Battery Charger & Power Supply Solutions

This is interesting and has a familiar look to it:
http://www.hobbypartz.com/75p-1030-charger.html

Need a power supply? Might want to start your car or something:
http://www.hobbypartz.com/26p-efuel-60a.html

Smaller car? No problem:
http://www.hobbypartz.com/26p-efuel-20a.html

...Tiger

So... I was looking at that 1030 charger I linked above and the thing that really grabbed my eye was the ability to "discharge" up to 1000 watts. Wow - That seemed impossible, but I could really use a good discharge capability so I downloaded the manual (http://ibuyrc.com/manual/75P-1030-Charger.pdf). Turns out the 1000 watts was a little deceptive on their part. The charger can only dissipate 80 watts max. However... It has a pretty cool feature that allows you to use an external resistor to dissipate everything in excess of the 80 watts. Not as slick as I hoped, but still pretty slick in that it still manages the discharge for you by computing the voltage and power drop across the external resistor.

The reason I was really interested in this is that I have learned the hard way that you can't leave your batteries charged when you're not using them. You can for a little while, but not very long. You really need to bleed them down to about 3.8v for storage. The best way is to fly them out and then store them, but somehow you always think you're about to fly again and charge them when you get home. Then you get off on something else and there they sit. Discharging other than by flying is a real pain. Take my 3300mah quad batteries for example. My current charger can only discharge at a 1A rate so it takes three hours to discharge them. Multiply that times three or four batteries and it's a long long time so you tend not to do it. This charger, even without external resistors, would discharge them in 30 minutes. With an external resistance, you could do it in just a few minutes. This is sounding really good to me! Almost all of the batteries I've ever put in the trash have died a lot more from storage than use. How many times have you heard "I've hardly used it and it's already junk"? It's usually not the battery. It's how you used it!

I don't need this thing as a charger, because I'm really happy with what I've got, but I'm getting really interested for it's discharging capability and other features. By "other features", I mean things like its "foam cutter mode", "motor drive mode", and ability to read cell internal resistance (read the manual). This thing is really feature rich and very intelligent. The manual was even written by someone that (mostly) speaks english so you will actually be able to use all the features. This thing is pretty cool. It doesn't seem inexpensive, but considering the cost of the batteries I've thrown away, maybe it is. Anyway, if I ever need to charge that huge 10 cell Lipo or a 25 cell NiCad, I'll have just what I need!

...Tiger

PS: This charger does have a "buck-boost" inverter so it can charge high cell count batteries from a lower voltage power supply. (see discussion earlier in this thread)

I got a similar power supply:
http://www.helidirect.com/skyrc-heavy-duty-power-ready-efuel-1200w-50a-power-supply.html

The one I got is only 50 Amps but goes up to 30 VDC. I don't know if it was worth the extra $75 for 6 more volts and 10 Amps less.

The charger I got can discharge 10 Amps (I posted a link to the manual higher up in this thread). What is interesting is the "Regenerative Discharge" feature. They claim that you can discharge your RC battery back into a car battery, for example.

The Powerlab 8 can also measure internal cell resistance and there is a very comprehensive piece of software available that can do all kinds of interesting things that I will probably never use. More info in the previously posted links.

I agree with you on storing LiPo batteries charged. Certainly I have "puffed" a few by keeping some batteries charged just waiting for that next flight.
For a while I've been using one of my chargers storage charge mode to bleed them down to 3.86 volts or so but indeed this takes more time than I like.

Being able to fast charge batteries can also save money because instead of needing to charge and carry a bunch of expensive batteries I can field charge fewer batteries quickly.

With regard to your statement about discharging at 10A, here is what your manual says: "
Internal discharge 10mA to 10A, 100W max". What you may have overlooked is the "100W max" part of that. You can only discharge 10A up to a battery voltage of 10 volts (power=volts x amps or 10 x 10 = 100W). With this in mind, a 4 cell Lipo which is charged to 16.8v (4.2x 4) would have a maximum discharge rate of a 5.9A. I'm not saying this is bad, I'm just saying that some of the specs on these things are really misleading. It's like my charger advertising 1000W discharge. Not really! Same stuff applies when they are talking about charge rates. You need to look at the maximum charge "power", rather than any voltage or current rating. All these guys seem to twist the specs to be technically correct, but totally misleading to the average user.

As for regenerative discharging, it's an interesting concept, but who would want to use it? Maybe if I was charging from my motorcycle or something with a tiny battery. The vast majority of us are running on AC so it's of no practical value at all.

All this said, I really like your charger. It's that multi battery adapter part that I'm suspicious of. I'll be interested to look at that when we get together tomorrow.

...Tiger