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LiPo Charger & Charging Questions

Posted: Tue Feb 07, 2012 1:33 pm
by LTO_Dave
The time is finally here...I'm going to LiPo. :lol:

After looking for a charger, the MRC Super Brain 992 Palm seems like a good choice for me. But I'd like to know if it will be capable of charging my LiPo's.

http://www.modelrec.com/search/product-view.asp?ID=11405

It's AC/DC, which I prefer, and charges up to 5A at 50W max. I have a TrakPower 2S 4800 20C saddle pack. If I charge it at the 1C rating of 4.8A, will that be over-working this charger??? I don't really plan to charge anything crazy like a 2S 6500 60C battery, so would this charger be good enough for batts under 5000 mah?

Also, instead of balancing both cells at the same time while charging, can I just set the charger to 1S and charge each cell separately at the same 4.8A??? Or what voltage would I use for 1S?

Any help would be appreciated for this LiPo n00b. :mrgreen:

Re: LiPo Charger & Charging Questions

Posted: Tue Feb 07, 2012 7:00 pm
by lpddpd
Still learning myself, but I am starting to wish for a 6 amp charger, just for the purposes of charging some of the larger capacity batteries at 1C rather than below. (It is ok to charge a 5300mah battery with a 5 amp charger right?) I have a Venom saddle pack, but I don't charge the cells separately. But, I don't know enough about the lipo voodoo to tell you why or why not to charge individually. Hopefully someone else here can.

One thing I can tell you, is on my charger (Racer's Edge Surecharge 2000) the charge wire leads are long, but the wire for the balancing card is short. Makes it hard to get the battery into a lipo bag.

Re: LiPo Charger & Charging Questions

Posted: Tue Feb 07, 2012 7:06 pm
by Coelacanth
I thought the general rule of thumb was, charge your battery according to the final mAh rating. I charge my 4600 mAh Gens Ace batteries at 4.6A. My charger is an iMax B6AC (version of the B6 that includes the 120VAC adapter). I'm a relative LiPo n00b myself but it seemed pretty easy.

Re: LiPo Charger & Charging Questions

Posted: Tue Feb 07, 2012 7:16 pm
by Goatless

Re: LiPo Charger & Charging Questions

Posted: Tue Feb 07, 2012 7:36 pm
by lpddpd
Goatless wrote:I have the Racers Edge Sure-Charge pro

http://www.google.com/products/catalog?rlz=1C1RNPN_enUS436&q=racers+edge+charger&um=1&ie=UTF-8&tbm=shop&cid=7316533994135393432&sa=X&ei=sL0xT9DuL4L5ggfshJSOBQ&ved=0CHMQ8wIwAw

Great charger for the price AND it comes in a fancy aluminum carrying case :lol:
Ya, that's the one they came out with after I got mine. That one goes to 8 amps?

Re: LiPo Charger & Charging Questions

Posted: Tue Feb 07, 2012 8:35 pm
by LTO_Dave
Well, I just bit the bullet and placed an order from A-Main. I got the MRC charger, LiPo bag, PureTech straps, bullet connectors and RPM rod ends for under $100 with free shipping. And I just bought a second new TrakPower 4800 saddle pack for cheap.

I think after LiPo, I'm going to go with a 2.4 setup and then brushless.

I'm getting my runner RC10 ready for the new batteries. I moved the ESC, receiver and antenna after removing the old PureTech strap. Now I have to fab some type of LiPo tray/holder to keep them in place side-to-side.

Re: LiPo Charger & Charging Questions

Posted: Tue Feb 07, 2012 8:38 pm
by Goatless
Very nice! I love my brushless and lipo's. The power/runtime have been amazing. Used to, I could tell after a few minutes my packs were running down, especially on straight-aways. Not with lipo's. Sometimes I can go 2 heats on the same pack.

Re: LiPo Charger & Charging Questions

Posted: Wed Feb 08, 2012 12:11 pm
by THEYTOOKMYTHUMB
Coelacanth wrote:I thought the general rule of thumb was,
Actually my general is: Never get involved in a land war in Asia. :wink:

Dave, I don't know of any way to charge the cells separately. I believe they are wired so they have to be balanced together. I balance mine every time I charge them because the plug is right there, but some guys only balance theirs every 6 months or so.

Well I should say I balance them all every charge except for the Slider, but that's because it takes an act of Congress and a Voodoo Sorceress to get the battery out. :roll:

Re: LiPo Charger & Charging Questions

Posted: Wed Feb 08, 2012 1:07 pm
by LTO_Dave
THEYTOOKMYTHUMB wrote:[Dave, I don't know of any way to charge the cells separately. I believe they are wired so they have to be balanced together. I balance mine every time I charge them because the plug is right there, but some guys only balance theirs every 6 months or so.

