greyS60

I have a Pro Peak Delta 3 AC Fast 4-8 NiMH/Nicd Charger 2/3.5/5.0A and a Trinity 6 Cell 4200 mAh battery (TRI20063). How long will it take to charge this battery on the 2 or 3.5A setting? Any help would be appreciated.

guver

My Feedback: (325)

"Amps" is the rate, think of it as amperes or "amps per hour"

2 amps is 2 amps per hour. 3.5 is 3.5 per hour.

sheograth

that only makes moderate sens if youre talking about batteries, but electically speaking "amperes per hour" doesnt work at all. An ampere is a compound unit that has a time factor already.

MonkeyFist

It may not be technically right, but it make it easy to understand. Thats the key.

sheograth

Cant deny that.

greyS60

So, I can assume that at 2A, it would take 1.5hours to charge a 3000mAH battery and 2 plus hours to charge a 4200mAH battery. Also, on 5A, it would take 35-40 minutes for the 3000mAH battery and 50-55 minutes for the 4200, correct?

snowbl!nd

Yep that's how it works, though exact times will depend upon how much residual charge is in the battery before charging.

guver

My Feedback: (325)

I try to make it as easy to understand as saying a rate of "miles per hour"

You can state that rate to nearly anyone and they can understand exactly what it means. It is within the terms itself (if you know what a mile and an hour is)

DaveG55

When you charge (or discharge) a battery at a rate equal to it's stated capacity (ex: a 3000mah battery charging at 3A) then you are charging at what is called "1C". When you charge at 1C it takes about 1 hour to charge, charging at 2C will take 1/2 hour and charging at 1/2 C would take 2 hours. Charging at 1C is usually the maximum rate that a battery can be charged w/o the possibility of suffering damage. Charging at a higher rate can cause heat build up (among other things) that can harm the battery or shorten its life. If you have the time it's far better to charge at 1/2C - in your case 2A. That will give you a fuller and longer lasting charge.

greyS60

So, with a 4200mHA battery, I can charge it at 3.5A or 2A, with 2A being the preferred choice. With the 3000mHA battery, I would be better to stay at 2A. I get it, kind of like a long trickle charge instead of a fast charge.

Now, discharging, I am unsure about that. I have been told that I can get some lights from the suto store (ie 1157) and discharge the battery like that. What is the best way to discharge a battery? I am new at all this, so if these questions seem elementary, I am sorry.

DaveG55

You can get a bulb style discharger. Or a kit to make one. Or electronic devices made to discharge batteries. Or many chargers have a built in discharge function. One of my chargers does this and it can be set to discharge and then automatically charge the battery once a preset voltage is reached. Check on Tower. Last time I looked there they had a lot of different choices for any of those methods. Whatever way you go be very careful not to discharge the batteries too far. That will damage a battery very easily. Also keep a close eye on the battery temp when discharging. Heat is probably the batteries worst enemy.

IMHO the absolute best (and most fun) way to discharge a battery is to run it out. Even then you should stop running when you notice a performance drop and not run it until the battery is totally dead.

Codeblack

wow, I've learned something to day too. very very good thread, should even be in the battery FAQ section.

TenergyRep

Just to add to what Dave was saying. On a NiMh cell you really shouldn't go much past .9 volts per cell on a discharge. Some chargers go as low as .5 volts, that is just to risky in a pack configuration as you can never be certain that all the cells in the pack have the same residual charge in them.

SManMTB

~3 hours on the 2A setting
~1 hour 40 mins on 3.5A setting

Assuming the pack is completely empty.

SManMTB

No, 2 amps is just that. A current of 2A. It has nothing to do with time but I see what you're saying. Just being picky here
Running at 2A for 1 hour will charge 2000mAh but there are losses so the correct way would be:

Charging time (T) = Battery capacity (Ah) / Current (A) x 1.4

TenergyRep

Using this formula, note that it is using Amp Hours (Ah) not milliamp hours (mAh). Convert mAH to Ah by dividing mAh by 1000.

guver

My Feedback: (325)

It's a rate, imbedded in the term is a unit per time. Rates are something per something.

miles per hr, rpm,beats per minuite, ect. I know of no easier way to state it than to say 2000 mah PER hour. It is capacity per hr. It does have an understood 1 hr time in it.

It's a rate. I guess I get tired of the question "how long will it take to charge xxx at xxx amps? It's exactly like asking how long will it take to drive 50 miles at 100 miles per hour. Imbedded in the phrase "miles per hour" is the units needed to figure out the answer.

Rather than answering a specific question about rate and time , explaining the current as "amps per hour" should allow one to then figure any chargeing time out.

It is also good to express it as the amount of charge that "the charger delivers" rather than "takes xxx amount of time to charge xxx battery"

guver

My Feedback: (325)

Using 1.4 works ok around a rate of c/10 , but slides towards 100% at 1C and slides towards 200% at maybe around c/20 and is another good reason to use a "delivered capacity" by the charger without mentioning the battery.

SManMTB

I get what you mean but you are still messing up the units. There is no 'understood' 1 hr time in the unit Ampere (A).

To get into delails the definition of Ampere (A) is the amount of electric charge delivered / second, which is Coulomb (C) / Second.
1 Coulomb (C) = ~6.24150948×10^18 electrons.

Sorry guys, got carried away.... move on.

osuwins

is it safe, and possible to charge these batteries in the holder with a charger

guver

My Feedback: (325)

sure, that would be fine.

If I could only figure out how many Coulomb they hold.

guver

My Feedback: (325)

I'll try to add file. Ah, can't seem to add the file. It's a spreadsheet showing capacities and rates.

Pulse,Ice,MRC Triton, Dig Pir
AMPS AMPS
Mah / hr Mah / min Mah / sec
0.92 1 917 15.3 0.25
1 1.1 1000 16.7 0.28
1.37 1.5 1375 22.9 0.38
1.5 1.6 1500 25 0.42
1.83 2 1833 30.6 0.51
2 2.2 2000 33.3 0.56
2.29 2.5 2292 38.2 0.64
2.5 2.7 2500 41.7 0.69
2.75 3 2750 45.8 0.76
3 3.3 3000 50 0.83
3.21 3.5 3208 53.5 0.89
3.5 3.8 3500 58.3 0.97
3.67 4 3667 61.1 1.02
4 4.4 4000 66.7 1.11
4.12 4.5 4125 68.8 1.15
4.5 4.9 4500 75 1.25
4.58 5 4583 76.4 1.27
5 5.5 5000 83.3 1.39
5.04 5.5 5042 84 1.4
5.5 6 5500 91.7 1.53
5.5 6 5500 91.7 1.53
6 6.5 6000 100 1.67
5.96 6.5 5958 99.3 1.66
6.5 7.1 6500 108.3 1.81
6.41 7 6417 107.9 1.78
7 7000 116.7 1.94
8 8000 133.3 2.22
9 9000 150 2.5
10 10000 166.7 2.78

well, that doesn't look too good. [:@]