[done] someone pls draw me a simple eagle/diptrace board

[izeman]

this ask for help goes out to all the guys who know how to draw a quick schematic and board layout.

for two days i tried to make one board which should be uploaded to osh park for making, but i just can't handle eagle or diptrace good enough to make it happen. i watched several tutorials, but the result is never as expected i downloaded the jst-xh connector library, but as soon as it comes to traces on the board it get's weird.

in short words: maybe there is someone out there who can do me a favor and make this for me?? it doesn't have to be perfect, and i guess as soon as i have something to work with i can refine it to my needs.

it's quite simple: 4x xt60 male plugs soldered to the board in parallel. orientation doesn't matter. trace should be as fat as possible. solid wire will be soldered on bottom of the board for higher amps.
6x jst-xh6 soldered in parallel. orientation (pin1 up or down) doesn't matter. why 6? because the 5th one will go to the bms, and the 6th one will be a monitor connector for a celllog.

this is what it should look like - more or less. the smaller the better, as long as you can pull the connectors from the board.
4 small mounting holes 3-4mm in diameter on each edge.

2-sided routing is fine. but only 2 layers. not more.

THANK YOU VERY MUCH IN ADVANCE!!!

 

[nieles]

are you dead set on the drawn layout?

for laying out the board it would be better to put the xt-60 connetors on the left and jst on the right (or the other way around).

i could draw it up for you. could you post the library you used for the connectors?

 

[izeman]

btw: if it's easier to make: there don't need to be traces between the xt60 connectors. i can make the connection with solid wire only. so solderpads alone would be fine as well.

 

[izeman]

are you dead set on the drawn layout?

for laying out the board it would be better to put the xt-60 connetors on the left and jst on the right (or the other way around).

i could draw it up for you. could you post the library you used for the connectors?

GREAT!! THANK YOU!!

no the layout can be changed. the board should not be much bigger afterwards. especially those 60mm width is crucial. the board has to be symmetrical as there are 2 lipos left, and two on the right side.

the xt60s may be moved to the outer side so there is enough space for the wiring of the jst-xh connectors. did you notice my addition to the initial post regarding traces between xt60 removed?

somehow like that:

 

[izeman]

THIS for example would works as well, and maybe is the easiest one to make:

library can be found here: https://bot-thoughts-eagle-library.googlecode.com/svn-history/r2/trunk/con-jst-xh.lbr

 

[izeman]

if i think about it, and move my lipos and connectors around on the table, this maybe is the best design, as the left and right side will be seperated from each other.

i hope i doesn't get too confusing, but i hope you can see my requirements

 

[nieles]

here is one like the first drawing. not ideal with the long traces between some of the jst connectors

 

[nieles]

do you have the dimensions for the xt60 connector? i can make a library part for them but need the following:

-diameter of the hole in the board
-pitch between holes

 

[izeman]

just left home. i can give this in some hours. the diameter is 4.5mm for the hole. and afair they are about 7mm apart - midpoint to midpoint. but those 7mm are just a guess out ofy head.
btw: cant open the zip file on my iphone as well. will have to wait until i'm back home.

 

[Alan B]

I just threw this together quickly, didn't have dimensions for the XT60 pins and spacing either, and didn't tweak it or clean it up. It is 60x80mm. The XT bodies are about the right size, found a drawing for that. Heavy pours, clearance for soldering to them on the back, heavy traces on the back for the balance connections. It is a starting point, not a finished product.

I used five XT connectors, the middle one should be used to take power out of the board. It could be changed to wire landings or a larger connector.

You don't want long traces on the power leads, this board is arranged for low impedance so it is not quite the physical arrangement requested. Might be able to distribute the balance leads around the XT's, but the traces would not be ideal.

 

[izeman]

hi alan
thanks. unfortunately it has to be symmetrical. otherwise the leads are too short.
why care about impedance? 3cm more or less cable shouldn't make any difference?! or am i missing something?

