LiPo and Nimh charge advice

[Layloo9136]

Hi. Sorry if this is old ground for you guys and I did search posts for advice but nothing really matched my enquiry.

Last time I was charging batteries was old Nicads over ten years ago. Yesterday I picked up a Core UAC-50 with my Losi 8ight.

Thus I have 2 lipos - 2500mah 2s (for starter box). So set it at 2.5 and 7.4 and they charged in around 34 minutes and they didnt even get warm, in fact they didnt change temperature at all from the cool temp they started.

So question 1) - Is this normal for Lipo?


On the flipside, my 8ight receiver pack is a 6V 1400 Losi pack. So I followed the instructions and maths in the manual which give the following exampled of charge maths


Cpacity Current Safety Time
2000mah 2.0A (2000/2.0=1000)/11.9=84 minutes
3300mah 3.0A (3300/3.0=1100)/11.9=92 minutes
1000mah 1.2A (1000/1.2-833)/11.9=70minutes


What I dont get is - if the top example of 2000mah says a 2.0 current, why does it say on the 1000mah example 1.2A? Surely 1.0A would be correct?


So, with my 6V 1400mah Losi receiver pack I put it in NiMh mode and charged at 1.0A. Using the above maths would be (1400/1.0=1400)/11.9 would be 117 minutes. The instructions state that if you follow these safety times then 140% of the capacity will have been fed into the battery.


So, I started it at (time) 16:05 so thought at 18:03, 117 mins later it will be done. However, the charger bleeped saying it was full aafter only about 72 mins and the pack was rather warm. I wouldnt say hot hot, but rather warm indeed.

So question 2) Is this normal for Nimh's to get quite warm and lipos stay cold?


Question 3) Is 1.0A too much for an NiMH or should it be set to less? The Core UAC 50 lets you charge at 0.1 going up in .100 incriments, so would it be better to do it on 0.5? If thats the case and it took 72 mins at 1.0A I assume it will take 144 mins at 0.5?


Sorry for the laborious post, but modern bettery tech is new to me and with all I keep reading about flaming lipos and exploding NiMH's, its a concern to know whether I am doing it right.

(I now have my 1800mah NiMH charging at 1.0A, so assuming that will turn itself off a little after the 1400 pack did?)


Thank you