parallel connection 1st or in series?

ok, the title is a little confusing......
i bought 16 x 5000mah, 5s, zippy packs. i want to make 20s, 20ah. my question is, should i parallel 4 packs then run series?
or should i make 4 packs in series then run parallel.

4 parallel, 4 parallel, 4 parallel, 4 parallel then run series.
20ah , 20ah , 20ah , 20ah
5s + 5s + 5s +5s = 20s, 20ah
or

4 series, 4 series, 4 series, 4 series then run parallel.
20s 20s 20s 20s
5ah, + , 5ah , + 5ah , + 5ah = 20ah, 20s

dont know if my diagram makes sense lol.
just want to know if there is any difference between the 2 ways of making the connections if there is any?

cheerios

Using small cells ( 5ah) most of us parallel first, then put those blocks in series.

when using LARGE expensive cells ( 100ah cells for example ) most EV people will series then parallel to use complex BMS to monitor each cell ..

a generalization..

my personal opinion. P first. S after.

saiyan said:

just want to know if there is any difference between the 2 ways of making the connections if there is any?

cheerios

Click to expand...

No. If you mean by capacity and how it perform.

I would go with

saiyan said:

4 parallel, 4 parallel, 4 parallel, 4 parallel then run series.
20ah , 20ah , 20ah , 20ah
5s + 5s + 5s +5s = 20s, 20ah

Click to expand...

because it will make charging much easier. You just break up the series to 2 10s and charge it using some 10s charger

If you make series first, then you need 20s lipo charger. Or break it up to 10s and then parallel it to charge. Much more hassle IMO.

As long as all the cells are fairly close in voltage, it won't matter one bit.

thanks for the quick replys guys. think i guna P then S.

cheerios........

Easier to charge generally, if you make bricks of paralelled packs. Each brick of packs can then charge as a unit on a normal charger. That is, if you are using 6s or 8s chargers.

Then make the series connection.

For a pack that size though, it would be nice if you could buy 1s 4p 20 ah hardcase packs.

I vary my capacity enough that I do series and then parallel the S groups into whatever Ah/Wh I need for the task at hand.

Parallel first usually means balance taps too but I don't like to hide bad cells among good ones. Series first all my RC Lipo cells are available for testing and individual charging at any time via the balance connectors.

There's the beauty of the RC lipo (lico). About a zillion ways to do it all right, for one purpose or another. When you see the sparks, you know you found one of the few wrong ways.

I tend to have all my RC lipo paired in 10 ah bricks. Then if I go for a 20 ah ride, I ride one set down, then switch to the other. Never really need to have another set of paralelling wires that way. I never really carry 5 ah, so it works great for me.

I have the same batteries as the OP: I create “units” in series, and then parallel those to create the capacity. They are set for 15S (3x5S) by <whatever> in parallel. I have the option of charging 15S units singularly or in bulk. I made and break the parallel connections first, and then the series connections once the units are isolated.

The charger is a Meanwell assembly and good for 15S. Although I recently resurrected my old LiFePO3 charger to support quick balancing charges for 10S (2x5S).

~KF

This may be a silly question, but I figure better safe than sorry. Is it better to wire batteries in parallel, then series? Or series, then parallel? Or does it make no difference?

EXAMPLE: I get six 4s 5ah 20C batteries. I want to have a 12s battery pack. Obviously, I just take 3 of those 4s batteries, wire them in series, and viola. However, lets say I want to use those other 3 batteries to make a second pack, and parallel them.

Is it better to make 2 packs of 3 batteries in series, and then take those packs and wire them in parallel?
OR
Is it better to make 3 sets of 2 batteries in parallel, and then wire those in series?


Sorry if that doesnt make sense. Thanks in advance for the help!

How you are charging the pack will have to be considered in how you arrange them. If you are charging it as a 12s pack without having to break it down at all I would make 3 pairs of paralleled packs then connect them in series. I would also parallel them at cell level via the balance taps as well as the power cables. joining them at the cell level will make every cell part of a 2 cell string which helps to maintain voltage balance throughout the pack.

11/15/17: dogman dan on parallel or series connection 1st
https://endless-sphere.com/forums/viewtopic.php?f=14&t=91533#p1334664

Hobby King Pack -> Anderson Series/Parallel Harnesses
https://endless-sphere.com/forums/viewtopic.php?f=31&t=45298#p660278

If you have a 12s charger or higher than serial makes the best sense, but unless you change the wiring harness terminals the most you can charge on a 12s charger with 4s packs is 8s lipo. I love to series first and then parallel as I have a 14s hyperion charger and I make sure each pack is balance charged individually....
What type of charger do you have or use?
What makes most sense is what is the easiest to charge and manage each and every individual pack.. I do it quite nicely with my charger, but if you had a 6s or 8s or 10s charger than the combinations of connections between packs become what your ability to manage or charge them is.

mark5 said:

parallel connection 1st or in series?
http://endless-sphere.com/forums/viewtopic.php?f=14&t=41462

Hobby King Pack -> Anderson Series/Parallel Harnesses
http://endless-sphere.com/forums/viewtopic.php?f=31&t=45298#p660278

Click to expand...

'sactly! :wink:

That said, I don't think it makes a hill of beans. Whatever works best functionally for your setup.
Harnessed either way, KF

Bricks already arrive series wired - 6S, 5S, 4S, etc. What you're seeking is if it's better to parallel balance leads along with parallel main power leads?

