Hi all,
I would like to charge the batteries of my MCP-X with the cellpro multi4.

If i put 2 of them in parallel, and I would like to charge them a 3C, since they have 300mAh each, i should set it at 1.8A, right?

However the setting for 1s/2s small balance batteries has a maximum charging rate of 500mA.

Can I use the normal setting for chrging standar Lipo instead of the specific 1S charging option?

Moreover, if i use this 1s serial charging cable, http://www.ebay.it/itm/Blade-mcpx-mc...item2a183df3f7
shouldn't be the charge more accurate and precise?


Thank you in advance for your help,
Luca.

Originally Posted by demiluk

Hi all,
I would like to charge the batteries of my MCP-X with the cellpro multi4.

If i put 2 of them in parallel, and I would like to charge them a 3C, since they have 300mAh each, i should set it at 1.8A, right?

However the setting for 1s/2s small balance batteries has a maximum charging rate of 500mA.

Can I use the normal setting for chrging standar Lipo instead of the specific 1S charging option?

Moreover, if i use this 1s serial charging cable, http://www.ebay.it/itm/Blade-mcpx-mc...item2a183df3f7
shouldn't be the charge more accurate and precise?


Thank you in advance for your help,
Luca.

Yes, if you want to charge two 1S 300mah LiPo's in parallel at 3C the correct charging current is 1.8 amps.

What version of the Multi 4 firmware do you have?
I am running V1.67 and the setting for 1s/2s small non balanced charge amps has a range of 250 ma to 2 amps.

Glen

To charge 2 - 300Mah packs at 3C -
.3 X 2 X 3 = 1.8AMPS
Set the charger to 1S and 1.8AMPS.

To serial charge set the charger to 2S and 3 x .3 = .9AMPS.

That charging cable is a serial cable. You need to balance the packs when is serial.
When charging in parallel there is no balancing because it is a big 1 cell pack.

Originally Posted by TheWoodCrafter

To charge 2 - 300Mah packs at 3C -
.3 X 2 X 3 = 1.8AMPS
Set the charger to 1S and 1.8AMPS.

To serial charge set the charger to 2S and 3 x .3 = .9AMPS.

That charging cable is a serial cable. You need to balance the packs when is serial.
When charging in parallel there is no balancing because it is a big 1 cell pack.

Thank you all for the replies-.

Anyway, i think the "serial" method is more accurate than the "parallel" one, due to the fact that each single cell charge almost independently, isnt'it?

No. Read more about parallel charging here:

https://www.rcgroups.com/forums/showthread.php?t=932319

Originally Posted by demiluk

Thank you all for the replies-.
Anyway, i think the "serial" method is more accurate than the "parallel" one, due to the fact that each single cell charge almost independently, isn't it?

Either serial or parallel is good. I don't think you can say one is more accurate than the other. You do get a better look at individual cells when serial charging.

Also in serial mode the cells are not really charging independently. All of the charging current is passed through each cell. However the balancing is independent. It's a small technicality. In either case at the end of the charge all cells will be charged to the same value.

However I don't think the cable you referenced will work with your Multi 4. I think the connector that attaches to the charger is not compatible with the Multi 4. It is most likely a JST-XH and the Multi 4 uses a different connector.

You could get the proper connector with wires from FMA and make up your own serial cable though. You would have to make seperate cables for charging 2, 4, or 4 cells.

Glen

This is just my opinion, but for 1s cells, I have a hard time to get excited about serial charging.

At least for the balance adapters I have, a serial setup would always require that you charge the same number of cells each charge cycle.

Secondly, you need to use cells that have the same capacities, otherwise I think you will be spending a lot of time in balance mode.

Thirdly, the cells need to be discharged to about the same level, otherwise you will possibly be kicked into safe charge mode, and/or, you again will be spending a lot of time in balance mode.

Parallel charging 1s cells just seems so much easier to me. If I do want to check the health of a single cell, I can charge it by itself occasionally. Usually you can tell that by performance.

In either case at the end of the charge all cells will be charged to the same value.

True, but serial charging requires more time for this. One never discharges all individual cells with the exact same capacity. These capacity differences must be equalized by the balancer during serial charge, which can be avoided using the superior parallel charge method, where all cells equalize to each other automatically.

With serial charging, while balancing, you need to be very aware of the correct wiring of the balancing plug. You can't just plug in anywhere. You have to use them in the correct order or sparks fly.

Originally Posted by Julez

These capacity differences must be equalized by the balancer during serial charge, which can be avoided using the superior parallel charge method, where all cells equalize to each other automatically.

That's not completely accurate. While cells in parallel "automatically" balance each other, this process is not very fast. If parallel charging is performed slowly, or the cells are allowed to set connected to parallel harness/board they will balance, eventually. Serial charging with a charger with a high balance current can perform balancing faster and more accurately.

