Going to buy the MCPX-BL

[Peteski]

Looks like a good deal above for both from a reputable shop. I'd probably go for that if I was looking for one.

[5hane]

Second hand version of the charger with integrated ac adapter.

MHSH36 | IMAX B6AC CHARGER (SECOND HAND)

they also have have a cheap mcpx Bl if you haven't bought it yet!

MHSH40 | BLADE MCPX-BL (Second hand)

Thanks for your help James. You might want to sit down for this: I have finally ordered a charger! It was one previously linked to earlier in this discussion that I missed.
I am in contact with the seller of this mcpx you kindly spotted. The chaps going to try and find out a little history about this particular item and get back to me.

[james_2k]

Nice one, you will love charging multiple batteries at once. So much more flying

just remember, add the capacities together of all the batteries you are charging. Then divide by 1000 to get the amps to charge at for 1c charging. (You can't charge the 2s mcpx batteries with the 1s packs you have at the same time - not on the same charger anyway)

eg. 6 x 150mah packs

6 x 150 = 900 / 1000 = 0.9 amps - set charger to 1s charging (3.7 nominal, will be at 4.2 when fully charged)

or for the mcpx Bl

6 x 200mah packs

6 x 200 / 1000 = 1.2 amps - set charger to 2s charging (7.4v nominal, 8.4 fully charged)

if if you have multiple packs of the SAME voltage but different capacities, it's ok to use those leads, just do it the same way as said above

e.g.

2 x 200 and 4 x 250 mah packs

200 x 2 + 250 x 4 = 1400 / 1000 = 1.4 amps for a 1c charge rate.

obviously to get higher charge rates you simply multiply the amps by whatever you want. To take the last example you would do 1.4 x 2 for 2.8 amps to get a a 2c charge rate.

i normally charge at 1c though, supposed to be easier on the batteries.

Also note that you have to charge at the rate of the lowest rated pack. Eg, if three of your batteries can take a 2c charge rate and three can only take a 1c rate, then you must charge all at 1c.

another note is that you don't have to charge using all the connectors at once if you don't want to. Eg if you have that 6 battery parallel cable you can charge any number of packs up to 6. Just amend the above maths accordingly.

edit, this all applies if you buy a parallel charge lead. If you buy a series one, then it's different.

[5hane]

Thanks for the detailed explanation James.
I must have reread that 4 times to try and get my head around it all, and I'll probably reread it all again.
I should have paid more attention in Electronics at secondary school

Q. When charging multiple packs of different capacities, are each of those packs charged to capacity then? That might be a daft question, but I was under the impression that the charge is balanced. Therefore each cell will end up with the same capacity.

[james_2k]

imagine it like several different sized glasses all linked at the bottom by a tube. as water goes in the top they all fill up the same % as the larger glasses take more water, its transferred between the glasses as well as new water from the top.

basically they all charge at the same time and will all finish at the same time.

oh i forgot one thing, its best practice to only connect batteries together that are of similar voltage levels (within 0.1v). i.e. one battery is 3.7v and one is 3.8v thats generally ok. and if you have balance leads (for the 2s or more batteries) then connect the main charge cables before the balance connectors. this insures that the current flow that will happen as you connect them up, flows through the larger cables and not the balance ones. this is mainly a factor for when you get larger batteries though

here is some useful info:
How-To: Parallel Charging - TJinTech

it was new to me a few months ago, only started parallel charging when i got my goblin which uses two batteries at a time and it was a huge pain to charge singly like most things in this hobby, just lots of reading

[5hane]

imagine it like several different sized glasses all linked at the bottom by a tube. as water goes in the top they all fill up the same % as the larger glasses take more water, its transferred between the glasses as well as new water from the top.

basically they all charge at the same time and will all finish at the same time.

oh i forgot one thing, its best practice to only connect batteries together that are of similar voltage levels (within 0.1v). i.e. one battery is 3.7v and one is 3.8v thats generally ok. and if you have balance leads (for the 2s or more batteries) then connect the main charge cables before the balance connectors. this insures that the current flow that will happen as you connect them up, flows through the larger cables and not the balance ones. this is mainly a factor for when you get larger batteries though

here is some useful info:
How-To: Parallel Charging - TJinTech

it was new to me a few months ago, only started parallel charging when i got my goblin which uses two batteries at a time and it was a huge pain to charge singly like most things in this hobby, just lots of reading

Good explanation
At this point I should probably go to that How To Parallel Charge link as the Similar Voltage explanation has thrown me, and I have questions probably too embarrassing to ask.

<edit> Sorry, im going to have to ask a stupid question: I thought a battery maintains it's voltage whatever it's capacity, hence why it is able to power the intended item until the battery capacity is drained. So why would any of the 3.7v batteries become 3.8v?

[myxiplx]

Best way to learn is to ask questions, and this hobby has a steep learning curve at the start, there's a ton of stuff to learn :-)

Battery voltage will vary with it's level of charge. A fully charged lipo cell will be around 4.2V, when discharged it will be nearer 3.7V, although they'll last longer if you keep them above 3.8V.

If you connect a bunch of batteries together in parallel, they will all equalize their voltage. Which means that if you charge a bunch of batteries in parallel, they will all hit 4.2V which means fully charged at around the same time.

mCPX BL packs are a little more complicated, as they have 2 cells in series, which is why they're called a 2S pack. Packs in series add their voltage together, they don't equal out and can potentially be at different levels of charge. They do give you more voltage from the battery, and a 2S pack is effectively an 8.4V battery. A 6S pack is a 25.2V battery!

