Sigma II EQ and charging

[dam74]

The other day I took my Trex450 out and flew them to the point where I could tell power was low. Probably a bit premature given the temperature with the snow. What I wanted to know is when charging them do I just give them a charge at 2.1amps (both 2100mAh and 2150mAh batteries) and the charger will work out exactly how much to charge into them or do I have to work out remaining capacity and calculate accordingly?

All a bit new to it as I only ever used the old Blade400/Eflite Charger before this.

[sacko]

Just stick em on charge.

The charger stops when it is fully charged. It will tell you the Mah put back into the pack, use this to workout how long you should fly for.

[dam74]

Paul, sorry still a bit new to all of this. How do you work it out based on how much is put back in?

[sacko]

If you have a 3s 2200mah pack, for the first 5 cycles I tend to break them in by charging them at 0.5c (0.5% of mah) - roughly just over 1amp

After that, charge them at 1c (10%) of the mah - 2.2amps

[dam74]

Yeah but how do you work out how long you should fly for?

[asomaro]

Paul, sorry still a bit new to all of this. How do you work it out based on how much is put back in?

Hi Darryl,

I'm not sure which charger you have but when the charge ends you should get some kind of display which will tell you that the charge is now full or completed.

It should also tell you how much charge has gone back into the lipo. So if your lipo is a 2200 and you have put back in say 1750 then you have put back in 79.54% (divide 2200 by 1750 then multiply by 100 to give you the percentage).

The rule of thumb is to leave about 20% in the lipo (ie don't use more than 80% of its capacity) so if you are putting back more than say 1750 then you are leaving less than 20% in the lipo which may reduce its life span. If you are using more then simply reduce your flights by 30 seconds of so and see what difference it makes to the amount put back in.

I also assume you have a balance option on the charger? Bring it with you on Sunday if you like and we can run through it.

Cheers,

[trillian]

Yeah but how do you work out how long you should fly for?

You just keep an eye on how much is put back in and I think the rule of thumb is to keep your usage at less than 80% of the pack's capacity.

So if you're still putting a lot back in then just up the flight time and then see how much is put back in until you get close to the target you want.

Right now I get 7 minutes out of most of mine (2200 and 2250mah packs) with the mild type of flying I do.

(I have a Propeak Sigma By the way, but not the 'EQ')

[sacko]

Yeah but how do you work out how long you should fly for?

Until you put 80% of the mah back into the pack..

...but no more than 80% is a general rule of thumb.

[Mart61]

Bottom line:

Set your Tx timer and fly for say 5 minutes. Then, when you charge your battery, see how much the battery takes. If you've only put back 60%, set your timer for 6 minutes. Repeat the process until you're putting back 75-80% or so.

[Stuart]

Flight times are dependant on a no of factors, from motor drain, ambient temp, bec drain etc.

The charger will charge the pack till it full then go fly went you start to see the heli not responding as quickly and lagging power its time to land. The power drop off will be gradual to a point then it will just die off completely so you need to have enough in reserve to land safely.

Spartan and others do a lipo alarm flashing LED that tells you that the batt is near the end....

[Stuart]

The spartan lipo guard - I think most retailers stock it....

Spartan RC

[Brian Gifford]

I've got a lipoguard, but I only use it for backup, I time all my flights, aim to put back 75-80%, as other posts on here.

[dam74]

Stuart, the Align battery off my Trex450 which is 2150mAh just required 1998 put back into it so 92%. The last flight was in the snow and I was flying until the power in hover resulted in a loss of altitude.

[sacko]

You have taken way too much out of it. 80% is the rule of thumb.

[dam74]

Sacko, I know but how would a flight time be an effective way of working out of reaching max capacity to drain out of a battery as ambient temperature is a factor in the equation as Stuart pointed out and as I have experienced in the past when photographing during winter times (battery on camera dies quite quickly in freezing conditions).