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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Tim Stagg on June 22, 2017, 12:42:15 PM
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guys,
I am currently using (2) Thuderpower 3S batteries in series to make a 6S pack. I am currently charging them separately as (2) 3S packs and balancing them as specified.
Question: can I charge them in series @ 6S and how to I balance them when they each have their separate balance plugs? can they be wired together somehow?
or is this just a bad idea.
I am trying to get rid of excess wire and weight ion the battery compartment.
Thanks
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Not sure exactly what your are doing in the plane, but in sounds like using 2 packs of 3 cells to make a 6 cell pack. Perhaps for balance or room. I'm not sure about weight/wire in the plane part. I assume a Y type joiner for the power side of the batteries.
Are you removing the batteries to charge and then parallel charging, or single charging?
Are you trying to charge in the plane, or out, with a single charger as a 6 cell pack?
If you want to join the balance plugs to one, try this
http://www.ebay.com/itm/JST-XH-6S-TO-2x-3S-BALANCE-SERIES-Harness-ADAPTER-CHARGE-AS-6S-Lipo-battery-/272099458882?_trksid=p2385738.m2548.l4275
You could hard wire the two into a single pack by soldering up your own Y for power and balance, but again not sure what you want to do. It seems easy enough to take them out, unplug the series, and charge them together on a parallel board.
Add more info about your connections if I totally missed the point.
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If you have a 6S balance charger you could make a Y adapter harness and tie the two 3 cell balance plugs into a 6 cell balance plug. Takes some knowledge of how to wire the plugs but it can be done. y1 Just remember LiPo batteries pack a punch. If you short something out it can get real bad in a hurry. n1
PS What the previous post said. A ready made up Y harness will do the trick.
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Sorry for the confusion
I already have a wire harness for the series connection that I have been using to make the (2) 3S packs work like a single 6s pack. The problem is the harness and the battery leads take up a lot of room in the airplane not to mention that 1/2 ounce of weight I could save eliminating the extra deans plugs and wire for the harness.
What I would like to do is hard wire the two 3S into one 6S battery. I can make the power connections work properly, my problem is I dont know how to make (2) 3S battery balance plugs into one 6S balance plug...or even if it can be done.
Thanks and sorry for the lack of info
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Look at the Y harness in the link and follow what they did. You are in essence joining a ground of one to the last cell of the first, floating the ground. You can follow that in the plug made. That plug is small wire and not much weight, probably the easiest to use. It doesn't need to be joined in the plane, the balance plug is not connected, it is open ended, in the plane. Join them out of the plane for balance charge if that is what you are trying.
Make sure that you float the ground on the same pack as you did with the power leads, or you can get burned. Pun intended.
If you can't visualize the connections from looking at the harnesses, then you may not wish to try to solder it up.
Of course you can remove the covering and join at the cell solder connections and make a 6 cell pack and then re-cover. That is the least wiring weight but most work and supplies, unless you have that size shrink laying around.
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A few alternatives after re-reading what you are doing. It seems that there are two separate issues, weight and charging.
A simple solution to charging is to use the packs as you are and then remove them from the plane for charging. Once removed, use the mentioned balance plug Y harness for charging, and charge them as one with both the power and balance harnesses. The balance harness can be removed for flying. Mark pack 1 and pack 2 so that the power Y and balance Y join the packs the same.
Or create hardwiring of those harnesses using the harnesses as "templates," for some weight savings.
Or hard wire the power Y and use the balance y for charging only which saves weight.
Another easy solution for charging is to remove the power Y connection, back to two 3 cell packs and use a parallel board to charge and balance the packs at the same time. Technically simple, but same weight as now.
The lightest is to totally rewire at the solder end and make a 6 cell pack as above. Technically a bit more difficult, but saves weight and fiddling each time, once done.
Or wait for better ideas as others enter the discussion, which could be the best idea :)
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Y harness for the balance ports is a bit dangerous, plug it in in the wrong order and you will burn out some wires!
I would do it as you have been, charge in parallel and discharge in series. This was always what was suggested by TP.
Pat MacKenzie
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Thanks all for the suggestions.
Fred I think I will take your idea and buy the balance adapter and hard wire the packs
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I'v built my own 2x3S to 6S adapter using instructions I found in this page:
http://scriptasylum.com/rc_speed/lipo.html
Just check if your charger can charge through balance leads (low amp) or through power leads (high amp).
I used this particular scheme for my adapter:
(http://scriptasylum.com/rc_speed/images/bal_gen_3s3s_wmain.gif)
Vitalis
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Tim, sounds great. As emphasized, make sure that the power lead and balance lead are correctly connected. The risk you will run is connecting the balance lead each time, minimized if leads and batteries are clearly marked.
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I'v built my own 2x3S to 6S adapter using instructions I found in this page:
http://scriptasylum.com/rc_speed/lipo.html
Just check if your charger can charge through balance leads (low amp) or through power leads (high amp).
I used this particular scheme for my adapter:
(http://scriptasylum.com/rc_speed/images/bal_gen_3s3s_wmain.gif)
Vitalis
It will balance better (quicker) if you connect that "not used" wire to minus wire of that other battery.
BTW those cables are available in shops ... for example:
https://hobbyking.com/en_us/6s-battery-pack-balance-charge-adapter-lead.html
https://hobbyking.com/en_us/hxt-t-connector-series-pack-lead.html
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Sorry, I know it is not exactly the topic that has been put to discussion but can I charge two packs in parallel with having the balance plugs put in parallel as well? Thing is, I have 10 batteries but only two chargers. It takes me nearly 5 hrs to charge them all with two chargers only and I am not willing to buy more chargers.
The question is therefore rather whether the balancing of two packs in parallel works.
Any ideas? Please don't tell me to buy another charger capable to handle 4 packs :)
Thanks!
Christoph
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I found this article helpful. Remember that when charging packs parallel, the individual packs are not balanced, but the gang of packs.
http://www.tjinguytech.com/charging-how-tos/parallel-charging
The group of cells 1, 2, and 3 are balanced, but on any given pack there may be some differences. When not really pressed for time, I charge the packs to about 4.15 in parallel, then finish (4.2V) one at a time with balance. One charger with appropriate amperage output and a parallel board will charge 6 pack at a time. Since you are combining packs into twos, you might just charge 2 in parallel with balance, and then fly/discharge them.
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Thank you Fred, that is a really helpful article.
Christoph
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Christoph, those paralel charging boards are also available on hobbyking Netherland, they work nice.
for example:
https://hobbyking.com/en_us/hobbyking-parallel-charging-board-for-6-packs-2-6s-xt-60.html
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With some luck, we maybe be able to convince TP that there is a need for a 6S 25 C 2200 pack.
Speak with Kim Quinette at TP.
I did just today.
It might help if others ask, too.
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Tim what capacity do you have on those 3S batteries