Batteries in series

[Glen]

Hi All

I have just purchased a Align trex 600 helli

It runs on 2 X 6 cell lipos

My question is how do I wire these up in series on the model and is there a way to stop the sparking when connecting such large lipos

Advice would be very much appreciated

Kindest regards

Glen

[Dave Hopkin]

Spark Arrestor Design - **LINK**

Batteries in Series (this is for deans lugs, but its the same for any type of connector)

[Frank Skilbeck]

Jeti also do a very nice 4mm and 5.5mm set of connectors with built in antispark I use these on an 8s setup using 2 x 4s batteries, using 5.5mm connectors on all the batteries.

[Allan Bennett]

Of course, you can omit the connector at the top of Dave Hopkin's picture, and just have the two wires from the ESC going straight through to the left and right connector. I use this arrangement on a couple of my fixed-wing models, and have got spark arrestors just like Dave Hopkin's link. They actually came installed on my HobbyWing HV ESCs, and work well -- just have to remember the correct sequence of plugging things together.

[Glen]

Hi Guys

Thank you so much for your replys Could you just explain what sequence I have to use on plug in

Many thanks

Glen

[Phil Green]

Posted by Dave Hopkin on 29/12/2014 00:58:36:

Spark Arrestor Design - **LINK**

I read the Scorpion importers advice and IMHO I think its tosh!
​At 1500 ohms there will be more leakage into the ESC electronics than charge current into the caps. In normal use the input caps are passing several amps of ripple-current so there is no need to limit the inrush to a few milliamps. With the supply at 1500 ohms impedance the ESC input voltage is going to drop to almost nothing when it attempts to signal arming by modulating the armature with AF.

The other contributors later in the thread have the right idea - a much lower resistance.

Cheers
Phil

[Dave Hopkin]

Posted by Phil Green on 29/12/2014 22:33:51:

Posted by Dave Hopkin on 29/12/2014 00:58:36:

Spark Arrestor Design - **LINK**

I read the Scorpion importers advice and IMHO I think its tosh!
​At 1500 ohms there will be more leakage into the ESC electronics than charge current into the caps. In normal use the input caps are passing several amps of ripple-current so there is no need to limit the inrush to a few milliamps. With the supply at 1500 ohms impedance the ESC input voltage is going to drop to almost nothing when it attempts to signal arming by modulating the armature with AF.

The other contributors later in the thread have the right idea - a much lower resistance.

Cheers
Phil

If you read all the thread it says towards the bottom that a more successful resistor was 510 ohm which cut the cap charge time from about 60 seconds to a much shorter gap

[Phil Green]

Maybe Skorpions are special Dave but I cant see how a conventional ESC can drag enough current through a 500 ohm resistor to arm. Arming takes significant current when the armature is used for the beep signals. The input caps wont sustain that current at the charged voltage for the duration of the beeps, the input voltage will simply collapse through its 500 ohm impedance.
Also by significantly delaying the power-on rise time the ESC electronics are being forced through brownout every time its connected and who knows how the processor will react to that. Processor POR is usually in the region of tens of ms (PIC is 72ms) so the ESC processor will come out of reset long before the supply has stabilised. Further, the onboard BEC will be supplying this sub-5v, unregulated, slow rise-time power to the rx and servos. How will they react?  They expect to be either on or off, not slowly ramped up to 5v over a period. Sorry I think the suggested values are tosh and I'd guess an order of mag below 500 at the most!

But its only a personal observation, YMMV as they say!

Cheers
Phil

Edited By Phil Green on 29/12/2014 23:21:35

[Peter Jenkins]

Never had a problem with my ESCs arming when using the Jeti anti spark device on either my 5S or 10S setups. The lack of any drama when connecting up is a great relief!

[Dave Hopkin]

I dont know enough about the internals of ESC's to comment Peter, but going back to basic City and Guilds Radio & Line Transmission isnt the resistor simply there as a spark quench to permit a reduced current to charge up the Caps before the main power comes on line? I seem to recall we had similar spark quench circuits in power switching in underground facilities

[Allan Bennett]

I don't know what the value of the resistor is in my Hobbywing anti-spark, but it's low enough that there's no spark with 12S when I connect the bullet a couple of seconds later.

Glen, if you're using an anti-spark similar to the one in Dave's link, you first make sure that the bullet connector is disconnected, then you connect either of the two 6S packs to the series harness, followed by the other. When they're both connected a small current will flow through the anti-spark resistor and gently charge up the capacitors in the ESC. It may be enough to make the ESC arm, and your receiver (if you're using a BEC) initialise and bind. Then connect the bullet connector, and you're ready for your pre-flight checks, and flight.