 

[Alan B]

I started with something fairly optimal from a pc board resistance point of view. It is easy enough to move things around on the board, but splitting the connectors the way you showed creates a mess of the traces.

Impedance/resistance of traces is pretty high on a pc board, especially with the thin 1 oz copper. Your layout proposal has traces wrapping around the board making lots of resistance. It might work, but these are not wires, they are traces which have very little copper compared to wires. Trace current capacity can be calculated, here is an online calc:

https://lh6.googleusercontent.com/--cX624u1lzU/UpoNJ_qsyqI/AAAAAAAAH6U/Z55HrPexZmU/s800/batt%2520ifc%2520xt60.png

In 1 oz copper a 2 amp balance current trace should be at least 2mm wide. If you pop a balance trace you'll never know until you have a major balance problem, so you want them to be fairly substantial. If you want to use up to 4 amps balance current you can put 2mm traces on both sides. If those connectors aren't lined up close together you will have a lot of trace area to route.

I don't really know your essential requirements, my packs have enough lead length to reach the board if the board is on the batteries, it should be right on the ends of the batteries. That is one reason mounting holes don't make much sense, the board needs to float right on the batteries to keep the leads short and avoid extensions. If extensions are needed then wires are much lower resistance than small pc board traces.

The output leads need really low resistance and inductance, you don't want to spread them out on the board, even if you add copper. Resistance is loss and heat and inductance and that's where the real current is flowing. They should be packed together on the pc board. Inductance is bad for the controller, generating voltage spikes when the current changes.

 

[Alan B]

The XT-60's pins appear to be 7mm spacing and about 4mm diameter on the PCB side, I can't find one right now that doesn't have heatshrink covering the back so my measurements on diameter are approximate.

 

[izeman]

The XT-60's pins appear to be 7mm spacing and about 4mm diameter on the PCB side, I can't find one right now that doesn't have heatshrink covering the back so my measurements on diameter are approximate.

just measured them: i was remembering right. 4.5mm diameter for the through hole and midpoints are 7mm apart.

 

[Alan B]

I was afraid of that. The ones I have measure around 4.3mm including heatshrink. These are female pins, wonder if that matters. Yes, a sample male pin measures 4.82 with heatshrink.

I hope they are standardized. The fact that the drawings never show the rear pin sizing worries me. They may vary.

 

[izeman]

... I don't really know your essential requirements, my packs have enough lead length to reach the board if the board is on the batteries, it should be right on the ends of the batteries. That is one reason mounting holes don't make much sense, the board needs to float right on the batteries to keep the leads short and avoid extensions. If extensions are needed then wires are much lower resistance than small pc board traces...

the requirement is easy and bullet proof operation. so no boards flying around in the box. no boards that can move and cable insulation can be broken. every connector is always at the very same place. remove a battery and you can be 100% sure where to re-insert and re-connect it to. that's the goal.

battery leads are a problem, as the batteries are 4x 8000mah 6s lipos. lying on the flat side, 2cm apart on the long side, and 6cm on the short side. so you can not turn those in 4 directions as with square 50x50mm 5000mah packs. those packs are 72x50mm. so the power leads are either next to each other, or most far from each other. in the worst case 15cm apart, and they have to be connected to one board.

maybe this little sketch shows explains the situation better:

 

[Alan B]

Another mistake. 6S batteries use 7 pin JST-XH's.

 

[izeman]

Another mistake. 6S batteries use 7 pin JST-XH's.

LOL. you're right. thanks! would have been a bad awakening trying to solder those connectors to the board. i don't know how many extensions, parallel harnesses and stuff i soldered till today, and still make such stupid mistakes

 

[Alan B]

That layout is pretty, but perhaps not optimized for high current.

