Question:
Scorpion: Up until now, I’ve been a user of Kontronik Kosmik/Jive and Jeti Mezon ESCs. One of the reasons I selected those units was the ability to place a fully charged 2S lipo directly in parallel with the BEC as a very simple and effective power backup for the model’s electronics. Can that be done with the new Scorpion Tribunus 200A ESC without risk of damage to the BEC? Thanks.
Answer:
You can do that and the BEC will not be harmed in any ways.
But is this a good idea? NO it’s not! not on any ESC of the market.
let’s me explain, a few scenario can lead to catastrophic results on your plane or heli.
Scenario 1,
The back up lipo is small in general, and generally speaking not well taken care off since it’s nearly always at full charge, let’s say you have 1 of the cell going bad, and will not take charge in any more, or taking much slower then the other cell what happen in this case is the BEC will continue to provide the set voltage to the 2 cell lipo, you may have 1 of the cell stuck at let say 3.2V, the BEC is set at 8.3V, so the other lipo will be getting a charge up to 5.1V, results is that cell will explode.
Scenario 2.
You forgot to charge the backup lipo, or you charged it but left it on for some time, so the lipo voltage is lower then the BEC voltage, in this case, the BEC will start to charge the lipo up until the 2 are at identical voltage, sound good so far?
No, it’s not good, because the BEC is not a charger and do not have current limited at a set amperage, so let’s say you have a 800Mah lipo as backup, the most popular size people use for this purpose, our BEC has a maximum continues output for up to 14Amps, ( we publish 10 A to be conservative ) , short peak out of nearly 30A ( we publish 20A) , so the lipo will be charged at maximum burst of 30A ( 37.5C charge rate) and continuously minimum at 14A ( 17.5C charge rate), what happen next is your lipo can’t take charge with such a high C rate and it may/will explode.
Using a dedicate backup system such as Scorpion backup guard or a Optipower backup guard that has the above mentioned scenario in kind when they been designed is the safe way to go, do not use a simple lipo as backup, the risk is too big!
Warm rgds.
Georges van Gansen
http://www.scorpionsystem.com
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