Li-Po Battery Capacity Meter  
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Li-Po Battery Capacity Meter - 8/14/2006 7:42:45 PM   
yiyan


 

Posts: 7
Joined: 6/20/2006
From: castro valley, CA, USA
Status: offline 		Please check the picture, it's very useful Li-poly battery capacity meter to indicate the Li-poly battery power left during the aircraft flying.
It's easy to use:
1. Connect with Li-poly Battery through Balance connector
2. Six LED to indictae the Li-poly Battery Capacity when Li-poly battery is used for flying
3. Three supper blue LED to indicate if the Battery capacity is still high
4. Three supper red LED to indicate if the battery is lower power status
5. If the two of three Blue LED becomes dim,it means the battery doesn't have enough power, and you should land your aircraft soon.

more information, please go to www.uce-bestbuy.com

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RE: Li-Po Battery Capacity Meter - 8/14/2006 9:56:33 PM   
Red Scholefield



Posts: 4980
Joined: 12/8/2001
From: Newberry, FL, USA
Status: offline 		This device does not check capacity. It is a state of charge indicator that reads the pack voltage. With the large number of balancing connectors it would be good only for a few specific packs. You will need an adapter for other packs. Note that there are packs on the market with identical connectors but they are wired in reverse of each other. The question should be asked is this device reversal protected?

If you have a balancing charger with individual cell voltage readouts (CellPro, DN Power, Common Sense R/C, ) you can check the state of charge quite easily at the field. A simple check with a digital voltmeter will also give you a good state of charge reading. Your wattmeter is also a viable way to check the state of charge.

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Red S.
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(in reply to yiyan)
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RE: Li-Po Battery Capacity Meter - 8/15/2006 3:41:40 PM   
richrd


 

Posts: 780
Joined: 7/18/2005
From: Waterford, PA, USA
Status: offline 		Also no load verse full load data is so wide you would need your own conversion table to predict capacity. Open cell data is use full to safley maintain LiPO's. Newer ones seem to not like to go below 3.5V at full load to open cell test. Go figure soon you'll ownly safely to get 60% from battery before charger will take recharge safely. So having an on board monitor volt at landing time is a very good idea and could save pack from beening over discharged if one was to note it's condition at each landing voltage state.
BTW wish we could team up and force a connector standard boycott anyone? Long live LiPOs
Rich

(in reply to Red Scholefield)
       Post #: 3

RE: Li-Po Battery Capacity Meter - 8/15/2006 4:44:34 PM   
yiyan


 

Posts: 7
Joined: 6/20/2006
From: castro valley, CA, USA
Status: offline 		To check Li-poly battery capacity is very important in field. Of course the capacity meter doesn't include CPU, it's purely hardware based Li-poly battery capacity montor, which uses the exactly same idea as Richrd point out.

If you need a CPU based Li-poly capacity meter, please check another threads, it's "A smart MCU based Li-poly battery/Ni-MH battey Charger", the charger has the digital voltmeter function. please check the link: http://www.rcuniverse.com/forum/m_4621877/tm.htm
And I think Richrd's suggestion is great, we need to force this kind of connector's standard. Please give your suggestion, I'll convince some factory to manufacture it.

(in reply to richrd)
       Post #: 4

RE: Li-Po Battery Capacity Meter - 8/15/2006 6:30:56 PM   
Red Scholefield



Posts: 4980
Joined: 12/8/2001
From: Newberry, FL, USA
Status: offline
quote:

ORIGINAL: yiyan

To check Li-poly battery capacity is very important in field. Of course the capacity meter doesn't include CPU, it's purely hardware based Li-poly battery capacity montor, which uses the exactly same idea as Richrd point out.

If you need a CPU based Li-poly capacity meter, please check another threads, it's "A smart MCU based Li-poly battery/Ni-MH battey Charger", the charger has the digital voltmeter function. please check the link: http://www.rcuniverse.com/forum/m_4621877/tm.htm
And I think Richrd's suggestion is great, we need to force this kind of connector's standard. Please give your suggestion, I'll convince some factory to manufacture it.


I'll say it one more time. hopefully people will understand the difference between capacity and state of charge. Voltage measurement in itself can only give you the state of charge. The only way to measure the capacity is by discharging the battery, recording the discharge current (mA) vs time (hr) to come up with mAh.


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Red S.
AMA 951 Leader Member

(in reply to yiyan)
       Post #: 5

RE: Li-Po Battery Capacity Meter - 8/16/2006 2:07:05 PM   
richrd


 

Posts: 780
Joined: 7/18/2005
From: Waterford, PA, USA
Status: offline 		Ha Ha so true Red just think for 50 buck send be your money cause my gadget will check your battery during fight and look into the future and tell you that the battery is going to fail. If you buy now I’ll include for free the ronco auto land feature to get the plane down for you.
PS for those that are gullible 100 bucks please
Rich

(in reply to Red Scholefield)
       Post #: 6

RE: Li-Po Battery Capacity Meter - 8/17/2006 7:26:59 PM   
CGRetired



Posts: 4224
Joined: 9/14/2004
From: Galloway, NJ, USA
Status: offline 		Think of this as a bucket of water. Fill the bucket with water until it's full (fully charged battery). Now if you decide to empty the bucket, how much you pour out will be the current flow. The pressure behind the water (in this case, gravity) is the voltage.

If you take a hose, and put on a nozzle like you would use on a garden hose to wash your car, you squeeze the handle and water comes out. The pressure behind the water is the voltage. The amount that comes out of the hose is the current flow. The higher the voltage the more current that will flow until you reach the maximum capacity of the flow or run out of water. You can only get out as much water as the hose will allow to flow. If you add pressure, the water will come out faster but you can only get so much out based on the limitations of the size of the hose. Same with wires and batteries.

Checking the open circuit voltage (nothing attached to the battery) is synonymous to the pressure behind the valve before opening it. Once you open the valve, or attach the battery to a load, motor and ESC for instance, current will begin to flow and, depending on the load (motor and speed control setting), the amount of current, and the voltage measured, will change. The more current you draw at any given time, the less the voltage will be (slight differences) until you completely drain the battery or source. If you have an 1100 mah battery, that is 1.1 amps, you consume 1100 ma and the battery is drained. If you pour out the entire contents of the bucket, it's empty.. drained.

Over simplication to some of you, but perhaps someone will wake up and realize the meaing of the above. As Red said.. there is a difference between voltage and current. Current will define capacity and vice versa.

< Message edited by CGRetired -- 8/17/2006 7:31:19 PM >

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Skylark 70 - OS 75 AX; Venus II - OS 1.20 AX; Tiger 120 - OS 1.20 AX; Protege - OS .75 AX. Airtronics - Spektrum. AMA 705964. Semper Paratus!

(in reply to richrd)
       Post #: 7

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