I would think you would want all the high current leads together, minimize that wiring first, then minimize the balance leads. And reduce spacing between the batteries to the minimum. No extra lead length on high current lines. Bus Bar is the best way to connect them, heavy wire next, PC board a distant runner-up. I use a hydraulic crimper and layers of heatshrink, sometimes with the internal hot glue to make a very solid wiring harness that minimizes the resistance and inductance to the controller, and cannot be connected wrong or short due to polarized connectors. You can see what I did in my GreyBorg thread. The PC boards are good for balance leads.

These pouches want to be compressed to maintain their capacity. The shrink is on them for a reason, packaging them together helps also.

I generally strap the batteries together and strap the boards to the batteries, with appropriate protection between. Nothing moves, it is a solid brick. If these things vibrate, they will become damaged. Any pressure points can be a problem.

 

[izeman]

this is a 4p setup. 1500-2000w. so we are talking 40-50a, that's 10-12a per battery. they want even notice the load
as said i may not even use traces for the xt60 connections but solid wire. even 1.5mm2 or 2.5mm2 will do that easily.

 

[Alan B]

Just for fun I put in 50 amps to 1 ounce copper, and the calculator recommends 172mm traces.

They also indicate that that the data goes to 35 amps so this is extrapolating beyond the data, always dangerous.

50 amps is fairly substantial. Too much for #12 wire, for example. That calls for 8 gauge or a pair of #12's. I used a pair of #12's on the Borg, was easier to handle than #8. That is if you want the wiring to handle it for a long steep grade without heating up more than 10 degrees C.

 

[izeman]

Just for fun I put in 50 amps to 1 ounce copper, and the calculator recommends 172mm traces.

They also indicate that that the data goes to 35 amps so this is extrapolating beyond the data, always dangerous.

50 amps is fairly substantial. Too much for #12 wire, for example. That calls for 8 gauge or a pair of #12's. I used a pair of #12's on the Borg, was easier to handle than #8. That is if you want the wiring to handle it for a long steep grade without heating up more than 10 degrees C.

that may be correct. but those 5000mah 6s packs got 10awg installed, and are capable for 30c max. that's 150amps. i used 12awg for my hs3540 and it was for 50a battery, 120a phase amps. wire got warm, but never has been a real issue. not ideal power loss wise, but running 8awg everywhere on a 1500w bike is an overkill in my eyes. i'll do 12awg for phase and battery wires, 40a battery and 80a phase.

 

[Alan B]

I think a lot of folks under-wire their ebikes. I've seen a few connector failures on commute bikes here on ES. The heat from the wires peaks at the connectors. Wiring and connectors should not heat up significantly in heavy use, and pretty much not at all in normal use. When that happens thermal cycling eventually causes failures. But few folks ride their ebikes frequently or hard enough to have those problems even with incorrect wiring. But if you want a reliable daily driver then following the long established wire rating system makes sense.

We know the batteries are way over-rated, as well as the wire they use. 10 gauge wire is normally rated for 30 amps; with 90C insulation is rated to carry 55 amps in open air, and that is going to be a very warm wire. 150 amps will overheat that wire pretty quickly. We just can't believe their ratings by a factor of about five in this case.

80 phase amps in #12 wire will overheat it pretty quickly, the only reason it works as well as it does is the phase current drops off quickly in normal use. But stay in that region doing multiple hard starts, carrying a heavy load, towing another bike, or climbing a too-steep hill at low speed and the phase wire (and possibly the motor) may well overheat. You definitely don't want to use any lighter gauge than the wire that comes out of the motor.

 

[izeman]

so. now i spent two more days getting familiar with eagle, and i'm quite happy with the result. it was a bit of work to understand how the program thinks, and what the underlying idea regarding layout work was.

this is the outcome (pictures may be (c) by osh park who did the rendering. i hope it's ok posting them here. at least i did the design

you may have noticed two things: balance wire traces are on top AND BOTTOM to double the copper.
and there is NO trace between the power lines. this will be made with solid 2.5mm2 or 4mm2 wire connecting the xt60 pins in a rectangle shape. the two big solder pads are for connecting the battery.

what do you think?

 

[izeman]

this is how wiring should look like: