Charging a LiPo w/o balance?

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I've never heard of discharging to 3.5v damaging batteries.
Its all relative of course and never as cut and dry as numbers imply. Typical rule is to use 80% of your capacity and you have some safety margin. 80% is at 3.74V per cell. At 3.6 you are roughly at 5% i.e. if you go for just one more punch to jump you are almost guaranteed to do damage due to stress. You can sit idle with low discharge and nothing will happen damage wise. 80% is a good number for planes, not that critical for cars. You will find all kinds of opinions on this, mine is just one of them.
Damage is always shown by increase in internal resistance, as above. 1 cell is stressed, unless there is a wire or connection issue.
 
Its all relative of course and never as cut and dry as numbers imply. Typical rule is to use 80% of your capacity and you have some safety margin. 80% is at 3.74V per cell. At 3.6 you are roughly at 5% i.e. if you go for just one more punch to jump you are almost guaranteed to do damage due to stress. You can sit idle with low discharge and nothing will happen damage wise. 80% is a good number for planes, not that critical for cars. You will find all kinds of opinions on this, mine is just one of them.
Damage is always shown by increase in internal resistance, as above. 1 cell is stressed, unless there is a wire or connection issue.
If having one cell at 1 above the other 2 means it's damaged then I'm screwed ? I don't think I own a single battery that has the resistance the same for all cells.
 
Yup you are screwed :ROFLMAO: doesn't mean that the fun stops. Mine are still nice and balanced. Only have an issue with one pack that I ran to Lvc shutoff by acciden. That one is now out of whack as well but it only means a couple minutes less run time and longer charging.
 
So, based on what I'm hearing, no one should be relying on the LVC in the ESC, since it measures the total pack voltage, not individual cells, and cuts off unpredictably (sometimes 3.7, sometimes 3.5, some cells may be below that). I've seen Rich Duperbash and RCDude81 hit LVC in almost every video, are they risking damage to their packs every run (aside from the obvious physical damage)? I don't get why the ESC doesn't have a balance port to enable it to measure individual cell voltages, or even balance the discharge the same way chargers do.

Are people using voltage alarms or stopping to check cell voltages periodically during a run?
 
Its all personal preference if you rely on it. From ideal ESC standpoint and max lipo life a balance/cell port should be available but in reality nobody would buy it incl myself. Added complexity, added cost and too intrusive. In addition balance leads are short and now you add complexity that will stop your motor if a pin/wire wiggles loose.Would need a Spektrum type battery/esc design to make it work but that is a different can of worms.
Keep in mind that damage is a loss in capacity/duration not some critical event. Easy to absorb a couple minutes in performance loss if you physically destroy them with hard landings etc. Simply might not matter if you purchase packs every 6-12month anyway.
 
Are people using voltage alarms or stopping to check cell voltages periodically during a run?

I installed the precision low voltage alarm from SMC. When I have it set to 3.6v I find the cells come to about 3.68 according to the Hota D6+. With the LVA set to 3.7, they come in at about 3.78 on the charger. I've yet to hit the actual LVC on the ESC.


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no one should be relying on the LVC in the ESC, since it measures the total pack voltage, not individual cells, and cuts off unpredictably

More that the ESC LVC is too low and can't be adjusted. Which is really dumb, but I digress.
 
I installed the precision low voltage alarm from SMC. When I have it set to 3.6v I find the cells come to about 3.68 according to the Hota D6+. With the LVA set to 3.7, they come in at about 3.78 on the charger. I've yet to hit the actual LVC on the ESC.


View attachment 66211
That's where I'm at as well. I've added a rubber band between battery lead and the checker to keep the connectors together.
Any better ideas are welcome but had these come loose in rough spots.
 
So, I just wanted to see if this is typical in others experience. Storage charging my 5000mah lipos from 3.5ish V takes on average about 45 min. The last 40 of that seems to hover so close to the desired target, it seems unnecessary. Does anyone know what the charger is accomplishing? Why not just stop when the cells are all within 0.1v of 8.2?

Its called balancing precisely dude. Why question the charger?? Let it do the work for you.
Your lipo is already damaged from discharging to 3.5 and internal resistance of each cell is now different.
Charger is trying to balance the voltages but due to mismatch aka balancing it now takes a lot longer, to the point that it will run into timeout. What you see is normal for your case. A healthy pack should be done in 20 min at the right rate. No need to throw it away but you pay in increased charge time and less capacity. If you cut the time short you will increase the damage as capacity between cells is different and one cell will be stressed.
Stay above 3.6 to avoid this issue.
I disagree.
 
Its called balancing precisely dude. Why question the charger?? Let it do the work for you.
Why question? I suppose general curiosity and a great wealth of knowledge here. It doesn't make sense to me, but I'm sure there is an explanation. If another charger would reduce my storage charge times (x2 batteries), that may be worth my $$$
 
No matter the charger or lipo, balancing is controlled by software. The speed of your charge is in the first 95% or there abouts. When the pack goes out of fast charge rate mode (1C for instance) to full balance, there is no way to speed that up. The rate drops low. You cant control that. It is slow from that point on. We all go through this. All chargers and lipos. Older lipos with very poor cell IR's get even slower to balance.
 
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