openinverter forum

Hi!
Just found out that https://www.zeva.com.au/ has gone open source. Products are published under MIT License.
Design files, source code etc. can be found under product page, all in a zip file.

That seems like kind of a big deal, assuming ATmegas are more plentiful than STM32 chips. Might be a nice simple BMS option.
Lots of other really useful stuff on that site as well.

Neat, does this potentially improve any of the projects or efforts underway in this community?

MattsAwesomeStuff wrote: ↑Tue Sep 14, 2021 5:38 am Neat, does this potentially improve any of the projects or efforts underway in this community?

I'm pricing up getting the BMS boards made. If they are reasonably cheap and available it will be a pretty easy BMS solution. Canbus communication is default as well which helps allot.

If that works I'll probably look to incorporate more of those parts into my current and future projects.

A BIG +1 for Ian Hooper putting all his designs into the OpenSource domain.
I'm using his Zeva BMS products for years in my projects and was somewhat worried when he announced stopping the Zeva business this year. Now having all the info needed to have his designs manufactured when needed is a big plus.

That's a nice way to end a business. The designs look quite DIY friendly with 3D printed cases and cheap, minimal parts. I bet someone will start a spin off business out of these, given the extremely liberal license.

celeron55 wrote: ↑Tue Sep 14, 2021 1:02 pm That's a nice way to end a business. The designs look quite DIY friendly with 3D printed cases and cheap, minimal parts. I bet someone will start a spin off business out of these, given the extremely liberal license.

I'm currently getting everything together for a first batch of 30 units BMS12 but availability of certain components makes it hard to get it all from one place (JLCPCB).

prensel wrote: ↑Tue Sep 14, 2021 1:42 pm

celeron55 wrote: ↑Tue Sep 14, 2021 1:02 pm That's a nice way to end a business. The designs look quite DIY friendly with 3D printed cases and cheap, minimal parts. I bet someone will start a spin off business out of these, given the extremely liberal license.

I'm currently getting everything together for a first batch of 30 units BMS12 but availability of certain components makes it hard to get it all from one place (JLCPCB).

I got a price from PCBway for 5 BMS24, around $800 including shipping and fees. ATMegas and the CAN transceivers are around 20$ each thought which is skewing the price up a fair bit.

LRBen wrote: ↑Tue Sep 14, 2021 2:28 pmI got a price from PCBway for 5 BMS24, around $800 including shipping and fees. ATMegas and the CAN transceivers are around 20$ each thought which is skewing the price up a fair bit.

So, for a normal 96s pack, $640?

That's not terrible, especially during a chip shortage.

There's also good info here in terms of if you want to run an EV business, because you can look at your costs and look at what he was selling them for, and to some degree all the legwork has already been done in terms of what you might expect to need for overhead.

I have finalized the order for a first batch of 25 units BMS12 (without the 3D printed housing but STL file is available).
Prices wil be around 50 - 60 euro per 12 channel module.
If anyone is interested let me know.

prensel wrote: ↑Wed Sep 15, 2021 8:25 pm I have finalized the order for a first batch of 25 units BMS12 (without the 3D printed housing but STL file is available).
Prices wil be around 50 - 60 euro per 12 channel module.
If anyone is interested let me know.

I didn't have much luck with JLCpcb, did you need to swap in allot of parts from their parts library?

LRBen wrote: ↑Wed Sep 15, 2021 8:58 pm I didn't have much luck with JLCpcb, did you need to swap in allot of parts from their parts library?

When using the Zeva BoM against the JLCPCB parts list is somewhat hard to find the correct part.
But searching for BoM part number at Digikey and use the Digikey part description at JLCPCB gave all parts exept for the connectors and rotary switch. The atmega16m1 and ltc1602 are not in stock so I have these ordered from Mouser with the connectors.

I'm still waiting for a quote from PCBWay but it is still at 'being reviewed' .
For the housings I have received a quote from Hubs for about 15 euro per set (front and back) of 3D printed BMS12 housing.

prensel wrote: ↑Wed Sep 15, 2021 9:05 pm When using the Zeva BoM against the JLCPCB parts list is somewhat hard to find the correct part.
But searching for BoM part number at Digikey and use the Digikey part description at JLCPCB gave all parts exept for the connectors and rotary switch. The atmega16m1 and ltc1602 are not in stock so I have these ordered from Mouser with the connectors.

