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-   -   Whats the lipo or A123 (http://www.rcuniverse.com/forum/batteries-chargers-84/10809577-whats-lipo-a123.html)

stang2112 11-13-2011 06:12 AM

Whats the lipo or A123
 
I have Yak with a DLE 30 and wanted to know what the best type of battery to use with electronics? Currently I have 2 2600 lithium ion one for radio and one for ignition. They work great for about 10 months. At $75 for the two its too pricey, any suggestions? Whats the difference between lipo and ion in that configuration? Thanks for your help..

john4648 11-13-2011 06:56 AM

RE: Whats the lipo or A123
 
I have used A123 exclusively for several years now. Do not fly the large ignitions but do fly jets. The A123's have several advantages, first is no chance of fire if abused or mistreated. Second can be recharged in as little as 15 minutes. Third they seem to last forever. Forth no regulator is normally needed, with most receivers/servos made today you may power the airborne electronics directly. Fifth cost is relatively low at about $10 per cell (26650 2300ma), two cells per pack of course. I have a set on the bench (electronic test bench) that have over 3500 cycles (APR18650M1-A 5 amp charge/2 amp discharge). Now they have not failed however they are down to 50% of stated capacity and 60% of actual original capacity. Normal recommended use is to 80% of stated capacity. This was still over 1000 cycles. Probably more life than you are experiencing with the LiPO batteries. The industry is getting better producing LiPO's all the time. The C ratings of the LiPO's far exceed the C rating of the A123 which is really only important if using the different chemistry for propulsion. The A123 have to managed differently. The charge cutoff voltage is different. Balance is not as critical when the cells are newer but becomes an issue as the cells age, so they do need to be balanced. A123's like LiPOs do not like to be discharged to zero volts. The A123's will take it maybe once or twice but each time capacity/life is reduced. (dont ask me how I know...). I always use two packs in parallel, two switches and the packs are isolated with high current diodes (low volt drop). That way if a pack fails, voltage drops or shorts it is removed from the circuit.
Good Luck
John

stang2112 11-13-2011 07:33 AM

RE: Whats the lipo or A123
 
John, Thanks for taking the time to respond. I was leaning towards the lipo as a replacement to the lithium ion because in electrics they seem to last a long time with lots of power available and the price has significantly dropped. However to your point they are a fire hazard and a DLE 30 vibrates a lot. What brand A123 do you use, I currently have two regulators in place one for each battery.

john4648 11-13-2011 11:12 AM

RE: Whats the lipo or A123
 
The A123 is, at least at this point in time, a unique animal. It is not specifically Li ion nor is it LiPO. Rather it is a version of LiFe that A123 calls Lithium Nano Phosphate. They can be ordered from several vendors such as Duralite https://duraliteflightsystems.com/in...lite-plus-a123 or can be obtained from Dewalt packs such as http://www.ebay.com/itm/DeWalt-DC936...item5193194ad5 (just an example many more are listed). There are 10 cells in the Dewalt pack. Black & Decker had a line called VPX and each battery pack contained two of the smaller 1100ma cells. This line was discontinued some time ago though there are still some packs floating around. When searching for cells beware the standard LiFe is not the same as the A123 cell. The charged voltage of 2 A123 cells is 7.2V vs 8.4 for two LiPO's. Lightly loaded the A123 2 cell voltage drops to 6.6V which is pretty close to a 5 cell NiCd pack of about 6.25V. Hence why we are not running regulators. You will probably not need the regulators with the A123's. Loosing the regulators simplifies as well as rids the craft free of another failure point. On my 2.4G pattern craft I assemble the plane at the field and plug the batteries in direct to rx. They remain plugged in until I disassemble the plane to go home. After flying about 8 flights each pack needs about 250ma to top it off. These are the 1100ma cells, the smaller ones. No need for switches either. Eliminates another failure point... this is just what I do - no recommendation here. You will have to draw your own conclusions, yes?
All the best
John

Capt Lou 11-13-2011 02:02 PM

RE: Whats the lipo or A123
 
Stang:

Go to the site www.hangtimes.com He is an excellent source of A123 batteries. Also, he provides a lot of good information. A123 is the way to go.

pkoury 11-13-2011 08:45 PM

RE: Whats the lipo or A123
 

Quote:

ORIGINAL: stang2112

John, Thanks for taking the time to respond. I was leaning towards the lipo as a replacement to the lithium ion because in electrics they seem to last a long time with lots of power available and the price has significantly dropped. However to your point they are a fire hazard and a DLE 30 vibrates a lot. What brand A123 do you use, I currently have two regulators in place one for each battery.
A123 is the brand name. I use A123 cells in all my airplanes. Most of them I purchase from www.RadicalRC.com and I have charge with an FMA cellpro 4S charger.


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