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Old Jan 05, 2008, 05:55 AM
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Madras India
Joined Aug 2006
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Quote:
Originally Posted by Fuegodeth
Both work just fine. Balancers can be bought separately. Standalone balancers work by bleeding energy off the high cell or cells to keep them in balance. The balance charger is nice because it will show you individual cell voltages during charging. Also it's impossible to have a wrong cell count with a balancing charger because it is charging each cell individually. You don't have to set the cell count. It sees each cell, and so it knows 100% for sure how many cells there are. Also, higher charge rates are possible with a balancing charger because no individual cell can ever get over 4.2v per cell. With a standalone charger and balancer, it is possible to have a wrong cell count or for a single cell to be overcharged at higher charge rates. A balancer works by bleeding off the high cell(s). If you are charging a large packs at 10A and the balancer can only dissipate 50ma, then a single cell could outpace the balancer and get overcharged. However, it's a pretty rare thing to happen like that. Everyone has their preferences though.
Thanks a lot .
I assume your suggestion would be a Balance Charger as a better alternative to a Balancer + Charger . We would mainly be using LIPOS of 3S 1500 MAH max for GWS Planes.
The reason I am asking is I have stand alone Charger and was debating if I should go in for a balancer to add to this charger.
rgds
sai
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Old Jan 05, 2008, 06:13 AM
Will fly for food
Maryland
Joined Sep 2004
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It depends. Some balancer/charger combos work just like two separate units (balancer disharges high cells to mathc them).

Others, like the CellPro and DN Power actually charge each cell at a different rate to achieve balancing. These types are better. The DN Power does have some issues, so my choice is the CellPro.
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Old Jan 05, 2008, 07:36 AM
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There are two features being discussed here, charging and balancing.

A balancer only balances and does nothing or charging. But it does provide the very significant value of keeping your packs in balance. This leads to longer life, and better performance. And it has some safety benefits too.

The balancing benefit is significant but it need not be critical to every charge cycle. Packs don't go out of balance THAT fast. It might happen over 10 cycles or 20 cycles and it builds up over time. So using a regular charger that charges through the power plug is fine. If you balance every few charges, that would be adequate, but you have to remember to do it and you have to have a way of being sure you are doing it.

A balancer can only drain power so it does reduce the charge level of the high cells. It does not bring up the low cells. But I don't think that is a big deal.


I do feel the balancing chargers are better BUT not enough that it should be a big concern if you don't feel you want a second charger or the higher charge rates that some of the newer ones can offer.

Because the CellPro, and some others, charge each cell individually then can charge them faster. If one cell is a little slower than the others the charger compensates so higher rates can be tollerated, or so the charer companies claim. This is a side benefit of the balanced charge process. If charging your packs faster, safely, is important to you, then these types of balancing chargers are a good value.

I have a CellPro 4S, the older version, and I love it. My Cellpro charges at up to 1.4C. The newer one charges at up to 3C. Higher charge rates can not be provided by a balancer.

So, from that respect, certain chargers, let's call them balanced chargers, bring more benefits than others.

I have 5 lipo packs with CellPro balance taps. Most of the time I charge them on my CellPro charger but I also charge them on my Triton charger and on an AC wall wart Lip charger too. Only the CellPro balances, but the packs get on it every few cycles so they will be balanced on the next charge cycle. And only the CellPro charges at the higher rate. The others are limited to 1C and I will not push them.

Cold Weather Cycle

I don't know if this is a common feature but the CellPro 4S also has a cold weather cycle. It actually detects the temperature of the surrounding air. If it is below a certain level, it only charges the cells to about 95% of full charge. This has very little impact in practical use but it provides a safety effect. If you were to charge a lipo pack at the field, say at 30 degrees, then not use it, when you it home, as it warmes the cell voltage would rise taking it over the desired 4.2V level. I can not say how serious an issue this may be, but it seems to make sense that it could present an unrecognized problem. This charger accounts for it automatically. I am sure there must be others that do it as well.

