| Author |
Message |
califbob (199.174.218.161)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 08, 2004 - 1:19 am: | |
Beside my 04 I have a 1976 GMC front wheel drive (Toranado) motor home.
It has a big convertor.
Question, why not just put in a good battery charger? Dosn't a convertor just change AC to DC.and charge the battery? If I'm pluged in or have the gen. running would not a charger work?
I got one of those Costco inverters works fine for my needs. |
John the newbie (199.232.240.154)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 08, 2004 - 7:38 am: | |
Some DC electronics and appliances need filtered DC. Most
all battery chargers do not employ filtering since it's not
necessary if just to charge a battery. Aftermarket filtering
can be added, but it's never as good of a filter than a converter
that was engineered to be used for electronics. Even simple
things, like a dc clock will not work properly on unfiltered DC. |
califbob (199.174.218.17)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 08, 2004 - 6:09 pm: | |
Thanks John, now I know. That has always been a mystery to me and everyone I asked did't have the answer. |
TWO DOGS (65.179.209.80)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 08, 2004 - 6:44 pm: | |
on my converter...only one terminal is filtered..but all have fuses...also..the converter has a separate(left) side for 110...can be purchased for 100 to 400...try Catlows in Mo. |
Stan (68.150.140.91)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 08, 2004 - 9:02 pm: | |
Converters are designed as stand alone units. They are useful for places where no 12 volt battery is available. In a RV with house batteries, you draw your 12 volts from the battery and then must have a method to maintain the charge or to recharge it. Since the battery is the ultimate filter, you will get pure DC from it even when it is being charged.
If you have followed this board you must have seen all the references to three stage chargers which will make your batteries last longer by better control of charge voltage.
The bottom line is you don't need a converter in a RV. |
TWO DOGS (65.179.192.157)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 08, 2004 - 9:19 pm: | |
well....guess so....but...ya' got to have a centraly located junction box any way....guess a 100.00 square D would do for the 110 part...additional box for 12 volt...& some kind of fuse panel....hey....I'm describeing a converter...if I throw in a battery charger... |
John the newbie (199.232.240.165)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 08, 2004 - 10:34 pm: | |
Stan....
You're not going to get "pure dc" from any battery while it's
being charged. That AC wave will ripple through that battery
and make a mess out of any DC only electronics. Try using a
DC television or hand-held ham radio plugged in that cigar
lighter while the battery's being charged with an AC charger. |
Stan (68.150.140.91)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 09, 2004 - 11:08 am: | |
John
The 60 hz or 120 hz from a cheap battery charger should not cause a problem with well designed electronic devices. If they are made for automotive use they have to deal with the 5000 hz noise from the engine alternator along with all the ignition noise. There are battery chargers on the market (including very expensive ones) that have sharp turn off spikes that radiate through the entire vehicle.
The price of a converter should tell you that it is not a high quality DC power supply. They put out raw rectified AC and as Two Dogs has noted, one line has a filter on it, so you don't gain anything by installing it.
You are correct in saying that if you want absolutely pure DC you have to take it from a battery or a high dollar power supply, or use the high dollar power supply as a battery charger. This method lets you use a low current charger to maintain batteries that are capable of sourcing high currents when needed. |
John the newbie (199.232.240.99)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 09, 2004 - 11:45 am: | |
Thanks Stan.
I assumed the poster was talking about a low priced,
conventional (cheap) battery charger, not a more expensive
type that's designed for ripple-free DC voltage to the battery,
as some are.
We have had DC digital clocks work erratically due to
dirty dc, thanks to the battery charger in use. Inexpensive
DC TV sets, VCRs and radios all show signs of AC hum
when in use while the batteries were being charged. Generator
and/or alternator noise would also cause major problems
with those same devices, at times.
Most newer inverters are designed to provide clean DC
for all the new technology that's being used. Older models
(as in our old Winne-bag-o-*&^%) may only have one
"clean" terminal with older technology heavy duty filtration.
It's my opinion, that it's best to use a DC supply designed for
clean DC use for all those "luxury" items, than to suffer the
consequences of using an inferior supply.
For Amateur Radio use, I use a separate 40 amp DC supply
for all equipment. Those types of power supplies provide
extremely clean DC output and range in price from $50 to
$150. The Ham Radios I used (fairly sophisticated equipment)
all suffered hum, frequency drift, and major "memory" problems
while being powered by the Motorhome's battery while it
being charged.
Better safe than sorry. |
Scott Whitney (69.35.62.177)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 09, 2004 - 5:25 pm: | |
Most RV converters are junkola. Couldn't give me one. Sometimes they put out a nasty, noisy DC. Much preferred to get your pure 12VDC fresh off the battery bank. Then use a 3-stage charger to keep batts topped up. The batteries become the filter. Even better, use an inverter with built-in 3-stage charger, in my opinion. Automotive ATC fuse boxes and household breaker boxes can make for an inexpensive load center that you can size to suit.
Scott |