does charging lipo's at low amp decrease punch?
 

i heard that if you had a 3300 mah nimh and charged it at less than 3.3 amps, you get more run time but less punch in your batteries.
is this the same way for lipos? what if i had a 5k lipo but charged it pretending if it was only a 1k lipo, and just charged it 5 times...will it be less punchy?

Well you wouldn't charge it 5 times, you would just charge it for 5 hours, but to answer your question, I don't think it will make a difference like with NiMH. That only really works when there fresh off the charger anyway (NiMHs that is).

most chargers have a built in "safty timer" that prevents you from charging it that long...

True.

Can't the safety timer be changed? I know that charging at smaller amps isn't doing much to help the battery, but some chargers have a low power limit and NEED longer charge times to compensate.

As for the initial question, I do not think a slow charge will do anything for performance. As long as the pack is in balance and all of the cells are matched well you should be fine. If your pack goes out of balance (as the cheaper packs will) a slower charge can give the balancer more time to do its job during the charge. This depends if you have a charger with a built in balancer or use a stand alone charge thru balancer. Or you may have a non charge thru balancer (like a blinky).

All said and done I do not think a slow charge will benefit the lipo at all.

ok cool . thats all i needed to know. cus my zippys need to be slow charged to give it time to balance all 3 cells.
what about if after everytime i use the zippys, they are all unbalanced again. Does this mean the zippys have a lost in performance? i bought these zippys used, so i have no clue how they performed when they were brand new.
my guess would be they were alot more punchy and gave more runtime as im only getting like 20 mins with a 2200mah 3s for my rc18mt.
im trying to figure out if i need a new lipo or not. ill definetly get one if im losing performance with these unbalanced packs.

This is a very good question that I was wondering also, I purchased a 4s pack at 4000mah and I'm having a hard time finding a charge through balancer that will handle more then 3 amps for a reasonable price (not over 50). So I should be fine charging at less amps it will only take a little longer, Is that the answer?

Get a hyperion lba10. They can be had for 40 bucks from most places. I know BPP has them.

You generally don't want t6 charge at much higher than 2A through the balance leads as they are too small and will develop voltage drop across them making the charger's reading inaccurate. The best solution is to use a charger than charges through the main leads (which are designed for higher currents) and use a balancer to bleed off excess charge on high cells.

back to my second question haha. does the unbalanced cells decrease power/punch in the performance of the lipos? i know off the charger, the cells are balanced, but after running the truck, all the cells are unbalanced again.

In my exp there is no loss of punch at a lower charge rate. Before i got my Duo2 I used a buddy's Polycharge 4 that had a 3 amp max rate, and I am getting the same punch out of my packs charging them at 6-8 amps now.

"all the cells are unbalanced again"

How much out of balance?

If it's a lot then one cell will always be working harder and will of course make the pack weaker overall... but if it's not much then probably no worries other than shortening the lifespan of the pack.

after the run, my 3s lipos reads 3.90 4.11 4.01
i would say thats pretty bad haha. so you think i would see a power/punch increase if i was to purchase the EXACT same zippy lipos or will i just see an increase in run time?
one other thing, why are my zippys so unbalanced in the first place? is it because theyre cheap batteries, cus if thats the case, wouldnt brand new ones do the same thing?
or is it because those lipos are getting old? i bought them used with the truck.

Low charge rates should not affect the punch. It is good for getting a way out of balance pack in line (balanced). As far as checking balance on a partially discharged pack; I know at least one manufacturer that says not to worry about balance at a partially discharged state. They say to only balance a fully charged pack since the packs are matched for max voltage and min voltage as well as capacity, but the voltage can vary quite a bit between the cells as they are being discharged. So, charge it up and then worry about balancing.

Yes, cheap packs may not be well balanced to begin with.

remember Zippy lipos are still chinese lipos they are cheap for a reason, but good bang for the buck....I prefer to use enerland cells I do have a Zippy 6s pack and it just doesnt have the punch my FPs do

the lipos were checked after the entire run. not just a partial run.
not sure if you guys are understanding me correctly. i know that zippys are cheap cells and are not as pwerful/punchy than the good enerland cells.
but what im saying is lets pretend i have a polyquest pack, and after bashing, the cells hit the lvc, and when i put it on the charger, its unbalanced. but of course, after charging it gets balanced again.
so while bashing, are these cells not as powerful and punchy due to the fact that the cells are getting unbalanced.
basically i just wanna know what happens performance wise due to unbalanced cells during bashing.

i'm not sure about the punchyness factor... because most packs' surge rating is quite high, so i would think it would not matter. as for your other issues, if you are reading 4.11, 4.1 and 3.9 after a run and the lvc is hitting, you arent getting a full run out of your batteries! If you have a castle ESC, I would not use auto lipo, and set your cutoff manually to around 9.2-9.4 volts. Its safe to keep your lipos from going below 3v per cell, but it isn't damaging until you go to around 2.5v per cell, or drawing lots of amps on low cells. the normal cell you see is probably a cell that is going bad.If I'm right, when you charge and balance, you will see it will start as an abnormally low cell, but then it will reach 4.2v faster than the other cells by alot, which will inrease your charging time too. I had a bad cell in a protek lipo, and my charger would stop after 2 hours of charging, and I would have to restart it to fully charge my batteries. The good news is that lincpimp can take care of you when it comes to lipos.

Looking at your info i would have to say that you have a weak cell in that pack. I would guess that either it was weak from day one, or that the previous owner ran the pack near the edge, overdischarged it, or let it get out of balance by not balancing it every time it was charged.

Best method is to use a charge thru balancer like the lba10, or fp v balancer. That way you can charge at full rate as those use the main leads. Plus if anything goes wrong, such as one cell over charges past 4.2v the balancer will interrupt the charge. Or buy a hyerion with a built in balancer. The second is preferable... That is what I do, and as many have noted I do seem to have some lipo experience.

If you had a polyquest pack, and it did not have any damaged cells, if it came out of the truck that much out of balance I would say that you are pushing the pack too hard. It would also be very warm, which is the best indication you are overdrawing the pack... If it is not warm (your zippy) you just have a weak cell, and that could be caused by a number of reasons, including the fact that they are cheaper for a reason. Most if not all of the mfgs that use enerland cells have some sort of matching process. I am only familiar with fp's process. I will say that the enerland cells seem to be made to a higher std, and use better materials. That is why you do not see much variation in the cells from lot to lot.

I have paired cells from different packs that were not factory matched and could definitely see the difference between a strong cell and a weak cell. This has been the case with every cell type save for enerland cells. The tolerances of the production must be much tighter to show such small variances.

I have a feeling that he is hitting the lvc, and it is the 3.9v cell that is sagging much more than the other cells under load. Lipo voltage will "bounce back" after you let them sit, that explains the higher voltages. Just indicates to me that he has a weak cell in that pack.

I routinely see my enerland cell based packs at 3.4 to 3.7v after they cool off. Just depends on how hard you pull them. If you have a very low draw setup like a crawler you may be able to drain the cells close to 3v. But a high draw app that is pulling the lipos hard will make them sag enough to hit the lvc. Remember that lipo mah ratings are not necessarily good for them if run at their cont amp rating. It will be less most of the time. Unless you have underrated lipos...

I charge everything at 1c. I could charge my PQ pack at 2c but just choose not too.

I do not really see a benifit, unless you plan to run all day and the 2c charge happens to match the runtime of a matching lipo... That way you can have a pack ready when your other is drained.

Most of the setups I have can do 30+ mins and I get bored at about the same time... Maybe the backlog of lipos I have to repair are just nagging on my mind....

I agree.