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Jun 10, 2016, 01:38 PM
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Thread OP
Help!

Paraboard???


Is paraboard good way of charging multiple batteries or is it a safety hazzard?

If it is safe, what paraboard do you recommend with hitech chargers to charge 3s battery with ec3 or t connector?
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Jun 10, 2016, 01:54 PM
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Ken Myers's Avatar
This thread suggests some paraboards that you might not want to consider for purchase and why.

https://www.rcgroups.com/forums/show....php?t=2675694
Last edited by Ken Myers; Jun 10, 2016 at 02:25 PM.
Jun 10, 2016, 01:59 PM
http://www.sgvhumane.org/
cmdl's Avatar
Why not use harnesses? Easier to work with if you have an issue.
Jun 10, 2016, 02:24 PM
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Thread OP
Harnesses? I have been flying only a year so I don't really know different options that's avaliable with charging multiple lipos.
Jun 10, 2016, 02:27 PM
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Ken Myers's Avatar
Visit Progressive RC and look under the heading Wire & Connections

http://www.progressiverc.com/

You will find charge cables and charge boards
Jun 10, 2016, 02:29 PM
http://www.sgvhumane.org/
cmdl's Avatar
Quote:
Originally Posted by lov2flywarbird
Harnesses? I have been flying only a year so I don't really know different options that's avaliable with charging multiple lipos.
https://www.hobbyking.com/hobbyking/s...6xJST_XH_.html
and
https://www.hobbyking.com/hobbyking/s...g_Harness.html
Jun 10, 2016, 02:44 PM
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Thread OP
Thank you guys
Jun 10, 2016, 03:00 PM
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Race Miata's Avatar
I use both methods: paraboard, and harness (aka squids).

Squids are easy to plug/unplug but are more expensive and since balance leads are quite fragile in general I would rather lose the single 7-lead harness from the paraboard to the charger than to lose the entire balance lead squid. The former is easier/cheaper to replace. Yes, I have both failed before, multiple sets.
Jun 10, 2016, 03:25 PM
http://www.sgvhumane.org/
cmdl's Avatar
@RaceMiata: I read that connectivity problems are harder to diagnose in paraboards (understandably so, since you have to disassemble the item whereas with harnesses), it may typically be a single lead with the rest working fine. If paraboards aren't as susceptible to issues as I imagined (maybe even misread), I may order them instead (I need backups) since 4s harnesses are out of stock at HK and taking forever to stock up. Your thoughts?
Jun 10, 2016, 03:56 PM
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Race Miata's Avatar
HK paraboard has just foam padding at the back so for any diagnostics just peel out the foam and check continuity and put back the foam afterwards, possibly with new double-side tape. The squids are easier to use but there are more failing points whereas with paraboard it's usually the 7-lead harness that fails first on normal wear-and-tear, unless you mistakenly shorten some packs and burn out the traces on the board itself which is not uncommon and can be fixed by soldering in wires manually. Squids are less likely to burn out but that means when you short out energy has to go somewhere. IOW, you can think of the traces on the paraboard as fuse. There are pros and cons for each but since the squids are hard to come by at HK perhaps it's not a bad idea to get the paraboard for now and consider squids when they have in stock.
Jun 10, 2016, 04:06 PM
http://www.sgvhumane.org/
cmdl's Avatar
Gotcha. Thanks. I'll order the boards then - unfortunately, they're also out of stock (EC3), so I'll wait for them too.

One last question, is there a recommended procedure to plugging-in the batts?

Reason I ask is, one poster on the HK site cautioned EC3 connectors first, then balance plugs:
"always plug the battery leads first when you use one of these"

Another posted cautioned against plugging-in opposite balance connectors (whatever that means):
"Balance ports on different sides of the paraboard are arranged in REVERSED direction. This is a critical feature. The HK version is designed the same way. When I attempted to connect the balance plug on the opposite side I made certain that the guides on the balance plug were aligned correctly. When I inserted the plug it blew the fuse. So, you can say the safety feature worked. But the more troubling part is the paraboard was probably not wired correctly."

Thanks.
Jun 11, 2016, 01:40 AM
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Race Miata's Avatar
I know people disagree but I strongly believe in plugging in balance leads before plugging in main leads. My reasons are many. 1. With most main lead connectors it's very unlikely to be able to mistakenly plug in +ve to -ve or vice versa which is only a concern when the balance leads have already been plugged in along with other pre-plugged batteries. OTOH, it's extremely easy to plug in balance plug 1 pin off on the balance board. If you already have the main leads on and there is at least 1 more battery have both main and balance leads plugged in, a 1-pin off situation will guarantee sparks and smoke. If you plug in balance plug 1-pin off but with main plug out, you still have a chance to double-check and unplug before plugging in main plug to see damage.

2. When you're plugging/unplugging balance leads it's extremely unlikely the stray main leads can go into one of the main lead connector on the paraboard in such a way that +ve touches -ve or -ve touches +ve. OTOH, if you're plugging/unplugging main lead connector while the stray balance plug goes near the paraboard it's very likely any of the pins on the balance board (see there's so many of them on a paraboard) will plug into one of the stray balance plug holes. Any pin on the balance plug going into any pin other than the corresponding pin on the paraboard (6 out of 7 chances) you're guaranteed to get sparks and smoke.

