JR1222 with A123, which batt is bad?
07-28-2009, 05:54 PM
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JR1222 with A123, which batt is bad?
I am considering the following setup on a 50CC plane..
Dual 1200 mAh A123 packs
JR 1222 power safe receiver.
5 8611 servos..
So, here's the deal.. I want to use low capacity dual packs to keep the weight down.. I have enough capacity to finish a flight if I have a failure in flight. However, I am not sure how I can tell if a battery has failed during flight.
Does the 1222 indicate anything other than basic "voltage is there" with the battery lights?
I considered adding mAh counters to each pack to ensure they are being discharged evenly, but that then requires independent switches for each pack, which adds another hardware layer prone to failure, etc, etc..
Maybe 2 Fromeco soft switches, with 2 mAh counters is the only way to go?
Dual 1200 mAh A123 packs
JR 1222 power safe receiver.
5 8611 servos..
So, here's the deal.. I want to use low capacity dual packs to keep the weight down.. I have enough capacity to finish a flight if I have a failure in flight. However, I am not sure how I can tell if a battery has failed during flight.
Does the 1222 indicate anything other than basic "voltage is there" with the battery lights?
I considered adding mAh counters to each pack to ensure they are being discharged evenly, but that then requires independent switches for each pack, which adds another hardware layer prone to failure, etc, etc..
Maybe 2 Fromeco soft switches, with 2 mAh counters is the only way to go?
07-29-2009, 09:02 AM
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RE: JR1222 with A123, which batt is bad?
Well a couple of thoughts for ya....
First, while it may be a "fine" point to some, if your batteries are 1200 mah rather than the 1100 VPX size cells they are not A123's. They're the LiFEP04's which is a similar chemistry and characteristics, but substantially less power output capability.
Second, the chances of having a battery failure are extremely remote but having first installed a dual battery system in my 50cc size bird, I guess I understand the concern but my 50cc size now has a single 2300 mah A123 with dual ouputs for higher amperage capability. I'm guessing the LiFEP04's are a somewhat similar weight, but the 1100 A123's weigh 3 oz each and the 2300's are 6 oz each so whichever way you go is pretty much a wash on the weight. There can be charging issues associated with dual rx packs depending on which charger you use as most won't handle the common ground issue.
Third, the PowerSafe rx's may not actually "tell" you if the voltage is there since if one battery has more voltage than the other, you'll likely see only one blue light on until they equalize.
Now I've not got the model I have which is getting the R1222 finished yet, but it's a 35% size and it's getting dual 2300 A123's and I don't plan on changing how I do the charging thing with it that I'm not already doing on the others with dual batts. I know about how many mah's each will use per minute and basically I can fly my usual number of flights during a day with no worries about having to recharge. If you really feel you want a running total, you're gonna have to get something like the Fromeco switches which have that capability. I have seen reports that those switches are not all that accurate when compared to checking the mah's put back in the batteries when charging and mine are always balance charged. Plus, the mah readout switches are fairly large and not inexpensive.
Hope that helps.
First, while it may be a "fine" point to some, if your batteries are 1200 mah rather than the 1100 VPX size cells they are not A123's. They're the LiFEP04's which is a similar chemistry and characteristics, but substantially less power output capability.
Second, the chances of having a battery failure are extremely remote but having first installed a dual battery system in my 50cc size bird, I guess I understand the concern but my 50cc size now has a single 2300 mah A123 with dual ouputs for higher amperage capability. I'm guessing the LiFEP04's are a somewhat similar weight, but the 1100 A123's weigh 3 oz each and the 2300's are 6 oz each so whichever way you go is pretty much a wash on the weight. There can be charging issues associated with dual rx packs depending on which charger you use as most won't handle the common ground issue.
Third, the PowerSafe rx's may not actually "tell" you if the voltage is there since if one battery has more voltage than the other, you'll likely see only one blue light on until they equalize.
Now I've not got the model I have which is getting the R1222 finished yet, but it's a 35% size and it's getting dual 2300 A123's and I don't plan on changing how I do the charging thing with it that I'm not already doing on the others with dual batts. I know about how many mah's each will use per minute and basically I can fly my usual number of flights during a day with no worries about having to recharge. If you really feel you want a running total, you're gonna have to get something like the Fromeco switches which have that capability. I have seen reports that those switches are not all that accurate when compared to checking the mah's put back in the batteries when charging and mine are always balance charged. Plus, the mah readout switches are fairly large and not inexpensive.
Hope that helps.
07-29-2009, 10:33 AM
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RE: JR1222 with A123, which batt is bad?
Hi Zeeb-
Thanks for all your inputs..
Yeah, I know the chance of a failure is pretty remote, but I was stung by a dying 5 cell NiMh pack, and I really don't want to relive that little nightmare..
I was considering the 1100mAh A123 from Fromeco.. As mentioned my concern is that if I have a 'soft' pack, I could be pulling on just one pack for the first flight.. My fear is that I wouldn't know about this condition, and would then initiate a second flight, thus putting myself at risk.. At least in my mind, if I can't find a reasonable method of determining the status of both batteries between flights, I might as well go back to a single cell and put the extra cash towards a backup airframe..
I am leaning towards running 2 milliamp counters and no switches.. There will be some discharge between flights, but it should be incredibly small.. This would allow me to see that both packs are being pulled down at a similar rate.. Recharge cycles would determine the number of flights before a recharge is required.. I should easily get three 10 minute IMAC practice flights from this power system.. At the end of the session I need to disconnect my batteries either way to prevent discharging from the monitoring circuit in the 1222..
Thanks for all your inputs..
Yeah, I know the chance of a failure is pretty remote, but I was stung by a dying 5 cell NiMh pack, and I really don't want to relive that little nightmare..
I was considering the 1100mAh A123 from Fromeco.. As mentioned my concern is that if I have a 'soft' pack, I could be pulling on just one pack for the first flight.. My fear is that I wouldn't know about this condition, and would then initiate a second flight, thus putting myself at risk.. At least in my mind, if I can't find a reasonable method of determining the status of both batteries between flights, I might as well go back to a single cell and put the extra cash towards a backup airframe..
I am leaning towards running 2 milliamp counters and no switches.. There will be some discharge between flights, but it should be incredibly small.. This would allow me to see that both packs are being pulled down at a similar rate.. Recharge cycles would determine the number of flights before a recharge is required.. I should easily get three 10 minute IMAC practice flights from this power system.. At the end of the session I need to disconnect my batteries either way to prevent discharging from the monitoring circuit in the 1222..
