Parallel Charging

[cjm180]

Hey Guys

I am getting fed up having to spend the day before a planned fly charging up packs. Also a few times now I have seen a break in the weather and missed an opportunity because I don't have packs charged.

As my heli fleet has expanded over time, I am now getting a collection of packs of various sizes. I have around 12 x 1800 6s for the 450, 10 x 3300 6s (5 sets at 12s) for the 600l. I have 2 packs (1 x 12s set) for the trioblin, but this will be expanding exponentially soon.


I bought one of Ian's fantastic charge cases, that houses a 406duo, which I know is good for 1400w, or 1000w max on a particular channel.

So using my basic understanding, and using full voltage, I get:

based on 3300 6s packs

4.2v per cell x 6 = 25.2.

to charge all 10 packs, that would equal a combined capacity of 33A.

To charge at 1C:

33 x 25.2 = 831W.

So I am well in, and can go from zero to 5 sets of packs in 1 hour on my charger. is this correct?

The issue I al looking at tho is I run supra x connectors, as well as ec5's and xt60's. I see on fast lads they sell the boards for ec5's and xt60's. But what do you do for the supras?

What I ideally need is a parallel board that takes 4mm banana plugs. Does anywhere well them in that way? How are others managing the cabling with parallel charging?

[10x]

Hello Craig

I went from EC5's to XT150 on some heli's, so i already had some EC5 parallel boards so just made up leads with ec5 on one end and xt150 on the other...

[PKNEC]

Hi Craig, I bought my board from here ParaBoard when I needed xt60 but they do a full range of boards with different connectors.
it's great quality and I bought the V3 which is fused.

[Grumpy]

As the other guys say, just but a board that suits at least some of your batteries (XT60 is probably easiest) and then make up short adaptor leads for your other packs with an XT60 one end and the connector to suit the battery the other. This isn't a cheap exercise if you are using SupraX, but there is no other way around it.

No need to limit your parallel charging to 1C. You may as well let the charger stretch it's legs and push the whole 1400W into the batteries, should have them all charged in around 30mins that way..

[dwazzer]

The best thing I try and do is make sure you are using the same connectors on all of your stuff...However, that isn't easy especially when there is a size difference!

Like has already been said, the only other way is either to make adapters from your parallel board to your batteries or have several different boards! It is easy to change the connectors on the board IF they are on fly leads...a pain if they are soldered directly to the board!

All of my batteries run EC5 connectors and I just have EC5 to EC3 leads made up for the smaller stuff! I do have a few 'odd ball batteries' for certain models that I can't be arsed changing (I will at some point!) but I just charge those with my Cellpro-S through the balance leads!

Like Grumpy says, I would put a bit more juice into your batteries and cut down the waiting time....but MAX I will go is 2c, that's just a personal limit but my batteries seem to last OK!

My setup is a PL8 with the MPA parallel board and I can't fault it!

Cheers, Dave.

[myxiplx]

Yup, a bunch of adaptor leads is what I use. I've been flying EC3's and EC2's on my helis, so went with EC5 on the main board and built myself some adaptor leads from EC5 to EC3 and to EC2. It means that one board can work with everything I'm planning to fly.

The one tip I would give you for parallel charging is to get in the habbit of checking the cells on your batteries individually, that's one thing your charger can no longer keep an eye on when you parallel charge.

I picked up a Progressive RC CellLog 8m, it's a different kind of battery checker as it just gives you the voltages, but it's ideal for monitoring cells as you always see the voltage of every cell as soon as you connect a pack, and actually when it's cell voltages you see it doesn't matter whether you connect a 2S pack or a 7S pack, you can see at a glance if the pack is empty (3.7V), charged (4.2V), or at storage (3.85V).

[Grumpy]

myxiplx,

The CellLog 8M seems to just do what those cheapo £2 LiPo testers do... But I like the CellLog much better because it displays all the cell voltages on the screen simultaneously, unlike the cheapo units that scroll through one cell at a time. The cheapo ones aren't very accurate either.

So where do you get one?.. I see them listed for sale ion eBay but they are in the US, postage costs as much as the item itself.

[cycled]

I soldered up a bunch of "squid" cables myself. Actually, I went a bit more complex, and have a string of 3 EC5 plugs connected to a charger, and EC5-XT60 and -XT90 adapters (with 1-3 XT connectors each) to connect my packs, plus blade fuses soldered inline (probably overkill).

For the balance cables, I bought a pack of ten 6s extension leads on ebay then soldered several together. You might be able to buy pre-soldered versions. I opted not to put fuses in these because it might not be obvious when they blew, and then you could end up charging without balancing all cells without realising it.

The trouble with para boards (other than being awkward boxy things) — I've heard a couple of times that the balance traces can fail under normal 1A balancing, then leading to packs not balancing while charging (which could damage packs or even cause a fire if one cell dies and another is charged to a much higher voltage to try to make the total across cells in series "correct").

