E-Power Entry Notes- This will help you understand electircs

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Neons
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E-Power Entry Notes- This will help you understand electircs

Postby Neons » Fri Nov 16, 2012 5:11 pm

This is a great explanation from Nov AMA magazine article. It helps someone that has no idea what it is about and what the basics are. Click the pictures 2 times for a full page view. It is New Wave.
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AMA- Nov(0) - Battery Clinic.jpg
AMA- Nov (1) - Battery Clinic.jpg
Bob Pacheco

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Re: E-Power Entry Notes- This will help you understand elect

Postby admin » Fri Nov 16, 2012 8:51 pm

Nice Bob!... Red's an awesome fella... met him at an electric meet in NY several years back... we converse via email often too... smart guy!

Not to scare anyone away from Lipo's.... but thought I'd share some personal experiences (and saftey notes) to those considering electrics and use of LiPos :shock:

http://www.diyrc.com/RC-fire.html
Tom Laureanno

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Neons
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Now you can up your E-Powered Plane Power Redundancy

Postby Neons » Tue Apr 16, 2013 9:41 pm

This is a good article on having your ESC Bec activated and have an additional UBEC in line also. No need to remove the signal wire either. This gives you a dual powered system. When you are running a larger plane it is wise to have a higher amperage UBEC onboard. Most Esc controllers only give you 3 amps of safety in the built in Bec. Most are for 2 servos. 3 if on a 4s lipo.You would have to install a good UBEC with 5-8 amps if you have a ton of servos and other options just in case of a brown out glitch of power to the receiver. This system gives you a backup circuit to funnel power direct to the receiver when the Bec fails to provide steady current. Simple and very cheap to make this unit.

Info, diagrams, and video here.
http://www.rcgroups.com/forums/showthread.php?t=1854050
Attachments
Shottkey Bec circuit.txt
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Bob Pacheco

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Neons
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Re: E-Power Entry Notes- Battery Voltages

Postby Neons » Sat Aug 24, 2013 8:27 am

Originally Posted by Budge View Post
..<snip>... I have the alarm set for 99 (9.9v). And it goes from slow beep to constant in about 10 seconds. When I check the safe screen after "landing", it usually says it has 9.1 - 9.3v. Does this sound about right to you? ..<snip>...
Not in the least. You need to end the flight when the battery gets to about 3.7-3.8V and the voltage needs to be measured under load (that is the condition under which I assume the KK board is measuring it).

Here are some excerpts from some posts on the batteries forum, it is a few years old, some of the newest and best batteries do a little better, but it still applies to the majority of the LiPO packs that the majority of us use:

LIPO Capacity @ Voltage per cell (cell voltages, multiply by cell count for pack voltage, i.e. for 3S pack multiply x 3)

4.20v = 100%
4.03v = 76%
3.86v = 52%
3.83v = 42%
3.79v = 30%
3.70v = 11%
3.6?v = 0%

Capacity below 3.7V "resting" is not usable for flying, it's where the battery voltage dumps and damage begins.

Avg Resting V % Remaining Capacity (for 3S pack, divide by 3 for cell voltages)

11.0V-- 17% (3.67V per cell)
11.1 --- 26 (3.70V per cell)
11.2 --- 30 (3.73V per cell)
11.3 --- 37 (3.77V per cell)
11.4 --- 46 (3.80v per cell)
11.5 --- 50 (3.83V per cell)
11.6 --- 57 (3.87V per cell)
11.7 --- 63 (3.90V per cell)
11.8 --- 69 (3.93V per cell)
11.9 --- 77 (3.97V per cell)
12.0 --- 83 (4.00V per cell)

These values are the average of many discharges of different size/age/brand packs. As you can see, the values are not absolute. A new pack gives different results from a well used pack but the chart is still useful for the broad picture.

Within a few minutes after landing a pack that was down to 3.7V per cell will be back up to 3.9V per cell or so, in 15 minutes it might see 4.0V per cell. And when you recharge it you'll find that you are putting back 75-80% of the rated capacity. That is the real tell, the amount of capacity recharged.

Batteries should never be more than warm when you wrap your hand around them after a flight, like 105F or so. If they are hot they are suffering unrecoverable and irreversible damage and losing capacity. The next step is puffed cell packs, then very very hot packs and even rupturing and fires.

If you are only taking batteries down to 3.7-3.78V or so and they are getting hot you are discharging at too high a rate or for too long at a higher rate. The only real cure for that is batteries with more capacity to lessen the voltage drop buffer the discharge rate. Usually a higher demand motor like ducted fans or motors using higher Kv rpms like 2000 to 4000 Kv's are very hard on a battery. They eat a lot of amps in very short times. Low Kv motors like 1000Kv are slower and use large slow turning props. They are easier on the battery and flight times. If you go into helicopters or the Ducted fans boost the C ratings up to at least 40C for instance. General slow flying park flyers use 20-25C batteries.

Any one of the checkers below will monitor your battery before and after a flight. Do not ever try to make a high amount of minutes record flight with a new unfamiliar aircraft. Take it up for a 3 minute timed flight as a test. Land it and see the individual cell voltage. Look at the graph above to get a percentage of life left in the battery. Always leave some reserve. You never know when you have to abort a landing and you go around again for a new landing approach and do not make the field and spiral in destroying the plane. Common sense and practice. Always have a checker on your person while flying. They are cheap on eBay or Amazon. Buy a few.
http://www.ebay.com/sch/i.html?_nkw=lip ... ry+checker
Attachments
Lipo battery low voltage.jpg
It can be set for a low voltage alarm. Also an on board alarm with a spare channel to beep when you go in the corn field or grass. Indoor flight or low voltages on a multicopter too.
Lipo battery low volt check.jpg
Lipo battery checker.jpg
Last edited by Neons on Tue May 26, 2015 7:23 pm, edited 3 times in total.
Bob Pacheco

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Neons
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Re: E-Power Entry Notes- Have a low unbalanced cell?

Postby Neons » Tue May 26, 2015 6:40 pm

Here is a fast way to bring up a low cell. A good way to make a jumper is to use a servo straight wire extension. On the male pin end cut the plastic housing off around the pin housing and remove the white or yellow wire pin flush. Snip it off. Bruce talks fast with a New Zealand accent. You may have to run it through a couple times.
https://www.youtube.com/watch?v=wIbHLacozFo
Bob Pacheco

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Neons
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Re: E-Power Entry Notes- A Note on Battery fires

Postby Neons » Tue Nov 24, 2015 8:13 am

Tom's link above does not show the lipo fire. I do not have to tell you to double check the battery charger settings to match the Lipo battery size and amps. Fortunately the new chargers are smarter and will not start if the settings do not match the battery.There still are some older chargers out there that do not check the settings though. One way to tell is if you own a lipo charger that does not have balanc plugs built into it. But even that is not always the case. I use Imax B6 chargers. They are smart and work well.
Sample fire video here
https://www.youtube.com/watch?v=ZEkewCjiDs0
Bob Pacheco

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Neons
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Lipoly Basic Safety and Charging-How To Article

Postby Neons » Tue Nov 01, 2016 12:38 pm

Thanks to and article by T Jin Tech this will also give you almost all you want to know about using and handling Lipoly batteries the correct and safe way in your hobbies. All broken down here.Please spend some time here.

http://www.tjinguytech.com/charging-how-tos
Bob Pacheco


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