Chargers Just bought a charger.. Need some help.

I

Irishrover

Member
Hi there people.
I just bought a Robbe Power Peak C8 EQ-BID charger, not sure if you can get them in the states but they are German made distributed by he Align guys here in Austria.

Anyway the question is charging and discharging amps.

I have a LIGHTMAX 2100 35c Battery and need to figure out the charging amps.

The charger is good for 0.1 to 6.5a 110w charge and 0.1 to 5a (25 Watt) Discharge so what is the max amps I can charge and or Discharge these battery's at?

I remember seeing the math somewhere on line but cant find it again... and I am sure tony did a video on Battery's but I am not at my desk with a good internet connection.

If anyone has the formula can they share it please.
 
Tony

Tony

Staff member
To figure out the charging amp rate, at a 1c charge rate, you take the mah of the battery and divide by 1000. So a 2100 would be 2.1a. If you have a battery that can do a 2c charge, then it would be 4.2a max. There should be something on the battery telling you what amp rating to charge at. Hope this helps.
 
Tony

Tony

Staff member
Ah yes, thanks Sam. Do Not Discharge A Lipo unless you are storing it, then you only want to discharge to 3.8 volts per cell.
 
Tony

Tony

Staff member
Okay, so I worded that wrong lmao. Every time you put them in a heli or plane, or car, it's going to discharge them. So saying not to is kinda like saying don't use them lmao.

With NiCd or NiMh, you have to discharge them to a specific level, then charge them back up at a high amp rating where they are almost smoking hot when they are done. The reason for this is they will develop a memory over time, and if you discharge them half way, then charge them back up a few times, it will shorten the life to half the mah it had when new. Also, with these batteries, if you do a high amp discharge, then a high amp charge, you got more power out of them. I did this for years.

With lipo's, there is no memory, they will gain nothing by cycling them, and there is no need to discharge them under 3.8 volts per cell. Hope that clears it up a little lol.
 
RandyDSok

RandyDSok

Well-Known Member
breeze400 simply used a poor choice of wording... or perhaps I should say stated the issue incompletely...

A typical RC lipo ( there are other kinds ) should never be discharged less than 3.0-3.2 volts... I gave a voltage range because different experts claim different values.... I prefer to play it safe myself and try to not discharge a lipo below 3.2v when there is no load on it ( ie at a resting voltage )

As Tony said... when storing a lipo... it is best to leave it at 3.8v

and finally on the other end... never charge a lipo over 4.2 volts.... best practice is actually slightly less than this max value.

Following those guidelines should keep you from damaging the lipo and also help extend it's useable life.

Some safety tips... Always store or charge your lipo's in a firesafe container that is not sealed up... If it was in a sealed container and the lipo had a failure such as outgasing or catches on fire... the sealed container could cause it to explode since the gases would have no place to excape.

A lot of folks use an ammo box to store their batteries in and they work find but they do need to be unsealed and lined... the lining is to help prevent the battery from shorting out on the metal box. Removing the rubber seal found on the lid is typically enough to prevent an explosion if a battery were to fail. I don't have an ammo box... so I keep mine in a lipo safe bag and I store it on a large ceramic tile just in case. Other good ( and innovative ) storage devices... a charcoal grill, a terra-cotta flower pot or a couple of the terra-cotta saucers used for the flower pot ( one inverted over the other )... any high heat safe ceramic container ( again that isn't sealed up )...

It wouldn't be a bad idea to keep all types of batteries in a manner like I described since they all could fail ... it is just more important with lipo's since they aren't as stable as other more common battery types.
 
breeze400

breeze400

Spagetti Pilot
Guys you have to remember, if you runs lipo down past the limit, (3.0-3.2 volts pet cell), you can possibly damage the lipo or cause it to explode! All lipo chargers that I have ever messed with will auto shut down when charged! That's why you cant leave them unattended while charging. My spartan boat has failsafes built in to prevent you from discharging then to much. It will cut you to 20% power so you can bring it to shore! My align 600 same. Even my SR120 cuts power when discharged.
 
Morelight

Morelight

Fearless Freep
so far I'm charging my lipo's at .7 A max for a balanced charge. i always charge balanced. my batteries are always cool when charging to full, and never puff or swell. i use jumbo lipo safe bags and put the bag on a large ceramic plate, 5 ft. from a fire extinguisher and a window. who said Canadians can't be paranoid too?
 
Tony

Tony

Staff member
Are you only charging a 700 mah battery? If your battery is bigger than that, you can charge more than that. When I get my mcpx batteries, and the lead from Gaba, I will be charging my 1s batteries at 1.8 amps. I could safely go to 2 amps if I so wished. And this is with the little micro batteries in parallel totaling 1800 mah each charge.
 
Morelight

Morelight

Fearless Freep
I was also charging 1800mah 11.1v 3s 35C batts that way also. took about 2 hours. what would be a good setting for 5000 mah 6s 22.2 v 35c batts Tony?
 
Tony

Tony

Staff member
If your charger can handle it, 5 amps if it's a 1c charge rate battery, or 10 amps if it's a 2c charge rate. This means your charger has to be able to handle either 130 watts for 5 amps, or 260 watts for 10 amps. Not all chargers can do that. Most are rated for 100w max.
 
Morelight

Morelight

Fearless Freep
i'm going to get these battery's: TGHL50006C35 - G3 Li-Po 22.2V 5000mAh 6S1P 35C @ Great Hobbies and this charger for my blade 500 and chaos 700: http://www.greathobbies.com/productinfo/?prod_id=GPMM3156
I've decided what I want to do the 700 build with : this kit from RC Aerodyne : Chaos 700 Electric Flybarless Kit (Scorpion Edition) - RC Aerodyne | Scale R/C Helicopters, Airplanes & Parts Store and these parts to finish the build. Hope to have the money by May latest.

FUTBLS251 Servo Brushless Heli Rudder 149.99 149.99 Info
FUTBLS351 Servo Brushless Hi-Torque 149.99 449.97 Info
SPMAR7200BX AR7200BX 7Ch DSMX Flybarless System Heli Receiver 239.99 239.99 Info
SPMR8800 DX8 2.4Ghz DSMX/DSM2 TRANSMITTER ONLY 349.99 349.99 Info
TGHL50006C35 G3 Li-Po 22.2V 5000mAh 6S1P 35C 117.99 707.94 Info
 
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Morelight

Morelight

Fearless Freep
Yeah but Great Hobbies build quality stuff or put their name on it I guess. I'm buying expensive stuff because I went cheap on that 400 class heli thats now gone bye bye to "the farm".

Normally when I buy things, I try to buy a bit more quality which usually results in more money.
 
Tony

Tony

Staff member
I have been using the SkyCharger B6AC (the AC6 is the same, just a little cheaper now) from hobby partz and it's doing great. Only downside is the 50w max on the power supply. But, they have others with a 100w power supply. And, I have charged 6s packs on this charger without fault.
 
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