[myxiplx]

myxiplx,

The CellLog 8M seems to just do what those cheapo £2 LiPo testers do... But I like the CellLog much better because it displays all the cell voltages on the screen simultaneously, unlike the cheapo units that scroll through one cell at a time. The cheapo ones aren't very accurate either.

So where do you get one?.. I see them listed for sale ion eBay but they are in the US, postage costs as much as the item itself.

Honestly can't remember where I found mine, I just did a google search last year and picked one up. They're definitely more accurate than the cheap tester I was using before, this one agrees with the PowerLab every single time, it's not even a hundredth of a volt out. Definitely worth the investment, I have mine velcro'd to the back of my Jeti screen

[cjm180]

Thanks for the replies

Just a bit further....

My 600L uses ec5's. So I am thinking a board would be a little bit of a pain because stacking 6 packs (while stuck in pairs to a battery tray) next to each other so they can plug into the board will be a pain.

So I was thinking of these:

Quantum EC5 Parallel Charge lead 6 output Q-CL-0006

These are as good as the board are they not?

And these for the balance leads:

Quantum XH 6s Parallel x6 Q-B-0003

I take it for parallel charging I can plug any balance lead into any connector on that lead. From what I have read the packs will auto balance between themselves during the process. I have 2 sets of packs that are older than the others, anything to worry about?

I understand all packs should be within 0.1V per cell prior to parallel charging.

Interestingly I see that the quantum balance board is rated at 30amp continuous. So with the full 6 packs on that would be limited to around 1.5C for 3.3 packs. I presume this version will also be 30amps?

What is going to follow this exercise is a generator so I can field charge. I have a wall mounted power meter at home for charging. So once I get going I will look at the watts consumed at the wall (240 supply) and size a generator of that.

The two generators I am looking at is a Honda eu20i or a Yamaha ef2000is.

Honda EU20i Generator

Yamaha EF2000is Portable Generator

Both are rated for 1600w continuous. Which I calculate to be 6.6amps @ 240vAC. So will see what the meter says. What are you guys doing field charging wise with generators?

My field is 40 mins drive away. So I wanna be able to charge fast.

[Grumpy]

The 'squid' leads are ok and they do make connection easier for packs that are fixed to a tray. Only downside is that unlike some of the newer 'safe' parallel boards they aren't fused, so they are less tolerant of human error during connection.

If you did go for a board there are plenty of boards that are 40A rated, so if you have a 40A capable charger you really want one of those.

In my experience you can connect with bigger difference than 0.1v per cell, 0.2v wont do any harm. You get a brief rush of current on connection but it will be within the batteries charge rate so no harm done. Parallel charging older and new batteries is also no issue, as long as the batteries are still in decent serviceable condition with no cells on their way out.

[cjm180]

Grumpy, do me a favour, can u parcel up your brain and send it my way. I will return it when I am finished!!!!

I have a 406duo, 1400W max or 700W per channel. My electrical theory is not so great. I am reading back through some of your comments from 2014 / 2015 regarding generators.

I will look to see what PSU's I have in my case.

It should be possible to fit an inline fuse is it not? My issue is I have soldering ec5's. Too many close calls with the reaper trying to push the bullet into the housing with a screw driver. I really don't fancy making up 10 ec5 extension leads. That's 40 skirmishes with death I can do without.

I currently place the packs across the top of my charge case, which amongst other things causes scratches. So I really want to be able to move the packs off the charge case to the side. Also help with safety I guess.

Whats your rough thoughts on generator sizes? I know that's a shot in the dark depending on charge rates etc. I know my charger is supplied with 24vDC from the PSU's. DO you think 1600w generator should be ample?

I am not too fussed about charging one or two packs quickly. I want to be able to charge all 5 sets (10 packs) with that charger in less than an hour. So splitting them across two channels, I calculate 1.5c charge based on 5 packs per channel (550W per channel load).

[Guest]

As an example my 1000w/900w continuous will power 25v 1150w to PL8 at 30a to the mpa board. That's about the max you can get out of that size. I would go with a 2000w in all honesty which gives about 1600w continuous. Few variables of course but 2kw will cover your setup.

MJ

[cycled]

The 'squid' leads are ok and they do make connection easier for packs that are fixed to a tray. Only downside is that unlike some of the newer 'safe' parallel boards they aren't fused, so they are less tolerant of human error during connection.

If you did go for a board there are plenty of boards that are 40A rated, so if you have a 40A capable charger you really want one of those.

In my experience you can connect with bigger difference than 0.1v per cell, 0.2v wont do any harm. You get a brief rush of current on connection but it will be within the batteries charge rate so no harm done. Parallel charging older and new batteries is also no issue, as long as the batteries are still in decent serviceable condition with no cells on their way out.

As I said in my post, soldering blade fuses (standard car fuses) into the main charge cables is easy (pre-tin, solder a wire each side, bend the legs over to make it smaller and put heat shrink over the top).

Fusing parallel balance cables/boards could actually cause problems. I opted not to fuse mine.

[moyesboy]

Nitro