# Lipo and charger need help please.



## dakotanut (Apr 6, 2009)

Just got my new charger and Lipo battery. It is a 2 cell 4000 mah 25 C battery. What all do I need to know to charge it? Like should I balance charge it, fast charge it, just charge it or what? I don't want to screw this thing up. Thanks. I keep missing the race at river race track. If I don't get called out again?!.


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## GoFaster (May 4, 2005)

charge it no faster than 2.5 amps one tenth the C rating.

Balance charging is always good but not necessary all the time.


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## sixshootertexan (Nov 27, 2006)

What charger is it?


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## Courtney Vaughan (Apr 11, 2007)

I disagree with Ron......you can charge most of the newer 25C batteries at 3.5 to 4 amps.

balance/charge it once every 5-6 charges and you should be fine.

ditto.......what charger do you have? if it's a hyperion, it will decide for you.


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## GoFaster (May 4, 2005)

Courtney Vaughan said:


> I disagree with Ron......you can charge most of the newer 25C batteries at 3.5 to 4 amps.


I'm just skeered.  Don't want to burn down my house. lol


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## Courtney Vaughan (Apr 11, 2007)

i remember when the rule of thumb used to be 1/10 of the C rating, but now it's getting down into the 1/6 to 1/8 of the C rating.....and the newer technology batteries/chargers will be around half of that!


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## sixshootertexan (Nov 27, 2006)

Correct CV my Triton Jr decides for me according to the Mah size.


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## Courtney Vaughan (Apr 11, 2007)

GoFaster said:


> I'm just skeered.  Don't want to burn down my house. lol


Don't be skeered Ron! You can charge that Slash battery at 4 amps and it probably won't eve be warm to the touch when you're done charging it, and will take nearly half the time.


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## dakotanut (Apr 6, 2009)

I got a Turnigy Accucell-6 and a Zippy 4000 mah 2s1p 25c Lipo battery. When I go to charge it, the charger only shows .1 amp. I was wondering if that was low or what. What would I discharge it at using the charger? How do you know what C rating is what. Can yall give me an example. If I'm right, 25C x 4000= 10,000. Whick is the C rating right? I'm confused. I need math to explain this. What if it was a 1500 mah battery w/ a 30C rating?


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## Courtney Vaughan (Apr 11, 2007)

the problem is that the math doesn't line up from generation to generation of lipo batteries. We're on about our 3rd generation of lipo technology, and each generation uses different formulas. Check out RCTech.net in the brushless forums and there are about 100 different explanations, and they're all a little different. 

a 25C or 30C battery can be charged at around 3-4 amps......I'm telling you this based on current experience with current products.

Disclaimer: There are about 20 other settings on your charger that could be tweaked wrong if you don't know what you're doing, so don't blame me if you damage something! Hint: one of these other settngs being incorrect is probably why it's trying to charge at .1 AMP

You might google search for one of the Hyperion charger manuals....they have some decent explanations in them.


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## dakotanut (Apr 6, 2009)

I can change the setting from .1 amp to I think 10 amps. Maybe 5 amps. I don't remember. So basically, I should set it to 4 amps and 7.4 volts which is a 2s. Charge it just normally not fast and then balance it every 5 times? How about initial charging and all of that?

I went to rctech.net and didn't find anything on brushless.


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## Courtney Vaughan (Apr 11, 2007)

with a couple of lipos that I bought for my 1/18 scales a couple of years ago, the first few charges didn't seem to hold voltage quite as long, but after that they were fine. With my recent lipos, the first charge was as good as any charge. So there's nothing special you need to to for the first few charges.

4A 7.4V is what I would use. I run mine anywhere from 4-8 charges throughout a race day, and in between races I do a balance charge.......have not yet had any issues out of any of my lipos.

go to the electric off-road forum on RCTech and search for "lipo charging rates" that brought up about 20 pages of threads.....it'll be up to you to search through them, and you'll see what I mean about the different opinions. I can show you where MaxAmps says it's ok to charge a 25C 4000MAH battery at 8A as long as you use a balancer, and then I can show you where other people say that will fry your battery and make it catch on fire......there's not a lot of consistency. 

