Standardizing DB37 connector pinout for up to 32s

[CamLight]

Another failure mechanism to deal with when considering pinouts....
I think we also have to consider potential long-term problems. As connectors are used, dirt and other contaminants often build up inside. Keeping the voltage between any two adjacent pins as low as possible helps prevent a short in case of water or conductive dust (either slightly or very conductive) entering or building up near/on the pins. Or any other unforeseen problem.

About the porential failure would the silicon grease wouldreduce the risk ?.. i mean it is already used in many comercial EV for the low current connections ?.. I kow that the commercial connector also have sme sophisticated rubber seal but for a 37 pind iy might be $$$

At wich level should we consider the potential failure?.. i mean..all low current the connector on the controller are a as sensitive as all other but it still work for our kind of needs ?

Doc

My understanding about those greases is that they're only on the parts of the connector pins not actually touching the mating contact. That is, the grease is rubbed off where the two contacts, plug and receptacle, rub against each other when mating. I'm not sure that using a grease would help for us except for water intrusion? Grease is also a great dust magnet. Somebody with more knowledge about these greases and their use will hopefully chime in.

I like your choice of DB37. I don't think a different connector would be better. Projects here are budget-driven and DB37's are dirt cheap compared to other connector types. And electrical tape around the place where the connectors are mated goes along way.

The application for this connector are all low current...until two pins short together.
And while a sealed connector might prevent contamination and water intrusion, it still wouldn't address all the potential problems in having over 100V between two adjacent pins. Not sure how we should consider any potential trouble. I guess each person will make their own decision based on cost, time, and risk. But IMHO, any change that costs nothing but could even potentially prevent a problem should be made. Personally, I can't remember how many times my DMM probe tip has slipped off one pin and bridged two together.

[bigmoose]

John, I would be interested in what you might have as to a connector recommendation irregardless of price. It might open up my thinking.
1) I have MiniFit with a 9 amp rating if 3 pins are energized, dropping to 5 amps with 12 to 24 pins.
2) I also have some large TYCO 0.156 in spacing IDC style headers with 10 amp pin/terminal rating.
3) Then we go to the 16 contact size MIL-C-26482 mil spec stuff in a 24-31 insert shell arrangement, that will do the job at 13 amp tested; but is price uber prohibitive.

I would like to work in modules of 12 cells, with Kelvin leads on the top and bottom of stack, so something around 14 pins per bank.

So either way (cheap or expensive), I would appreciate your thoughts.

Next you gents need to know that I go real, real slow on this "fun stuff" development. I also do not like to release any details until I have successful prototypes running at TRL-4 which is: A system prototype demonstrated in a relevant environment. It just gets everyone all anticipatory, and typically it is a dry hole for me... (What can I say, I am pragmatic over my career, and more ideas fail then succeed.) I have been thinking about how to skin this cat differently for two years now. It takes custom magnetics and is currently heavy. Therefore I don't like the idea of it being on the bike/vehicle while it is "on mission." The current topology can prop up weak cells however while the main discharge is happening, but would require the magnetics to "hit the road..."

I also follow methy's threads in detail. I am a bit dismayed at how much work his HVC/LVC boards have been to manufacture in quantity in this country and by hand. I should be realistic and run the hand work numbers... because it just took me 20 minutes to R&R a single blown SO16 chip in one of my scopes this morning.

[johnrobholmes]

......

While we are on the subject of cell level connectors, I have a question for you geniuses. I am dabbling with an inductive balancing circuit that can either individually charge or discharge individual cells at 10 A average, 17 A peak while the stack is being bulk charged at whatever rate the bulk charger can supply. I am having trouble finding a multipin connector that I feel comfortable with to bring each cell's signals off the board.

I have a 24 pin connector that I use to charge my 20s pack. Harting Han E model, it was about $200 for the full thing with male/ female sides, bulkhead, waterproof cover, and strain relief compression nut. I've been testing it for about 6 months now. Wiring is done with pins 1 and 13 most negative, and ascending voltage pins going 2, 14, 3, 15.... with most positive at pins 24 and 12 IIRC. Pin 18 is the first 10s pack most positive, and pin 7 is the second 10s most negative. They are split so I can use two chargers. It is rated for 10a continuous (16a in some specs) on each pin and 18a bursts. 500v between pins, and 1000v if you skip every other pin. Commonly used in automated car washes. They make up to 24 pin with screw terminals and 46 pin with crimp terminals. They also offer bulkeads that allow for combining two smaller units into one large plug.

Specs on the Han-E line here http://www.harting-usa.com/imperia/md/c ... ess.ee.pdf


So far I can absolutely recommend it with flying colors. One of my friends is a sales rep for an electric supply house. We both searched for hours and couldn't find a single better choice for HV charging combined with balance charging. Certainly the single best thing I have done for an electric bike. I use two 1420I chargers with one big plug on the pack. Couldn't be any easier without an integrated BMS and bulk charger. If you want to try one out I can get a vendor discount for you.

