DIY 6S to 12S BMS with CAN - DieBieMS

23Farads? On the load side? Or as a battery?

23Farads it not an intended load for this bms XD you might have to upgrade to a higher values pre charge resistor and change the pre-charge timeout value in the source.

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Lol, yeah they are rather ridiculous. I had a feeling that might be a problem. Iā€™ll probably use something smaller with the bms. What size resistor would work for this cap pack? Or maybe about a 7F pack?

What are you doing with Farads as caps on the load side of the BMS (picture! :stuck_out_tongue: )? why are they there?

I do not have the bms installed yet. The capacitor pack is inline between my batteries and escā€™s (as close to the escā€™s as possible). LOL, youā€™re right to question that though, definitely not the right place to put them.

Updated my wiring diagram to show the intended power LED switch wiring. Ignore other versions of this figure in above posts, Iā€™d change them but canā€™t edit my old posts. The issue was that I had the LED between 3v and LED Smart, when it should have been between LED Smart and GND. This worked, but the LED does the opposite to what jtag intended (itā€™s actually not as bad as it sounds :wink:).

diebiebms_wiring

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Another happy DieBieMS user here. Such amazed!

https://www.electric-skateboard.builders/t/no-words-just-pictures-delete-words-use-pm/2992/6240?u=rpasichnyk

Can we have new firmware (binary file) with push to start (external CAN power up)? Will be adding support to Metr app and need a little help @JTAG :wink: When charger plug is connected do not shut down VESC (make this configurable). Please please

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Yes yes, will make this available asap (I am currently on a holiday in the UK and am only allowed minimal ā€œhobbyā€ time (she is asleep now, sshhhh dont tell her!))! As soon as I am back at my man(only)cave I will build and test a version specific for esk8 (recently I added a bunch of stuff to make it useful for an e-foil, I will need to retest everything when that is all disabled). Directly after releasing that ill finish the user interface for the computer and that will allow you to possibly implement some of those interfaces in your app, and man that would be freaking awesome!!! :heart_eyes::heart_eyes:

Yes charging during discharge is already coded into the firmware and is configurable ^^, I actually wrote it to allow me to use the TCP - bluetooth - vesc - can - bms bridge :blush:.

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@JTAG about the large capacitor pack, and the precharge circuit, if I were to use an anti-spark connector (as150) between the bms (load+ terminal) and the capacitor pack and escā€™s, would that serve to ā€œbypassā€ the precharge circuit on the bms? For example, I would power-on the bms, then connect the bms to the caps&escā€™s via as150ā€¦? Just curious, donā€™t want to damage anything on the pcb

So you are using caps for the ESC that are rated with a value in farads? Unless they are as big as a couple of times the size of your battery they are most likely nog suited for a high current buffering application that an ESC needs. Can you share a type number just to make sure?

https://emperformanceproducts.com/product/ripple-voltage-filter-energy-booster-cap-pack-23500-uf-12s-max-volt-8awg-wire/

These are the ones that Iā€™m running EDIT: mine is 23500 uF version

Ah ok, looks like this might work without any changes straight on the output of the BMS.

This does not seem to be a cap(bank) that totals in the farad range, it is 23.5 mili farad :sweat_smile:.

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Lol, you are correct sir! Hahaha, I am an idiot. I forgot to check my symbols. Thatā€™s great news (except the me being an idiot part) thanks for the enlightening reply

I just received my DieBieMS today! Iā€™m amped to get working on it.

One question, do the MOSFETs put off heat from both sides? The heatsink side is facing towards the board, but Iā€™d like to add an additional external heatsink on the top side of the MOSFETs as shown.

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The heat dissipates from the ā€œbackā€ of the mosfet, meaning youā€™re heatsink in that Picture isnt very effective

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Ha! amped :sunglasses:.

Fancy looking!!

Well normally with this small style of skateboards I rally doubt that you would need any heat sinking.

But if you really want to than the best method is cooling from the bottom and then go to somewhere where you can get rid of the heat. That said, getting rid of any heat will always help, so from the top will help as well. Just make sure to keep som distance between the wire terminals.

One extra thought, be sure to take into account the space balance leads might take up.

cool design, I think your battery layout is a bit tricky to wire up though

Glad I asked!

lol I hadnā€™t realized I dropped a pun till now.

Is there a reason that most traditional BMS systems have huge heat sinks on them, and the DieBieMS doesnt? At first glance (from a non-electrical engineer perspective) is it that the DBMS takes a more efficient, ā€˜smarterā€™ approach to battery management vs the traditional chips?

Would sinking to the bottom of the PCB actually have any direct heat conduction path from the FETs? I donā€™t believe the copper goes from one side of the PCB to the other, correct?

Maybe Iā€™m just completely over thinking this whole thing and donā€™t need to remove heat at all. Iā€™ll be maxing my system out at probably 70A pull from the battery.

For sure! Itā€™s going to have some weird wiring paths, but after like 4 iterations I think itā€™ll be the most space efficient setup with 26650 cells to avoid the case from hitting the ground on the flexy vanguard board.

Another question pertaining to building a battery pack with fuse wire to avoid fires.