I hope that that helps with your "balanced" decision process and in particular the understanding of the CellPro 4S charger.
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Old Jan 05, 2008, 09:33 AM
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Conroe, TX
Joined Apr 2007
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Quote:
Originally Posted by sbrv24
Thanks a lot .
I assume your suggestion would be a Balance Charger as a better alternative to a Balancer + Charger . We would mainly be using LIPOS of 3S 1500 MAH max for GWS Planes.
The reason I am asking is I have stand alone Charger and was debating if I should go in for a balancer to add to this charger.
rgds
sai
If money is a concern (and it always is) and you don't really want another charger, then I would just get a balancer like the blinky. I would try to use it every charge at first, to see about cell health. If there is a bad cell, then it will go out of balance rather quickly. If they are all good, then they may never significantly go out of balance.

I believe the cellpro is a better way to go, but a balancer is much cheaper than getting the whole charger.
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Old Jan 05, 2008, 11:49 AM
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Thanks for the great info on the battery, charging at home, balancing, etc...., and continuing from the charging process, a couple of questions..


[QUOTE=Fuegodeth]
Quote:
What to do after you charge the battery. First of all, you do want to use a whattmeter to determine what the full throttle current load is for your setup. It might differ from the calc system. You may have to step up or down in prop pitch or diameter to get it where you want. That's not too different from setting up a glow engine.
any suggestions on a wattmeter, and what am I looking for, how connected? so the battery charged, in the plane, the meter goes between the battery and esc or motor and esc, etc? then run the throttle up at full, and look for what numbers on the wattmeter?





Quote:
For long term storage it is recommended to only charge the battery to 40-50% charge. The cellpro has a charge mode for this. The cellpro cannot discharge though. There are external devices than can be used to discharge a lipo to a specific level for storage. Basically though, if you don't think you might fly for a few weeks or more, then use the storage charge feature. It will make your packs last longer. Storing at cooler temperatures also extends pack life. Some people use the refrigerator for long term storage.
I was looking at a charger/balancer/discharger, etc (BC-6, etc), thanks for input on storing the battery. Will plan on using the storgage functions of the charger. If the frige is not an option, what about storing in the garage or shed during the summer time, in the lipo bag, flower pot, etc. will the garage/shed be too hot. Sorry to belabor this, just want to eliminate the "risk of fire".

Quote:
If I can think of something else, then I'll add to this. please feel free to ask some clarifying questions. Also I'm sure others will add to this.
Thanks for the input, I am sure to have follow up questions. Will be purchasing the rest of the equipment, etc soon. I needed that comfort feeling that I had a basic understanding of battery, amps, watts, in relation to the motor size, charging, what charger, power source to charger, AC/DC input, using a wattmeter b/4 flight, how to hook up, what to look for on wattmeter, how to discharge battery after flight for safe storgage, eliminate risk of fire, etc. I know all this info is here, trust me, I saw it during my numerous searches somewhere, but having a general summary in one spot is helpful, at least to me and some specific questions being addressed.

Thanks again, the info on here is great, and makes trying electric from glow a reality for me.
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Old Jan 05, 2008, 02:34 PM
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Quote:
Originally Posted by rckymtn1
any suggestions on a wattmeter, and what am I looking for, how connected? so the battery charged, in the plane, the meter goes between the battery and esc or motor and esc, etc? then run the throttle up at full, and look for what numbers on the wattmeter?

.
I have the Watts up meter. Easy to use and works well. Just hook it between the battery and the ESC.
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Old Jan 05, 2008, 04:32 PM
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Canada, ON, Ottawa
Joined Feb 2006
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Quote:
I was looking at a charger/balancer/discharger, etc (BC-6, etc), thanks for input on storing the battery. Will plan on using the storgage functions of the charger. If the frige is not an option, what about storing in the garage or shed during the summer time, in the lipo bag, flower pot, etc. will the garage/shed be too hot. Sorry to belabor this, just want to eliminate the "risk of fire".
This is more an issue of getting maximum life out of the batteries, not of safety. Don't get too paranoid about it.

Flying is the easiest and most fun way to discharge batteries. My practice is when I'm flying frequently (every few days) simply to recharge after flying so I'm ready for next time. If I expect to be not flying for a couple of weeks or longer, I make a point of either simply not recharging after flying (if the resting voltage is above about 3.6 per cell) or only charging to about 3.8 v per cell if it's lower than that.

As for storage temperature, again, I don't see it as critical as long as you avoid real heat. I've never bothered with refrigeration, though I might if I were storing a battey for months.