3. When the packs to be parallel charged are not exactly the same voltages, current flow between them to act as self-balancing. If you plug in balance leads first the "self-balancing" current is low simply because of the IRs on the balance leads. If you plug in main leads first the "self-balancing" current is much higher depending on IRs of your packs. I've done an experiment by plugging in 2 4S 65C 1300 Graphene packs that differ in pack voltage by a mere 0.2V (that's 0.05V cell voltage difference) together thru' a wattmeter. It logged a peak of over 10A for not just mere milliseconds (my wattmeter logs graph also not just min/max). You get almost proportionally higher current with proportionally bigger capacity packs under the otherwise identical situation.
Jun 11, 2016, 01:52 AM
http://www.sgvhumane.org/
cmdl's Avatar
Thank you for the detailed explanation. I will plug in balance plugs first - your process makes sense.
Jun 11, 2016, 07:27 AM
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Quote:
Originally Posted by Race Miata
I know people disagree but I strongly believe in plugging in balance leads before plugging in main leads.
Count me as one who disagrees, and with equal but opposite reasons.

Quote:
Originally Posted by Race Miata
1. With most main lead connectors it's very unlikely to be able to mistakenly plug in +ve to -ve or vice versa which is only a concern when the balance leads have already been plugged in along with other pre-plugged batteries. OTOH, it's extremely easy to plug in balance plug 1 pin off on the balance board. If you already have the main leads on and there is at least 1 more battery have both main and balance leads plugged in, a 1-pin off situation will guarantee sparks and smoke. If you plug in balance plug 1-pin off but with main plug out, you still have a chance to double-check and unplug before plugging in main plug to see damage.
The potential for shorting exists whether plugging in main connectors first or balance connectors first. Remember, the main connectors and balance connectors on any balance board are not connected to one another so connection sequence is immaterial as it relates to shorting risk. For maximum safety, it's wisest to first fully populate the balance board or harnesses and then attach to charger. The exposed 4mm connectors that come on many parallel boards / harnesses should be replaced by an XT60, APP, or other connector to accommodate this.

Quote:
Originally Posted by Race Miata
3. When the packs to be parallel charged are not exactly the same voltages, current flow between them to act as self-balancing. If you plug in balance leads first the "self-balancing" current is low simply because of the IRs on the balance leads.
I've repaired better than a dozen parallel boards of folks at my local flying field who shared this notion. Yes, resistance in the balance leads is greater than the main leads but it will certainly not limit current to the point that it will have no chance of smoking traces in some non-fused parallel boards, which can be quite thin.

This is where connecting balance connectors prior to main connectors can create a massive safety hazard. If packs are large or have sufficiently low internal resistance and are at different states-of-charge, connecting balance taps first can easily burn traces between board locations and this can easily remain unknown by the user as the first position on the board will still be intact and will be connected to the charger. The other positions on the board will receive a non-balance charge and can easily lead to a lipo fire. I know of one fellow who was performing a balance charge on several packs with a parallel board and had a pack that vented during charging. Investigation after the fire revealed burned traces in the balance traces of his parallel board with the end result only one of the six packs actually receiving a balance charge. He inspected his two other identical parallel boards and they had similar open circuits in the balance traces. Common denominator - he had always been connecting balance taps prior to main connectors.

If one uses parallel boards and does decide to connect balance taps prior to main connectors, it would be extremely wise to verify the integrity of all balance taps on a regular basis. The simplest way to do this is to first populate the balance position furthest away from the output of the parallel board and then check the output with the charger in monitor mode or with a cell checker. If connecting in this manner, it would also be very wise to ensure that all packs are very close to the same voltage prior to connecting to avoid current that could cause an open circuit in the board.

With fused parallel boards, connecting balance leads prior to main leads can trip the polyfuses, which can cause degradation over time and lead to unpredictable results.

With harnesses, connecting balance leads prior to main leads can cause the leads to heat up a fair amount, but is unlikely to cause an open as the wires in the harnesses are typically of far greater cross section than parallel boards. Here, connecting balance leads prior to main connectors won't create the same safety hazard as it will with parallel boards.

My $.02.

Mark
Jun 11, 2016, 09:55 AM
http://www.sgvhumane.org/
cmdl's Avatar
Mark,
Thank you.
When I plug in my harnesses, I really don't pay attention to main connector vs balance connector first. Seems from your post that the order may not be an issue with harnesses but is with paraboards. Did I get that right?
Also, I am wary of connecting all batteries first and then to charger. I once did that with my 2s harness and being careless, I let the banana plugs touch. Battery did not survive. Granted it was me, but I am trying to foolproof against me.

PS - I finally gave up and ordered a whole bunch of 2x harnesses on HK since it doesn't seem like I may get the boards or the 6x harnesses and I'd rather charge two at a time than have my only 6x go bad and be stuck.


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