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Old Mar 01, 2013, 03:10 AM
RELAX. You'll live longer
785boats's Avatar
Brisbane- Australia
Joined Jul 2007
3,091 Posts
I've got to agree with Jim on the cycling of packs.
I charge new packs, note down all the cell voltages & IR's, Then run it in a boat that I know has a lowish amp draw (around 60-80A) & only take it down to around 40% left in the pack. I do this a couple of times. Then I run it in a race boat down to around 30% a couple of times. The IR of the cells usually drops a bit over those runs.

I think that all of my race packs are Haiyin now because when an old HK pack fails I only buy Haiyin packs. Always 4s or 6s 5000mah 40c.
They win me races (when I drive properly) so I'm happy.

Cheers.
Paul.
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Old Mar 01, 2013, 08:12 AM
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Land O' Lakes, FL
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Here is the correct link to the plastic caps I use on the 5.5mm male bullet connector:

http://www.stockcap.com/store/0.250-...p-100-Bag.html
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Old Mar 02, 2013, 08:18 AM
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Now that I've got the connectors figured out, I still would appreciate some suggestions on setting the low voltage cutoff. I've seen a lot of posts ranging from 3.25v to 3.8v and everything in between.

Eric sent me a great email regarding lipos and it indicates that the "suggested voltage range for Lithium Polymer cell is 3.0V-4.2V". I know that the resting/storage/discharge level should be 3.85v and I would never go to 3.0v, but what is a safe "low-end" so I can set my LVC alarm?
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Old Mar 02, 2013, 09:14 AM
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Ohio
Joined Dec 2009
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It's actually a lot of hair splitting. As long as you have it set for something in that range you will be fine,and if someone else is using a different number than you are you won't be missing out on any service life or performance.
I bought 4 5000mah 40c Haiyans over a year ago that go in a 12 cell heli set-up, they have somewhere around a hundred cycles in them and they are still A-1.
I have my LVC set at 3.3, though it's rare that I fly long enough to trigger the LVC.
Doug
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Old Mar 02, 2013, 09:44 AM
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United States, MA
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Mine is at 3.2V. Find out what your ESC does when you hit LVC. If it just kills the motor, and this is an aircraft, be extra mindful of never triggering LVC.

It is really there as a last resort (you put on a discharged pack, forget to start your timer, etc). In an ideal world, you should never hit it. But set it too high (e.g. 3.6V) and you will hit it.
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Old Mar 02, 2013, 10:14 AM
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doug47 & RedOctobyr...

Thank you very much for the input. My son & I are using the batteries in our 1/8th scale trucks, so no falling out of the sky. However, I like the idea of the LVC for those times when we are racing around the desert and lose track of time. The Castle Creations controller is programmable and I want to set it high enough to not hurt the lipos, but not so high that we are cut off too quickly - it's really easy to be racing around and not realize how much time has gone by. I think we will start at 3.5v, see how the run times are, and go from there.
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Old Mar 02, 2013, 11:10 AM
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Land O' Lakes, FL
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I prefer to sent my LVC a little higher, around 3.6V. At that point, you are on the rapidly declining end of the power curve anyway. I also always set my ESC for soft or slow cutoff. This means the motor will slow down rather than cutting off suddenly.

If you use 3.2V cutoff and then try advancing the throttle again to 'make it to the field', you risk taking the cells down too low and inducing possible 'puffing' of the cells and a hot battery.
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Old Mar 02, 2013, 11:12 AM
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United States, CO, Longmont
Joined Nov 2011
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Quote:
Originally Posted by timmyt101 View Post
doug47 & RedOctobyr...

Thank you very much for the input. My son & I are using the batteries in our 1/8th scale trucks, so no falling out of the sky. However, I like the idea of the LVC for those times when we are racing around the desert and lose track of time. The Castle Creations controller is programmable and I want to set it high enough to not hurt the lipos, but not so high that we are cut off too quickly - it's really easy to be racing around and not realize how much time has gone by. I think we will start at 3.5v, see how the run times are, and go from there.
if you set your LVC so that your resting volts show 20% or more left in the packs you are good to go..
it all really depends just how much amps your systems pulls vs LVC settings...
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Old Mar 02, 2013, 11:40 AM
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Rugby, UK
Joined Feb 2007
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Quote:
Originally Posted by sailr View Post
I prefer to sent my LVC a little higher, around 3.6V. At that point, you are on the rapidly declining end of the power curve anyway. I also always set my ESC for soft or slow cutoff. This means the motor will slow down rather than cutting off suddenly.

