd cells with the biggest
Ni-Mh cells he could fit in the case. Battery technology grows by leaps
and bounds. The case was full of C-size cells. The "newsed" pack now has
FOUR TIMES the A-H capacity of a B&D pack at 1/2 the cost. Of course, it
also takes the charger 4 times as long to charge them, but drill chargers
are always overcharging the hell out of them, unregulated, anyways. When
you pull the pack and plug it in the drill, you have a time stalling the
drill, now. The voltage on the giant Ni-Mh pack holds up much better than
the POS OEM cheap crap (any manufacturer is the same). I can use it for
days before it would go dead. The Ni-Mh cells DO NOT HAVE MEMORY so
recharging the drill when you're done with it from 60% charge, no longer
destroys the cheap Ni-Cd battery pack. The second pack is getting weaker
and will be, again, replaced with a "newsed" pack this way.....

Ni-Cd chargers charge Ni-Mh packs just fine.....albeit slower. I think the
new pack could crank the diesel in the truck...(c;

--
Larry

"Steve" wrote in news:DPSdne3EP8SwLaPeRVn-
:

I'm told and have noted myself that the wall wart type seem to work fine.

If you still want to charge with a battery charge station, then be very
observant for overheating.



For those with LESS than 12V battery packs only:

If you want to charge these packs in the boat, the solution is quite
simple. Use a voltmeter to determine which wire is + and -. Cut the wires
off at the stupid wall wart.

Get a tail light bulb socket or use any socket you can plug a tail light
bulb into....just one filament, like a backup light bulb...almost any will
work of the bright ones. Put the bulb socket in series with the positive
lead to your house batteries so the current to the battery pack is limited
by the filament in series with it. The bulb also makes a great current
indicator as to how much current the pack is drawing. The center wire of
the bulb goes to the house battery. Wrap any exposed metal on the light
socket with tape to keep it from grounding out to anything...it's hot to
the battery now. Plug in the battery pack to the charging stand and the
bulb will glow fairly bright until the pack comes up to voltage (7.2 or 9V
packs) When you notice the bulb gets dimmer and the pack starts to get
warm...it's charged. DO NOT LEAVE IT CHARGING CONSTANTLY this way as the
charge will continue indefinately. You adjust the charging current,
therefore the charging time, by changing to different bulbs. I'm using 6V
high-intensity lamps instead of tail light bulbs to charge the packs
quicker with more current, but they will easily destroy a battery pack if
you forget and leave them on too long. The packs will overheat on them.
The slower you charge, the better for the packs, of course. Sailboaters
got plenty of time...(c; Never let the battery packs get warmer than your
coffee cup and you'll be fine.

There. Now you don't need to waste power on an inverter. There are 3 bulb
charging stations like this on the house batteries to my work stepvan
glowing in the yard as I type this.

For you perfectionists, buy a little voltmeter or hook your boat VOM across
the charging stand wires so you can watch the voltage rise.

--
Larry

Larry wrote:

"Steve" wrote in news:DPSdne3EP8SwLaPeRVn-
:


I'm told and have noted myself that the wall wart type seem to work fine.

If you still want to charge with a battery charge station, then be very
observant for overheating.




For those with LESS than 12V battery packs only:

If you want to charge these packs in the boat, the solution is quite
simple. Use a voltmeter to determine which wire is + and -. Cut the wires
off at the stupid wall wart.

Get a tail light bulb socket or use any socket you can plug a tail light
bulb into....just one filament, like a backup light bulb...almost any will
work of the bright ones. Put the bulb socket in series with the positive
lead to your house batteries so the current to the battery pack is limited
by the filament in series with it. The bulb also makes a great current
indicator as to how much current the pack is drawing. The center wire of
the bulb goes to the house battery. Wrap any exposed metal on the light
socket with tape to keep it from grounding out to anything...it's hot to
the battery now. Plug in the battery pack to the charging stand and the
bulb will glow fairly bright until the pack comes up to voltage (7.2 or 9V
packs) When you notice the bulb gets dimmer and the pack starts to get
warm...it's charged. DO NOT LEAVE IT CHARGING CONSTANTLY this way as the
charge will continue indefinately. You adjust the charging current,
therefore the charging time, by changing to different bulbs. I'm using 6V
high-intensity lamps instead of tail light bulbs to charge the packs
quicker with more current, but they will easily destroy a battery pack if
you forget and leave them on too long. The packs will overheat on them.
The slower you charge, the better for the packs, of course. Sailboaters
got plenty of time...(c; Never let the battery packs get warmer than your
coffee cup and you'll be fine.

