| Author |
Message |
John (64.12.96.235)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 23, 2003 - 8:48 pm: | |
What's the difference between a converter and a inverter? Any and all help would be great thanks
John |
Scott Whitney (66.82.9.14)
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Votes: 0 (Vote!) | | Posted on Sunday, February 23, 2003 - 9:09 pm: | |
In basic terms, a converter takes your genset or shore power (120VAC) and provides 12VDC. An inverter does essentially the opposite. It takes 12VDC (or sometimes 24VDC) and provides 120VAC in place of shore or genset power.
Some converters have a DC load center (fuses or circuit breakers) built into them, and sometimes decent battery charge features.
An inverter can be just a plain inverter, or frequently, have a battery charger built into it. Sophisticated inverters use a good three-stage charging curve and automatic switching features. Others can be paralleled to double capacity and some are true sine wave (As opposed top modified-wave. . . chop, chop square wave). Lots of goodies are available if your wallet is phat.
In my opinion, use of a converter is old school. Preferred is a good inverter with built-in battery charger. That way you get the best of both worlds: AC on demand and high quality battery charging (no undercharged or cooked batteries etc.) An inverter is a much more efficient way to power small to medium AC loads than firing up a generator all the time. Also, a high power inverter/charger can really pack a punch into your battery bank, which can greatly reduce genst run time to recharge. When on shore power, a good inverter (with charger) keeps your bank on a nice float charge and ready for use at a moment's notice.
I may catch some flack for this post. I am sure there are good uses for converters. But I think if you are going to buy one or the other, get an inverter with charger. Or get an inverter plus a stand-alone 3-stage charger.
BTW, using an inverter/charger for powering 12V loads when you have shore power or genny running, you just draw from the battery bank, all the while it is being charged or floated. So your bank remains in top shape even when constantly being drawn from.
Scott |
John Clark (Jvc) (205.188.209.11)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 23, 2003 - 9:18 pm: | |
No flak from me Scott. I think converters are the number one destroyer of batteries in RV's (next to old age). jvc |
Tom Caffrey (Pvcces) (64.114.233.229)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 23, 2003 - 10:45 pm: | |
John, I think Scott is right on the money with his post. And a good RV inverter has even more good features he didn't even get around to mentioning.
Tom Caffrey PD4106-2576
Suncatcher |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 24, 2003 - 1:50 am: | |
But I see it completely differently!
I use a high quality 3-stage converter (50 amp capacity) to keep my house batteries happy, and then I run everything but the AC's, microwave and blender from 12 volts. Granted my computer system and datastorm dish have a small, separate dedicated 100w sine inverter, but that's the only inverter on the bus. Since there is no AC going from shore or gene power to the computer system, effectively the computer system operates from 12 volts too. Makes for one heck of a nice uninterruptable power source!!
Basically when I plug in the bus to shore power, what I'm really doing is plugging the converter in. It keeps the batteries happy and charged regardless of what I draw from the 12 volt system... interior lights, stereo, ventilation fans, water pumps, etc. If I'm out in the boonies and need AC, an instant heated dinner or a nice margurita, I fire up the onan. It's nice 'n quiet and since I have a 100 gallon tank of propane, I can run it as long or as little as necessary. Actually I find that I rarely use the microwave, because the wife does most of the cooking with the propane stove. And I only find myself using the blender when it's so hot outside that the gene and AC are already on, so that's a moot point most of the time as well.
Truthfully I've thought and thought about it, and I cannot for the life of me justify a big inverter for any reason! Well, it's my way for my bus and at least for me, it's simple, effective, and efficient!!! Definitely no quandry about what to do with all the grounds!!
Cheers
Gary |
FAST FRED (209.26.115.126)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 24, 2003 - 6:27 am: | |
In the "old " days there were converters & battery chargers, and inverters, and motorgenerators.
The converters were stoopid things that would sense when the volts dropped below about 12.8 to 13.2 and add power to restore the volts toward the set volts.
The idea was that the batterys would never see the house load and sit fully charged at the set voltage.
The set voltage was hopefully low enough that the water would not boil out in months of service. Worked sorta , best if the DC loads only switched on , less sucessfull with long term draws like bulbs , as overcharging could easily happen.
The usual problems were overcharging , and with such a low set point they took days to actually charge a big battset , if that was attempted.
