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How big of a generator do I need ?

Old 12-14-2011, 04:47 PM
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Default RE: How big of a generator do I need ?


ORIGINAL: OliverJacob

I used one of the cheap 2 stroke generators, it hat 1000 Watts and worked ok. But I would never run a computer or expensive charger to this.
Even if it puts a out a real nice sinus wave (which it doesn't) then you are still dealing with power spikes when the load changes.
The carb got gummed up fast, was hard to start and the engine seized after a year of no use. Used good quality 2 stroke oil, 1:25.
My opinion - get a good size car or truck battery, charge it at home and you'll have enough power to fly all day. Yes, it's heavy and bulky, but so is the generator.
How is it that an actual wound generator dosen't put out a true sine wave? wound improperly or something?



Old 12-14-2011, 05:01 PM
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Default RE: How big of a generator do I need ?

2nd the use of a Harbor Freight 800W generator, Used one all weekend at a contest and it did just fine. No issues with my power supply or charger. In my opinion after using that and a deep cycle battery I would choose the generator every time. They were on sale for 89. recently too.

maustin
Old 12-14-2011, 05:51 PM
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Default RE: How big of a generator do I need ?

I was considering this one:

http://www.homedepot.com/webapp/wcs/...25&R=100660525
Old 12-14-2011, 06:19 PM
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Default RE: How big of a generator do I need ?

An alternative approach would be getting 6 packs of battery and charge them at home.

Some advantages of this approach:

1. less usage on each pack
2. have quality number of flights at the field
3. have enough number of packs to go in a day in a contest
4. one less piece of equipment (the generator) to maintain and to carry to the field
Old 12-14-2011, 06:22 PM
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Default RE: How big of a generator do I need ?

http://www.survivalistboards.com/showthread.php?t=74036

if you own a scope, you can find out yourself when running under different loads....you'd be surprised how your wave will look.
Some electronics are 'forgiving' and handle these impuritys, some don't.
Old 12-14-2011, 07:15 PM
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Default RE: How big of a generator do I need ?

if you own a scope, you can find out yourself when running under different loads....you'd be surprised how your wave will look.
Some electronics are 'forgiving' and handle these impuritys, some don't.
Ditto,
Found out the hard way. Lost a laptop and a printer power supply. I will not trust expensive electronics to these generators ever again. It worked fine for a month, then BAM. Of course it happened at the worst possible time.

Live and Learn...
Old 12-14-2011, 08:48 PM
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Default RE: How big of a generator do I need ?

I have a Kipor 2000 and we have easily run 4 guys charging 1 set of batteries at a time on it. I would say a 1000 would be plenty for you. Look into the Kipor brand. You will not be sorry. Same as Honda.. Great generator..

Chris
Old 12-15-2011, 06:04 AM
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Default RE: How big of a generator do I need ?

4 battery packs does me fine - can make the 4 flights on a saturday (charge a pack or two off the truck if I want practice or late flying) and recharge in the hotel room. I have a 5th set - really only use all 5 sets for a full day of practice. Used to fly 10-12 flights when I started the hobby a few years ago, but now 4-5 good practice flights is about all I'm good for. Now have a foamy and another small plane for flying around later or between practice flights.
Old 12-15-2011, 06:55 AM
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Default RE: How big of a generator do I need ?

A slight different question.

On rare occasion, the batteries are charged but I can not go to the field for whatever reasons. These full-charged packs should be discharged to around 50% for longevity. How do you discharge these packs? I was not able to find a means to do so nicely.
Old 12-15-2011, 07:04 AM
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Default RE: How big of a generator do I need ?

Some of the chargers out there have a discharge feature which works very well. Not all have them, but many do.

Arch
Old 12-15-2011, 07:15 AM
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Default RE: How big of a generator do I need ?

My chargers (iCharger1010) have a storage (discharge) feature - it's incredibly slow, maybe 5-8hrs, to discharge a full pack to storage.

However, they do have 'regenerative discharge' - if hooked up to a battery instead of a power supply, they will discharge faster. Haven't tried it yet though, but plan on buying a small 12V tractor battery for discharging purposes to see.

Storage is about 3.8v/cell.
Old 12-15-2011, 09:12 AM
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Default RE: How big of a generator do I need ?


ORIGINAL: OliverJacob

http://www.survivalistboards.com/showthread.php?t=74036

if you own a scope, you can find out yourself when running under different loads....you'd be surprised how your wave will look.
Some electronics are 'forgiving' and handle these impuritys, some don't.
Yes I own an oscilliscope, I checked my 220V backup generator when I bought it a few years ago, the sine wave is quite good. I live in a neighborhood that has old utility systems in it, power outages are frequent, I am comfortable running any electronics I own off of it, (I plug it right into the main box when the need arises via a transfer switch). My little generator, (HF 800w) I haven't checked the wave but it is rock solid at 60HZ, about all I use it for is running a 25 amp DC power supply and some outdoor work lighting sometimes.

Old 12-15-2011, 11:06 AM
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Default RE: How big of a generator do I need ?


ORIGINAL: maustin

2nd the use of a Harbor Freight 800W generator, Used one all weekend at a contest and it did just fine. No issues with my power supply or charger. In my opinion after using that and a deep cycle battery I would choose the generator every time. They were on sale for 89. recently too.

maustin
I've got one of those that I carry with me to boat races (yeah, I'm one of those guys) and have used it at home during the many power outages that I have here. It's enough to power up my fidge without breaking into a sweat but also when I'm mobile I keep a deep-cycle battery and 2 power inverters in the trailer.
His main problem seems ot be that he lives in California which doesn't like most of anything 2-stroke powered. It seems like Harbor Freight does have one though that is 50-state legal. It's the best $90.00 that I've spent when you can catch them on sale for that price. Easy starting and fairly quiet. Under normal load a tank of gas will last over 4 hours.
Old 12-15-2011, 11:12 AM
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Default RE: How big of a generator do I need ?

I have the Sportsman generator listed earlier (got mine at Tractor Supply for $150 on sale) and have no problems with it. It is fairly quiet, but not as quiet as a Honda inverter model. I use it to run my 12V 20A power supply for field charging, as well as for my camper when I don't need to run the air conditioner. It also has a 10A 12V output (for charging a 12v battery ONLY) that can be used to keep a deep cycle battery topped off. Don't try using this output to power your lipo charger, though, as it is unfiltered DC.

[link]http://www.tractorsupply.com/sportsman-trade-2000-watt-portable-gasoline-generator-4458506[/link]

You can't charge a deep cycle battery in 15min from you car alternator, or any other charge source for that matter. Not going to happen. It has to do with how fast the battery can accept a charge. At the very minimum it will take 4 hours to go from about 50% charge to 85% charge. (AGM batteries can charge faster than the common flooded wet-cell batteries). The last 15% charge may take 12-24 hours to accomplish. When I camp, I try to keep my 12v house battery between 50% and 80% charge. Going below 50% charge shortens the battery life.

I don't recommend using the car alternator to charge a depleted battery. Don't ask me how I know. [] I know it sounds stupid, but the instructions that come with some (most?) alternators say they are not designed to charge a fully depleted battery. There are special alternators made for things like ambulance duty, but they are not common and are more expensive.

[link]http://econtent.autozone.com:24999/znetcs/psb/en_US/2/00/86/546-3tb.pdf[/link]

As to why non-inverter generators have noisy outputs, it has to do with how the voltage regulation is done. Some generators use a capacitor circuit to regulate voltage, others use an electronic AVR to do it. Both will have some distortion, but the electronic regulators generally have a cleaner waveform. I won't hesitate to use my Champion generator with my camper or to run anything. Most electronic power supplies are designed to handle distortion and transient surges (to a certain degree) without damage. The most likely way that a generator will damage electronics is if the generator's regulation circuit fails and drives the output high. The normal waveform distortion should not damage anything.

I have a WFCO converter in my camper, and I tried using one of the small inverter generators (ETQ) to run it. Did not work. The capacitor filter on the input drew too much current (inrush) when first connecting that it always tripped the output of the generator. I could use the ETQ to run my 12v 20A DC supply for my field chargers, but sometimes that would trip it as well. Once connected and running, it never tripped, it only ever tripped when first turning on the converter. I've never had that problem with my non-inverter generators. Other brand inverter generators may or may not have this problem.

Hope this helps.

Bob R.

Old 12-15-2011, 01:02 PM
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Default RE: How big of a generator do I need ?

Like I said, I'm a big fan of the Hondas.

If I were wanting a less expensive model, the reviews for the Champion generators are very good:
http://www.amazon.com/Champion-Equip...3982870&sr=8-9
http://www.amazon.com/s/ref=nb_sb_no...mpion+generato
Old 12-15-2011, 02:26 PM
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Default RE: How big of a generator do I need ?

Have you considered a solar panel?

Gary
Old 12-15-2011, 04:47 PM
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Default RE: How big of a generator do I need ?

Anyone have experience with a Honeywell?

http://www.newegg.com/Product/Produc...82E16803009081
Old 12-15-2011, 05:45 PM
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Default RE: How big of a generator do I need ?

I have been using my Kawasaki 500W generator (4 stroke) for over 10 years without a glitch. I have been running a 30 amp power supply all year with a Hiteh Quad Charger with 100% results.
Old 12-15-2011, 05:48 PM
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Default RE: How big of a generator do I need ?

