Need advice for field power.
 

Hi there!

It's been a while since I've flown but I'm trying to get some gear together so I can start again. I've been trying to decide which way I should go and wanted to get some input.
Should I?
1) buy an AC charger and a handful of batteries. Charge at home and bring the batteries to the field.

2) buy a big deep cycle battery, get a dc charger and only a few lipo batteries. (would need a charger/tender for that big battery which means higher cost.)

3) buy a jump starter that has DC and an inverter built in but less amp hours than the marine battery, and I'd have a few options for chargers, and get only a few lipos.

What would you guys do?I like the jump starter just because it has a few extra uses with a built in inverter and an auto charger for the battery which buying a marine battery is more expensive since I need a separate charger . Although a marine battery has significantly more Ah.

In the end . does anyone need power at the field for other stuff if they bring a truckload of ready charged batteries?

Thanks!

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i fly at a club field with a bunch of other pilots. my powerlab 6 charger with powersupply can be plugged into a generator or home outlet. i fly batteries in series and parrallel so for me it's easyer to charge a # of batts for saturday and sunday with 9+ flights possible. but rarely do i fly all the batts and still get plenty of air time.

thing is i don't mind buying extra batteries to be ready,but for those who want to save a few bucks they should buy a charger to plug into their car.[of coarse gas costs too]

skip the car jumper idea as it dosn't hold that great a power, and deep cycle batts work but weigh a ton.[popcorn]

Re: Need advice for field power.
 

I mainly do not want to run off of my car battery which is why this whole thing came up for me. I also my dc outlets in my car are deactivated unless the engine is running which I couldn't possibly idle my car for an hour just to charge my flight batteries!

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The car jump starter is a non-starter (excuse the pun). They are not deep cycle type so you would kill the battery in no time if you used one to charge lipos and took anything more than maybe 1/3rd capacity out of it on a regular basis.

True deep cycles are the only type of lead acid that can be deeply discharged on a regular basis without damage.

Personally i just charge several (eleven usually) batteries at home on a high output charger and take them to the field. This is perfectly feasible if you are flying small to medium size models but gets cost prohibitive if flying larger electric (which is why I'd go gas if i ever did the big stuff again).

I'd get a DC charger and a AC to DC power supply. That way you have your options open for field charging should you ever want to. In any case all the top chargers only come in DC type.

There's maybe 6 of us that fly consistently at our field. We generally charge our batteries at home but we have an automotive sized 12v battery at the field in a weather sheltered stand. On that stand is a 12v solar panel that feeds an automatic charging circuit that keeps the battery pretty well topped off. We generally don't charge more than 3 batteries at a time and usually the biggest pack is a 3s 2200. It works great for us. Another thing is most of us are of the "old fart" variety so we fly a bit, talk a lot, fly a bit, and talk some more.:)

On cloudy days at least one of us will bring along an additional extra 12v battery (lawn tractor size) just in case the field battery is weak. (the charging circuit pulls a little bit on it's own). The lawn tractor batteries are pretty reasonable at places like Lowe's Building Supply or Tractor or Farm Supply stores--like $30-$40. They'll run a couple of iMax B6 chargers near all day depending on the size of packs you're charging.

fly a bit,talk a bit,fly some more.thats what i do:ws:.






wait a minute......who you calling an old fart:mad:!!!!!....................:Q

Sounds like maybe you "represent" that remark!:D


I've been an old fart for a long time and I'm only 57. I used to work with all young guys (anyone under 40 is a young whippersnapper).:silly:

Firestem4,

Just use Al's van battery. He won't mind. ;)

Currently, I do a ton of batteries charged at home, call it quits when they are all gone.

I've thought about charging in the field... I was thinking (theoretically) in terms of one of those 2nd car battery setups with a deep-cycle unit. This sort of thing: http://en.wikipedia.org/wiki/Battery_isolator Dunno if I'll ever do it, but it seems like a possible solution.

Yea :D Thats what I do :Q and if Al's battery goes dead, then we just give him a Jump :p> LOL

Go to pep boys and get a BOSH Group 24 Battery, they have a lot of CCAs more than their Marine battery has, and use that to charge your lipo batteries with, charge the Car battery when you get back home, use a trinkle charger , you can get them from Harbor frieght tools for about $5.00 on sale.

