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Oct 12, 2016, 06:58 PM
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czajunia's Avatar
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Mini-Review

ISDT PC-4860 Safe Parallel Adapter - 40A Input


ISDT PC-4860 Safe Parallel Adapter - 40A Input

Not long after introducing two high quality smart chargers to the market ISDT comes back with a parallel charging adapter. Seems like they adopted similar philosophy when designing this product - smart and original design combined with using high quality materials and great attention to details. Similarly the packaging is very minimalistic.


First thing you notice when picking up the adapter is how small and relatively heavy it is. And this is not a bad thing. The case is all metal CNC machined and it screams quality.


I was a bit concerned that there won't be any accessories provided with the adapter as was the case with ISDT chargers. Luckily apart from the adapter, inside the box we also find a 14 AWG power cable and a balance lead. Oddly enough even though the adapter can parallel charge 8s batteries the supplied cable supports 6s only.


As expected there is no user manual included. The only two pieces of written information is a safety note on the box and diagram on the back of the adapter itself. This is pretty much all information needed to start using the adapter. The diagram shows how to connect balance leads which is very clearly explained. There is a dot above each balance port and that's the side the balance cable needs to be connected from. Also, the first tooth on this side is a larger one so it's really difficult to get this wrong.


Let's have a closer look at the adapter itself.

PC-4680 is designed to parallel charge 4 packs. There are four XT-60 power outputs to connect batteries on top of the unit. At the back there is basic specification listed plus a balance lead connection diagram.


The inputs are located on the top of the adapter. There is an XT-60 power input and the balance port. Both sides of the unit are exactly the same and contain a couple output balance ports each. There are no additional outputs to daisy chain another adapter. It's still possible to do that but it means that effectively the adapter will only have 3 battery outputs as the fourth one will be used to hook up another adapter.

The unit measures 88mm x 58mm x 19.5mm and weighs 212g. It is just a touch larger than a credit card. It has exactly the same length and width as the smaller of the ISDT chargers, SC-608. It was very likely designed to be a perfect companion for the charger and it probably means that ISDT might release a bigger adapter as well. Supporting 6 batteries for example.


Inside the adapter
So far so good. I must say that I am rather impressed with the quality and the design of the adapter. Hopefully it's not just a pretty face though. Let's have look what is inside.


There are no surprises here when it comes to the casing. The weight of the unit already indicated this will be all metal design. And it is indeed, nicely carved two pieces of anodised aluminum.



I am not a PCB design nor a soldering expert but the main board looks quite well made to me. Also, the ISDT put the word "safe" in the name of the adapter for a reason. There is a number of self resetting fuses present on the board which should protect individual cells of connected packs. Also, there are some fuses connected to the power outputs and I assume they provide some overcurrent / overvoltage protection. The product description on Banggood website states there are 32 fuses available. I only found 30 of them on the PCB. One way or another the total number doesn't make much sense to me as I thought there should be more of them if all individual cells should be protected and there is also extra over current protection. I guess there must some clever PCB design here and there are enough fuses on the board anyway. The case is anodised inside and out which means it's nonconductive and there is also additional insulation added for extra safety.

Specification:
Max Input Current: 40A
Max Output Current: 30A/Port
Max Balance Current: 2A
Number of Cells: 1s~8s

Specification looks quite impressive. The only problem is ISDT doesn't specify the maximum power so we don't know what voltages above values correspond to. I doubt this adapter can take 40A at 33.6V (8s) which is almost 1350W.

EDIT: Apparently this is not relevant in this case as the board would never dissipate anywhere near 1350 Watts (thank you for your comments John):
Quote:
The Power is effectively irrelevant. This is just a connector board. All the power dissipation within each of the individual circuits is limited by the current they can take. The heating in each circuit will be given by the ohmic dissipation. That is Watts = I*I*R.

The board does not dissipate 1340 Watts anymore than the connecting wires do - the charger is providing that power to the battery. The total resistance will depend on the polyfuse resistance and the connector resistance but it is unlikely to be more than a few milliOhm. Say if it was 10 mOhm the power dissipation is going to be 0.01 * 40 *40 = 16 Watts. That's still a lot and it is multiplied by the number of circuits in use but it is nowhere near 1350 Watts.
Unfortunately I won't be able to test this as I don't have a charger powerful enough nor have I such big batteries that would require so much power to charge. Certainly the metal casing should help in heat dissipation here and reduce the risk of overheating.