I might be missing something, but if you are using an inverter, to convert DC to AC so you can plug in a charger and convert AC to DC there might be a better way to go. Are you using a dedicated 12volt battery to run the inverter?  A 1000 watt inverter running near capacity will bang your battery pretty hard, in the vicinity of 80 amps.  Also, the inverters that have a stepped square wave output are not clean power.  Chargers that run on AC house current usually have a transformer as the load to mains and as such will be an inductive load.  the transformers(inductors) are designed to to be powered by a true sign wave as seen in our home.  The flat top of the square wave is DC until it for practical purposes immediately switches to a different DC level.  They result in a very noisy signal out of a transformer.  That is why true sign wave inverters are better for electronics, and they cost more because they are harder to engineer and build.  If you are using a big inverter connected to your car's 12volt system, you are going to really be working it hard.  Car batteries are not designed for sustained high current loads, they are designed for short term high current loads as seen when starting the car. 

But if you are using a 12 volt battery to provide your power to charge your batteries, why not use a charger powered by a 12 volt DC source and get the cleanest power available.   this takes the inverting circuitry, transformer, rectifier and filter circuits out of the equation.  I should note that there are switching power supplies that don't use transformers, but they are noisier still and probably not seen in these applications.  could be wrong on that. 

Generators are nice to have and I would not be opposed to having one for my charging but cost and maintenance would be a consideration.  Cost especially when clean power is important to you.  

I'd be inclined to use a 12volt deep cycle  to power a quality dc field charger of sufficient capacity for your needs.   Middle of the road deep cycles that I looked at claim 75amps continuous for 45 minutes, 25 amps continuous for 205minutes.  So a field charger drawing 8 amps or so and used intermittently should easily last you the weekend with power to spare. 

But I'm new here and like I said, I might be missing something. 

Old 12-15-2011, 06:42 PM
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Default RE: How big of a generator do I need ?

I have a couple generators, I finally bought a Honda for flying field use. I wish I had done that years ago. Buy a Honda and forget it, one of the best purchases you will ever make.... we even use it for small stuff around the house when the power goes out.

The best price I have seen on a day to day bases with no tax and free shipping is Generator Depot; http://www.generatordepot.us

Cheers,
Steve
Old 12-16-2011, 05:18 AM
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Default RE: How big of a generator do I need ?

I have been using a honeywell 1000i for two seasons for field use and for the ocasional power outage at home. I am very happy with it, so far no issues. A little louder than the honda (but not much) but only 1/3 the price
Old 12-16-2011, 05:40 AM
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Default RE: How big of a generator do I need ?


ORIGINAL: motomike

I might be missing something, but if you are using an inverter, to convert DC to AC so you can plug in a charger and convert AC to DC there might be a better way to go.
I think most of the discussion has been about inverter generators, where the generator has a variable speed engine driving an alternator, that drives a built-in inverter with a pure sine-wave output.

You open up another option, though, in that you could use a regular generator to power a 12v charger hooked up to a 12V batt. The generator does not need to be able to handle the peak load, but just enough to keep the 12v battery topped off. The advantage is that you don't need to run the generator every time, only when you are going to be charging a lot of lipos. Most 12V chargers are simple transformers that won't be sensitive to 120v waveform distortions or transients. One of the Harbor Frieght 900w jobs ($90) and a 12v charger (15A output, maybe $50) and a 12V deep cycle battery ($75 - shop around).

Someone mentioned solar panels. It would take a lot of panels and they are not cheap. Rated output is only in direct sunlight, so doing much charging on cloudy days is not possible. I would really love to install a few hundred watts worth on top of my camper, but by the time I count the panels, wiring, brackets, charge controller and battery bank, I'm looking at probably $1500. It is too easy for me to pull out my small $150 generator to justify that expense.
Old 12-16-2011, 05:50 AM
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Default RE: How big of a generator do I need ?

Buy a Honda. Only rich people can afford cheap stuff!
Old 12-16-2011, 06:03 AM
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Default RE: How big of a generator do I need ?


ORIGINAL: gaRCfield

My chargers (iCharger1010) have a storage (discharge) feature - it's incredibly slow, maybe 5-8hrs, to discharge a full pack to storage.

However, they do have 'regenerative discharge' - if hooked up to a battery instead of a power supply, they will discharge faster. Haven't tried it yet though, but plan on buying a small 12V tractor battery for discharging purposes to see.

Storage is about 3.8v/cell.
it will be great if the energy can be re-used instead of wasted. The regenerative discharge sounds interesting.

What else the energy can be dumped? Maybe hook up to an inverter to power a lamp or charge computer/phone batteries? An inverter capable of taking 21v DC should work.
Old 12-16-2011, 09:30 AM
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Default RE: How big of a generator do I need ?



I have used a Honeywell 1000 for two seasons and it has worked great.  Powers two Cellpro chargers without any problem.
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