capt17

Just a quick question. I'm putting in a 6V receiver battery to add to my Servo Torque in my new plane. I have a JR standard wall charger that I usually charge my 4.8V batteries in my other planes with. Will this work to charge my 6V? It doesn't say anywhere on the unit. Thanks!

goirish

It will, it just takes a lot longer. Philips make a wall charger for 6v- cost approx 5 yankee dollars.

RCKen

My Feedback: (9)

No, it won't work. Most wall wart chargers that come with your radio have an output voltage of 6 volts. This is what is needed to fully charge a 4-cell (4.8v) pack. These cells are fully charged when they are at 1.5v, so 4 cells times 1.5 volts/cell equals a total voltage of 6 volts. To fully charge a 5 cell (6 volt) batter you are going to need a charger that can put out 7.5 volts in order to fully charge that battery.

Ken

goirish

Sorry about that. I use my Accu Cycle Elite to charge my 6v. That is all that I have in my planes. Guess my guess wasn't very accurate. Please accept my humble apology.

ply2win

My Feedback: (3)

That's interesting because I have been using the wall wart that came with my radio system to charge a 6V battery. I bought one of those Hobbico Hydrimax batteries and it even says in the instructions that you can use a standard wall charger.

Based on what you are saying I assume it may not be getting a full charge but I have been doing it this way for 2 years and have never had a problem. Maybe I am just very lucky

capt17

So based on RC Ken's post, can anyone suggest a cheap wall charger for my new 6V battery? (JR connection) Thanks!

RCKen

My Feedback: (9)

It depends on the output of a wall wart. If it is over 7.5 volts it will charge the battery. Some wall warts are, some aren't. I guess that I should have said that in my first post. I am sorry that I didn't clarify that point. But if the charger doesn't put out voltage as high, or higher, than the max voltage of the pack you will never be able to completely charge it.


Ken

goirish

Philips
Reading from the charger itself.

Standard charger
class 2 transformer
Model 24392
input: 120 vac, 60Hz-3W
Output 6vdc-100mA

TedMo

Just to expand on the reply you were given. RCKEN was correct but another consideration should also be taken into account. That is the capacity of the battery. To properly fully charge a battery they should be charged at 1C. That means if it's a 1500 MA battery pack it should be charged at 1.5 Ma. for 14 hrs., if it has been run down. For further more complete info on batteries and chargers check the bat./ chargers site.

goirish

I believe that charger came from Onlybatterypacks.com

capt17

Yeah I just checked my wall charger Ken and it outputs 5.8V so I need a new charger to fully charge. Will this work? [link=http://www.maxxprod.com/mpi/mpi-9.html]Wall Charger[/link] Halfway down the page CH72.

ply2win

My Feedback: (3)

This got me to thinking so I decided to go and check the charger. On the wall charger it says the output is 4.8V so based on that I would assume it can't fully charge the battery. However, I checked the voltage of the battery with the radio system on and it reads 6.53V. How is that possible?

iron eagel

The reason that you may see a higher voltage than the 4.8 volts spec. is: the voltage you are reading is a peak reading produced by a poorly filtered dc charger. The charger takes the 110 AC from the wall and steps it down to a lower voltage which is the rectified and filtered to produce the DC voltage. If you were to look at the output of the charger with a scope you would see the DC voltage and a series of bumps which is the ac peaks riding on it, these peaks is what your voltmeter is seeing. An if you are making the measurement without a load on the charger it will read higher because it is not loaded by the battery. If you put a load on the charger such as a lightbulb, resistoro or dead battery you will see the voltage drop, with a load which matches teh output current of the charger you will see the voltage at leaast close to the spec reading. Now this may or may not be close to the 4.8 volts depending on the quallty of the charger and its regulator setup, in most cases you will find it close but not exact.
When charging standard batteries close is good enough...

Li-pols, lithium ion and alike are more demanding thus the chargers are much more expensive.

If you have a good variable DC power supply with current limiting function this may also be used to charge your batteries but they are not cheap...

SBOT

Tedmo

For a 1500 ma battery 1c would be 1500 ma or 1.5 amps, a 1hr charge would do it at that rate or as most wall wart type charges do 150 ma for 10 hrs.

