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Reformed Nitroaddict
07-24-2005, 02:26 AM
I have a hobbico mk II charger for my lipos and its not perfect but does the job. It only charges the 3S packs to 12.05V instead of 12.4

How big of a difference will I see in runtime at an 8C discharge if I were to purchase a charger that can charge to the full 12.4V?

Red Scholefield
07-24-2005, 11:35 AM
I have a hobbico mk II charger for my lipos and its not perfect but does the job. It only charges the 3S packs to 12.05V instead of 12.4

How big of a difference will I see in runtime at an 8C discharge if I were to purchase a charger that can charge to the full 12.4V?

Between 10 and 15% less.

Reformed Nitroaddict
07-24-2005, 12:51 PM
That's not too substantial on a 1300mah pack, maybe an additional minute, but if I were to goto the larger 2000mah packs and greater, the difference begins to get considerable.

Thanks - It looks like I need to start shopping. I am leaning towards the GreatPlanes charger someone was mentioning in another thread here.

luc
07-24-2005, 04:28 PM
note that a 3S is supposed to get a full charge @ 12.6V, not 12.4V or 12.05V.
Maybe you are using a battery instead of a regulated voltage supplier as input to your charger...

Reformed Nitroaddict
07-24-2005, 04:29 PM
luc - I am - my input voltage is coming from a 12v car battery.

luc
07-24-2005, 04:38 PM
so your charger cannot increase voltage from your input battery, hence the 12.05V...
a regulated power supply delivers 13.8V and there you could get the 12.6V final output..

Reformed Nitroaddict
07-24-2005, 08:00 PM
I wonder if that might be the problem - of course, the car battery doesnt really put out 12v exactly, I think its closer to about 12.5 - I will have to put the fluke to it and see. If its less than 12.5, that would seem to be the problem, huh?

ragbag
07-24-2005, 09:05 PM
I picked up a Pyramid charger for $39.99 a couple of years ago. Very good product.

http://www.etronics.com/product.asp?stk_code=pyrps14kx&store=&catid=4071

Then you could go to RC Battery Clinic and get the info on how to convert a computor power supply and use it for a power source. I use both.

http://www.rcbatteryclinic.com/

Sometimes I am charging 2S and 3S at the same time, two different chargers. Since I have to be there I might as well be doing more than one at a time. I never charge LIpo's unattended, too many airplanes in the garage to replace if there was a fire!!!!

George
Gainesville Fl

ragbag
07-25-2005, 01:58 AM
Sorry about the duplicate message. I went in and edit it and didn't realize it had been sent.

Also the smiley was supposed to be at the word fire. Ohwell, guess we are all learning.
George
Gainesville Fl

Reformed Nitroaddict
07-25-2005, 01:49 PM
No worries - hmmm....I wonder if that computer power supply would work for me.

luc
07-25-2005, 04:52 PM
Nitroaddict
that's the problem...don't look further...
to get your 12.6V, you need at least 13V input (because your charger does not have any integrated tension increaser).
A lot of people use these cheap pc power supply,...that should be ok

RickAvery
07-25-2005, 06:24 PM
What I did was to purchase a battery caddy jumper unit. It plugs into your 110vac to keep charged and you can then just clip your LiPo and other non-110 chargers to it. I'm using a triton charger and I get 12.59 to 12.60vdc in my LiPos.
Rick

Reformed Nitroaddict
07-25-2005, 06:55 PM
This sounds better than having to purchase a new charger - but how to I charge at the field? This is where I do most of my charging anyways. Also, if I use a fluke on my car battery and it reads over 12V, say 12.5v - will this be enough to get the extra V into the batts?

RickAvery
07-25-2005, 07:06 PM
I've never put the fluke to my caddy, but like I say, I get 12.6vdc in the batteries according to the triton. The caddy is a portable battery jumper & mine goes with me to the field where it powers up my chargers. Most have a little meter on it to tell you how much juice you have in the caddy.
Rick

Reformed Nitroaddict
07-25-2005, 07:17 PM
Rick - are you referring to the battery jumper boxes? What is a 'caddy'?