The critical factor in battery life in my view is not to overdischarge. I time my flying carefully and try never to use more than 80% of capacity. With my 3700 mAh packs, for example, I aim to put back in no more than 3000 mAh. I worked up to this by initially flying for a conservative 7 min, gradually increasing it over several flights to 10 min as I monitored the successive recharges. You should NEVER fly to the point where there is an obvious loss of power, as you will rapidly degrade the battery.

A good example of this issue is watching people fly Blade CX helis on a 2-cell 800 mAh pack. They typically fly till it won't stay in the air. The result is that they need new batteries after just a few weeks. I have packs that are into their third year and still going strong.

Of course, you also need to charge properly, including balancing, but you've got lots of good advice on that (I use an Astro Blinky for my smaller packs and it works well).

As for safe storage, some sort of fireproof arrangement is advisable. Inside a steel box or a cinder block on a concrete floor, for example. Or in the fireplace (if you don't have fires!!!).

Good luck.
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Old Jan 06, 2008, 01:34 PM
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Conroe, TX
Joined Apr 2007
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[QUOTE=rckymtn1]Thanks for the great info on the battery, charging at home, balancing, etc...., and continuing from the charging process, a couple of questions..


Quote:
Originally Posted by Fuegodeth

any suggestions on a wattmeter, and what am I looking for, how connected? so the battery charged, in the plane, the meter goes between the battery and esc or motor and esc, etc? then run the throttle up at full, and look for what numbers on the wattmeter?

The wattmeter will basically show you three things Watts, volts, and amps, and actually a 4th is total amount of current passed through for the session. The 4th value is not of much importance usually. The first 3 are important though.

Watts is your total power. Usually motors will list a max wattage figure. You don't want to go above that. Watts = Volts * Amps

Amps = your current draw. It is the actual number of coulombs of electrons passing through the power system. More amps equals more heat, but also more power. Amps is also how you tell how hard you are pushing your battery, and how long your runtime will be. Each battery has a C rating. A C rating is how many amps you can draw for 1 hour. A 1000milliamp hour (mah) battery (or 1amp hour) will ideally sustain a 1 amp draw for 1 hour. If you draw 4C which would be 4 amps, then you can run for 1/4 hour or 15 minutes. If you draw 20Amps, then that is 20C, and you can run for 1/20 of an hour, or 3 minutes. You usually do not want to reach the max C rating for your battery, or you won't have a battery for very long.
Motors also usually list a max amps figure that you won't want to exceed.

Volts is your battery voltage. This might seem obvious, like it's a 3 cell lipo, at full charge it is 12.6 volts (4.2 x 3). However, the harder you push your battery, the more the voltage will drop under load. If you go below 9v or 3v per cell, then you can damage the battery. Some say 3.2v per cell is the best safe limit. So, you can watch the volts drop on a full throttle 20 or 30 second burst. If you are staying around 10 - 11 volts, then you are in good shape. If it rapidly drops to 9v then you are pushing the batter way too hard. You can also use your wattmeter to check your resting voltage of your battery pack. You just hook it to the battery and can see if it is fully charged or not. You usually don't want your resting voltage to be below 10.8-11v after a flight. A full charge is 12.6v. Again this example is all for a 3 cell pack.

I was looking at a charger/balancer/discharger, etc (BC-6, etc), thanks for input on storing the battery. Will plan on using the storgage functions of the charger. If the frige is not an option, what about storing in the garage or shed during the summer time, in the lipo bag, flower pot, etc. will the garage/shed be too hot. Sorry to belabor this, just want to eliminate the "risk of fire".

They are usually quite safe during storage. Avoid major temperature extremes. Cool dry place is a good guideline. This is more for battery life than safety.

Thanks for the input, I am sure to have follow up questions. Will be purchasing the rest of the equipment, etc soon. I needed that comfort feeling that I had a basic understanding of battery, amps, watts, in relation to the motor size, charging, what charger, power source to charger, AC/DC input, using a wattmeter b/4 flight, how to hook up, what to look for on wattmeter, how to discharge battery after flight for safe storgage, eliminate risk of fire, etc. I know all this info is here, trust me, I saw it during my numerous searches somewhere, but having a general summary in one spot is helpful, at least to me and some specific questions being addressed.

Thanks again, the info on here is great, and makes trying electric from glow a reality for me.
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