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**Andy from Sandy** · 24-02-2009, 08:22 PM

When you turn the charger on it shows LiPo on the top line and 400mA and 3.7 volts on the bottom line.

You can change the charge current but what I am not sure about is what is the maximum current your battery can take.

If you press the enter/start/stop button momentarily the 400 will start to flash. Now press the inc to increase the value or dec to decrease the value. When set at the desired value momentarily press the enter/start/stop button again. The 3.7 volts now starts to flash and then press the start button again and all the numbers will be solid.

**David Drew** · 24-02-2009, 08:24 PM

For some reason I can't explain I don't like the sound of that.

Charging at 1C is the best & that is what you are doing.

Frustrating waiting I know. But if they are so cheap why not buy some more so the waiting won't matter so much?

David

**400blade** · 24-02-2009, 08:24 PM

you can buy leads from that well known auction site that lets you charge 3 or 4 cells at a time in series so you should be ok doing it this way i allways charge mine on my lipro plus 5 at 0.5 mah and it takes about 25 mins each battery

**Andy from Sandy** · 24-02-2009, 08:27 PM

If you then connect them in series you adjust the output voltage in increments of 3.7 volts. Every time you press the increment button whilst the voltage is flashing it will incease by 3.7 volts to a maximum of 18.5 volts which is 5 cells.

**Holst** · 24-02-2009, 08:28 PM

Originally posted by Evo Andy View Post

When you turn the charger on it shows LiPo on the top line and 400mA and 3.7 volts on the bottom line.

You can change the charge current but what I am not sure about is what is the maximum current your battery can take.

If you press the enter/start/stop button momentarily the 400 will start to flash. Now press the inc to increase the value or dec to decrease the value. When set at the desired value momentarily press the enter/start/stop button again. The 3.7 volts now starts to flash and then press the start button again and all the numbers will be solid.

So the 400 isnt the battery size, but the current charge in milliamps.

I must have misunderstood the instructions

So I can increase this to make the battery charge faster.

Does anybody with a 4#3B have any idea whats a safe charging current?

What do other types of lipo charge at? and how long do they take to charge?

**Andy from Sandy** · 24-02-2009, 08:32 PM

So the 400 isnt the battery size, but the current charge in milliamps.

This is the capacity of the pack and is described as the 1C charge rate.

So I can increase this to make the battery charge faster.

In theory yes, but I don't know by how much.

**Holst** · 24-02-2009, 08:32 PM

Originally posted by David Drew View Post

For some reason I can't explain I don't like the sound of that.

Charging at 1C is the best & that is what you are doing.

Frustrating waiting I know. But if they are so cheap why not buy some more so the waiting won't matter so much?

David

If it takes an hour to charge one then there is no advantage in buying more cells, as once I have flown one the second is still on charge..

you can buy leads from that well known auction site that lets you charge 3 or 4 cells at a time in series so you should be ok doing it this way i allways charge mine on my lipro plus 5 at 0.5 mah and it takes about 25 mins each battery

Thanks

I will have a look.

Do any of you guys have a lead like this?
Is it just a loom with connectors or is it more complex? (diodes?)

I will do some research.

**David Drew** · 24-02-2009, 08:41 PM

Originally posted by Holst View Post

If it takes an hour to charge one then there is no advantage in buying more cells, as once I have flown one the second is still on charge..
.

Lets be silly. Suppose you had twenty batts. You fly first & start to recharge. By the time you are on batt 6 the first has recharged, put in No2 etc. No 1 is waiting to be used again.

I have 4 x 3s for my 450 & 4 x 4s for my Swift. On a long flying day I keep rotating them & always have a batt to fly with.

**Holst** · 24-02-2009, 09:35 PM

Originally posted by David Drew View Post

Lets be silly. Suppose you had twenty batts. You fly first & start to recharge. By the time you are on batt 6 the first has recharged, put in No2 etc. No 1 is waiting to be used again.

I have 4 x 3s for my 450 & 4 x 4s for my Swift. On a long flying day I keep rotating them & always have a batt to fly with.

My problem is getting them all charged to begin with.

To charge six batterys takes just over 6 hours.

I only really want to use 4 (thats almost 40min flying) but it still takes a long time to charge them.

I like to fly as soon as I get home from work when the house is empty.
I could charge the batterys the night before, but I would prefer to be able to charge them up a bit faster when I get home.

**cjcj1949** · 25-02-2009, 02:23 AM

There's no problem charging them all in parallel if you don't mind doing a bit of soldering or buying a proper lead if they make them. After they've been used on the heli they should be at about the same voltage but you can't just connect two lipos in paralel as the voltages will be slightly different and very large currents could flow from one to the other. If you connect them up through a small resistance like 1 ohm then the cells will all get to the same voltage fairly quickly. Then you can safely connect them all in parallel without resistors and charge them all together.Charging cells at the same voltage is what balance chargers do, so all your doing is balance charging. Might be an idea to get a cheap £6 meter just to check things over. Multiply the charge current by the number of cells being charged

You can charge them in series if you want so long as you do it balanced. Same current this time but treat them as a higher voltage battery,so charge 5 as a 5S etc. You must do it balanced though. You don't have to worry about the voltage of each cell unless they are way out. Keep a check on the voltage of each cell until they are balanced.

If you've got loads of cells or batteries you can do a combination of series and parralel.

You can increase the current as well. The smaller batteries like the mcx are charged at 2C in 30mins and the CX2 batteries can be charged at 3C. Higher charge currents do shorten the life of the batteries though. The higher currents don't shorten the charge time as much as you think as the cells just reach 4.2 volts quicker,then the charge current going into the cell goes down as the cell needs less current to maintain the 4.2volts.

The constant current,constant voltage description makes it sound as though the charger is doing something clever. What is really happening is that the charger has two limits that apply all the time. A maximum current, usually 1C and a maximum voltage of 4.2 volts a cell.

Really clever chargers like the cellpro are able tocharge quicker without shortening the cells life, but nothing is published on how they do that or how effective it is.

Chris Bsc (Electron Eng)

Chris

**waveydavey** · 25-02-2009, 07:58 AM

If you follow Andys advice above you could charge all of your batteries at the same time in 1 hour. Don't charge them above the capacity of the battery, stick with what everyone is saying and charge at 1C 0.4A in your case. I don't know where you would find an adapter board though

**Holst** · 25-02-2009, 02:27 PM

Fantastic post Chris.

This is exactly what I wanted to know.

I think I can make my own cell ballancer without any probems, then I can charge all my cells together in one go. I dont mind waiting an hour if I can charge 4 or more at a time

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