There. Now you don't need to waste power on an inverter. There are 3 bulb
charging stations like this on the house batteries to my work stepvan
glowing in the yard as I type this.

For you perfectionists, buy a little voltmeter or hook your boat VOM across
the charging stand wires so you can watch the voltage rise.

I suppose one could break into the 19.2/1.2= 16 cells string and either
fit a series to parallel switch or simply a centre tap allowing charging
from 12v.
Dick

Richard Lane wrote:
Larry wrote:

"Steve" wrote in news:DPSdne3EP8SwLaPeRVn-
:


I'm told and have noted myself that the wall wart type seem to work
fine.

If you still want to charge with a battery charge station, then be
very observant for overheating.




For those with LESS than 12V battery packs only:

If you want to charge these packs in the boat, the solution is quite
simple. Use a voltmeter to determine which wire is + and -. Cut the
wires off at the stupid wall wart.

Get a tail light bulb socket or use any socket you can plug a tail
light bulb into....just one filament, like a backup light
bulb...almost any will work of the bright ones. Put the bulb socket
in series with the positive lead to your house batteries so the
current to the battery pack is limited by the filament in series with
it. The bulb also makes a great current indicator as to how much
current the pack is drawing. The center wire of the bulb goes to the
house battery. Wrap any exposed metal on the light socket with tape
to keep it from grounding out to anything...it's hot to the battery
now. Plug in the battery pack to the charging stand and the bulb will
glow fairly bright until the pack comes up to voltage (7.2 or 9V
packs) When you notice the bulb gets dimmer and the pack starts to
get warm...it's charged. DO NOT LEAVE IT CHARGING CONSTANTLY this way
as the charge will continue indefinately. You adjust the charging
current, therefore the charging time, by changing to different bulbs.
I'm using 6V high-intensity lamps instead of tail light bulbs to
charge the packs quicker with more current, but they will easily
destroy a battery pack if you forget and leave them on too long. The
packs will overheat on them. The slower you charge, the better for
the packs, of course. Sailboaters got plenty of time...(c; Never let
the battery packs get warmer than your coffee cup and you'll be fine.

There. Now you don't need to waste power on an inverter. There are 3
bulb charging stations like this on the house batteries to my work
stepvan glowing in the yard as I type this.

For you perfectionists, buy a little voltmeter or hook your boat VOM
across the charging stand wires so you can watch the voltage rise.

I suppose one could break into the 19.2/1.2= 16 cells string and either
fit a series to parallel switch or simply a centre tap allowing charging
from 12v.
Dick
Do you think that a 60 Hz series resonant LC circuit might provide
enough filtering to allow the use of a modified sine wave inverter?
Dick

I've been looking at true sine wave inverters on eBay. 300 watts for about
$150. Could be good for the laptop as well.

"Richard Lane" wrote in message
. ..
David&Joan wrote:

Not likely. Your "cheap square wave inverter" is probably a "modified
square
wave" as well. I haven't had much luck with the typical hand tool NiCd
chargers with these inverters.

David
"Richard Lane" wrote in message
. ..

I use a 19.2 v Sears drill to raise the sail on my Nonsuch 26 and find
that the 75 watt 115 v charger does not function on the output of my
cheap square wave inverter. Would it work with a "modified square wave"?
Dick



Thanks for your interest, I guess I'll have to wait till I have shore
power since "true sine wave" inverters cost more than the drill, Dick

Inverters and NiCd chargers
 

"Gordon Wedman" wrote in
news:rCf0f.291283$tt5.93571@edtnps90:

Could be good for the laptop as well.

Switching power supplies like the laptop could care less. The first thing
they do is digest any waveforms fed to them into unregulated DC to feed the
hungry power FETs doing the switching. Notice how it says any voltage is
fine between 85 and 280VAC at any frequency?

--
Larry

Inverters and NiCd chargers
 

Inverters and NiCd chargers
 

Do you think that a 60 Hz series resonant LC circuit might provide
enough filtering to allow the use of a modified sine wave inverter?

Or how about runing the inverter output through an isolation
transformer? With either strategy, I think that I'd take a look at the
resulting voltage and waveform on a scope before risking any expensive
equipment.