Warren Sloan Posted June 23, 2022 Share Posted June 23, 2022 Hi, I’m having power problems with my viper, I’m running it on overlander 6s 3350mah 35c! It started of great and now has gone really gutless, will only just get off using the full strip! I’ve tried calibrating the speed controller and no joy! It is doing the same on both Lipos which were purchased at the same time! I’ve also taken the motor out and no sign of any damage on the blades! Do you reckon might be a coincidence that both both lipos have started to fail or speed controller? Didn’t want to get more lipos if might be speed controller or motor ?♂️ Just seeing if anyone else has had this? Also what does everyone recommend for the best size lipos to use with the viper 70mm? thank you ? Quote Link to comment Share on other sites More sharing options...
Graham Bowers Posted June 23, 2022 Share Posted June 23, 2022 I'd start with checking the voltage reduction under power. Also you could see what happens if you parallel up your two lipos for a static ground test. 1 Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted June 23, 2022 Share Posted June 23, 2022 35c rated batteries are rather low for an EDF application which I am assuming a "Viper" is? It's likely you killed the packs and their internal resistance is on the way up, leading to the loss of performance. As above, if you check the pack voltages at high throttle settings, you will see the voltage collapsing if the packs are damaged/old. 1 Quote Link to comment Share on other sites More sharing options...
SIMON CRAGG Posted June 23, 2022 Share Posted June 23, 2022 Is the motor noisy or screaming? The bearings in a 70mm fan unit motor are tiny. If the bearings start to wear the shaft to the fan goes out of balance, and worst case the fan blades will touch the casing. It might be worth changing the bearings before you start throwing money at Lipos. It might be worth trying a different ESC, I have found the top end can be vastly different between makes. 1 Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted June 23, 2022 Share Posted June 23, 2022 You don't have to throw money at Lipos. Just measure the battery voltage as two posters have suggested. I'd rather check the voltage before throwing money at changing bearings. 1 Quote Link to comment Share on other sites More sharing options...
SIMON CRAGG Posted June 23, 2022 Share Posted June 23, 2022 35 minutes ago, Alan Gorham_ said: You don't have to throw money at Lipos. Just measure the battery voltage as two posters have suggested. I'd rather check the voltage before throwing money at changing bearings. I know that fella, I just don't want him wasting money, and am trying to be helpful. If the lipos are good I am suggesting some other options. No biggie. 1 Quote Link to comment Share on other sites More sharing options...
Shaun Walsh Posted June 23, 2022 Share Posted June 23, 2022 If it started off ok I would guess that the batteries, if used singly, have been heavily worked, the model has a 130A esc and minimum recommended battery is a 6s 4Ah 30c which would indicate that it's likely that the motor makes good use of the ESC capacity. E-Flite suggest that lower capacity batteries are used in parallel which would be my first suggestion. 1 Quote Link to comment Share on other sites More sharing options...
Warren Sloan Posted June 23, 2022 Author Share Posted June 23, 2022 6 hours ago, Shaun Walsh said: If it started off ok I would guess that the batteries, if used singly, have been heavily worked, the model has a 130A esc and minimum recommended battery is a 6s 4Ah 30c which would indicate that it's likely that the motor makes good use of the ESC capacity. E-Flite suggest that lower capacity batteries are used in parallel which would be my first suggestion. I have just seen these on Amazon for £115, do you reckon it’s worth trying them? There also 60c ? Quote Link to comment Share on other sites More sharing options...
Graham Bowers Posted June 24, 2022 Share Posted June 24, 2022 11 hours ago, Shaun Walsh said: If it started off ok I would guess that the batteries, if used singly, have been heavily worked, the model has a 130A esc and minimum recommended battery is a 6s 4Ah 30c which would indicate that it's likely that the motor makes good use of the ESC capacity. E-Flite suggest that lower capacity batteries are used in parallel which would be my first suggestion. Please note the OP stated his model was the 70mm EDF version, not the 90mm. Quote Link to comment Share on other sites More sharing options...
Shaun Walsh Posted June 24, 2022 Share Posted June 24, 2022 54 minutes ago, Graham Bowers said: Please note the OP stated his model was the 70mm EDF version, not the 90mm. Indeed so, I missed that, ignore previous comments but it's still worth monitoring the voltage drop at full throttle to check to stste of the batteries. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted June 24, 2022 Share Posted June 24, 2022 Not everyone will necessarily be able to follow the (excellent) advice to measure the voltage under load, which may sound daunting to someone without a modicum of electrical knowledge and without the ability to make suitable connections. It would be far easier to beg, borrow or buy a Wattmeter which makes connection simple and will display the under load voltage along with the current, calculated wattage etc. Quote Link to comment Share on other sites More sharing options...
Shaun Walsh Posted June 24, 2022 Share Posted June 24, 2022 (edited) 17 minutes ago, Martin Harris - Moderator said: Not everyone will necessarily be able to follow the (excellent) advice to measure the voltage under load, which may sound daunting to someone without a modicum of electrical knowledge and without the ability to make suitable connections. It would be far easier to beg, borrow or buy a Wattmeter which makes connection simple and will display the under load voltage along with the current, calculated wattage etc. I have a wattmeter but for a simple on the field check I just attach my voltmeter to the battery balance lead and open the throttle, you can see how much and how quickly the voltage drops and also check for cell balance. Edited June 24, 2022 by Shaun Walsh Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted June 24, 2022 Share Posted June 24, 2022 Or, if the OP has voltage telemetry, he can use that - either watch the tx with the aircraft on the ground, or better still, have the tx read out ever few seconds in flight...... Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted June 26, 2022 Share Posted June 26, 2022 On 23/06/2022 at 23:28, Warren Sloan said: I have just seen these on Amazon for £115, do you reckon it’s worth trying them? There also 60c ? A couple of us at the club use these and they perform well. Noticeable difference between these in 3S2200 size and equivalent well used/puffy Nanotec's if thats anything to go by. Just seem a bit more punchy at the top end as see no reason for the performance to drop off. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 30, 2022 Share Posted June 30, 2022 My own view is that a suitable Wattmeter with the right plugs is an essential bit of kit for any EDF and particularly for a high power 6s set up. Without such you really have no idea what is happening. Watt meters are a modest price and should avoid purchasing an unsuitable size but still expensive LiPo. 1 Quote Link to comment Share on other sites More sharing options...
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