Noob question re lipo charging

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Xanda2260   100 W

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Noob question re lipo charging

Post by Xanda2260 » Feb 20 2012 2:36am

Hey guys, apologies if this is already posted. I have read every lipo thread I can find and am still unsure. If anyone has a link to the relevant thread, that would be awesome.

Ive just ordered up 6x 6s 5ah turnigy packs from HK. Now I'm wanting to bulk charge most of the time using a BMsbattery charger BUT, Im thinking I may need a normal RC balancing charger. i'll be getting some batt medics, and I know they can be used for balancing. My problem is, what if my packs arrice with some low cells? I cant bring cells up using a batt medic, so I would need to be able to charge the individual cell. Does this sound right? I'm gonna need an RC charger as well as the bulk charger?

I do have a variable power supply lying around (low power), would it be possible to use that to charge any low cells, avoiding the need for a seperate balance charger?

Many thanks in advance guys!

Alex
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miuan   10 kW

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Re: Noob question re lipo charging

Post by miuan » Feb 20 2012 2:58am

I've been living without a balance charger for years now. All I need for balancing are halogen bulbs, cell phone charger, and a reliable timer. With battery medics, you are totally safe. I also have some, but still prefer to do the job myself, so I use them just for voltage checking. I recommend one of these too, clamped to your stem: http://www.ebay.com/itm/270918541287? if you don't already use some other kind of meter.

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neptronix   100 GW

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Re: Noob question re lipo charging

Post by neptronix » Feb 20 2012 5:26am

i'm sorry but you're not totally safe if you're starting out with iffy packs...

Think about this, the battery medic is discharging at 300mA on one cell, but the bulk charger is putting in 3-8A..
It would take a very long time to get a cell down from >4.2v...

Do not skimp on the battery balancing hardware, especially when you are dealing with the most dangerous / volatile battery chemistry available. I strongly suggest something like an iCharger or hyperion 1420 ( 14S charger ) to start out.
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Scottyf   100 W

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Re: Noob question re lipo charging

Post by Scottyf » Feb 20 2012 8:18am

Probably best to get a cheaper 6s Lipo Balancer. Even a 50w Dual power one will be ok (Although slow) to balance each individual pack.
There all pretty cheap and even in the UK from a UK supplier they cost about £40.

In the USA it will be much cheaper. An even cheaper from Hobby King.

There handy to have as a charger anyway as you can charge pretty much all chemistries safely.
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dogman dan   100 GW

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Re: Noob question re lipo charging

Post by dogman dan » Feb 20 2012 8:29am

Personally, I think it's a good idea to have at least one RC charger around the house. If you want to bring up a low cell, it's just so much easier to hook an RC charger to just that cell through the balance wires, and then walk off knowing the charger will stop when you want it to. I nodded off one evening doing the cell phone thing, and sure enough ruined a pack. Yeah, a timer should have been used. But the RC charger is much more reliable.

One note, keep the amps low when charging a single cell through the balance wires. 2 amps max. The nice thing about the RC charger is it keeps it safe, by tapering the amps way down as the charge gets close to termination. The cell phone charger just keeps blasting it with 2 amps.

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Ykick   100 GW

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Re: Noob question re lipo charging

Post by Ykick » Feb 20 2012 9:30am

dogman wrote:Personally, I think it's a good idea to have at least one RC charger around the house. If you want to bring up a low cell, it's just so much easier to hook an RC charger to just that cell through the balance wires, and then walk off knowing the charger will stop when you want it to. I nodded off one evening doing the cell phone thing, and sure enough ruined a pack. Yeah, a timer should have been used. But the RC charger is much more reliable.

One note, keep the amps low when charging a single cell through the balance wires. 2 amps max. The nice thing about the RC charger is it keeps it safe, by tapering the amps way down as the charge gets close to termination. The cell phone charger just keeps blasting it with 2 amps.
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spinningmagnets   100 GW

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Re: Noob question re lipo charging

Post by spinningmagnets » Feb 20 2012 9:40am

Heres what I'm using, inexpensive but "light duty", no problems so far...
http://endless-sphere.com/forums/viewto ... 65#p341300

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Xanda2260   100 W

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Re: Noob question re lipo charging

Post by Xanda2260 » Feb 20 2012 10:26am

Cheers for the advice guys.
Seems it is possible to do without, but not easy or advised.
Since I'm a total noob to the lipo scene, I think I'll pick up a cheapy 50w balancer, and grab a bulk charger as well.

