My flying field as no electricity available, so I would like to know the bestpower sourceto use for my charger to charge my LiPo.

I know that I can use my car battery but how much charge I can do before draining it without needing to start the car to recharge the battery, if my bigger Lipo pack is 10000mah 5S (18.5V)?

Or can I use some deep discharge marine type battery as a power source? Or something else?

Thanks

Perhaps a combination of solar recharging and some deep cycle lead acid cells might be the solution. You probably wouldn't need many batteries to serve the needs of the club, and they would have plenty of time to recharge via solar panels between flying sessions. The same thing could be accomplished using a small wind turbine to recharge the deep-cycle cells.

Portable generator...........

It's only for my personnal use that I need to know, not for an entire Club



It's noisy and messy... I'll like a more quiet and cleaner solution, that's the reasonI fly electric

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Do any of you uselead acidbattery for charging at the field ??? How many charge can I do with this solution? Is there a formula that I can used.

Thanks

Noisy and messy?? Ihave a small 1000 watt generator that runs on 2 stroke gas/oil mix, just like a weedeater. Iput it in front of my truck in the parking lot and run an extension cord to the back where my charger is at, not noisy or messy at all. You can't even hardly hear it running.
Unless you're looking for some sort of miracle power source that requires little or no effort from you, I don't have any other suggestions.
You could take a bunch of car batteries and use them to charge, then recharge them at home, but lots more hassle than a generator.

If it's just for you, all you need is one deep-cycle battery and a solar charger. You can get them on Ebay for reasonable prices. They are intended for maintaining the charge on mobile home batteries and are fairly rugged units. A battery of that size ought to provide many recharges.

Those solar chargers are trickle chargers, and would never be able to recharge the battery at or near the same rate as the discharge from the battery charger. The length of time the lead acid battery would last depends on many factors-Charge rate of your battery charger, battery pack capacity you're charging, C rate at which you're charging at,amperage rating of the car battery being used, outside temperature, etc.
Then, you would have to recharge that lead acid battery at home, either with a wall charger, or some sort of solar trickle charge setup, but still involves a lot of hassle either way you look at it.
Ihave a Triton EQ charger that I use at the field. It has a max charge rate of 5 amps. Iused to use the battery in my truck to charge, but now use the generator. Isafely charged packs up to 2650ma at near 2C, probably 10-12 packs in a day of flying, and never even noticed a slow crank afterwards. But, keep in mind, if it's not a deep cycle battery, a regular car battery is not designed to be discharged and recharged over and over like that. It's designed to have reserve power to initially start the vehicle, then the Alternator/Generator takes over.
If your pack is 10k ma 5S, even at a 1C charge rate, you're still talking about a 10+ amp charge rate. You can drain your car battery in just a few hours at that rate.
My little generator runs for 5 1/2 hours on 1 gallon of fuel, and it only cost me $130.00. Not a bad option if you really think about it.

I think the idea would be to leave the battery at the field with its solar recharger. It would be constantly recharging between flying sessions and ready to supply at least a few hours of recharging capacity. A deep-cycle battery would be the best bet. It ought to be easy to tweek solar recharge and battery capacity to suit an individual's flying requirements. Also, you would need to be confident that the battery and recharger would be secure at the flying field during flight sessions.

Your best options are:

1) Car battery. Monitor the car battery voltage and start it up occasionally to charge it up.
2) Deep cycle marine battery.

I know a few guys that use option 1. You'll probably figure out how many batts you can charge, or how long you can charge before you have to start it up and run it for a few minutes.

For option 2, figure out how many Watt-hrs you need at the field for battery charging (nom batt pack voltage x total amp-hrs you want to charge), and try to get a battery with at least that Watt-hrs rating you need. Watt-hrs rating for a marine battery will be approximately 12V x amp-hr rating.

Example:

You want to recharge six 3S 2200mAh battery packs: Watt/hrs required = 6 x 11.1V x 2.2Ah = 146.5 Watt-hrs
So you want to get a battery with at least 150 Watt-hrs of capacity = 150Watt-hrs/12V = 12.5 Amp-hrs

The charger will require some power, and there will be some power loss due to charger inefficiency, so you may want to add 10-20% to that Amp-hr rating to be sure you can charge that many batts.

