PL8 - Parallel Charging - A Basic Guide

[Aidi]

I have been meaning to do this for a while, and finally got around to it.

There are a lot of threads starting these days with regards to parallel charging, what is needed in the way of leads etc. I have done a few photos to show how the batterys are connected together and then to the charger.

In this instance they are hooked upto a Powerlab PL8.

DSC01823.JPG

The balance board and bananna plugs hook up to the PL8 as per the norm. The 6way balance lead then plugs into the balance board. Each battery is then connected to the discharge cables and the balance plugs as per the pictures.

The parallel cables i am using are these ones:

EC5 Parallel Charge Cable X6 [9507] - $12.95 : EP Buddy, We Power Your RC Hobbies!
6S JST-XH Parallel Balance Cable X6 [9556] - $7.95 : EP Buddy, We Power Your RC Hobbies!

Although these were bought in the USA, i believe they are now starting to be stocked in various UK Heli Shops.

DSC01824.JPG

So, now you have then hooked up, time to get the charger doing its stuff. I am using a PL8 and a Server PSU in this example, however i have been using a Ripmax 13.8v 20A 275W TwinOut PSU with no problems.

Contrary to belief, it is not absolutely necessary to have the biggest most powerful PSU in the world to charge like this. Basically, it comes down to time. The higher capacity PSU you have the faster you can charge. So, if time is not problem for you, then a good PSU with a good amp outage will suffice.

Time becomes the key factor here as the lower spec PSU you have will determine how many amps you can push to the charger. At the moment i am charging at 10amps to the batterys (20amp draw on the PSU).

This is where the time factor kicks in. Due to the limtations of your PSU, you can only charge at the max amp output. When parallel charging, the amount of amps pushed out of the charger to the batterys is diveded equally to each battery.

In this case, i have 5x 6S 5000mAh batterys hooked up. Each one was between 23 and 26% discharged when checked on my battery monitor. Parallel charging at 10amps takes in around 2hours to get them all back to 100% and fully balanced. Yep, alot longer than charging at 1C, but as said, if you are charging at home after a days flying, time should not be against you!

Here are a few pictures from the PL8 software to show the settings etc:

PL8_1.jpgPL8_2.jpgpl_8_3.jpg

As you can see, it shows the PSU input to the charger, and the output to the batterys. Because you are charging in parallel, you will only see 6 cells which will be an average of 36 physical cells connected, and likewise the IR reading, it will be an average across the range. Its not a bad idea to charge each battery indivdually once in a while so you can get a true reading from the cells and its IR.

I hope this help a few and show the process for parallel charging. Some will say that its not safe, but there are a few of us at DMHC who use this method, and like any lipo charging, if you give them the respect they deserve this will do the job quite effectively and safe.

Rgds
Aidi

[ROCKET RONNIE]

Im thinking of getting a PL8, thank for the info, nice one

[jamiem]

The PL8 is superb, a really nice evolution of the Cellpro 10s I had previously. Currently I'm only charging 2 packs in parallel, and the most I've pushed it to so far is about 450w output power charging 2 6s 5000's at 2c - barely even breaking a sweat!

The only issues I can see with your setup is that by not separating the packs using the "official" balance boards, you don't have any separation, and therefore the cgarger will struggle to see if something suddenly goes wrong with one pack, and same with the main discharge leads - no fuses, although personally this one I don't see much of a problem with.

[cjcj1949]

It is wrong to say that parallel charging isn't safe. Mainly because safe is not an engineering term and not defined. All engineering processes can fail and we can make estimates of the probability of failure. Lipos are known to have the ability to burn if treated incorrectly or if they have been manufactured incorrectly or if they just don't like you. I would think that driving to the flying site is the biggest risk factor in our hobby, although possibly not when I'm flying.

[ChrisB]

Nice write up Aidi,to add I have been running these leads on the cellpro 10 and more recently on the pl8 and have excellent results every time.

I do keep an eye on proceedings when charging,but I can certainly see the benefits of using the specified boards for the charger from a safety point of view.

[aviatech22]

What can say guys on the new pl6 will it do parallel charging as pl8 does? but im determined to get pl8 i already build 900w psu thanks ......ken

[cjcj1949]

Any charger will do parallel charging. If any battery doesn't seem right then don't parallel charge it. As Aidi does, check the volts before plugging in. A weak battery could cause a problem. Most weak batteries would show up in flight. Charging slowly and connecting batteries at roughly the same voltage makes a lot of sense and makes them last longer.

I think a harness is better than a pcb, as the wire connections will be more reliable than copper tracks. Peak currents can be high and you may not notice a burnt out/broken track.

[muscleflex]

Ok - a bump on this because this thread keeps popping up everytime I google.
I am using a friend's PL8 v2
I want to charge 2x Turnigy 6s 5000mah (for my 700e DFC)
I basically want to know what options I need to choose on the PL8
Upon switching the charger on, I get the following choices on the charger:
POWER SOURCE? I choose DC Power Supply
PRESET? I choose 2: Faster Charge
PARALLEL PACKS? Do I choose Yes? if so, do I choose 2P or what?
SET CHARGE RATE? Do I choose this: >2.00A 2P=4.00A ?

[r4nd0m]

well if I were you I would use HighPower Accurate Fast Charging - a high power preset is needed else it will cap charging at 4A
Parallel Packs:yes, 2P
Charge rate: 5A (1C), 10A (2c), 15A(3C) - your get it - but it means the charge rate for a "single" pack

by selecting 2P (2packs) 3P (3packs)..., the charger will then use a multiplier of the single pack set charge rate - make sure your PSU can deliver the multiplied AMP

[iceuk]

muscle flex,


one 5000 mah lipo = charge at 1c is 5 amps

one 2600 mah lipo = charge at 1c is 2.6 amps


so if u wanted to charge 6 X 2600 mah lipos @ 1c 2.6 amps x 6 = 15.6 amps

[enterpryse]

I try not to parallel charge in general although I believe the principal to be safe enough for me to have some control over so I do do it occasionally.

The reason I try to avoid it is simple. When plugging in the batteries there will be a period where they all stabilise themselves by discharging and charging directly from battery to battery or cell to cell. This could lead to a cell going above 4.2V, or one going under. Also while the batteries are stabilising there is nothing to limit the current between the batteries. If the balance leads are plugged in it would also be very easy for the balance current to exceed the rating of the connector and/or the cable. So for my own peace of mind unless the cells within a few mV I'll balance them separately.

I understand that everyone has their own procedures for charging, these are mine

Soz, this is a bit off topic Whoops.

[muscleflex]

Thanks - This is the first time I'm going to parallel charge. I've never done it before. I've always just charged singularly but I thought maybe it's time I should try it?

I try not to parallel charge in general although I believe the principal to be safe enough for me to have some control over so I do do it occasionally.

The reason I try to avoid it is simple. When plugging in the batteries there will be a period where they all stabilise themselves by discharging and charging directly from battery to battery or cell to cell. This could lead to a cell going above 4.2V, or one going under. Also while the batteries are stabilising there is nothing to limit the current between the batteries. If the balance leads are plugged in it would also be very easy for the balance current to exceed the rating of the connector and/or the cable. So for my own peace of mind unless the cells within a few mV I'll balance them separately.

I understand that everyone has their own procedures for charging, these are mine

Soz, this is a bit off topic Whoops.

[muscleflex]

So... for my battery, I should choose:
2P
and set the charge rate to: 5.00A? (for 1c charging?)

oh and should I choose that High Charge Rate preset? I don't have the USB dongle to hook this up and when I tried before, I had endless trouble trying to get the USB to work on my PC so I gave up in the end

well if I were you I would use HighPower Accurate Fast Charging - a high power preset is needed else it will cap charging at 4A
Parallel Packs:yes, 2P
Charge rate: 5A (1C), 10A (2c), 15A(3C) - your get it - but it means the charge rate for a "single" pack

by selecting 2P (2packs) 3P (3packs)..., the charger will then use a multiplier of the single pack set charge rate - make sure your PSU can deliver the multiplied AMP

muscle flex,


one 5000 mah lipo = charge at 1c is 5 amps

one 2600 mah lipo = charge at 1c is 2.6 amps


so if u wanted to charge 6 X 2600 mah lipos @ 1c 2.6 amps x 6 = 15.6 amps

[enterpryse]

Thanks - This is the first time I'm going to parallel charge. I've never done it before. I've always just charged singularly but I thought maybe it's time I should try it?

Tons of people do it, including me, just be careful is my advice

Stuart

[iceuk]

muscle, I use to charge single lipos but it really is a ball ache parallel charging is fine just have to be safe, don't ask to much from you PSU and just keep a check on charger every now and then,

6 packs charged in 40 mins is great (-: especially when we get sunshine, you can fly all your packs, put them on charge have a cup of tea and a pee and your ready to go again (-: