Electrifly Over-discharged (solved)
08-21-2004, 09:14 PM
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Electrifly Over-discharged (solved)
The soft LVC on my Jeti ESC always works on my TP batts, but for some reason didnt kick in on my new Electrify 1500 3s1p. First time I flew with it today, I took it all the way down to 8.32V (~2.73V/cell)!! I was shocked, as I never noticed any power dropoff. Thankfully the battery didnt balloon or go into thermal runaway (it was only slightly warmer than my hand immediately after landing, so I know it didnt even reach 130F).
Naturally, the "SafeCharge" protection circuit seems to be kicking in and preventing my Astro 109 from charging it. Is there a procedure for trying to revive a lipo that was over-discharged? It's only 9% under the normal cutoff, so I figure it shouldnt be too far gone to "resuscitate."
Anyone know a way to bypass this protection feature? I am 100% confident in my Astro 109, so I am not at all interested in the "SafeCharge" circuitry. Is it pretty easy to remove? I've converted a TP1320 3s1p to 2s1p when a cell took some physical damage, so I'm not afraid to take this Electrifly battery apart, just want to make sure there isnt a simpler workaround before I try that.
Any advice is appreciated.
-EDITED-
OK, so I plugged the Astro into the "discharge" lead and it charges fine. So my question now is, what is the purpose of the charge lead, if I charge and discharge from the same lead (discharge)?
Naturally, the "SafeCharge" protection circuit seems to be kicking in and preventing my Astro 109 from charging it. Is there a procedure for trying to revive a lipo that was over-discharged? It's only 9% under the normal cutoff, so I figure it shouldnt be too far gone to "resuscitate."
Anyone know a way to bypass this protection feature? I am 100% confident in my Astro 109, so I am not at all interested in the "SafeCharge" circuitry. Is it pretty easy to remove? I've converted a TP1320 3s1p to 2s1p when a cell took some physical damage, so I'm not afraid to take this Electrifly battery apart, just want to make sure there isnt a simpler workaround before I try that.
Any advice is appreciated.
-EDITED-
OK, so I plugged the Astro into the "discharge" lead and it charges fine. So my question now is, what is the purpose of the charge lead, if I charge and discharge from the same lead (discharge)?
08-21-2004, 11:01 PM
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RE: Electrifly 1500 Over-discharged
If there were some way to bring it up slowly on another charger then the 109 might work.
I don't know how to disable the Safe Charge.
I've charged some 2s packs with a cell phone charger, but they were not 3s.
I don't know how to disable the Safe Charge.
I've charged some 2s packs with a cell phone charger, but they were not 3s.
08-22-2004, 08:44 AM
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RE: Electrifly 1500 Over-discharged
I read their spec sheet and it states the minimum discharge voltage is 7.5V, so I would think I would be OK at 8.32V. Stupid "safety" circuitry! And what is the point of having separate charge/discharge leads, besides adding weight?
08-22-2004, 10:11 AM
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RE: Electrifly 1500 Over-discharged
Not familiar with that pack, but is one of the leads so you can check the voltage of each individual cell to be sure they are in balance?
Some packs have a little pin sticking out that you can put a voltmeter on to check each cell.
One meter lead goes to the pin, the other to one of the power leads, read the voltage, then switch to the other power lead for the other cell.
Some packs have a little pin sticking out that you can put a voltmeter on to check each cell.
One meter lead goes to the pin, the other to one of the power leads, read the voltage, then switch to the other power lead for the other cell.
08-22-2004, 10:43 AM
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RE: Electrifly 1500 Over-discharged
No, the separate leads state they are for charge and discharge. Plus, this is a 3-cell, so there would have to be 3 leads for that purpose, no? Below is a pic of the battery (1500 3-cell at the top).
But get this, I plugged the DISCHARGE lead into my Astro and, voila, it starts charging!
So I wonder if they mis-wired it at the factory or something. Anyway, unless someone can shed some light on this for me, I figure I will just cut off and seal the charge lead, as it seems completely useless in my current configuration. I'll save half a gram and inherit an extra JST connector, yeeha.
But get this, I plugged the DISCHARGE lead into my Astro and, voila, it starts charging!
So I wonder if they mis-wired it at the factory or something. Anyway, unless someone can shed some light on this for me, I figure I will just cut off and seal the charge lead, as it seems completely useless in my current configuration. I'll save half a gram and inherit an extra JST connector, yeeha.
08-22-2004, 10:51 AM
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RE: Electrifly 1500 Over-discharged
Sounds good. Never heard of discharge leads before.
Why would they put them on when lipos don't need to be cycled?
Only reason I can think of it for storage, to store them half charged.
Why would they put them on when lipos don't need to be cycled?
Only reason I can think of it for storage, to store them half charged.
08-29-2004, 04:19 PM
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RE: Electrifly 1500 Over-discharged
Dave,
The SafeCharge circuit in the new ElectriFly cells is really a marvelous safety feature. These are the first production Lithium packs with true cell balancing.
The separate JST charge jack can only be used when the pack is not connected in parallel with other packs. In my 6s4p configuration (eight 3s packs) I charge the whole pack together with my AF 109 charger. On occasion, the "super" pack is broken down and charged separately through the red JST connector.
The SafeCharge circuit ensures that each cell only charges to 4.2 volts. It uses a thin wire tap to each cell in the pack. This will become the new norm for Lithium packs by Kokam.
Sometimes, when a pack is over discharged, the voltage sensing circuitry kicks in for safety. This is also seen on the "smart" chargers like the Apache 2500. You can often charge it momentarily at a lower cell count setting or briefly run a current limited (1C) voltage into the pack for a kick-start.
I would recommend keeping the JST connector and use it to occasionally balance your pack.
The SafeCharge circuit in the new ElectriFly cells is really a marvelous safety feature. These are the first production Lithium packs with true cell balancing.
The separate JST charge jack can only be used when the pack is not connected in parallel with other packs. In my 6s4p configuration (eight 3s packs) I charge the whole pack together with my AF 109 charger. On occasion, the "super" pack is broken down and charged separately through the red JST connector.
The SafeCharge circuit ensures that each cell only charges to 4.2 volts. It uses a thin wire tap to each cell in the pack. This will become the new norm for Lithium packs by Kokam.
Sometimes, when a pack is over discharged, the voltage sensing circuitry kicks in for safety. This is also seen on the "smart" chargers like the Apache 2500. You can often charge it momentarily at a lower cell count setting or briefly run a current limited (1C) voltage into the pack for a kick-start.
I would recommend keeping the JST connector and use it to occasionally balance your pack.