Hope that helps!

pkh, he's talking about recharging a 10,000ma battery pack. With the associated power loss from the charger, even charging at 1C rate, which would take over an hour to recharge that pack, a standard car battery would only be good for a few hours at best. It's NEVER a good idea to use the car's alternator to recharge a low battery, it's not designed for that and will eventually result in a dead alternator. The voltage regulator will sense the low voltage condition, which results in a 'full field' condition, or close to it. The alternator can't run at full field charge rates for too long without damaging it, especially at idle.Also, it would take more than a few minutes of run time to recharge a weak battery. You will get a high surface charge initially, but to restore the battery to full capacity takes a lot longer.
If he were dealing with smaller packs, as you mentioned, the car battery would be just fine. Some of the guys Ifly with bring a car battery on a dolly to the field for charging, but all of them use smaller packs, 4000ma packs or less, or only recharge rx batteries. Every time you discharge a non deep cycle battery, it will never be able to be recharged to 100% capacity. Each time you discharge and recharge it, you lose some capacity until the point that the battery is no good. A deep cycle battery doesn't have this problem, and is designed to be discharged and recharged multiple times, but are more expensive.
Let's say for examle he's charging at 1C, figuring in a 20% power loss due to the charger, you're talking about a min 12 amp draw on the battery. To compare that to a car, a modern fuel injected car/truck uses about 7-10 amps with the key on and engine not running to power up the electrical systems (on average). The average passenger car battery is around 540 cranking amps on average. If you leave the key in the on position without starting the car, you will come out to a dead battery in 3-4 hours or so. I don't know about you guys, but Ican easily spend more than 3-4 hours at the airfield .

crazyronnie, if you do decide to go the car battery route, please consider using a separate battery and not the battery in your car, and just recharge it at home. With the charge current you will be drawing, it would suck to get stuck at the field with a dead car battery, especially if no one is around to give you a jump.
I'm not talking out my ***** on this subject, it's what I do for a living. I'm an electronic engine management specialist for Ford. I deal with car electical systems daily.

Look at a Honda 1000...very queit, very clean.
Yes, there AREnoisy ones, the Honda isn't.....


I also have a marine deep cycle battery in my trailer for charging.....

Combination of the above
Run the vehicle to bring the deep cycle marine battery back up as needed.
Pete

You're right exeter, the Honda is very quiet, can't hardly even hear it. A portable 12v air pump/tire inflator is louder than the Honda. I have a Chicago Electric that is only a bit louder than the Honda.

To charge an 18V battery at 10A means your charger will have to draw at least 15A from the battery (18V/12V x 10A), since they are basically switching boost converters, and power in = power out + overhead power + inefficiency losses.

Again, you can calculate how many Amp-hours you need out of a marine battery, and purchase the appropriate size. If you use your car battery, your alternator will certainly handle a 15 -20A drain on the battery.

Like I said, if you use your car battery, monitor the voltage and be sure you start it up before it gets too low. The guys with the larger LiPos leave their engines running quite a bit, if not all the time.

540 cranking amps is NOT a capacity measurement. It is a measure of max current output for a short period of time.

Marine batteries can have 80-100 amp-hr capacities. With say 16 amp-hrs to charge one of his packs, that means he could charge 5 to 6 of his batt packs off of a deep cycle marine battery.

Also, as far as being 'cleaner', my gen can run for 5 1/2 hours on a gallon of fuel at a 50% load. That's pretty clean if you ask me. A Prius emits more pollution than that.

Like I said, if you use your car battery, monitor the voltage and be sure you start it up before it gets too low. The guys with the larger LiPos leave their engines running quite a bit, if not all the time.

540 cranking amps is NOT a capacity measurement. It is a measure of max current output for a short period of time.


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You completely missed the point Iwas trying to make. If he charges the pack 1 time, sure that would only be a 15-20 amp loss, not enough to hurt anyhing. BUT, repeated charging at the field will bring the battery down MUCHmore than that, then you will need to rely on the alternator to RECHARGE the battery, NOTAGOODIDEA!!!! Why do you think the others 'leave their cars running quite a bit, if not all the time'?????????? The alternator can certainly handle a constatnt 15-20 amp draw if the car is RUNNING, but not a good idea to use the alternator as a recharging tool.Leaving the car engine running will most certainly use more gas than the 1 gallon in 5 1/2 hours that my generator uses.
The amperageratingis the capacity of the battery, much the same as the mah rating on your batteries. Car battery manufacturers don't print the total amperage capacity on the batteries except in a 'cranking amps and cold cranking amps' rating, but the end result is the same. To tell you the capacity of the battery.
Also, a 12 volt car battery is actually 12.6 volts base battery voltage. The actual voltage while the engine is running is more like 14.2 volts, so the calculated draw will be different. 15 amps draw @ 12.6 v, more like 13 amps draw @ 14.2 volts. Better to charge with the engine running, except for the large ammount of fuel that you will use.
Any way you look at it, a small generator is still the best way to go.

Everybody driving to an air field has a car. Not everybody has a generator.

CCA ratings have nothing to do with capacity.

Deep cycle Marine battery=$125.00 average cost
12v charger to recharge said deep cycle battery= $30-50.00 for a lower end charger
Cost of electricity at your house to recharge said deep cycle battery=Varies
Cost to replace vehicle alternator= hundreds of dollars in most cases

1 800-900kw Chicago Electric generator= $129.99 ($99.95 on sale at Harbor Freight Tools)
1 gallon of low octane fuel in Co. $2.39
2 stroke oil $1.50 for 6.8oz, or 2 tanks full.
You decide.

