More than what a prizmatic can offer when it is needed most...howzat? Average consumption is usually not the issue, high (current) loading which causes the PTC (an over-current protection device present on all lithium cells) to activate and reduce current flow is.
If activated by exceeding the cells operating parameters, it essentially heats up rather quickly (time-based on the load excursion) reduces current flow to near-zero. On prizmatics, where the cell's specification is to deliver relatively low current for long periods, it can act rather quickly and take it's sweet time recovering. This goes for all PTC's actually. Another trait is the recovery time is not consistant from cell-to-cell (PTC to PTC). We did experiements to look at the complete system including awg on harnesses, connector losses, and various load supplies (NiMH versus NiCD) as it relates to high speed flight. We rigged flaps and ailerons to measure actual surface deflection (using separate onbaord linkages and positioning measuring equipment) to record deflection during launch phase and hi-G pull-outs (where surface loading is the highest) and then proceeded to change the above mentioned parameters. Amongst other things, we observed servos falling below their operating V thresholds, especially on configurations where PWR and GND have been shared between more than one load (not something I recommend at the best of times). Average consumption tells you little. It is the loading that occurs at maximum surface pressure that dictates operating system integrity. On most aircraft this is hardly noticeable. But those which may employ Lithium thechnology where the PTC has been activated, you will notice in a hurry... Simon Van Leeuwen PnP Systems - The E-Harness of Choice Radius Systems Cogito Ergo Zoom Quoting Bill's Email <[EMAIL PROTECTED]>: > > > prizmatics would fit our current moldies, they offer no where NEAR the > required > > current demands due to their internal structure. > > > I am curious what you feel are the current demands of a typical 6-servo > TD ship. > > I can give you some documented loads from other uses. > > Raptor 50 heli with 5 mid-sized digital servos in 3D - 2 amps average, 5 > amp spikes. (Fromeco has data on their site) > > 40% IMAC plane w/14 Large digital servos - 3 amp average, 20 amp > instantaneous loads during snap roll series. The EMCOTEC site has this data. > > 10 large digital servo 38% Extra (mine) - 2.5 amp average current load. > > 8 large digital servo 33% Edge - 1.5 amp average load. > > I have also determined that my 6-mini-digital servo TD ships average > about 350 mA for the load. > > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and > "unsubscribe" requests to [EMAIL PROTECTED] Please note that > subscribe and unsubscribe messages must be sent in text only format with MIME > turned off. Email sent from web based email such as Hotmail and AOL are > generally NOT in text format > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
