Plane Losing Power - what's most likely cause?

[Tony Smith 7]

I guess I should just get the brushless motor ordered and then see if I can work out how to fit it.    I was actually thinking of this one, which is cheaper still  FC2812 1650kv   Ideally I'd have wanted something that can be reversed to fit behind the "firewall", but maybe I'll just have it sticking out the front.  

 

If I go Lipo ... I guess something like this would do as a charger Dirt Cheap Lipo Charger (plus some sort of explosion proof enclosure, because I'm not going to stand watching it charge with my hand hovering over the Off switch for a couple of hours each time).

[Tim Mackey]

It wont be cheaper by the time you add on a speed controller though will it.

The charger will do I guess, but if I had penny for every time someone says they wish they had bought a better charger I would be rich.

A "proper" multifunction auto charger costs very little and will outlast this one as you will surely get into more electric models - despite what you might think now

Edited By Tim Mackey - Administrator on 16/08/2010 18:27:26

[Erfolg]

Tony

 

I have followed this thread for some time.

 

I know it is difficult, but at present you are using the equivalent of a "Black and White" tubed television. It is only when you get a "Coloured, LCD, flat screen, running HD" that it becomes apparent that the world has fundamentally changed.

 

Black and white, is fun for a few minutes, then you want the real thing.

 

As has been mentioned Chargers are the point where the most money is wasted. Not by buying an overspecified model, but a model with few adjustable and limited parameters. The  example charger Tim has shown, can be be bought under many names, I have a clone of the same model, called Imax, which i have seen for as little as £20 +p&p. But I have two chargers that are  no use, due to limited capabilities and the need to purchase additional checking equipment and balancers, these have cost me much more in total.

 

It is possible as with most things to spend a fortune, for chargers, motors, ESC, Lipo. My own experience is that although most expensive models are better, but not proportionally to purchase costs. My biggest disappointment was a Kontronic motor and their ESC. Most are only marginally better (Ahhh, I hear the sound of people getting ready to die in a trench, in defence of .................).. 

[Tony Smith 7]

While we're on the subject of chargers, why is it that the cheap Lipo chargers just connect to the balance connector and charge the cells individually, whereas it looks like the more expensive chargers use a separate charge and balance connections?  (And it looks like these discharge to bring cells into balance which implies they're correcting an overcharge, rather than topping up an undercharge)

 

Edited By Tony Smith 7 on 17/08/2010 13:09:23

 

Sorry - another Q.   Do these chargers have a way of charging Lipos to the special "Storage" voltage, for safe storage?   Or do you just run the battery down a little to get to the magic figure?   Thanks,

Edited By Tony Smith 7 on 17/08/2010 13:17:15

[Erfolg]

Tony

 

If that is the case, it was not always.

 

My earlier chargers, only charged via the power lead. You had to purchase a in-line balancer, which then charged by the balance lead. As it apparently is done now.

 

How present chargers charge and balance i do no know. Although I suspect there may be two methodologies. Given the small amounts of power use in charging, efficiency is almost certainly not an issue, unless you are of an absolutists of dogmatic mind.

 

I always charge at 1c so the current is low. If the battery says 5c, I still charge at 1C. If higher charge rates are wanted and appropriate, the methodology of how much current is passed down the balance lead may be important. Being cautious, using the appropriate type charger is all that matters.

[Tim Mackey]

The cheapy little simple ones charge through the balance connector because they are only passing very low charge currents. If you want to charge at decent rates ( I am often at 10A for example ) then these sort of currents must be fed via the main power leads. Balancing "shunt" currents are only in the m/a range so the weedy balance leads are fine for that.

[Peter Beeney]

   Taking a bit of a sideways slant here, charging the battery via the balance leads may just stand up to a slightly closer dollop of looking at. If the currents charging each cell are more or less the same then the current actually flowing in the individual lead is very little. If the currents flowing are exactly the same, then the current flowing in the lead is zero. However, the first positive and the last negative wires of the pack do carry the charging current so this has to be considered. But it’s quite surprising just how much current these thinner wires can carry. I’ve not given any balance leads a bashing, but the standard rx battery lead will certainly carry 5 amps indefinitely. There’s always a volt drop to contend with but as the balance leads are fairly short even this may not be a big cause for concern.

   Just thought I’d mention this as a point of curiosity, really.           PB