Here's my solution. How about getting one of the ammo cans from a local army supply store. Then stop at a feed store along the way home and pick up a 12v gel cell. I have the battery mounted inside with a cigarette plug on the side and then a toggle switch leading to two bolts sticking out the front that have those drywall plugs to insulate them from the side of the box. I use the bolts sticking out the front to connect my starter for gas powered planes. You can put in multiple cigarette lighter plugs if you want. Make sure you put in a fuse at the positive lead to the battery to protect in case of any kind of a short.

I use the car battery charger to get it topped off before going to the field. Well I used to. I fly mostly at home now and not even sure where the box is in storage. If I can't find it I will be making a new one soon as I want to stop charging from the car.

I wouldn't want to lug around a big giant battery. So I always just hooked my chargers up to my cars battery. Running 4 chargers non-stopped for about 6 hours doesn't damage it.

This all depends on the size of the models you are planning to fly. If you are only flying small foamies, a cheap riding lawnmower battery will work OK. Might have to replace it every year or so, but, they're only about $25.

If you are working with motors up to about a kilowatt or so, and models up to about 8 pounds, you need a big, heavy, deep cycle battery. We're looking at a 120 Ampere Hour deep cycle battery. Around Wisconsin, they run about $75. They will last one or two seasons, depending on how you treat them.

If you are running 2500 and 3000 watt motors like I am, IMHO, those deep cycle batteries just won't do the job. For me, they didn't last one year. So, I put together a Harbor Freight 212 cc $99 engine and an 80 Amp automotive alternator. That, will provide sufficient DC power to charge virtually anything.

If you do the kilowatt sized models, a solar type field charger for the deep cycle battery simply can't provide enough ampere hours for a days flying. Unless you get a real big ($$$$) solar panel that can charge at 20 amps or so anyhow.

????
57 years? I'm 71, and still learning!

I have a power inverter and cable i picked up in my travels now i need a couple good battery's in the rear of my van so i can charge them on my way to the field then run my power inverter when i get there to plug in my 110 ac lipo charger. This is still a plan in the works but i think it's better than dragging my honda generater around. joe

Depends on the size of the battery. My Cellpro Powerlab 8 pulls 25 Amps while charging a 6S2P A123 battery pack, and 55 Amps while charging a 12S2P A123 pack. That 12S2P pack is reconfigured as a 6S4P pack while charging at 30 Amps.


Twenty five or fifty amps out of an auto battery will kill it in short order.

Yeah, here's what I use. (That is a 19X12 prop on that Giant Big Stick model)

Harbor Freight Gasoline/Alternator Setup
http://www.wattflyer.com/forums/showthread.php?t=66066,

Thanks for the input all. I think i'll go with a DC charger and an inverter. JetPlaneFlyer has a point is that at least with a DC charger, I can upgrade to field power later on when I decide I really need it. I only have (and imagine using for a long while) small parkflyers, so I don't need a generator for any big stuff.

Thanks!

Depends on the size of the battery, and load obviously. This is the supposed dfferance between a car battery and a deep cycle one.

My station wagon has a 850 amp cold cranking batttery. Should still take several hours to fully discharge it, and when I drive away in the car, it will be fully charged by the time I get home from the flying feild.

There is a difference between 850 Amp cold cranking, and 120 Ampere Hours.

In theory anyhow, a 120 Ampere Hour deep cycle battery can not put out the high current pulled by your auto's starter in cold weather. But the deep cycle battery can put out 12 amperes for 10 hours.

Compare that to a typical auto battery that is designed to put out very high currents for short times. But the auto battery is not designed to put out much lower (like 12 Amps) for 10 hours.

As far as that goes, one of those electric power station backup substation batteries also have about 150 Ampere Hours. But, these things weigh over 160 pounds, and cost over $700! Methinks those Walmart or marine deep cycle batteries are not even in the same ballpark.

Well I ordered a Thunder AC680 from amazon (had a gift card I'd been trying to figure out how to spend! Lol). It has AC built in and DC available so it gives me the best of both worlds for now and in the future. Prior to this I only had a walkera ga005 charger so this will be a significant upgrade!

Thank you everyone for pitching in your thoughts.