No. Its a simple calculation. The post I was responding to suggested a $240 battery would equate to a dollar a flight if it was good for 240 cycles. If each flight uses an average of 75% of the capacity 240 cycles = 320 flights. 240/320= 75c. What have I missed?Your spell check messed up, that post or yours above said it was “75 cents per flight”!
Discharge batteries to storage condition
- Thread starter raylo32
- Start date
The reality on how LiPo's progressively degrade. My assumption was based loosely on $1/flight but even my olden Mavic 1 battery with ~115 or so cycles already has lost some 600-700mAh capacity. It still stays in the air for a reasonable amount of time, but I also find the cell voltage doesnt seem to hold up as well as it used to under load. At some point you gotta throw in the towel and and ditch the cell for a new one. I'm starting to wonder if it will even make it to 200 flights/cycles (depending how you look at it). And this is coming from someone who almost religiously keeps batteries at storage levels almost always.
Understood. My response was simply to suggest if a high priority of yours is to be frugal then the reality is better news than the cost/flight outcome you arrived at.
m0j0
Well-Known Member
I have this charger. It does exactly what it says it will. Charges up to 65 and shuts off.
Yes, looks like a good charger but that is not the issue. Discharging an unflown battery to storage is the problem. A good discharger like the one I posted above makes short work of it.
kilomikebravo
Well-Known Member
Ray: I took a look at the Protek chargers and I immediately became interested when I read, "10 Charge/Discharge Profiles." But my question is, where do you find the M2 battery cables to use with the charger?
Mike,
The problem with the Proteks (and other typical RC chargers, I assume) is that their LiPo storage and discharge profiles require that you connect a battery's balance lead... IOW the charger functions as the BMS.... and it will not work if that connection is absent. There is no straight LiPo discharge profile that works purely on overall pack voltage. Of course the M2 batteries have a built in BMS and no balance lead. I suppose you could open them up and connect one but these are too $$$ to mess around like that. However it is interesting that they do have a charge profile that works with smart batteries based on pack voltage and no balance connection. So why don't they also have a discharge profile like that? I dunno. Makes no sense.
I pinged ProTek and they said that you may be able to use the discharge profile for another chemistry like NiMh that only uses overall pack voltage. These are customizable as to amps and cut off voltage. I haven't tried that but it should work. Just be careful to set the cutoff where you want it, something like between 15 and 15.5V.
For now I bought that Gforce discharger from Amain hobbies that I linked above. Just set the voltage cutoff and discharge rate. It works great but it is a shame I had to buy a separate device for this. Why don't the aftermarket charger guys incorporate this feature??
As for connectors just go on Amazon and buy a couple of the cheap Mavic 2 car dual chargers that can be had as low as $12 and cut the connectors off. Be careful about polarity, the ones I had did not have black and red wires in the connector leads. Generally black or green is always negative but the positives have been white and red. The connectors use 8 pins to charge, 4 pins will be + and 4 will be -. Use a meter across any of these to test. The 2 center pins must be data/AC comms which is not used during charging. I also bought an extra car charger to keep in the truck. Might come in handy sometime to charge in the field.
The problem with the Proteks (and other typical RC chargers, I assume) is that their LiPo storage and discharge profiles require that you connect a battery's balance lead... IOW the charger functions as the BMS.... and it will not work if that connection is absent. There is no straight LiPo discharge profile that works purely on overall pack voltage. Of course the M2 batteries have a built in BMS and no balance lead. I suppose you could open them up and connect one but these are too $$$ to mess around like that. However it is interesting that they do have a charge profile that works with smart batteries based on pack voltage and no balance connection. So why don't they also have a discharge profile like that? I dunno. Makes no sense.
I pinged ProTek and they said that you may be able to use the discharge profile for another chemistry like NiMh that only uses overall pack voltage. These are customizable as to amps and cut off voltage. I haven't tried that but it should work. Just be careful to set the cutoff where you want it, something like between 15 and 15.5V.
For now I bought that Gforce discharger from Amain hobbies that I linked above. Just set the voltage cutoff and discharge rate. It works great but it is a shame I had to buy a separate device for this. Why don't the aftermarket charger guys incorporate this feature??
As for connectors just go on Amazon and buy a couple of the cheap Mavic 2 car dual chargers that can be had as low as $12 and cut the connectors off. Be careful about polarity, the ones I had did not have black and red wires in the connector leads. Generally black or green is always negative but the positives have been white and red. The connectors use 8 pins to charge, 4 pins will be + and 4 will be -. Use a meter across any of these to test. The 2 center pins must be data/AC comms which is not used during charging. I also bought an extra car charger to keep in the truck. Might come in handy sometime to charge in the field.
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You can use any "dumb" discharger, it doesnt need to balance when discharging. In fact, you can charge or discharge any lipo without balancing it.
Here, Im discharging a Mavic battery at .4 amps using a 10 year old charger. This charger can go up to 1amp discharge, my others can do alot more than that.
Mavic batteries are smart. They dont need a smart charger, just a charger or discharger that will draw current.
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I know all’s you need is a dumb discharger for smart batteries. But while the Proteks and other RC chargers have a dumb bulk charge LiPo profile they don’t have a dumb discharge profile for LiPos. You may be able to gin up one manually or by selecting another chemistry that never uses balance function.
Which charger do you have? The LiPo discharge profile on my Prodigy 610 will not work unless the balance lead is connected.
None of my chargers require balancing during discharging. Here is 1 inexpensive 1 that I use. It's already 10 or more years old
I have 2 chargers. The Protek quad and and a VistaPower dual that both have identical firmware, settings and behavior. They both fail to discharge these smart batteries under the LiPo profile due to lack of balance connector. The charger will not discharge in this mode. They will however do a non-balance charge of these same batteries.
Here s the setup to discharge a 4S LiPo to the cutoff of 3.8v/cell or 15.2V overall for the pack.
Here is the error they both throw when you try to start the discharge:
And this is what that error means, basically that it isn't seeing cell voltages from a balance lead. What that means is this is NOT a dumb discharge mode but a balance discharge mode. And there is *no other* LiPo discharge mode.
Here s the setup to discharge a 4S LiPo to the cutoff of 3.8v/cell or 15.2V overall for the pack.
Here is the error they both throw when you try to start the discharge:
And this is what that error means, basically that it isn't seeing cell voltages from a balance lead. What that means is this is NOT a dumb discharge mode but a balance discharge mode. And there is *no other* LiPo discharge mode.
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And the other odd thing about these is that fully charged M2 batteries throw a "connection break" error on these chargers which means that the chargers don't see the batteries at all (yes, they were turned on). Which is strange because the DVOM clearly shows 16.95V on the probes. The battery BMS is apparently doing something that causes the charger's battery check routine to flake out. Same thing on both chargers.
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m0j0
Well-Known Member
I understand that. My solution is fly your batteries and then charge them to storage capacity. When you are going to fly charge them to 100 and go. Works well enough for me.
m0j0
Well-Known Member
Why waste a charge? Put it to good use. Fill your car tires.
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Ask Thunderdrones; Thunderdrones Repair Thread
This is a thread for folks who have problems and would like my help in solving them. I will update it regularly with answers to questions and problems already answered.
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