Li Po charging without balancing

[Leebert]

Hi All
I have been lent a T-rex 450 SE to play with for a while and it has a Flightpower 3s1p 1800mAh Li Po. I am intending to charge it using a Pro Peak Prodigy 2 charger but no balancer.

What sort of of rate is ok to charge it?

Thanks,

[muscleflex]

1c is the preferred method...so charge it with 1.8

i usually charge mine using 1.5, sometimes 1amp (takes longer) when i have time on my triton. i don't have a balancer neither...yet

[Smoothound]

1C is the stated norm but if you have no balancer it is a good idea to charge very slowly every now and again, 200/300mAh.

You can charge at 2C but without a balancer I wouldn't bother.

Also make sure you are only putting 14-1500mAh back into the packs after a flight, any more and your pack will suffer

[Leebert]

Thanks for that Smmthhound. I had let the carger do it's thing until it beeped. Now I'll disconnect at around 14 - 1500 mAh.
Cheers,

[Smoothound]

I think you misunderstand

You don't want to "need" to put back anymore than 14-1500mAh, the charger should be finished charging around there.

If you are charging and the charger is putting back 1800mAh you have broken the 80% rule and are probably harming your packs. 80% of 1800 is 1440mAh.

[Leebert]

Thanks Phil
I think I understand.

To confirm...

Set the mAh to 1440 on the Pro Peak and then take it off when it beeps.

Just to double check - I like to be right with Li Pos!

Thanks,

[extreme3d]

Your battery has a capacity of 1800 mah.

Charge your battery at 1C (which is 1.8A).

BUT what SMOOTHHOUND is saying, is that when the pack is fully charged (ie. the charger beeps) the amount of charge put back into your battery (shown on the top right of the display) should be around 1440mah, which is 80% of your battery's capacity.

Should you put any more than 1440mah back into the pack, you will be damaging the lipoly, and shortning it's life.

Your initial flight time with that battery pack should be about 8 minutes. After 8 minutes of flying charge the battery as above.
If you put more than 1440mah into the pack reduce your next flight time by a 30 to 60 seconds, if you put less than 1440mah, you can increase your flight time slightly.

[muscleflex]

can't believe no one's managed to explain this any easier - what they're saying is....if you're using an 1800 capacity battery, make sure you only use about 80% of the total amount of the battery's capacity...in this case, 1440!

in simple terms - do not run down your battery all the way down till the motor cannot spin any more!

this is why some people set a timer of about 7-8mins flight time....just to be safe!

[Leebert]

Now I've got it !! (I think )

Thanks Muscleflex.
To recap...

Charge as normal at 1800mA until it beeps.

BUT discharge only 80% capacity (i.e. still have 20% left)

Am I right??

[Smoothound]

Am I right??

Yes

[Leebert]

Yippee !!!

Thanks Guys!

[muscleflex]

LOL! phew! finally!


now, the first 3 of my posts have been all here! haha!

hello to all by the way! Ade_law mentioned this forum to me over at rcgroups!
he said this is for UK people only!

[G-DAVE]

Never found flattening a Lipo a problem with helis - It's becomes obvious when to call an end to the flight - the performance drops off . At that point I call an end to the flight .
The other guide is my timer I set it for 10 mins and call it a day when that bleeps.That's on a Zoom with a Flightpower 1800 evo 20 pack - it will probably fly for 13 mins if I went the distance .
Regards Dave

[Ade_Law]

its always worth calling it early they do seem to last longer that way.

Ade

[bandicoot]

li-po's are a mine field for the first timer..i keep meaning to take the plunge and stop using nimh but its the whole terminology, dos and don'ts that im having trouble getting my head round.