RickAvery
07-25-2005, 08:38 PM
I guess you could call it a jumper box. I picked mine up at costco for $40 or $50 bucks. It has a set of battery jumper clamps, a work light and a small compressor built in. It also has a small meter which reads red, yellow, green as to the voltage avaliable in the battery. I've had as many as 5 different chargers hooked up a the field and we all charged up our packs. It was quite depleated by the end of the day. I've also used it to jump-start my motorhome to life after an extended park. It plugs into 110vac to charge itself up and we just clip our tritions to the jumper clamps. They are propably a gel-cell or sealed lead-acid battery with the ability to put out 40 or 50 amps for a short time to accomodate jump starting a vehicle. They're kind of heavy as you would figure a lead battery would be, but have a nice handel for carrying. I've been happy with mine for over a year.
Rick

Reformed Nitroaddict
07-25-2005, 09:07 PM
Rick - I am very familiar with those types of boxes. So, I can hook up my charger to it, and it should deliver more volts to the charger than my standard car battery, huh?

RickAvery
07-25-2005, 09:12 PM
According to my, and my bro-in-laws tritons, we get 12.59 or 12.60 vdc into our LiPos. Hey, I've got a good buddy who lives in RR Texas. Don Lackey. Runs DLR, (Don Lackey Racing) specializing in high performance motorcycle suspentions and off-road 4-stroke engines. Know him?
Rick

Reformed Nitroaddict
07-25-2005, 09:21 PM
Thanks - I will have to look into that - I have a friend who has one of those, so will have to try my charger on his first to see if it works before buying one of my own.

As for your friend, no, I havn't heard of him or the shop. Do you know whereabouts it is in Williamson County? Right in Round Rock or more out towards Flugerville? I bounce back and forth between TX and FL due to my job, so sometimes things come and go while I am gone.

flypaper 2
07-31-2005, 01:27 PM
I use one of those lawn mower batts. about 2/3 the size of a car batt. 200 cranking amps. to run the Triton. Also a 110 volt inverter to operate the hot glue gun for quick repairs. Everybody uses it to keep them flying.:D

Reformed Nitroaddict
07-31-2005, 01:39 PM
Very interesting, Fly - I never thought about that.

drksyd
08-08-2005, 05:39 PM
Unless your car battery is about to die it shouldn't be a problem getting the pack to 12.6volts. I field charge my packs and they always reach full charge.
Try charging your pack on someone elses charger and someone elses pack on your charger and this will tell you where the problem is.
If getting a new charger the Duratrax Ice, Triton and Astro Flight 109 are good chargers. For no brainer chargers, the Apache units are great.

PiedmontQC
08-11-2005, 01:31 PM
I too am using the Mark II charger and it only gets my 3 cell packs up to
11.56 volts. When my truck is running it's putting 14.4 volts into the charger. This is happening on 3 different packs, all new and none of them
has ever been below 10 volts. All three packs get exactly 11.56 every time. I think Hobbico set these chargers on the conservative side.
I charged one pack on another guy's Triton and it went to 12.3.
So now since Hobbico thinks I'm so stupid that I can't handle a fully charged battery I have to buy another charger. Thanks Hobbico.

.................................................. ....................AL T.

Reformed Nitroaddict
08-11-2005, 01:59 PM
Pied - yep, same thing here. Just tested the theory this past weekend. Charged one pack on my MK II charger and the other on the Triton running off the same car battery at the same time. The MK II charged to 11.94V, the Triton to 12.59v.

drksyd
08-12-2005, 08:43 AM
At least you know it's the charger. I charge my TP 3S2P 4200's on both my 109's and they always hit 12.6 volts. If I top of the pack goes slightly higher. Sounds scary but I have total faith in the 109's. Although, one of the guys here had a pack explode while charging because his 109 didn't pick up the correct voltage for the pack.

Matt Kirsch
08-12-2005, 01:20 PM
DO NOT "top off" LiPoly packs. They don't need it, plus you run the risk of destroying the pack and causing a fire if your "total faith" in the charger is misplaced. A 3S pack over 12 Volts can easily be detected as a 4S pack by the 109 (3 times 4 equals 12, must be a 4S pack...). Your friend already proved to you that the 109 cannot always be trusted. No charger capable of charging multiple cell counts can, or should, be trusted to that degree.

drksyd
08-12-2005, 05:46 PM
Very true. I always check the display to make sure it does see the correct voltage for the pack so I my statement is not that true. Most times I don't intentionally top off, I just can't tell/remember which packs need to be charged until I put them on the charger. In most cases the packs are down to 12.54 volts so I leave them on.
The only chargers that really did not need checking were the Apache's. If the jumper settings weren't right it wouldn't charge at all.