As far as cranking amps: A car battery is rated at 540 Cranking amps, but only has 190 cranking amps available (remaining capacity). Your car's starter requires 225 cranking amps to turn engine over.
Result? You're stuck at the airfield. Nuff said.

"Amps" is just current. "Amp-hrs" (amps x hours) is capacity.

CCA is just a max current rating.

That's like saying a 20C LiPo has more capacity than a 15C LiPo, even though they have the same Amp-hour rating.

Get your units straight!

Nuff said!

Automotive batteries don't come with the same types of capacity ratings printed on them as LiPo batteries. They only come with a stated cranking amperage capacity, such as 540 amps, 650 amps, 750 amps, etc. If you look at the battery in a passenger car, the label will read something like this: BXT 65-650. BXT 65 is the battery series, or the dimentions, if you will. A 65 series battery fits a certain vehicle. A 34 series battery fits a different veh, etc. The second number, 650, determines the amperage rating of the battery. Usually there will be 2 different numbers, the Cranking amps, and the Cold Cranking amps. This is the only determining factor you have at your disposal when selecting an automotive battery. Yes, amperage IS current rating, but when talking vehicle batteries, the CA and CCA are the only capacity ratings you have to go by, and the only difference in the two is temperature.The amperages are still calculated using Ampere-Hours, as with all current, but you use the CA and CCA ratings to determine the correct capacity for your application. Automotive batteries aren't designed to be discharged and recharged, only to supply cranking power for the starter motor. Once the vehicle is running, the charging sys takes over and runs all electric components. Thus, a standard Ah capacity rating is not used to determine capacity as you are defining it, only CA and CCA. You still use these ratings to figure capacity,however.
A 650 CA battery will still require 650Ah to chargefrom a completely discharged state.
This may sound like a whole different direction than what this thread was started on, bit it has everything to do with the OP's question. I'm trying to suggest ways for him to recharge his high capacity batteries at the field without leaving himself stranded, not get into a pissing contest with someone who doesn't (or chooses not to) understand my point.

So you're telling me you think that a car battery with a CCA rating of 650 has 650Ah of capacity????

You've got to be kidding!!!

The CCA amp ratings are based on something like a 30 second current draw. There's no way the CCA rating = the Amp-hour rating of the battery!

Hell, if your car battery had 650Ah of capacity, you could charge 40 5S 10Ah LiPo packs on a single charge!!

pkh, I owe you an apology. As I sometimes do, I didn't think about what I was saying. I completely overlooked discharge rate . I'm at work right now, and have many numbers floating through my head currently. A 650 CA car battery would be more like a 130 amp charge capacity, not 650Ah. Car batteries are not labelled with charge capacity and discharge rates as we're used to in this hobby, and my mind was somewhere else. So, go ahead, say it. I'm a dumbass sometimes.............
I still think that a 10,000 mah battery is too high a capacity to recharge using the car battery, the alternator is not designed to be a recharge tool, and it will ruin it after too long. Either a deep cycle auxillary battery or generator would be the better choice.
If the car battery was discharged even just 50 amps, it would still take the average alternator an hour plus of driving to replace it. So just starting the car and letting it run for a few minutes isn't a good option, especially since you would most likely use even more capacity cranking the engine over than you would replace in a few minutes of ilding. The alternator needs airflow to cool it just like a motor does, and idle speeds are too slow to cool sufficiently at high charge rates.

No problem, it's can be a confusing topic.

You taught me something new: I didn't realize you get generators so cheap! I have a Harbor Freight nearby, I'll have to check them out. Although I think you meant 800-900W generators, the 800-900kW generators would power every house on my street! 

See! I did it again! . Icertainly meant 800-900 watt, not kw................
I think i'm losing it lately.
As far as the generator is concerned, so far it has been great. It even has a measuring cup for the 2 stroke oil built right in to the gas cap. It takes 3.4oz/gal, and runs for 5 1/2 hours at 50% load. I don't think my little chargers are going to load it to 400 watts, so it's perfect. I'm going to try running 2 5 amp chargers on it this weekend and see how it does. My biggest batteries are 5000ma 2S and 2650ma 3S that Irun in series on 2 different planes, the rest are 2200 & 2550 ma 3S packs, so the small gen is fine.
For $129.00, Idon't see how you can beat it for the airfield. It has a handle on top, and only weighs about 20 pounds or so.
The Honda generator that was mentioned earlier is more like $500-600.00, not really worth it at that price, i'd buy a deep cycle batteryinstead for a lot less.
It really is surprisingly quiet too. I leave it in the backof the truck with an extension cord to the front, and you can't even hear it. It's nowhere near as loud as a weedeater, and it has a 63cc engine. Give it a look.
Our club has a 5000w gen at the airfield, but they won't let us use it except for club events.
With gas prices below $2.50 a gallon, the generator is perfect for me. I only fly electrics now, so Ineeded a better solution than my truck battery.

People are still charging with their car battery. It can be exciting when they do.