If you use 3.2V cutoff and then try advancing the throttle again to 'make it to the field', you risk taking the cells down too low and inducing possible 'puffing' of the cells and a hot battery.
Sailr,

Not wanting to start an argument but I really think that 3.6V is too high. The unknown is the load which will determine the point at which the Esc starts to close it down, but if you are using the lipos at any where near their current delivery capacity, then 3.6v is too high.

I have recently posted a load test on the Haiyin 3S2200 20c pack discharged at 20C and you can see from the discharge plot that at 3.6V. (10.8V for a 3S pack) the pack is only about 25% discharged.

http://static.rcgroups.net/forums/at...0%40%2020C.jpg

The best way is to time the run as we generally fly or drive in a consistent fashion, and aim for the 80% discharge rule, using the Esc cutoff as a safety valve, but set to about 3.3V

Wayne
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Old Mar 02, 2013, 06:14 PM
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United States, CO, Longmont
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Quote:
Originally Posted by Wayne Giles View Post
Sailr,

Not wanting to start an argument but I really think that 3.6V is too high. The unknown is the load which will determine the point at which the Esc starts to close it down, but if you are using the lipos at any where near their current delivery capacity, then 3.6v is too high.

I have recently posted a load test on the Haiyin 3S2200 20c pack discharged at 20C and you can see from the discharge plot that at 3.6V. (10.8V for a 3S pack) the pack is only about 25% discharged.

http://static.rcgroups.net/forums/at...0%40%2020C.jpg

The best way is to time the run as we generally fly or drive in a consistent fashion, and aim for the 80% discharge rule, using the Esc cutoff as a safety valve, but set to about 3.3V

Wayne
better packs need a higher LVC set... to low and the pack may be drained to much
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Old Mar 02, 2013, 06:53 PM
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It also probably varies by the application. I've only used LiPos (and a logging ESC) in a helicopter.

Helis have to use comparatively small batteries (too large and you couldn't get off the ground), and can have pretty high current drains. I've hit peaks of around 30C with my current setup (which admittedly isn't terribly aggressive). Let's say 10C average, to pick a number.

Small packs and fairly high intermittent loads are more likely to have deeper voltage sags (so if I used a 3.5V or 3.6V LVC, I'd probably hit it fairly often). After hitting a 3.2V LVC, the cells might be at 3.6V after resting (hypothetical numbers).

Something like a car/truck model might be different? I presume larger capacity packs can be used, since weight is less critical. I don't know what kind of currents they pull, and what those are in terms of C.

If a car pulled a consistent 3C, for discussion, it wouldn't have voltage sags as deep. As a result, you'd want a higher LVC number. If a car hit a 3.2V LVC, maybe the cells would be at 3.3V after resting (again, hypothetical).
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Old Mar 02, 2013, 08:38 PM
|Taranis|
scott page's Avatar
United States, WA, Richland
Joined May 2009
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Quote:
Originally Posted by sailr View Post
Here is the correct link to the plastic caps I use on the 5.5mm male bullet connector:

http://www.stockcap.com/store/0.250-...p-100-Bag.html
Get a bag of red and a bag of another color -- use them to ID charged and discharged batteries. Just saying....
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Old Mar 21, 2013, 06:08 AM
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United States, WI, Slinger
Joined Mar 2006
501 Posts
I need some new batteries and have been trying to decide who to go with. Finally pulled the trigger and ordered some Haiyin's, a couple of 3S 25C 2200mAH and a 6S 25C 5000mAH pack for my Swift heli and the Astrohog I'm building. Can't wait to see how they do.



Mike
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Old Mar 21, 2013, 06:15 AM
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mattox's Avatar
peoria,az
Joined Sep 2009
491 Posts
Please tell us how they perform when you receive them!! All my 6s 5000 packs are still going strong!
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Old Mar 21, 2013, 06:51 AM
Life Is Good.
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Texas
Joined Jan 2011
566 Posts
I'll be running these just as soon as I get the plugs changed over to EC3's.

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