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-   -   Lipos and higher than rated Mah??? (https://www.rcuniverse.com/forum/e-flight-power-sources-126/3021064-lipos-higher-than-rated-mah.html)

RCaillouet3 05-28-2005 10:02 PM

Lipos and higher than rated Mah???
 
Hello all, and thanks in advance!!!

Well, recently I purchased 2 Tanic 3S 1550 MaH. I have owned a few types of Lipos in the past and have found, and been told, that they generally won't take the rated MaH for a while, and then you should only hope to get within 10% of the rated capacity. An example is with my wonderful TP 3S 1900 will generally take around 1850 MaH charge.

Now with the one Tanic I have used so far, here is what I did. On Triton charger, I discharged the Tanic to 9.0 Volts and took out 749 MaH. Then something happened during the charge, it took 1839 MaH during its first charge!!!! I have since run this pack on numerous flights (over 30 so far.) and have run it to the first hint of the LVC kicking in. At that point I have landed and removed the pack form the plane. On EVERY charge, it has taken MORE MaH into the pack than the rated capacity!!! On the last one, I ran it to a point that when put on a Voltmeter, and using a 200 MaH discharge current it held right at 9.1 Volts. I then charged it and according to the Triton display, it took 1685 MaH into the pack!!!

Am I nuts with seeing this??? Should I be concerned with the pack taking MORE than its rated capacity??? I have never seen a Lipo, or heard of them, taking MORE than its rated capacity. Any advise on this is VERY greatful!!!

Thanks again!

Reg

PS Anyone even thinking of getting the Tanic packs should!!! I am running mine on a few different planes and have had PLENTY of power from this pack!!!!!! Plus the leveling capability of them is EXCELLENT!!!!

VULTCH 05-31-2005 12:50 AM

RE: Lipos and higher than rated Mah???
 
Battery pack ratings are based on average. Generally they are very close but in manufacturing they can go beyond their ratings. Most of the Li-PO batteries we use are discharged above their rated capacity in RC usage. This is the reason most cells will not give the rated MAH in 10C discharge, but if discharged at 1C or less will usually produce the rated current or better. This is not implying they cannot be used at 10C or above as a lot of battery packs can go that with no problem. You have evidently ran across a good run of batteries so just enjoy it. Manufacturing specs generally will have a minimum value to hold to but the maximum is something that is very seldom complained about by the customer. As with other packs Ni-Cd, Ni-Mh matched cells are important due to one or more cells discharging prematurely thus causing stress on them as the other cells discharge into them, this also holds true in Li-Po series arrangements with cells. If all the cells are close on specs then everything is great, even if they are well beyond their ratings.

Vultch


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