[johnrobholmes]

I also concur that it would be best practice to place cell taps in a way that keeps pin to pin voltage differences to a minimum. I have built 4 packs using D sub connectors and I always did it this way. I have also had a few accidents and it saved my butt from totally blowing up the balance wires.

[Doctorbass]

OK so let's declare that we can conclude that the pins arrangement MUST be in a way that keeps pin to pin voltage differences to a minimum

But i stick with the idea of a simple , cheap and compact connector type.

The DB37 appear to be the best. I recall that the main idea is to provide a connector NOT FOR CHARGING but for monitoring and\or balancing.

I think that bypassing everyone that want a 30 or 32s setup in a profit of using the saved pins in parallel for carying higher current for charging is not the best solution.

lt's keep this standard for the rest of the connection than the charging current right?

Doc

[johnrobholmes]

For something cheap the db37 can't be beat! I needed to charge through the same plug as balance, and the low connect/ reconnect of computer cables made me search out more industrial solutions.

[jonescg]

I still can't see how you would short something no matter how the boards were laid out. Provided the female plugs are used for any power application, the only risk of a short is during construction. Once built, it's impossible to short them if the same wiring format is used. Personally I like the pin one = cell one pin two = cell two arrangement...

I think these DB-37s are "the shizzle" (Trademarked copyright Hyena all rights reserved)

[bigmoose]

Thanks John, that is a fine connector! With charging to every cell we have to factor in a connector that can do more than 20 or 30 mate cycles. You found one! Was it correct to summarize that one mated pair with hoods etc. was near that $200 mark in wholesale terms?

[CamLight]

I still can't see how you would short something no matter how the boards were laid out.

All sorts of ways you can still short things out...
Water, conductive dust (more common than you think at >100V), overheated insulation being pushed aside due to pressure and/or vibration, debugging a pack problem, testing after replacing a cell. But, there's always room for different pinouts!

[CamLight]

John, I would be interested in what you might have as to a connector recommendation irregardless of price. It might open up my thinking.

OK, at 10A-17A we're limited. I was going to recommend the circular MIL connectors, but you're right, they are expensive. The plastic shell versions are less so though. The Han-E's that John recommended are also fabulous.

For lower pin count, Neutrik has up to 7-pin XLR circulars that are incredible for applications that require over 1000 mating cycles. But, you're limited to 7-pins. The 3-pin versions are rated up to 16A but the 7-pin drops to 5A. I haven't had any problems at >10A though as long as the wire insulation isn't 80C-rated stuff.

If the Han-E's look good for you, I say go with them. Especially with that discount.

[NeilP]

http://www.winfordeng.com/products/brk37.php

I just finished making up a break out board on a piece of vero board..damn

[Bison_69]

Hi Guys,

I think it is kind of odd that you are looking for such a cheap connector as the “D-Sub” type… which is not rated at all for outdoors used nor for harsh environment.

Mostly for the huge investment ($$$$.$$) you made so far to build and convert your ebike… it is somehow hard to understand why to invest on such a cheap component to risk the loss of your battery pack while there are so many better choice out there on the market. (I don’t mind to pay a little more for a connector kit which I can rely on long term and keep my mind in peace)

Here is a very good source to look at for technical info…
http://www.ept.ca/pressroom/

Still for those which only believe in the D-Sub type connectors… I enclosed is a technical specs pdf to better help you and understand that those connector are really not offering much beside indoors small signals and computer used which they were engineered for in first place.

SG

[jonescg]

Well I wouldn't be putting my D-subs out in the breeze for crap to collect anyways. They are going under a sealed, waterproof cover and will have their own rubber condoms to protect them from any stray dust. The idea will be to have a pack that's so well balanced you don't even need to access them more often than once a month or so.

However, despite their 2-5 amp ratings (which is pretty good I would have thought) they aren't really rated for repeated plugging and unplugging. 500 insertions I read on that data sheet? Now, from a LiPo perspective, 500 cycles is a good lifespan! So I really don't think the d-sub will be the limiting factor here. But a touch up with graphite powder and a good blast of compressed air would make them process much smoother.

[amberwolf]

Just be careful with the graphite powder, so you don't wind up with conductive paths for leakage currents between cells. Very important at the voltages you're going to be at, especially.

A little humidity and the graphite and maybe other contaminants could mix and make interesting compounds that would probably be conductive enough to cause problems.