Constavolt , by La Marche was best of the bunch.
A batt charger is great for pulling the voltage of a discharged batt up to about 14.4 to recharge .
The problem is if used as a converter the charger will frequently see the load as a discharged system & full charge again.
Result overheated batts & fast water loss.
The marine chargers are better at "live aboard" as there is an almost constant load from a cheapo DC fridge unit , with ocasional loads from pumps , lights TV etc.
Thankfully the cheap computer chip lets them work better.
The best of the bunch is an invereter, with batt charging built in.
These will not only make the AC for toys, they have expensive enough brains in the computer chip to be able to work the house system without overcharging.
The added ability to equalize the batt set is a bonus for someone that actually will be living on the batt set for extended time.
But good invereters are priced as any good equipment . Trace , Heart , Exeltec and a few others will kick a $2,000 hole in your budget if you need BIG AC .
The big true Sine wave AC inverters are necessary if a large motor load ( like an air cond ) is contemplated. The tiny chop chop will usually run a microwave , TV or Sears frige.
NONE of the chargers , converters or even Sine wave inverters will charge batterys at the advertised rated in a camper.
The usual camper gen set does not put out the same voltage as house current in terms of power (area under the sine on a scope).Therefore the invereter working as a charger has less power to work from.
Secondly many inverter mfg report charge ability into a 50% discharged batt set .
This is much lower charge ability than when your at 85% full and waiting forever for that last NECESSARY , percentage.
There advertising a 1 volt rise into a batt at 10.8V, your needing rated amps at 14.4 V.
If you need fast recharges the marine DC gensets (or backyard DC) with that big inverter could solve the problem of long boondocking.
FAST FRED |
DaveD (216.18.113.69)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 24, 2003 - 9:42 am: | |
For someone who spends a lot of time in campgrounds, plugged into shore power, a converter is a reliable cost-effective way to go. Good converters give you well regulated 12V dc output, a nice load centre for 120V ac and 12V dc circuits, connections to 12V dc from the batteries (such as for absorption type refrigerator electonics)plus a decent charger to maintain the batteries. Good quality converters are very reliable. This is what I installed in my bus.
For those who spend a lot of time on the road or boondocking, an inverter is especially great because it converts dc to 120 V ac, allowing one to run a number of appliances that would otherwise require shore or generator power. Inverters typically have a higher intial cost than converters, but given they perform a different function, it's not fair to compare them directly in terms of cost. It's really a matter of how you plan to use your bus. |
Tom Caffrey (Pvcces) (64.114.233.40)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 24, 2003 - 10:00 pm: | |
At a minimum, you are best off with a smart charger, whether inverter or converter. If you are looking at a converter because they cost less, be sure it has a smart charger if you want the best from your batteries.
Good luck!
Tom Caffrey lPD4106-2576
Suncatcher |
modelt (208.18.102.200)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 25, 2003 - 11:02 am: | |
I have a Phillips converter, I just purchased it (old one finally bit the dirt) but the info is not real clear. It is not a cheap unit but I do have a question that you with experience can help;
I use a lot of shore power and have never cooked out the water or had any other problems, but I was wondering if I should unplug it from the bus when on road or running generator for A/C?
I have a receptacle in the battery compartment and when engine is running I have been unplugging it, concerned about conflect with engine output (charging) and battery charging from Onan. Does it have diodes that should not require me to unplug it while running engine or generator? This recept is powered when every I have 120V connected either via generator or shore power. I know it is hard to say without the model etc of my converter. But do most have protection for such?
Larry |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 25, 2003 - 12:01 pm: | |
I don't know your converter intimately, but virtually every converter or battery charger has to have diodes in it's output to create DC, so It's a 99.9% bet that not disconnecting it is fine. I've never disconnected mine or any other converter or charger I've had, and I've never had a problem.
That said, there is one output topology in some switcher type power supplies called "synchronous rectification" that could cause problems because it doesn't use diodes to do the rectification, but that technology has, to my knowledge, never ever been used in a battery charger, so it's probably not an issue.
Go for it!
Cheers
Gary |
modelt (208.18.102.61)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 25, 2003 - 7:04 pm: | |
Well thanks Gary, that was what I had thought but I sure, could have been overlooking somthing or something new.
I don't think any synchronous type rectification was used in this manner either, or at least for small converters.
Thanks again Larry |
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