Well I should say I balance them all every charge except for the Slider, but that's because it takes an act of Congress and a Voodoo Sorceress to get the battery out. :roll:

The TrakPower saddle packs aren't actually hard-wired together. They're just a 1S + 1S with a jumper wire connecting the two cells. And if you look at the pic, you can see the small 2mm female bullet connector for balancing on the right above the 4mm connector.

Image

I've read you can just charge each cell separately instead of charging and
balancing both at the same time, but it will take longer. If I would balance the pack, I have to buy an adapter that has a Deans plug on one end, and two 4mm bullet connectors, one 2mm bullet connector and a balancer plug at the other end.

I'll have to wait until I actually get my charger to see exactly what balancer plug it takes since there are several different ones and no industry standard. :roll:

Re: LiPo Charger & Charging Questions

Posted: Wed Feb 08, 2012 1:34 pm
by Coelacanth
Does the "balancer plug" actually detect cell balancing? I seem to remember in my B6 manual that this is just for thermal detection. I can balance-charge with a Duratrax Onyx 230 charger and it lacks that plug entirely. I think that plug is only to determine if a battery is getting too hot....please correct me if I'm mistaken.

Re: LiPo Charger & Charging Questions

Posted: Wed Feb 08, 2012 1:50 pm
by LTO_Dave
Coelacanth wrote:Does the "balancer plug" actually detect cell balancing? I seem to remember in my B6 manual that this is just for thermal detection. I can balance-charge with a Duratrax Onyx 230 charger and it lacks that plug entirely. I think that plug is only to determine if a battery is getting too hot....please correct me if I'm mistaken.

I'm fairly certain it's for a balancer wire after doing some online research. Since the saddle packs don't have the 2mm connectors integrated into the cells like the 2S stick packs, the center wire is used to make a connection between the two and balance them. Here's a pic of one hooked up to a TrakPower balancer:

Image

And here's an adapter plug I can use once I figure out what connector is on the charger:

Image

Re: LiPo Charger & Charging Questions

Posted: Fri Feb 17, 2012 4:00 pm
by LTO_Dave
Ok, I received my MRC charger today and have a question before I attempt to charge my first LiPo...

I have a TrakPower 2S 4800 20C saddle pack as listed above. I'm planning to charge each cell separately so I don't have to balance the pack.

Should I set the charger to the 1C charge rating of 4.8A and 1S, and not charge them above 4.2V per cell???

Any help would be appreciated. :mrgreen:

Re: LiPo Charger & Charging Questions

Posted: Fri Feb 17, 2012 7:07 pm
by THEYTOOKMYTHUMB
LTO_Dave wrote:Should I set the charger to the 1C charge rating of 4.8A and 1S, and not charge them above 4.2V per cell??
Sounds fine, but I think you're over-complicating it and I'm still not sure they'd be balanced in the charger's eyes. Do you have a balancing board with a matching tap? If so, I would just hook it up as 2s and charge at 4.8A. Just my .02 though. :)

Re: LiPo Charger & Charging Questions

Posted: Fri Feb 17, 2012 8:07 pm
by LTO_Dave
THEYTOOKMYTHUMB wrote: Sounds fine, but I think you're over-complicating it and I'm still not sure they'd be balanced in the charger's eyes. Do you have a balancing board with a matching tap? If so, I would just hook it up as 2s and charge at 4.8A. Just my .02 though. :)

I'm thinking that as long as the charger charges each cell to the cutoff voltage or 4.2V of whatever it is, then both cells should be at the same voltage if they're charged separately or together...it may just take a little longer to charge. Doesn't balancing a pack just ensure that both cells reach the same cutoff voltage while being charged together, like if you had a 2S stick pack in which the cells are connected together? :?

The charger did include a small balancing board, but in order to balance them I'd have to buy a balancing cable like the one I linked to above. And I don't really know which balancing connector it would need to plug into the balancing board. :?

Re: LiPo Charger & Charging Questions

Posted: Fri Feb 17, 2012 8:25 pm
by slow_jun
Just charge them at the same time and use the balancing cables, thst way they will charge at the same voltsge and at 1C, not sure about your charger but some charger dont allow charging single cell, something about having cell balance, well thats what i learn from my charger... That is 3 years old.... Your connection seems to be correct, just dont forget to place em inside the bag if your not yet comfortable charging lipo... And and and.... Dont leave em unattended.