Iceracer

iTrader: (1)

Any opinions on the Integy Indi 16x307 charger?

http://www2.towerhobbies.com/cgi-bin...p?&I=LXPPD3&P=

At $54.00 it looks like a real bargain, charging at up to 6.5 amp rate.

Disaster

I like the 6.5 amp available charge rate, and the fact that you can choose to charge only to 4.15...if cycles are more important to you than full power. However, I'm concerned it could be too easy to bump the amp wheel and fry a battery. Also, it doesn't have any built in balancing. You could use an external balancer, but that costs more, and depending on the balancer, you'd lose the option of the 4.15 peak (some balancers only balance when cells hit close to the 4.2v rate....some do continuous balancing during the charge cycle.)

In general I think this could be called a "stupid" charger...and that can allow you to be stupid and ruin a battery. All this charger does is charge at constant amperage based on the settings you chose (cell count, amp rate.) It doesn' attempt to determine the true cell count or battery size. In comparison the CellPro automatically calculates the cell count and automatically determines the battery capacity and then automatically sets the charge rate based on the 1C rule. The CellPro is idiot proof and I've been known to be an idiot now and again.

Iceracer

iTrader: (1)

Good points Disaster.

How does auto current sensing work? How does the charger know you've plugged it into a 700mah or a 4800mah lipo cell?

Disaster

That is a good question.

When I watch the Cellpro display during startup it will slowly increase the charge rate, then decrease it back slightly and hold it at that level. I'm guessing it is some sort of logic, similar to delta peak based on the voltage that must be applied to get the constant current. After a minute or two of this feedback it determines what the capacity must be and then it gives you a percentage charged. Lipos charge/discharge rate is affected by temperature and it has a built in thermistor which it probably uses to improve the accuracy (as well as protecting against overcharging in cold climate.)

Unfortunately the Cellpro is limited to 3 amps....which is good enough for my current batteries...barely. Hope they come out with a more powerful model in the next year or so.

Mike Schumacher

iTrader: (37)

What is CellPro? Any link? Also, any good balancer you guys recommend?

MrBlack

THis depends on the charger many chargers that top out at 1.5Amps have shown to not fully charger the battery also those that do take upwards of 2 hours to chrge the cell properly and having a charger running hard for 2 hours straight can prematurely burn up the charger.

Disaster

Here is a link to the CellPro. It is a great charger up to about 3000-3500mAh batteries. If you charge a 4400mAh battery with it, it will take about an hour and a half to charge vs. 1 hour, 4 minutes, for the 3200mAh battery. It won't hurt the charger according to FMA Direct...just take longer.

The Cellpro automatically balances as it charges so you don't need a separate balancer. You will need to buy or make an adapter, depending on what brand of Lipo you have.

http://www.fmadirect.com/products.htm?cat=45&nid=4

MrBlack

I have just gotten the graph this morning from Kokam, here is a chart showing the 3.2A (3200) cells being tested at 2C charge rates:

or8ital

iTrader: (38)

So Im confused. This suggests that charging at 2C doesnt rapidly deteriorate the cells (contrary to lingers chart)?? Can someone interpret for me?

Disaster

Wow, that is pretty incredible performance...especially compared to Linger's results. Is that a new technology or the stuff they are already using?

Iceracer

iTrader: (1)

Mr Black, how does that compare to 1C charge over the same # of cycles?

linger

iTrader: (1)

It just means that the larger kokam cells are a lot more resistant to higher charge rates compared to the smaller kokam cells. Thanks for the info Cliff.

MrBlack

1C is still better but not by as much as you would think.

MrBlack

Ling is correct the larger cells have the ability to take more abuse then the smaller cells due to increased capacity.

This is one of the reasons why we try and use fewer larger cells then assemblies that use several smaller cells such as those found in laptop batteries which do not require the amp draw that our cars do.

or8ital

iTrader: (38)

So in the experts opinions am I ok to charge at 2c (6.4A)?