![]() |
|
General Discussion A place to post off topic discussions. |
![]() |
|
Thread Tools | Display Modes |
|
#1
|
||||
|
||||
![]()
i agree with ESPEE fan for the most part. I have a good bit of experience with LIPO packs as most of my hobby time has been spent with Air Planes. I have several planes that run on LIPO packs and probably 25 packs of various size and voltages. LIPO's are finicky, and there are a lot of rules of thumb that you will hear from people some true, and some B.S. LIPO packs also vary widely in the quality between manufactureres and a lot of manufactures claims for capacity and C ratings are optimistic at best. As you would expect you usually get what you pay for although I have some cheap rhino packs from Hobby King that have out lasted and performed all the others in my collection.
I never discharge my packs below 3.3V per cell. Most flights I only take them down to about 3.6V per cell. My packs have all given me a good life cycle and I have only had one go bad so far and it was a cheap pack that never performed well in the first place. I never cycle my packs unless I am trying to get one to balance as they do not have memory problems like other types of packs and they only have a certain number of cycles before they go bad. Why accelerate thier demise? Also if it is very far out of balance there is usually a bigger problem with the pack and I would be suspicious of it and probably just get rid of it. I may cycle it once to see if it is fixed, but if not it would be gone. I always, balance charge them. I never charge them at more than 2C rate (4.4 amps for a 2200mah pack). If they are going to be sitting for a while I store them at 3.6V~3.8V per cell. I never store them for more than a week fully charged. Lipos do not like to be abused, and can become dangerous if they are not properly cared for. I had a pack with a bad cell go off in my hands as I was about to dispose of it because it would not balance. I was getting it out of the case and was going to puncture it in a fire pit with a spike when it just went off in my hands. 1 Minute earlier and it would have gone off in the storage case (ammo box) with all my other packs and likely would have burned my trailer and airplanes up with it. At best it would have coated all my hobby stuff with soot and smoke. A lipo that is more than a little puffed is dangerous. You should think about getting rid of it. It is not worth burning down your house or damaging a plane or the piece of equipment it is powering. Youtube has plenty of videos of LIPO fires and counting mine I have seen three in person and they are pretty wild. Long story short, Joe you may be pushing your packs a little to far, but it does not sound like you are abusing them. Like anything if it is continually operated at its limits it will fail earlier. I imagine that your packs have quite a few cycles on them with the amount of work you have been doing. You may want to up your voltage cut off a little to help lengthen your pack life and always balance charge them. Oh, and to the original question in the thread to test capacity (mah) you have to use the pack in its usual fashion and time the run time you are getting and see what the digital charger is putting back into it. Last edited by FlyingBeagle; 12-04-2012 at 10:00 AM. |
#2
|
||||
|
||||
![]()
Thanx for the reply Nathan. I should note that the Venom lipos started out working normally w/4600+ & starting on the charger above 12.5v. I think it was sometime after seeding when capacity started to drop, the packs would have been left fully charged for a month or longer. I can't remember when exactly they started to puff outward, but they have ballooned quite a lot now.
I was getting about 50mins run time with casual digging with the bucket, and around 40-45mins ripping - maxing the hyd press constantly.. about 10amp draw? Cheaper pack? they run me about $65ea, what do the better ones cost? I have a 3300NiMH 7.2v paxk that's been in my bd trl 6 - 7yrs now, pretty good life span for a pack, though it's not a huge drain running the pump for less than 20s per load. The original 3 lipos might be around 250 charges, I always let packs cool before charging, does that matter either way? One of the three, I forgot the hoe on over night & drained the lipo well below, I tried the trick with the NiMH setting to get the volts back up & it worked with no issues for many recharges later. I charge my lipos in a large glass cookie jar with its metal lid, it all sits in front of me while I watch tv & surf the net. Quote:
Quote:
Today I set my packs out in the yard & shot one of them with my .22 rifle about 5x to see what would happen.. maybe it would worth filming.. nothing happened! ![]() I walked over to it carefully after 5mins of distant observation to only smell a sweet aroma coming from the pack & a faint hiss. So back to my rest & emptied my clip into the other two with no drama to be seen. Went into the house to put my gun away (took a couple mins) and came back out to clean up the mess with a shovel when all of the sudden the fireworks started with one of the last two shot! Sparks flying pretty good & then it burst into flames!!! Then other one was like a smoke bomb, big cloud of white smoke, that's all. Scraped them all up & dumped the remains in the burning barrel. All 3 were fully charged prior to shooting at them, but they sat 4hrs on my cement step in -10C before I destroyed them. Quote:
![]()
__________________
Sharing knowledge is one thing that defies basic arithmetic logic --- the more you share, the more you get! Joe |
![]() |
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests) | |
|
|