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pdm52956 -> RE: Hobbico Electristar Select EP Trainer RTF (8/7/2008 11:31:47 AM)
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Cuda, at the risk of having everyone jump down my throat and tell me not to charge my batteries this way, I'll tell you what I was told. The guy that explained this to me is LA Johnston. There are a lot of people that may know him since he's been around this sport longer than I've been alive! He pretty much flys electric exclusively. By the way, I don't look so much at the voltage, but rather pay more attention to the mah. I can see the peak charge in volts on my charger, but I do worry about false peaks. I've come to realize that the charge in mah seems to be the best indicator.
Anyway, I was charging my batteries at 1C or less. Again I'm using the 8.4 3000 mah Nimh batteries. We checked the load on the ESC and even at full throttle, the draw was less than 30 amps. The ESC is rated for 45 continuous. Anyway, he asked me how I charged the batteries. When I told him I was charging at 1C, he kind of chuckled and said to take it up to 2C if my charger would. He also told me to go ahead and charge the night before, but if I did that I needed to top off before I left for the field. In simple terms, he said that the battery was like a muscle and it needed to be flexed.
In order to check the charge condition of the batteries, I take the amount of time they were charged, divide it by 60 and multiply it by the charge rate. For example, if I charge the battery for 24 minutes at 6 amps (2C), I'll take the 24 minutes and divide it by 60 and then multiply that amount by 6 amps. Comes out to 2400 mah. Since the battery is a 3000 mah capacity, I know I should have a pretty full charge now. At 1C I kept finding myself with a total of about 1800 - 2000 mah charge. Big difference! In short, I wasn't getting a full charge.
Well, that's my story and I'm stickin to it. I've opened the door for everyone to say that I'm ruining my batteries, but there are a number of people at my field that have discussed this and after seeing what it did for my situation, have pretty much changed their minds. Everyone was sceptical, but in turn also said that if LA said it.........do it.
Please be aware that I'm not telling you that this is the way you should charge. I'm new to this and don't want anyone to decide this is what's best for them based on my example. That's something that you might want to get further advise on before hand from those that know more than I. It wouldn't be hard to find those people trust me! I decided to take the chance and it's worked out very well in my case. I've long ago lost count of how many flights I've put on my Estar and haven't had a glitch with my batteries yet.
Hope I've helped some. Paul
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