[Bison_69]

The ever best made all purpose dielectric grease is made by DOW CORNING which I have been using for the last 25 years....
(We were using it a lot during my military service)

http://www.dowcorning.com/applications/search/default.aspx?R=402EN
It prevent oxydation on electrical contacts, lubricate and also keeps rubber boots in good health (avoiding them to dry)

This stuff is pretty amazing.

SG

[Doctorbass]

13 april 2012 Upgraded desing on first page.

Thanks Camlight and Bigmoose for the advice.

I did not wnat to be too far from a config with pin number corresponding to cells for easy understanding... but safety and longevity is the best so this way the connector pins will have minimal voltage from each adjacent pins

Doc

[bigmoose]

Doc, I like your new layout. Looks good!

I am heading towards an AMP CPC Plastic connector with near Mil spec Pins. The cheap pins are good for 13 amps at about $0.75 a pin pair; and if things get dicey there are 17 amp rated pins at about $2.40 a pin pair in Series 1 size 17-16 pins will do 12 cells; but for 48 volts I have to go with Series 1, Size 23-37 pins. That size 23-37 connector is like 1.75 inches in diameter though!

[Doctorbass]

Doc, I like your new layout. Looks good!

I am heading towards an AMP CPC Plastic connector with near Mil spec Pins. The cheap pins are good for 13 amps at about $0.75 a pin pair; and if things get dicey there are 17 amp rated pins at about $2.40 a pin pair in Series 1 size 17-16 pins will do 12 cells; but for 48 volts I have to go with Series 1, Size 23-37 pins. That size 23-37 connector is like 1.75 inches in diameter though!

I already used these Amphenol connectors. They are excellent!.. but a bit pricey compare to the DB

Do you know why i like the DB connector?

D... B........ Doctor Bass Connector

Doc

[caspo6]

I have a 24s2p pack of LiPo 5aH bricks with Methods parallel boards and x2 Hyperion 1401 balance chargers on their own power supplies.

I want to be able to balance charge with a single DB37 connection to my pack.

I was thinking of creating a balance board with the layout and pinout below. I would solder a 12 gauge wire to the wide traces and use Anderson power poles to the battery chargers. Any thoughts?? Am I missing something? Is it okay to balance the two 12s groups using the common lead between them to the two chargers? Are 0.3 mm trace gaps and 0.54 wide traces adequate on a 1 oz board?

DB37 24S JST-XH BALANCE BOARD.JPG (89.48 KiB) Viewed 101 times

DB37 24S JST-XH BALANCE BOARD PINOUT.JPG (77.71 KiB) Viewed 101 times

[Toorbough ULL-Zeveigh]

Do you know why i like the DB connector?

D... B........ Doctor Bass Connector Doc

Cannon's part-numbering system uses D as the prefix for the whole series, followed by one of A, B, C, D, or E denoting the shell size, followed by the number of pins or sockets, followed by either P (plug) or S (socket) denoting the gender of the part. Each shell size usually (see below for exceptions) corresponds to a certain number of pins or sockets: A with 15, B with 25, C with 37, D with 50, and E with 9

[jonescg]

Holy thread revival batman!

I don't have much to add except that I've come around to the non-sequential pinout being advocated. Mostly as a result of soldering a live pack into the back of a DB25. I followed something similar to Doc's first image. No sparks whatsoever because I shrunk down each lead after soldering it

Now for my race bike I will be using four of these D-sub 44 HD plugs:



Unfortunately there is only just enough pins for my 43 balance wires. I believe 28 gauge wire will suffice for monitoring or balance charging at an amp or so.

[Toorbough ULL-Zeveigh]

Now for my race bike I will be using four of these D-sub 44 HD plugs:
Unfortunately there is only just enough pins for my 43 balance wires. I believe 28 gauge wire will suffice for monitoring or balance charging at an amp or so.

if you need a few more lines then DD50 might be the way to go.
takes up less length anyways than DC37 while retaining regular spacing & full sized pins.
or did you happen to miss this caveat from page1?

I already used the DB44 connector for a 40s BMS but.. the pins are too fragile and too close!

[jonescg]

Yep, I did miss that one

I didn't realise the 44s used smaller pins / solder buckets. In that case the double D ( )50 might be ideal.

[johnrobholmes]

..... Is it okay to balance the two 12s groups using the common lead between them to the two chargers?

Split the common lead into two paths, this way you do not need multiple isolated charger power supplies.

[Doctorbass]

Do you know why i like the DB connector?

D... B........ Doctor Bass Connector Doc

Cannon's part-numbering system uses D as the prefix for the whole series, followed by one of A, B, C, D, or E denoting the shell size, followed by the number of pins or sockets, followed by either P (plug) or S (socket) denoting the gender of the part. Each shell size usually (see below for exceptions) corresponds to a certain number of pins or sockets: A with 15, B with 25, C with 37, D with 50, and E with 9

Oh you are right !