Oscar

Jetdesign

My Feedback: (8)

What if you adapt the radio side of the wall wart that is 9.6v, 70mah - will this charge a 6v battery? I would assume you wouldn't want to do this, but I don't know a ton about electronics.

iron eagel

The Ch72 says it will output 6 volts at .1 amps so it would take ten hours for a 1000ma, to charge it fully. If your pack is larger as pointed out it will take longer but it is simple to figure it out take the size of your pack and dived it by 100 (100ma=.1amp) so a 1400ma pack would take 14 hrs, a 1700ma pack would take 17 hours and so on. Keep in mind I think this setup is for Nicads only I am not sure if it works with NIMH type of packs. For 12 bucks I do not think it is one you could hope to use with all types of batteries. For around 50 bucks you can get a charger the will handle Nicads, NIMH, or Li-pols so you can do any type of battery except for Lithium Ion cells. But if you don't care to spend a lot the $12 should do the pack you have, the fifty buck set up you would have to switch to the proper settings, and if you have it set wrong you can cook things (battery/charger) or other things...
And you can also get chargers that do any battery and does so automatically but you can spend a lot on them but it is cheaper than having one charger for each battery type like I have done over the years.

iron eagel

You would have to have it set up so that you are not going to produce over voltage or current to the pack. you would need to have a voltage and current limiting circuit that you could set for the max voltage and current for the pack. It is far safer to get the right type of charger especially if you do not have an electrical or electronic background. I just bough a charger that auto detects the battery and does everything on its own myself and it was roughly around 100 bucks it is a triton if I recall, because I have all different types of pack for glow gas and electric planes.

JohnW

My Feedback: (6)

"On the wall charger it says the output is 4.8V so based on that I would assume it can't fully charge the battery. However, I checked the voltage of the battery with the radio system on and it reads 6.53V. How is that possible?"

NiCd have a nominal voltage of 1.2v per cell and a a fully charged voltage of abiout 1.4v per cell. A fully charged 5 cell pack has a nominal voltage of 6.0V and a fully charged voltage of 7.0V. The wall wart is rated for it's RMS voltage or average voltage, the peak voltage will be higher. Assuming a RMS of 4.8 volts, the peak voltage of the wall wart will be about 6.7V. This means in theory, assuming no losses, it could charge a battery up to 6.7V. Fudge the numbers a bit, account for losses, etc., and your packs get charged to the 6.53 volts you mentioned. While the 4.8v wall wart will work on 6V packs, 6.53V is not fully charged yet (but close) so it is probably better to use charger that outputs 6V RMS at current rating that is 1/10 the capacity of your battery.

-Cheers

Rodney

There is no clear cut answer as to Yes or No on using the charger normally used for the 4 cell batteries. It is easy to tell for sure if you have a voltmeter or multimeter. If the open circuit voltage is greater than 7.2 volts, it will charge the battery. Now, if you have the multimeter, measure the current that flows when you have the battery connected to the charger. If it at least 0.1C it will charge the battery fully, just take longer. How long? Divide the battery capacity by the current you read with the multimeter and multiply by 1.6 to get the hours it will take to fully charge the battery if it were fully discharged at the start of the charge cycle. It has been my experience that most of these chargers that come with a radio system WILL fully charge a 5 cell battery. Your batteries will also last longer (more charge/discharge cycles) if done at a lower rate of charge. The only reason for using a faster charge is if you are using a charger that depends on a voltage drop to trigger cutoff of the charger. Remember, to get that voltage drop, you had to intentionally overcharge the battery to initiate that voltage drop which in itself does a very minor bit of acceleration of battery deterioration internally.

TEBerg

My Feedback: (1)

I use the Hobico "Multi Charger" (http://www3.towerhobbies.com/cgi-bin...&I=LXL331&P=FR)for my 4.8 and 6.0 volt airborn packs. I also use it to charge my transmitter packs and even my 12 volt field box battery when I want too..

The simple explanation, just following the instructions, you match up your charging requirement based on the capacity (milliamps) of the pack and charge at approximately 0.1C for 14 hours..

I understand that it works for the different voltages because the voltage load is a lot less sensitive than the charge rate.. So, you can charge a 4.8 volt pack, your 6.0 volt pack and your 9.6 volt Transmitter all on the same charger by just setting the correct charge rate..

It's a great price, works great and I really like mine...

Disclaimer, I also check all my packs with the Futaba battery checker(http://www3.towerhobbies.com/cgi-bin...&I=LXEYM6&P=ML) to make sure this thing is doing it's job...