BTW, all the batteries I've bought have had at the very least a small piece of paper or a label stuck on them that has the charging capabilities on them. For example, my latest battery says not to charge at a rate higher than 1C.....it's a 5000MAH battery. One bit of math that hasn't changed over the last few years is that when they give you a .5C, 1C, 2C, etc charge rate (not to be confused with the instantaneous discharge rate i.e. 25C, 15C, 30C, etc), that is 1/10 of the battery capacity. So, my latest battery said on the small piece of paper to charge it at 1C. 1C x 5000MAH = 5 amps charge rate. Does your battery, package, or label say anything similar? Last year, I had a couple of 2000MAH 20C batteries, and they said to charge at 2C. 2C x 2000MAH = 4 amps charge rate. See....not a lot of consistency.


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## nik77356 (Jun 8, 2007)

For normal charging, you should charge a lipo at 1C. 1C is equal to the Ah rating of the battery. 4 Ah (or 4000mAh) would warrant a 4 amp charge rate, 6 Ah (6000mAh) would be 6 amps, and 2.5 Ah (2500 mAh) would be 2.5 amps. Some lipos have come out that are capable of 2C (twice the Ah rating of the battery) or even 5C (5 times the Ah rating of the battery!) charge rates. While those rates are not the best for the life of the battery (and sometimes not even recommended by the manufacturer) you can charge them at those rates.

As to balancing, I would recommend balancing every charge. As Courtney stated, you can get away not balancing every charge but only on 2s batteries. Once you start charging batteries with more cells in them, you HAVE to balance them every charge. I really don't see why you wouldn't balance a battery every charge since most chargers now have a balance charge feature built in. And for those that don't, you can get an Astroflight Blinky balancer for around $30.


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## Courtney Vaughan (Apr 11, 2007)

good point Nik.....I have never used more than a 3S battery.


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## dakotanut (Apr 6, 2009)

Thanks Courtney. That was a tremendous help. I'll have to rep you now. I can understand that. I'll have to look at the battery and see. It didn't come with any literature. I had to download the manual for the charger from their website. I'm in the process of converting a PC power supply for the charger. Shouldn't take me very long. OH. Thanks Nik also.


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## dakotanut (Apr 6, 2009)

I was curious of the charge rating so I went to the site and got the info. It says maximum charge rate (C): 2 Does that mean I can charge it at 8 amps? Isn't that kinda high?


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## nik77356 (Jun 8, 2007)

Yes, that means you can charge it at 8 amps. I really wouldn't recommend that you do as it shortens the life of the battery.


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## Courtney Vaughan (Apr 11, 2007)

I can't say I'd recommend that either......I wouldn't go over 4A, or maybe 5A if I was in a hurry.....and I'd for sure be using the balancer if I was charging that fast.


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## dakotanut (Apr 6, 2009)

Ok! That is what I wanted to know. Sorry for all of the questions. I'm new to these batteries. NiCd and NiMh aren't this hard. I'll get it with yall's help. I sure appreciate it. This is what keeps me here. Other forums just don't give out the help like yall do.


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## nik77356 (Jun 8, 2007)

No problem dude! Glad to help. We were all in the same position at one time.


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## dakotanut (Apr 6, 2009)

That is good to know. If it was Nicd's or Nimh's, then I wouldn't be here asking yall and bugging yall. I read and get told so many different things about Lipo's and the chargers for them. Everyone has their opinions. You know what they say about opinions?


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## dakotanut (Apr 6, 2009)

Just an update. I was looking the battery over and it says never to charge it above 1C. So 4 amps is what I will set it at and leave it. I can set my charger up for more than 1 battery. I think it has like 10 memories for different batteries. I just got a Deans male plug so I can use it. Now just need and LVC. So many projects, so little time.....and money!


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