For full specification please visit the product page here.


Quick comparison
Before wrapping up let's have a look how this adapter compares to a cheap parallel adapter from Aliexpress. By cheap I mean $8 or so cheap.




As mentioned already the ISDT adapter is compact but relatively heavy. Compared to a larger 6 packs compatible all plastic adapter it weighs almost 100g more. It is comfortably smaller though and has no protruding parts which makes it is pocket friendly.

In terms of safety and offered protection please see how ISDT compares to the cheap Aliexpress adapter as well as the benchmark in parallel charging safety, Revoelectrix MPA adapter.


The cheap adapter only has one main fuse which should provide some overcurrent protection. And that's it. There are no additional fuses protecting individual cells. Revoelectrix MPS not only has a line of self resetting fuses related to cells in each pack but also has 12 additional fuses on the top plate that provide reverse polarity and overcurrent protection. So in terms of safety looks like ISDT seats somewhere in between.


Conclusion
Let's have a look at a list of pros and cons first.

Things I like:
- original design
- excellent build and material quality
- small, pocket friendly size
- metal casing helps in heat dissipation
- safety features on board also providing protection for individual cells

Thing's I do not like:
- only 6s balance lead provided
- price
- quite easy to scratch

Thing's that didn't bother me much but may be important to someone else:
- only 4 ports
- lack of additional outputs to daisy chain another adapter. One of the battery outputs can be used for that but it means we are losing one output
- compared to Revoelectrix it feels like the adapter could offer a bit more protection

In terms of the design and manufacturing quality of the adapter ISDT has introduced something truly unique to the market. It's a real beauty and the weight and finish inspire confidence from the moment you grab it for the first time. Luckily it's not just a good looking adapter and ISDT also focused on designing the main circuit to include some safety features which should protect your cells or charger in case something goes wrong. Unfortunately I won't be able to verify what is the maximum power rating of the charger but the specification if accurate is also very impressive.

As always quality is not cheap and this adapter sells for about $38 dollars. (Currently available at Banggood for $34 until the 15th October). I don't think it is prohibitively expensive though. Especially considering the build quality and the fact it has safety features built in. However this means it won't be for everyone as most of us prefer to get something cheaper that gets the job done. Also, those looking for charging more than 4 batteries will have to look elsewhere.

It's rather hard to get excited about something such as a parallel charging adapter but this ISDT product can make you do just that. No doubt it's a premium product but whether there is a place for such an offering in the RC hobby world only the time will tell.


The charger for this unbiased* review has been provided to me by Banggood.com and can be purchased from their website here. It's currently on offer and it's available for $34 with free shipping. EDIT: The special offer has finished and the adapter is back to $37.99 now. To get a similar price plesae use the 10% OFF coupon code 'RCpower'.


*In short an unbiased review means that if I don't like something I will say it. It also means that I have not been paid to write this review. I was only provided the product free of charge without obligation to write a positive review.

Last edited by czajunia; Jul 15, 2017 at 08:54 AM.
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Oct 12, 2016, 10:24 PM
ancora imparo
jj604's Avatar
Nice review!

Just a comment on:

Specification looks quite impressive. The only problem is ISDT doesn't specify the maximum power so we don't know what voltages above values correspond to. I doubt this adapter can take 40A at 33.6V (8s) which is almost 1350W.

The Power is effectively irrelevant. This is just a connector board. All the power dissipation within each of the individual circuits is limited by the current they can take. The heating in each circuit will be given by the ohmic dissipation. That is Watts = I*I*R.

The board does not dissipate 1340 Watts anymore than the connecting wires do - the charger is providing that power to the battery. The total resistance will depend on the polyfuse resistance and the connector resistance but it is unlikely to be more than a few milliOhm. Say if it was 10 mOhm the power dissipation is going to be 0.01 * 40 *40 = 16 Watts. That's still a lot and it is multiplied by the number of circuits in use but it is nowhere near 1350 Watts.

John

PS You can daisy chain these. You just connect the input of the second board to one of the outputs of the first. You get 7 not 8 outlets of course. It's probably also worth mentioning that the case is anodised inside and out and so is non-conducting. iSDT have added additional insulation as well so it should be pretty robust electrically.
Oct 13, 2016, 03:39 AM
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czajunia's Avatar
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Thank you for your comments John. I am happy you shared your analytic and scientific views here. Will update the review to reflect them.