I'm still waiting for a quote from PCBWay but it is still at 'being reviewed' .
For the housings I have received a quote from Hubs for about 15 euro per set (front and back) of 3D printed BMS12 housing.

Ah yeah that did help a bit. Seems they are missing quite a few parts for some of the other Zeva things. I'm pricing up the EVMS3, EVSE interface, and the current sensor as well with PCBway. Unfortunately they are out of stock of a couple very high pad count which I'm hesitant to try and do myself. Might not have much choice though.

I'm also talking to some UK based pcb assemblers hoping they may have stock, but I can't see them being able to compete on price very well.

I'm getting a bit tired of this chip shortage!

I believe PCBWay supports having you sent them the missing parts so they can install them for you ?
With the BMS12 I only have to flow the atmega, ltc1602 and solder the non-smt connectors which should be doable.
After the BMS12 units have arrived somewhere next week I'll look into the other BMS parts to have them reproduce (or buy-in).

I would be interested in joining up with anyone looking at the BMS24 and possibly EVMS3 if it helped for bulk ordering!

nkiernan wrote: ↑Thu Sep 16, 2021 7:11 am I would be interested in joining up with anyone looking at the BMS24 and possibly EVMS3 if it helped for bulk ordering!

'Bulk' at this time is limited to about 25 or 30pcs because of the stock they carry.
I initially had 30pcs of the BMS12 but when finalizing the order just one component had only a stock of 29pcs to I had to lower the complete order to 25..

I will look into the BMS24 and EVMS3 also, available from mainland EU (LRBen is from the UK, 'former EU..')

So it seems component prices are making things a bit expensive. For parts like the current sensor, monitor, EVSE interface it's cheaper to buy it from Zeva and ship it to the UK than it is to have just the pcb boards assembled with PCBway. Even then there are hard to find components missing from the pcb boards.

For the EVMS3 its a tiny bit cheaper to have the boards made up, with one additional more common component you need to source.

For the BMS24 it's about £50 a board cheaper to have the board made up, with all components currently available. Component cost per board is about 126$. I think bulk ordering would probably help with the assembly charge.

I am going to have a bit more of a conversation with PCBway to confirm some parts and query some of the pcb prices. I should also hear back from the UK company this week to get a comparison.

First batch of BMS12v3 arrived from JLCPCB today.
The missing parts should arrive this week also so they can be completed and tested/programmed next week.

prensel wrote: ↑Mon Sep 27, 2021 11:20 am First batch of BMS12v3 arrived from JLCPCB today.
The missing parts should arrive this week also so they can be completed and tested/programmed next week.

IMG_0555.jpg

Am I reading the Zeva info correct, the BMS24 is simply two BMS12's packaged together? So two of these could make up a BMS24?

Hey prensel, how are you getting on making the bms boards? I'd be interested in buying some off you.

Dusty4 wrote: ↑Fri Oct 22, 2021 12:32 pm Hey prensel, how are you getting on making the bms boards? I'd be interested in buying some off you.

Ready to go (almost) !
I have about 12 boards ready to be programmed.

Cool, I have ended up having a go myself, I have made the bms24s. I am hoping to test in the next few weeks.

Dusty4 wrote: ↑Sat Nov 20, 2021 12:01 pm Cool, I have ended up having a go myself, I have made the bms24s. I am hoping to test in the next few weeks.

Who did you use to make up the boards? All the companies I tried had component supply chain issues with some key parts.

I had them made at jlcpcb, I then sourced the rest from Digi-Key, mouser and eBay.

Dusty4 wrote: ↑Sat Nov 20, 2021 12:01 pm Cool, I have ended up having a go myself, I have made the bms24s. I am hoping to test in the next few weeks.

Do you think you can drop the link for your revised BOM with parts that JLCPCB stocks by any chance?