The downside of series connections is that the individual cells don't even out their voltages, so could potentially charge at different rates. Because of that you have a balance lead, which has connections to every cell in the pack. That lead means the charger can monitor the cells individually, ensuring they all charge to 4.2V.

On your 2S batteries for the mCPX BL you will see the leads actually have 3 wires. For convenience on those little packs they just have a single lead that works for everything.

PS. That's probably a lot of new stuff to absorb in one go. Don't worry too much about it yet, it'll sink in as you progress in this hobby. Trust me, one thing you learn a ridiculous amount about is batteries! I thought I was learning to be a pilot, not an electrician!!

[5hane]

Best way to learn is to ask questions, and this hobby has a steep learning curve at the start, there's a ton of stuff to learn :-)

Battery voltage will vary with it's level of charge. A fully charged lipo cell will be around 4.2V, when discharged it will be nearer 3.7V, although they'll last longer if you keep them above 3.8V.

If you connect a bunch of batteries together in parallel, they will all equalize their voltage. Which means that if you charge a bunch of batteries in parallel, they will all hit 4.2V which means fully charged at around the same time.

mCPX BL packs are a little more complicated, as they have 2 cells in series, which is why they're called a 2S pack. Packs in series add their voltage together, they don't equal out and can potentially be at different levels of charge. They do give you more voltage from the battery, and a 2S pack is effectively an 8.4V battery. A 6S pack is a 25.2V battery!

The downside of series connections is that the individual cells don't even out their voltages, so could potentially charge at different rates. Because of that you have a balance lead, which has connections to every cell in the pack. That lead means the charger can monitor the cells individually, ensuring they all charge to 4.2V.

On your 2S batteries for the mCPX BL you will see the leads actually have 3 wires. For convenience on those little packs they just have a single lead that works for everything.

PS. That's probably a lot of new stuff to absorb in one go. Don't worry too much about it yet, it'll sink in as you progress in this hobby. Trust me, one thing you learn a ridiculous amount about is batteries! I thought I was learning to be a pilot, not an electrician!!

Thanks, slowly but surely it's sinking in.
So if I keep the capacity of the 2s packs above 20%, the voltage won't be an issue though? I assume each 2s pack has to be tested before each parallel charge just in case.

[tomatwalden]

Thanks, slowly but surely it's sinking in.
So if I keep the capacity of the 2s packs above 20%, the voltage won't be an issue though? I assume each 2s pack has to be tested before each parallel charge just in case.

The 20% rule is true regardless of 1S, 2S, 3S, etc ...

A good page to read : Understanding RC LiPo Batteries

[myxiplx]

Try to keep them over 30%, give yourself some leeway. Cold temps, or binding, or just flying harder can easily use up a little more power.

No need to check them before charging, so long as you have a balance charger just plug in and go. Even charging six packs in parallel just plug them in & charge it. With these small packs you really don't need to worry.

[5hane]

Try to keep them over 30%, give yourself some leeway. Cold temps, or binding, or just flying harder can easily use up a little more power.

No need to check them before charging, so long as you have a balance charger just plug in and go. Even charging six packs in parallel just plug them in & charge it. With these small packs you really don't need to worry.

Ok cool. Yes I think I read that when they are all connected the voltage balances out anyway. Although others have said that you have to be careful of voltage variations, but if it all balances out why worry
Also, I assume these chargers come with balancing leads, or don't they?

[myxiplx]

On these small packs you don't need to worry. On larger packs, you have to bear in mind that LiPos can discharge a *lot* faster than they can safely charge.

So while they'll balance out, the concern is over how quickly that happens. If you were to plug a fully charged 6S 5000mAh pack into a fully discharged 6S 5000mAh pack you're likely to get an almighty spark (potentially enough to weld the wires together), followed by one pack being charged at significantly over the recommended rate.

But on the smaller packs you're going to be using here, they're lower capacity and have higher resistance, so even if you do plug two together there just isn't going to be such an extreme reaction, they'll just settle down nicely and equalize their voltages.

[5hane]

On these small packs you don't need to worry. On larger packs, you have to bear in mind that LiPos can discharge a *lot* faster than they can safely charge.

So while they'll balance out, the concern is over how quickly that happens. If you were to plug a fully charged 6S 5000mAh pack into a fully discharged 6S 5000mAh pack you're likely to get an almighty spark (potentially enough to weld the wires together), followed by one pack being charged at significantly over the recommended rate.

But on the smaller packs you're going to be using here, they're lower capacity and have higher resistance, so even if you do plug two together there just isn't going to be such an extreme reaction, they'll just settle down nicely and equalize their voltages.

Cool, I will worry no more. I think im right in saying that packs under 3s don't have balance plugs on them anyway <edit> my mistake, 2s do
The items are now marked as dispatched, so here's hoping they arrive tomorrow.

[5hane]

To avoid disappointment, please can I just check that what I have ordered will charge my MSRX batteries.
I'm confident I have ordered the correct parallel lead for the MCPX-BL as it has banana plugs which connect directly to the charger, but the parallel lead which fits the MSRX batteries doesn't have banana plugs, but instead very small plug, possibly called a jst.
When I placed the order I assumed that banana plugless parallel lead would connect to one of the included leads that come with the charger, but now im not sure.

Here is the charger and banana plugless lead in question:
Turnigy MAX80W 7A Lithium Polymer Battery Charger (UK Warehouse)
2 Pin 6 x Pico Plug Charging Set Eflite compatible. (UK Warehouse)

Thanks

[james_2k]

this is what you need: Q-LP-0036 Quantum XT-60 Female To JST Adapter 20awg Silicone 100mm Model Helicopters