LiPo Battery Question - 2 x 1S in Series?

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GregGleason

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I am a noob with regard to LiPo battery technology.

What is the best way to wire 2 x 1S LiPo's in series without cutting the connectors? Is that possible?

I'm looking into this to power my MAWD (which PerfectFlite says is fine to do).

Greg
 
This technique is not unique to LiPos -- it is what you'd do for any set of batteries or battery packs that you want to combine in series.

Assuming you do not want to cut off the connectors, buy the matching (mating) connectors in kit form at your hobby shop and build an adapter harness. A positive from one battery and the negative from the second battery (via the leads from the new connectors), are connected together (solder together and cover with heat shrink tubing), and the remaining positive lead from one battery, and the negative from the other, are your new connections (again, via the leads from the adapter harness).

I'd probably be tempted to just cut off the connectors, to make it more compact, and treat it as a 2S battery when charging. With an adapter, you can at least use them as 1S batteries again (and charge them as you have been doing) by removing the adapter.
 
Hobbyking, and rc-connectors.com both sell just about any premade harness you might need. If you order from Hobbyking, be sure to select either of the US warehouses for faster delivery/cheaper shipping.

David
 
I do this but disconnect to charge as separate 1S batteries afterwards.

I am a little scared to connect to a balance charger; I can make some guesses as to how the balance lines work but no one has been able to tell me authoritatively.
 
Hobbyking sells premade harnesses for connecting batteries in series.

Hobbyking, and rc-connectors.com both sell just about any premade harness you might need. If you order from Hobbyking, be sure to select either of the US warehouses for faster delivery/cheaper shipping.

David

Thanks. I didn't know that. I need one with a 2-pin Moles connector.

Greg
 
I do this but disconnect to charge as separate 1S batteries afterwards.

I am a little scared to connect to a balance charger; I can make some guesses as to how the balance lines work but no one has been able to tell me authoritatively.

Why are you scared of balance chargers? They are used extensively and without issue in the RC hobby.

The typical balance connector has a common ground and separate leads to each of the positive taps on each of the cells lipo pack. The charger does the math and tweaks the charge current so each cell is very close to the same value. (A very few pack makers have a common lead for positive and separate balance leads for each cells negative post, but these balance leads will not connect to balance chargers designed for balance leads with a common negative lead.)

I own about 60-70 lipo packs for RC model aircraft ranging from 1s 60mAh to 6s 5000mAH. Never any issues balance charging with various brands of balance chargers.

As long as you have decent packs, it is not necessary to balance charge every time you charge a Lipo pack. I check new packs for balance and as long as they are within .01 or .02 volts, I typically charge normally and not through the balance connector. More often than balance charging, I stick a lipo monitor on the balance lead during charging to spot check each cell voltage.

One of my 6s5000 packs has 40-50 cycles on it and has been balance charged about twice.
 
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Why are you scared of balance chargers? They are used extensively and without issue in the RC hobby.

The typical balance connector has a common ground and separate leads to each of the positive taps on each of the cells lipo pack. The charger does the math and tweaks the charge current so each cell is very close to the same value. (A very few pack makers have a common lead for positive and separate balance leads for each cells negative post, but these balance leads will not connect to balance chargers designed for balance leads with a common negative lead.)

I own about 60-70 lipo packs for RC model aircraft ranging from 1s 60mAh to 6s 5000mAH. Never any issues balance charging with various brands of balance chargers.

As long as you have decent packs, it is not necessary to balance charge every time you charge a Lipo pack. I check new packs for balance and as long as they are within .01 or .02 volts, I typically charge normally and not through the balance connector. More often than balance charging, I stick a lipo monitor on the balance lead during charging to spot check each cell voltage.

One of my 6s5000 packs has 40-50 cycles on it and has been balance charged about twice.

Sorry, I was unclear. I also use balance chargers extensively, with commercial 2S and up batteries. What I meant was that I am hesitant to connect my home brew multi cell batteries and instead break them back down to 1S to charge individually.
 
Sorry, I was unclear. I also use balance chargers extensively, with commercial 2S and up batteries. What I meant was that I am hesitant to connect my home brew multi cell batteries and instead break them back down to 1S to charge individually.

I have balance charged some homebrew packs that a few times with no issues. Added my own balance taps.

Simply copied the balance tap wiring from a commercial pack.

Another way to charge 2 identical 1s packs at the same time is to have a parallel charge adapter. You can charge both single cells at once at two times the rate used for a single cell. No balance leads needed.image.jpg
 
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I have balance charged some homebrew packs that a few times with no issues. Added my own balance taps.

Simply copied the balance tap wiring from a commercial pack.

Another way to charge 2 identical 1s packs at the same time is to have a parallel charge adapter. You can charge both single cells at once at two times the rate used for a single cell. No balance leads needed.View attachment 270024

Awesome, thanks! Funny how I asked electronics guys and got no answer. Obviously rocket guys are the best!
 
Below are the listings of all 1S LiPo cells and 2S LiPo battery packs currently available from Hobby king..

https://www.hobbyking.com/hobbyking...y=86&LiPoConfig=1&sortlist=W&CatSortOrder=asc

https://www.hobbyking.com/hobbyking...y=86&LiPoConfig=2&sortlist=W&CatSortOrder=asc

I personally prefer the Turnigy nano-tech batteries. They are a quality battery and readily available. You will see from the above to lists (sorted by weight) that almost all of the single Turnigy cells are available as a 2 cell battery so there really is not good reason not to purchase an assemble battery.

The 300 mah 2S batteries are identical in size to a 9 volt transistor battery. Simply by a balanced charger and be done with it. Use it and your batteries will always be balance and not over or under charged. It's a no-brainer.

Bob
 
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