Rookie to electric R/CNeed Help?
 

I have used Nitro R/C cars fro over 10 Years. I'm trying electric and have NO CLUE on how to charge the batteries. The charger I have is a dynamite VIsion Peak Ultra. I understand there is Nicad, Nimh, and Li-po. I know Li-po is a whole differnt ball game tahn the other two. The battery I want to charge is a 7.2 v 110mAh NiMh. How do I know how many AMps to charge the battery?? I can choose between 0-5.0. Is there a set standard. Also as the battery is charging it shows the voltage. It will read as high as 10 volts. How could this be the battery is only 7.2 volts. I need help with the basics. Please reply, I really want to like electric, but do not understand the battery deal. Thank you![:o]

RE: Rookie to electric R/CNeed Help?
 

Did you mean 1100 mAh capacity? Is this a main battery pack for a car or an airplane pack or what? Generally for lower capacity NiMH cells like that, stick to a charge rate of maybe 1 or 2 amps (max). Someone else can be more specific possibly. I charge my GP3300 car packs at a full 5 amps and it's fine for them, but smaller cells like yours don't like to be charged that fast.

7.2 volts is the nominal voltage rating for your battery pack. A fully-charged battery will actually have higher voltage than its rated voltage. Additionally, when the charger is forcing current into the battery pack during the charge process it "sees" a higher voltage than the pack will actually be at when you take it off the charger. 10 volts still seems a bit high, though. I'd expect more like 8.5 to 9.0 volts for a 7.2v pack (or thereabouts). When you take the pack off the charger and measure the pack voltage with a meter, it will show lower than what the charger said.

Another thing to consider is the peak threshold. This is the voltage drop that the charger looks for before it stops the charge. As a battery is fully charged the voltage actually drops slightly, which the charger can sense. If you set the peak threshold too high, though, the charger can overcharge the battery. This could be the reason why your pack reaches around 10 volts during charging. Your charger may do it automatically, I don't know about that one. But check for the peak threshold setting, and make sure it is set to 5mV OR LESS per cell. That will be good for NiMH.

RE: Rookie to electric R/CNeed Help?
 

Yes I did mean 1100mah. The battery is for a Duratrax Quake. A Tiny Truck!! I also have a brushless Rustler with bigger batteries. I checked for a peak threshold setting, and there is none. I really appreciate the reply. It helped a lot. So bigger packs for the rustler can be charged at a full 5 amps! That good to know because I was charging them @ 2.5 and it was taking forever! Thanks again!

RE: Rookie to electric R/CNeed Help?
 

hey i had a question i have a helicopter that every time i fly it the lipolys fill with air and then the swelling slowly goes down does anyone know what causes this?

RE: Rookie to electric R/CNeed Help?
 

1A for the 1100mAh - that's what they call 1C (or close). 1C charging is preferred. Higher than 1C could shorten the life of the battery - or worse, cause a cell to burst if too high. Someone here reported trying to charge such batteries (2/3 A cell) with 5A and blew up a cell. At most, use 2A for 1100mAh batteries but 1A is preferred.

RE: Rookie to electric R/CNeed Help?
 

Is a good rule of thumb to charge the battery according using a "amps =maH" For example a 5000maH, cahrge at 5 amps and 1100maH cahrge at 1 amp? Is this a good theory, or am I way off?

RE: Rookie to electric R/CNeed Help?
 

amps = mAh - that's pretty much the 1C rule. You can go hotter in terms of say charging a 4500 mAh battery at 6Amps for "fast charging". Some will say charge at 1/2C (which is 2A for a 4000mAh battery) to help with longevity of the battery. I kind of baby my batteries and charge at 1C or lower - have them in good shape after a season of racing (NiMH, mainly 4200IB and 4500Elite and Tenergy Propel).

RE: Rookie to electric R/CNeed Help?
 

I'm assuming you have NiMh batteries. With NiMh you'll want to charge the 1100MAH batt. at 1.1 amps max. Charging at any more than that harms the battery and will shorten the life. Lets say you have a 4200MAH NiMh, same math, charge it at 4.2 amps max. You can also charge them at a lower rate too. This will help to increase battery life, but it will take longer to charge. I generally charge my 4200MAH NiMh's at 3.5 - 4 amps, but if I'm in a real hurry I charge at 4.2 amps. Their is also such a thing as "form charging". I would advise you to take some time and read through several of the other threads. Look for titles like, "cycling", "form charging", "charging and discharging", etc... All of the questions you have have been covered in here many times. In fact many of the questions you have will have answers in recent threads. Good luck educating yourself. If you have any questions the other threads don't answer, post them.

RE: Rookie to electric R/CNeed Help?
 

Its called puffing. There is a few reasons lipos puff when used. Pack imbalance causing over discharge or just an over discharge in general, to high of an amp draw for the pack, or the pack getting to hot. What ever the reason is, your pack is getting ready to go. May last another month or may no last the next use. Be careful with it.

RE: Rookie to electric R/CNeed Help?
 

I bought a rtr 1/16th electric with a 7.2v battery (1800mah). If i get a higher voltage, will it make my buggy go faster? I have a VERY basic charger. How long should i charge it? help me please. BTW im 12, this is my first ever rc buggy.

RE: Rookie to electric R/CNeed Help?
 

Yes, a higher voltage battery (8.4v, 9.6v) will make it go faster. You need to know that your ESC (Electronic Speed Control) can handle that voltage first. MAH means miliamp hour, this determines how long the battery will last. The bigger the MAH number, the longer you can drive your car. Voltage is what controls the power. What kind of charger do you have? Timed, peak?

RE: Rookie to electric R/CNeed Help?
 

I do not know what kind of charger. I think timed becuase it isnt very fast. And thanks for the reply you helped alot. How do i find out if my esc will handle it?

RE: Rookie to electric R/CNeed Help?
 

You'll have to look in your manual or go to their website in order to find out what your ESC can handle. If you can't find it anywhere call the company and ask Customer Serivce directly. If it's a timed charger you will put the battery on the charger and have to crank a time switch (like an egg timer) and then it will charge. If it's a peak charger you will have to plug the battery in and select what kind of battery and hit start. If it just plugs into the wall and has no buttons you just plug the battery in and it charges. This kind of charger is known as a wall wart. If you have a WW I would suggest saving money for at least a cheap peak charger. They can be had for around $30-40. What brand is your RC? Their may be a thread on this forum dedicated to that kind of brand where others may be able to tell you what your ESC limit is.