Quote:
Originally Posted by jj604
Nice review!

The Power is effectively irrelevant. This is just a connector board. All the power dissipation within each of the individual circuits is limited by the current they can take. The heating in each circuit will be given by the ohmic dissipation. That is Watts = I*I*R.

The board does not dissipate 1340 Watts anymore than the connecting wires do - the charger is providing that power to the battery. The total resistance will depend on the polyfuse resistance and the connector resistance but it is unlikely to be more than a few milliOhm. Say if it was 10 mOhm the power dissipation is going to be 0.01 * 40 *40 = 16 Watts. That's still a lot and it is multiplied by the number of circuits in use but it is nowhere near 1350 Watts.
That's great news. I wasn't sure if feeding such high current at higher voltages could cause overheating problems or not even though it is distributed across individual cells. So for the sake of simplicity let's assume there are no losses and we are feeding the adapter 40A at 33.6V which gives us 10A per port to work with. Do you reckon we could use this adapter to parallel charge 4 x 8s 5000mAh batteries @ 2C for example? Or do you reckon it would overheat?

Quote:
PS You can daisy chain these. You just connect the input of the second board to one of the outputs of the first. You get 7 not 8 outlets of course. It's probably also worth mentioning that the case is anodised inside and out and so is non-conducting. iSDT have added additional insulation as well so it should be pretty robust electrically.
I actually thought about this as well but as you said we are losing one output in such case so it's not ideal. It's probably worth noting this in the review though in case someone takes it as a negative point.
Oct 13, 2016, 04:24 AM
ancora imparo
jj604's Avatar
It's hard to know for sure because I don't know what the actual resistance of the polyfuses is.

My guess would be that it is likely to get pretty warm if you parallel charge 4x 8s 5Ah at 2c though.

At 40A per circuit and a total contact + polyfuse resistance of 10mOhm which seems a reasonable figure, that's 16 Watts per circuit x 8 = 128 Watts.

That's a fair bit. Think of a 100Watt old fashioned incandescant light globe. Pretty toasty. Whether the metal case provides enough heat sinking to keep the temperature to a reasonable value is hard to say without actually trying it.

There is just too much unknown, including my resistance assumptions. If it heats up, do the polyfuses increase their resistance and so it gets hotter till they open? Don't know. You would like to think iSDT have tested it and their claim of 40A is valid even for 8S however.

The only way to know for sure will be to actually try it.

On the plus side it is going to do better than other parallel boards - it isn't going to melt.

It is certainly a very elegant little piece of work and I keep mine in the LiPo field box with my iSDT Sc608. they make a perfect combination.


John
Quote:
Originally Posted by czajunia
Thank you for your comments John. I am happy you shared your analytic and scientific views here. Will update the review to reflect them.



That's great news. I wasn't sure if feeding such high current at higher voltages could cause overheating problems or not even though it is distributed across individual cells. So for the sake of simplicity let's assume there are no losses and we are feeding the adapter 40A at 33.6V which gives us 10A per port to work with. Do you reckon we could use this adapter to parallel charge 4 x 8s 5000mAh batteries @ 2C for example? Or do you reckon it would overheat?



I actually thought about this as well but as you said we are losing one output in such case so it's not ideal. It's probably worth noting this in the review though in case someone takes it as a negative point.
Oct 13, 2016, 04:45 AM
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czajunia's Avatar
Thread OP
Quote:
Originally Posted by jj604
On the plus side it is going to do better than other parallel boards - it isn't going to melt.
Good point
Quote:
It is certainly a very elegant little piece of work and I keep mine in the LiPo field box with my iSDT Sc608. they make a perfect combination.
Very smart set-up. You are not trying to impress someone, are you?
Oct 13, 2016, 05:06 AM
ancora imparo
jj604's Avatar
Actually it is a very practical setup. I am using a couple of older 6S 5000 LiPos that are past serious use but just fine at lower C rates to power the iSDT 608. I now only have to take 3-4 of the smaller 1500mAh size packs to the field. The Graphenes can be safely recharged at 5 C so I always have charged packs ready. One of our other club members was the first to point out that you can save a lot of money on packs this way as you only need a few.
Quote:
Originally Posted by czajunia
Good point

Very smart set-up. You are not trying to impress someone, are you?
Oct 13, 2016, 06:00 AM
Registered User
Only 24 poly fuses total, this is enough to protect 6 of 9 pins on each port.
Main port also seems to be protected, however at that size most likely fast acting smd fuse (non reset)

If fuse on main port indeed is non reset type with no indication if it is blown or not, then this is a huge design flaw.

