skyneverdie

I have a Team Orion hump pack (nickel metal hydride) at 1200 mah.
and a Piranha DC Peak Charger

the peak charger does 50ma or 4amp charging

how long does it take to charge at a rate of 50ma?
how long does it take to charge at a rate of 4amp?

I tried to charge it at 4 amp, the battery gets very hot.
is it normal?

Twobeers

I don't know how long it will take to charge at the 50ma rate, but it will take quite a while. 4a is way to high for that size of pack and will definitely shorten its lifespan in a major way. And you also risk the chance of the pack exploding or catching fire.[sm=drowning.gif][sm=bananahead.gif]

Dale Gribble

My Feedback: (4)

Never charge that pack at 4A ever - 1A max.

Even 2A and the peak detection circuit may not work properly. The 1A is the safest charge, and offers the best chance for a good peak detection.

I can charge 6v 5 cell 1200mAh packs with my Black Widow peak charger in about 25-30 minutes at 1A rate. A 50mA charge would presumably take twice as long so 50 min to an hour.

The 4A is for 6 and 7 cell 7.2v/8.4v packs.

Mike Rojas

My Feedback: (2)

Sorry Dale,but you are wrong. A 50ma charger will charge a 500 mah battery in 10-12 hours. Think about it 50mah/500mah=10hrs
so a 50 mah charger will charge a 1200mah pack in about 24hrs.
Mike

skyneverdie

24hrs O.o
omg

if i charge it at 4amp..... it takes only 18mins!!!

but the battery might explode... LOL

i8tweety

My Feedback: (11)

I wouldn't use the pirana DC peak charger for receiver packs. It is a 4 amp peak charger with a 50 milliamp trickle charge function. This means it will not shut off when the receiver pack is charged (and over-charging NiMH is not a good thing).

I strongly recommend purchasing an inexpensive charger such as the ones sold for electric park flyers (planes). Typically, they charge NiMH packs from 4-10 cells with a charge rate adjustable from 50mA to 1 amp (with peak detection).

Twobeers

I am not joking about the explosive or fire hazard bud-x. I have worked in commercial electronics for more than 30yrs. Heed my warning.[sm=drowning.gif][sm=drowning.gif]

Dale Gribble

My Feedback: (4)

My bad... I was thinking 500mA not 50mA. I know on a 1A current output, my 1200mAh rx pack will peak charge in 30 minutes. So, a 500mA current output charger will presumably charge in 2x that time.

Of course, that doesn't take into account that the Rx packs probably have 100-200mAh when I begin charging them in the first place, temperature variables, wire resistance, connector resistance, and efficency of the cells.

Oh well, this is besides the point. You got me.

skyneverdie

so a 50 mah charger will stil charge a 1200mah pack in about 24hrs????

Dale Gribble

My Feedback: (4)

Well, you are using a trickle charge feature of your peak charger to charge your receiver battery. First of all, the peak detection won't work since it is trickle charging only.

I think it is bad news. I think you should go buy the RIGHT charger for your receiver pack. Ofna makes a cheap $5-10 1200mAh AC charger for your pack.

Homebrewer

My Feedback: (8)

Nope, a 50 mah trickle charger will NEVER charge a 1200 mah pack fully. The trickle charge rate that will charge in an overnight charge is c/10 where C is the capacity of the pack. A 100-120 mah trickle charger is best for a 1200 mah pack.

I've seen so many crashes from dead batteries in rc airplanes when an individual upgrades a 600 mah pack with a 1200 mah pack and uses the same 50 mah wall charger. No go......

For NiMH packs, I would recommend never exceeding a C/1 charge rate. So for a 1200 mah pack, the best charge rage is 1200 mah. Any higher will probably decrease your packs life. Yes, there are some NiMh packs out there that claim a 2000 mah charge rate but I don't think the pack will last as long.

NICAD packs can easily be charged at rates greater than C. Some NICADS are specifically made to handle up to C4 charge rates. As a general rule of thumb a C charge rate or C2 at the field is ok if you need to get back up quickly. However, at the house, I personally prefer a C/2 charge rate on a peak charger after a discharge cycle.

monsterbill

I am a "newbie" with a Savage 25 RTR and an HPI 1200mah NiMH receiver battery without a proper charger.
Just read the posts above regarding NiMH chargers. One mentions OFNA making a proper charger for 1200mah NiMH battery packs, yet I can't find it (or other similar chargers) anywhere on the 'net
Please advise.
Regards,
Bill

NitroDriver

[link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXHCF1&P=7]Here[/link]

youngnbald

Look at it like this

Battery Rating (1200mAH)
-------------------------------
Charge Rate (mA)


equals hours of charge needed. (Battery Rating divided by Charge Rate)


1 amp = 1000 mA
.8 amp = 800 mA
.6 amp = 600 mA

1200mAH (milli amp hours) means this can supply 1.2 Amps for one Hour or 1200 milli amps for one hour.


1200 mAH charged at .6 amps or 600mA takes two hours. 1200 divided by 600, the milli and amp cancels each other giving 2 hours.







I think the charge you are speaking of is the same charger I have and it has an adjustable charge rate. The scale on the dial shows the charge rate capabilities for the two battery types. I never charge over 1 amp. Too abusive!!!

bibo

Actually it's mAh ( Battery ) / mA ( Charger ) X 1.2 = Charging time ( hours )

so 1200 mAh / 50 mA = 24 hours X 1.2 = 28.8 hours

Check this : http://store.yahoo.com/greenbatterie...tterycalc.html