This post below is consistent with my results. While cells in parallel will be fairly close within 10 minutes, that can be a problem if your charge cycle is only 15 minutes and the cells don't diverge until 80% state of charge. Charging different sized 1s cells, I've found that for fast charging (3c) the larger cells tend to be under charged, while the smaller cells tend to be over charged. Many parallel charge users may not see this if they are not checking cell voltages of each pack after the charge (disconnected from the charger) or are leaving the packs connected for more than 10 minutes after the charge has completed. While leaving the cells partially connected helps solve the issue, it does not prevent the over charge and adds extra time that is not required for serial charging.

If you have one of the chargers that does not high current balancing, then parallel charging may end up being faster.

Originally Posted by Donaldsneffe

Hi,
because I also do parallel charging with 6 batteries (for all 1s cells I use in my different Nine Eagles, Walkera and Eflite micro helis) if similar capacity, I made a test with different types of 1s batteries I use for my mCP x a while ago.
I made it "hard" - so very different charging status of all batteries AND different types of batteries.
Measured voltage before plugging them to the parallel charging cables (minute 0), and after 5, 10, 15 and 20 minutes.
No battery got warm or anything similar, and they balanced amazingly fast:



Walter

That is interesting.

I suppose it all depends on how we go about our charging.

For me, the number of cells I use at any given time is 6 or fewer. Actually fewer (3) is the norm, since a lot of my flying is done at lunch time, with some other guys. We do as much BS'ing as flying, so by the time I have to get back to the office, I may have only flown 3 times. So that is one issue for me.

After such a session, I typically plug all the used cells into my parallel adapter, and just leave them that way. So they have a lot of time to equalize.

Then if the weather looks ok for the day, I'll charge them. Also just leave them in the parallel adapter. Often don't even charge to 100%, since I don't think I notice the small loss of flight time (most of the battery time is actually spent walking out to pick up the mCPx and push the main gear back on!.

So I suppose it all depends. For me parallel charging suits me the best.

Like always it depends on the clells and the charger.

If you are charging 6 or 8 single cell 160 mAh in series with a FMA Power Lab 8 and charging at 5C as with Hyperion or other 5C charge rated LiPolys then the charge rate is 800 mA and the charger has 1,000 mA balancing power so even if some cells are at 3.7 and some at 3.8 the charger will have no problem keeping them all balanced without cutting the charge rate back.

If you are using a charger with a 300 mA balancer then yes there can be balancing power issues.

If you parallel charge them then they may take some time to in fact all becone balanced . This does not matter if you are charging at a low rate and you do not mind taking 3 to 10 hours for them to finish charging and balancing. Also as pointed out many times that most chargers will not fully charge a 1S unless it has both main power leads and balancing lead conected in parallel.

Charles

Hi Gregor,

I am sorry, but I connot make much sense out of your post.

Serial charging with a charger with a high balance current can perform balancing faster and more accurately.

How can anything be more accurately than parallel charging? By definition, all cells will be exposed to 100% the exact precise identical voltage. It is impossible to be any more precise than this. As soon as 0.0000001V difference would occur, balancing currents would automatically appear.
The balance stage of any charger has not much more than 0.005V precision.

One must not mix up the balancing process, that happens during parallel charging, with what happens when one just connects cells in parallel without charging them. The latter is of course a rather slow process, given the Ri of the cells.

Charging different sized 1s cells, I've found that for fast charging (3c) the larger cells tend to be under charged, while the smaller cells tend to be over charged.

It is technically impossible to overcharge single cells which are connected in parallel. The charger will not put out more than 4.2V. How should any higher voltage than that, which is required for overcharge, appear in the charge cable? All cells connected in parallel will, at any time during the charge process, have the exact same voltage.

it does not prevent the over charge and adds extra time that is not required for serial charging.

We have already established that overcharge is a technical impossibility during a parallel charge. No extra time is needed for parallel charging, either, as balancing is not neccessary.
If you put cells with a different Ri in series, the cells with the higher Ri will have a higher voltage, although they may have the same state of charge. This higher voltage is sensed as imbalance by the charger, which the proceeds to thread the cell with higher Ri with balancing currents, which leads, in fact, to an imbalance capacity-wise. This imbalance has to be dealt with later, by balancing the lower-Ri cell at the very end of the charge cycle. This back-and-forth balancing is time-consuming, unneccessary, and can be avoided easily by parallel charging.

Serial charging only makes sense when the cells are all the same, and are always discharged with the same capacity, for example because they are connected in an >1s pack.

Gregor99

you will never,ever get your point across that cells in parallel will not always be at the same voltage (state of charge) after being parallel charged and balanced.

I know it ,you know it as do many others who have taken the time and effort to do the testing.

Some parallel charge at 1/10C and sure their cells are all the same but some like to charge at 3C,5C even dare I say it 10C and for these levels parallel charging / balancing is not the best choice.

Charles

Originally Posted by everydayflyer

some like to charge at 3C,5C even dare I say it 10C and for these levels parallel charging / balancing is not the best choice

...but still FAR safer / faster than charging packs that are at differing charge states / capacities in series, especially if they're larger (>1000mAh) packs...

Mark