I’ve been in contact with @ethana4 about their Lite and what happened with their setup (fried their laptop’s USB port, which conked out the whole system), but I haven’t been able to pin down the exact failure mode on the BMS’ end that could have resulted in this. In the end we agreed that he ships his BMS unit back to me and I refund him the original purchase price + some shipping cost, that he intends to use on the repair of his laptop.
I want to personally first inspect the unit that he had and test it out to see what the possible cause could have been on the BMS’s end, before I feel safe to start shipping out more units. This is the first case of fried USB-ports that I’m aware of with 40+ total units that are out there in the world at the moment, but I want to first confirm that this isn’t a design flaw with the design before sending more units out.
I am also working on some essential FW updates based on the feedback from a couple powerusers, so I feel it would be good to get those release ready to ship out with the units.
The Lite would ideally sit between the battery and charger, as it’s a charge-only BMS. You would then be free to choose whatever switching method you want to have on the ESC side (loop-key, independent e-switch, ESC integrated e-switch…)
To be more specific. The battery stack monitor IC (the chip that measures the cell voltages, LTC6803-3) only supports up to 12 series connected cells, so that is the limiting factor for the amount of series cells in the battery pack.
There is the 79 units that will be available at some point in the future, but I am currently focusing on doing critical and functional updates to the firmware in collaboration with Bioboard’s @mackann , Metr’s @rpasichnyk along DAVEGA’s @janpom.
There are couple key features I want to get implemented and tested before starting to ship out units, especially the possibility to flash new FW over CAN with Metr as an example.
I also want to complete my investigation to @ethana4 's case where he fried his laptop’s USB-port for some reason.
This is a very important point which boils to the service when users use it. The ones who design a BMS or electronics in general imagine where currents will flow when assembling a battery system. But indeed it is very important to first connect the main battery terminals then the balance leads when assembling, when disassembling first disconnect the balance leeds then the main battery.
Next to this, a series connection failure in the battery pack will cause the full battery pack to appear at one input of the cell voltage monitor which also breaks it.
When these two failure modes or situations are avoided the BMS will live a long life .
Yes, a specific guide for flashing the new bootloader and user app will be made once they are ready for rollout. The old STM bootloader will likely still be kept accessible for legacy purposes, but hopefully we can move towards supporting flashing over the USB with something similar to VESC-tool or some other GUI solution.
There is a 5V and 3V3 available from the Lite when a charger is connected and at other times too depending on the FW-parameter configuration, so it should be possible. Can’t say for sure about the specifics at this point.
@SimosMCmuffin, soooo when can i get my hands on at least 2 of these bad boyz? I am patient but really wantz. Just skimmed the whole thread ( off grid homestead, outta the loop) sorry if you already stated
@SimosMCmuffin
I really could use one of these for my current build as I have absolutely no space in the case. If there is any place to drop my name or someone could sell please let me know.
Thanks
Happy new year everyone. Hopefully things settle down on 2021 with the international “situation”.
Got the production tester completed and ran the 79 boards through it. Average time for one board, once I got some final optimizations done, was a little bit under 2 minutes. This is a great improvement over the old setup that took about 7 minutes per board.
I’ll be opening sales soon and I’ll be adding UPS to the available shipping options. Not sure if I’ll be moving all shipping under UPS, but I’ll start doing logistics via them. CAN-bus supporting bootloader isn’t out yet, but will be ready to start testing phase in a couple of weeks. This will be a great feature for people who are using Metr to monitor their system.
You can have a peek here: https://finnkotronics.mycashflow.fi/
But do note that the site content is still being worked on, currently the checkout is disabled.
Biggest thing is that I’m waiting for my business’ payment processor application to go through, so I can take bank & credit card payments initially, with paypal support very likely coming soon after that. For businesses, invoicing is also available.
Store prices have the Finnish 24% VAT included, which will be removed if in the checkout if your country is outside the EU.
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