Looks more like false safety board in pretty packaging, but would need a board in hand to say for sure.
Oct 13, 2016, 06:19 AM
ancora imparo
jj604's Avatar
No it's enough to protect 8 pins on 4 ports. The fuses only have to be between pins so 3 fuses per 4 pins. And ground is common.
Quote:
Originally Posted by Jinkslynx
Only 24 poly fuses total, this is enough to protect 6 of 9 pins on each port.
Main port also seems to be protected, however at that size most likely fast acting smd fuse (non reset)

If fuse on main port indeed is non reset type with no indication if it is blown or not, then this is a huge design flaw.

Looks more like false safety board in pretty packaging, but would need a board in hand to say for sure.
Oct 13, 2016, 06:27 AM
Registered User
Ah, that make sense, but will this not leave your charger unprotected?

Edit: Against voltage on balance gnd.
Last edited by Jinkslynx; Oct 13, 2016 at 06:40 AM.
Oct 13, 2016, 07:34 AM
ancora imparo
jj604's Avatar
A balance board simply converts multiple packs into an equivalent single pack. The fuses are to protect for current flow BETWEEN cells when they are connected to the parallel board if they are at different voltages. Once they are all connected the voltages equalise and at any cell tap is the same for all the connected packs.

The charger is designed to deal with voltage differences between the new "combined" cells. That's what the balancing circuits in the charger do.

There is no voltage difference at balance ground. By definition ground is at zero. All other voltages are referred to it.

Quote:
Originally Posted by Jinkslynx
Ah, that make sense, but will this not leave your charger unprotected?

Edit: Against voltage on balance gnd.
Oct 19, 2016, 04:18 AM
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czajunia's Avatar
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The special offer on the adapter has finished and it's back to $37.99 @ Banggood now. To get a similar price please use the 10% OFF coupon code 'RCpower' at the checkout.
Last edited by czajunia; Oct 19, 2016 at 04:25 AM.
Oct 19, 2016, 02:52 PM
Frankenstein recycled packs
rampman's Avatar
I "finally" happened upon this thread. Nice change in parallel boards and this is coming from a guy that has burned many traces on un-fused boards, did one yesterday. Simple fixes every time so it is good to see a new take on these.

Now, I have a question.
Rated at 40 amps, I must assume 40 amps only if supplying 10 amps to each of 4 packs?
My reason for stating this is the traces on the top of the board are rated at 4 amps each. Looking at the bottom power carrying layer and knowing there has to be another power carrying layer sandwiched between the top and bottom, can it take 40 amps constant from the input to, say, the furthest away XT60 connector? Seems to me the via for the main connectors may get really hot.

40 amps is a LOT of power to carry across the thin copper plating on a PCB and it is interrupted in many places to allow connectors and via's to transfer from top to middle to bottom layers.

To answer the question of poly fuses and their relation to heat, they are all about heat. The hotter the board the lower the trip point.

I cannot attach a .pdf at work but here is the doc I was trying to attach.

https://www.rcgroups.com/forums/show...7&d=1464909601

Rick
Oct 23, 2016, 06:59 PM
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czajunia's Avatar
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Quote:
Originally Posted by rampman
Rated at 40 amps, I must assume 40 amps only if supplying 10 amps to each of 4 packs?
Yes, this is also how I understand the specification.
Oct 23, 2016, 07:19 PM
Registered User
It'll actually supply up to 30A to any single port according to the specifications listed on the product page. e.g. - If charging a single pack through the adapter, do not exceed 30A. Full rated 40A is available when charging two to four packs.

I have one of these and have started using it over the last few weeks. I've performed 6 charges with the board thus far and all packs were perfectly balanced at the completion of charge. Two of the six charges were performed at the full 40A output of my PL8 and the device worked flawlessly, as I expected. In all 6 uses, my board was fully populated with 4 packs.

I will continue to use it for field charging over the next several weeks and will compile a more comprehensive analysis. So far, it's been fantastic and is very robust and compact.

Mark
Oct 23, 2016, 10:07 PM
Registered User
Mark,
would this be the appropriate adapter to connect to a PL6?
http://www.usastore.revolectrix.com/...2/MPA-XH-PL_55
not sure I understand the plug for the ISDT? is it a "universal" JST H plug?


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