Many thanks!

Alex
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mxer   1 kW

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Re: Noob question re lipo charging

Post by mxer » Feb 20 2012 10:51am

miuan wrote:I've been living without a balance charger for years now. All I need for balancing are halogen bulbs, cell phone charger, and a reliable timer. With battery medics, you are totally safe. I also have some, but still prefer to do the job myself, so I use them just for voltage checking. I recommend one of these too, clamped to your stem: http://www.ebay.com/itm/270918541287? if you don't already use some other kind of meter.

I have one of these, but i struggled to find a 5v source from an external battery, Unless you have an alternative ?....

As for bulk charging my little 400w BMS charger is Fantastic!!!, But as above alway's handy to have a ballance charger hanging around if need be, There is an icharger in the forsale section atm from a member which is new and is the best/trusted ballance charger on the market, and the best thing it's at a great price.... :D


Edit, I can't see it anymore :roll: , Diddn't think it would hang around long, You can't go wrong with an icharger as you proberly know

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Ykick   100 GW

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Re: Noob question re lipo charging

Post by Ykick » Feb 20 2012 12:41pm

I keep repeating YES to the good info here but I'm a huge fan of the iCharger and it's the best tuition money you'll ever spend to better understand practically all major types of batteries. Once you have one, start looking around at old device packs (cameras, phones, laptops, UPS, etc) figure out connections and learn. Once dead Laptop packs are fun to reconfigure into small 12V bricks for lighting and/or automotive accessories.

Last year I revived my dad's digital camera Lipo battery that had puffed slightly and resting at 0V. With a little ingenuity and the iCharger we managed to get it working enough for a weekend outing. Everybody was impressed that they even made such a thing as the iCharger.
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Xanda2260   100 W

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Re: Noob question re lipo charging

Post by Xanda2260 » Feb 20 2012 1:48pm

Ykick wrote:I keep repeating YES to the good info here but I'm a huge fan of the iCharger and it's the best tuition money you'll ever spend to better understand practically all major types of batteries. Once you have one, start looking around at old device packs (cameras, phones, laptops, UPS, etc) figure out connections and learn. Once dead Laptop packs are fun to reconfigure into small 12V bricks for lighting and/or automotive accessories.

Last year I revived my dad's digital camera Lipo battery that had puffed slightly and resting at 0V. With a little ingenuity and the iCharger we managed to get it working enough for a weekend outing. Everybody was impressed that they even made such a thing as the iCharger.
Thats impressive! Think I'll be getting an icharger then!

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Xanda2260   100 W

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Re: Noob question re lipo charging

Post by Xanda2260 » Feb 26 2012 12:46pm

Hey guys, got another question for you. Apologies if its out there already.

Got 6 6s 5ah turnigy packs which will be running in 18s2p config for 66.6v and 10ah. For charging Im planning on using something icharger esque, and will parallel the packs 6s 6p for 22.2v and 30ah when charging. I intend to parallel each 2pack subgroup (6s 2p) at the balance taps, giving me 3 balance taps that will need paralleling in order to balance charge the whole 6s 6p pack.
As I understand it, i can't leave all 6 packs paralleled at the cell level when I connect for 18s, but i can leave the two subpacks paralleled that way (and through main leads).

Does that sound right? Have i missed something?
Gone over it again and again and read every thread I can find, but I have zero experience with this stuff and would really appreciate some of our more experienced members offering their opinion.

Also, if anyone has a link to a good lipo thread I'd appreciate it.

Many thanks guys

Alex
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NeilP   10 GW

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Re: Noob question re lipo charging

Post by NeilP » Feb 26 2012 1:09pm

Yes, sounds correct.

If ever you are unsure when connecting two wires together, either check the voltage between them first or cheaper and simpler. bridge the two wires first with a short length of very thin wire (fuse wire) ...a thin single strand of wire from a multi core piece will do. If it melts immediately you connect the two wires with it..you know you have something wrong
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Xanda2260   100 W

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Re: Noob question re lipo charging

Post by Xanda2260 » Feb 26 2012 4:34pm

Cheers Neil! I'll go ahead with that then. Nice tip with the voltage checking too.

Many thanks
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Re: Noob question re lipo charging

Post by NeilP » Feb 26 2012 4:49pm

yea, if you do not have a volt meter and are still unsure you have traced the wires correctly, zapping a short length of wire is better than zapping a balance lead all the way down tho inside the pack
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