For example, assemble 4qty 6S bricks into 12S2P configuration. 2qty 6S series wired to 12S and parallel that group via only power leads to make 2P or double Ah capacity.

Trouble with this scenario is that if one of the cells in the 12S group dies and shorts, now you have an 11S series group paralleled with 12S group. The higher voltage 12S group may drive the 11S group above maximum allowed voltage for RC Lipo cells. Bad juju....

But when paralleling the balance wires in proper relation to the main power wires any cell that dies/shorts may burn the associated balance wire and/or pull the paralleled cell(s) down with it.

While not a great outcome either way the later is probably a better choice for a pack you're not frequently reassembling into different configurations.

Of course, this ultimately wades into the BMS debate, etc...

I tend not to parallel balance wires for most of my eBike packs but that's mainly because I change pack capacity configurations frequently. But I do keep an intent eye on my RC Lipo every chance I get.

Recently, I have one 16S2P pack (8x4S bricks) I now parallel balance wires and have taken it a step further making 8S2P adapter cables so that I can connect a pair of 8S CellLogs and/or maybe add a BMS later down the road...

FWIW, I may be the only person on the planet that parallels the packs first, but does not parallel the balance leads.

To keep the packs a bit neater, with less plugs and adapters, I permanently connect the big leads, making pairs of packs in 4s 6s or whatever. But I leave the balance leads alone. This makes it take longer to check all the cells, but it eliminates the bulky adapters, or having to splice them. I can then tell exactly which pack, or which cell is wonky if that happens. If a cell is wonky, I DO NOT want another cell supporting it, and getting ruined. I'd rather have the problem show up quickly, so I can dump that pack from the battery assembly.

In the initial break in, or sorting good from bad, I use a parallel adapter on the main leads. But I ditch that when I know the pack is behaving ok. Then make my permanent crimped connections to have 10 ah sections.

Others do it very different. Series the packs to 12s 14s or whatever and then paralleling them also reduces the number of adapters you need. That is a method favored by folks who are bulk charging at 12s 14s or whatever. Like me, they can check individual cells anytime, and detect a bad cell. If your parallel at the balance leads, you may have a bad cell hiding among the good ones, since a good one will bring up the voltage of the bad.

This all pertains to running naked. If you have a bms, you parallel at the balance leads, or you would need multiple bms. But if you series connect first, then your bms has to connect it's main leads after the main leads are paralleled.

Ive done both but you really wanna parallel before you series. Ive had some retarded battery packs. One had 24 packs. It still had more wiring over all but I still paralleled before I series. To charge i just break the series connections and paralleled them to my Icharger 306b at the time and bulk charged. If i had the time I would balance charge the same way with a 24 to 1 parallel balance cable lol.

I switch to larger AH cells to reduce connections but I still parallel before I series.

so its been over a yr n half since i asked this question and my batteries are still going good.
i ran my 12x 5s packs in parallel then in series to make 15ah, 20s. i did not wire anything permanant. the main wires are run in parallel then i have another cable to run it in series.

my balance wires are untouched, i leave them as they are so i could pick out the dead packs. lucky i did this cause ive changed out 2 packs so far.
i always check my packs after atleast 2-3 runs to see if any packs are going bad or out of balance. its also good cause i can easily balance charge it whenever i want using bulk balance leads. (i have no bms) (i am the bms)

in this 1 and half yrs of riding on and off ive noticed that having 15ah and using 10ah or less when i ride, it keeps the batteries balaced itself.
do not discharge it to 3.5v -3.6v each cell. the only time the batteries starts to get out of balance is when it goes under 3.6v per cell.
either that or uve already got a bad pack.

1 last thing i wana add. when i bought my 20c, 5s packs i didnt know much about voltage sag and the quality of them. since i run over 100amps, it tends to sag abit especially that the packs are a lil older now aswell. and plus quality of the packs is not as good as higher c rate packs like nano packs.
the next packs i will buy will definatly be nano tech. it will help in voltage sag in high rate discharge aswell as last longer in life.

you will pay more for the packs but i think in the end it will be worth it.

hope this helps.....

cheerios

wineboyrider said:

If you have a 12s charger or higher than serial makes the best sense, but unless you change the wiring harness terminals the most you can charge on a 12s charger with 4s packs is 8s lipo.

Click to expand...

This makes sense, but I have a question.

Lets assume we have the following:
12s charger
three 4s bricks configured to 12s

When we charge them, as wineboyrider says, we would have to remove the series connection in order to balance charge the bricks (and we could only balance charge 2 of them at a time), because 3 batteries don't plug into two balance ports. One way around this would be to make (unless somewhere sells them?) some adapters to take the individual cell wires from 3x4s to 2x6s, like this:



So now lets assume this:
12s charger
six 4s bricks configured to 12s, wired in series first, then parallel to give us 10Ah

From what I understand, I can parallel the balance leads from each brick in the same position in a series "row" like this diagram:

But we're in the same situation regarding balance plugs from 3 series'd bricks, not plugging into 2 ports on the charger, so could we still use the same adapter to turn three 4s wires into two 6s plugs for the charger? Then we could also use two 6s cell voltage alarms instead of three 4s?

It all makes sense and seems OK in my head, but in my build I'll be using 18 of the 4s hardcase bricks, so I want to make sure before I blow up a lot of cells/fingers.