Richard Lane wrote:
Larry wrote:

"Steve" wrote in newsPSdne3EP8SwLaPeRVn-
:


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

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.

wrote:
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.

I would worry about an isolation transformer being rather heavy and not
being sufficiently "low pass" to attenuate the high harmonics of the
cheap inverter. I don't own a 'scope since I retired from microwave
engineering 13 yrs ago but do have an old Toshiba laptop with serial
port on my boat. Are there cheap A-D converters that could turn the pc
into a 'scope?
Dick