hobbyking

[Grumpy]

The Robotbirds deal on Hyperion G3 batteries looks pretty good. I've only tried a couple of Hyperion batteries before (years ago) but they were top notch. It's only the split pack thing that's a an issue but it looks increasingly like that's something we might have to get used to. First thing I'd do is re-wire the two 3S balance plugs into a single 6S plug so they could be charged as a 6S pack. Charging as two 3S sucks too many amps.

[jchbarnes]

Charging as two 3S sucks too many amps.

I don't understand this, please clarify- why would charging as 2x 3S use any more amps than charging as 1x 6S if the capacity is the same? Likewise many people use parallel charging boards or leads that have multiple connectors for 2-6s connectors that come off the same charger balance port so it would make no difference charging as 3S or 6S. For example my para board can connect 6 batteries - so it could do 6x 3S rather than 6x 6S but in reality the limiting factor is the max amps you can charge at (30A in my case) so it makes no difference.

[Grumpy]

I don't understand this, please clarify

You said it yourself; charging 6 x 3S 5000mA batteries takes just as long as charging 6 x 6S 5000mAh (because the charger is amp limited). But the point your missing is with split packs you will have twice as many batteries to charge, so actually charging all your batteries takes twice as long.

Looking at it another way, the mAh capacity is not the same. A split pack battery charged as 2 x 3S will have double the mAh capacity as the same battery charged as a 6S, therefore it will take twice the amps to charge in the same timeframe.

Most high power chargers are optimised for 6S charging.. For instance a Powerlab or big iCharger will do 40A or 1000W (whichever limit comes first). A 6S battery optimises the charger's ability because it runs close to both limits (40A x 25.2V = 1008A). On the other hand if you charge 3S batteries you hit the 40A limit while still at only half of the chargers power (40A x 12.6V = 504W), hence the comment I made about drawing too many amps.

[Ruston]

The Robotbirds deal on Hyperion G3 batteries looks pretty good. I've only tried a couple of Hyperion batteries before (years ago) but they were top notch. It's only the split pack thing that's a an issue but it looks increasingly like that's something we might have to get used to. First thing I'd do is re-wire the two 3S balance plugs into a single 6S plug so they could be charged as a 6S pack. Charging as two 3S sucks too many amps.

An alternative is a series balance board: https://hobbyking.com/en_us/turnigy-...-board-xh.html

[Grumpy]

An alternative is a series balance board: https://hobbyking.com/en_us/turnigy-...-board-xh.html

Very risky. If you get the sequence of connection of the two main power plugs and the two balance leads reversed them your balance connector goes up in a puff of smoke and flame! At the least you would have to colour code the power and balance battery connectors and the mating charge leads to give yourself a fighting chance of not getting the connections the wrong way around. Too risky for my tastes though.

[jchbarnes]

A split pack battery charged as 2 x 3S will have double the mAh capacity as the same battery charged as a 6S, therefore it will take twice the amps to charge in the same timeframe.

Sorry still confused! A 6S 5000mah pack has exactly the same capacity as 2x 3S 5000mah packs connected in series to make a 6S 5000mah pack. So my point is that a single 6S pack will use exactly the same amount of amps and time to charge as a 6S split pack. Therefore it is the charger output that limits the number of packs, not whether they consist of single 6S or split 3S packs (assuming you have enough connectors to parallel charge). This is obviously assuming you charge the split packs still connected in series as a 6S pack but you can still plug in the 3S balance connectors at will without them needing to be combined into a 6S connector. I think you mean the limit is if you are charging at 3S where the voltage and power are halved - but on your charger you could still do 8x 3S 5000 packs at 1C (i.e. 4x 6S packs), maybe I missed something...

[jchbarnes]

Very risky. If you get the sequence of connection of the two main power plugs and the two balance leads reversed them your balance connector goes up in a puff of smoke and flame! At the least you would have to colour code the power and balance battery connectors and the mating charge leads to give yourself a fighting chance of not getting the connections the wrong way around. Too risky for my tastes though.

I always plug in all the main power plugs first, then all the balance connectors afterwards. Not had any issues doing it that way - we all accept that parallel and series charging has plenty of additional risks over just charging 1 pack at a time though.

[Grumpy]

Sorry still confused! A 6S 5000mah pack has exactly the same capacity as 2x 3S 5000mah packs connected in series to make a 6S 5000mah pack.

That's where you are getting confused. two 3S 5000mA packs connected in parallel = 3s 10000mAh.. Therefore compared to the 6S pack the mAh capacity has doubled (but voltage is halved)

• To charge one 6S 5000 pack at 1C requires 5 amps

• To charge two 3S 5000 packs at 1C requires 10 amps

So as I said earlier, the same pack if split requires double the charge current which means you very soon hit the limit of even the best of chargers.

[Grumpy]

I always plug in all the main power plugs first, then all the balance connectors afterwards. Not had any issues doing it that way - we all accept that parallel and series charging has plenty of additional risks over just charging 1 pack at a time though.

With series connection it's not which one you connect first that's critical, it which port you plug the leads into. Unlike parallel you cant just plug the battery in to any open connection on the board. With series one battery becomes low voltage and one high voltage... It's kinda hard to explain but trust me on this, if you don't know what I'm talking about don't try it!

[scallybert]

Meanwhile, I have an email from FedEx...

[Grumpy]

Meanwhile, I have an email from FedEx...

Ahh.. I'd completely forgotten what the thread was about! So what do you owe them?

[jchbarnes]

Therefore compared to the 6S pack the mAh capacity has doubled (but voltage is halved).

Yes that's why I presumed we were talking about charging the 3S packs still connected in series - not really any point in unplugging the series connectors to then parallel charge them in 3S when they are already combined as a 6S pack. Confusion resolved, we were talking about different scenarios.

[jchbarnes]

The thread was initially about the issues getting 6S 5000 packs sent via post so people are considering using split packs to get around this (so the 3S vs 6S is quite relevant!). Even with the customs/VAT/charges I suspect the packs are still cheaper than buying them in the UK, unless you buy one at a time.

[Ruston]

That's where you are getting confused. two 3S 5000mA packs connected in parallel = 3s 10000mAh.. Therefore compared to the 6S pack the mAh capacity has doubled (but voltage is halved)

• To charge one 6S 5000 pack at 1C requires 5 amps

• To charge two 3S 5000 packs at 1C requires 10 amps

So as I said earlier, the same pack if split requires double the charge current which means you very soon hit the limit of even the best of chargers.

Why would you charge a split pack in it's split state? Just make the connection between the 2 packs and charge it as a 6s.

[Mark_T]

Why would you charge a split pack in it's split state? Just make the connection between the 2 packs and charge it as a 6s.

That was where this chain of confusion started

If the pack is supplied with 2 x 3S balance connectors then you can't just 'charge it as a 6S' you either charge it as 2 x 3S, or use a Y harness for the balance connectors or replace the 2 x 3S balance connectors with a 6S connector as was the original intention in this thread...

Just for the record, one reason why you may want to charge as 2 x 3S is if your charger has multiple ports but is limited on the Watts per port...

Not the case here where it is Amps that is the main concern so therefore much better to charge as 6S.