stuart

I implemented that logic in my diybms as well.

@MoominPapa just for information, I've implemented the DIYBMS v4 code tonight to provide a pulsed output on the relays should it be required. The relay switches on for about 100ms - anything less and the relay can't switch fast enough so nothing happens.

I've used PCBWAY and JLCPCB, no problems with either.

You'll like my youtube video of reflowing using a frying pan then !!

It will be fun soldering that by hand! Are you going to get those machine assembled ? Thats the nice part of PlatformIO - you get to keep the Arduino 3rd party libraries but in a much more friendly way.

I agree, thats why I don't use it - take a look at platformio or the Visual Studio Code solutions, much better developing and debugging platform. Are you building the alternator regulator yourself ?

Should be easy enough to change my relay code to provide a pulse relay output instead of latching. At the moment I'm not reading current, but the system is designed to allow this - I was looking to use the ACS758 (hall current sensor - up to 200A). Although I could also design a seperate module specifically for this purpose if needed.

I'm sure I can russle up a green screen terminal for it ? The BMS was designed for large battery banks - take a look at DIY Powerwalls - there are people with 100kWh+ of battery capacity powering their off grid homes for weeks at a time. The trouble with most chinese BMS type systems and ebay specials is the balancing current is tiny - 50mA or less in most cases and would take forever to balance a large pack.

At present the BMS drives 4 seperate relays (it could go up to 8 ) and you can configure what each relay is for based on need. I don't do anything clever with the timing at the moment, but thats easy enough to do with a microcontroller. Assume for these bistable relays, a "disconnect" rule would just connect the relevant driving relay for 15mS and then disconnect.

Hi @Dr Bob my BMS was designed originally for people recycling laptop 18650 cells but it works okay with LiPo and LifePO4 cells as well - aka DIY Powerwalls. The DIY BMS has a simple moduler design, temperature monitoring, along with generic relay outputs which are controlled by software defined rules. So it would be quite trivial to have rules designed to switch relays off at certain voltage set points or raise alarms when cells are above/below set voltages or temperatures. The cost is also low, each cell module is about £5 and the controller about the same. The code may need a bit of tweaking for use on a boat, but nothing that can't be easily solved. Let me know if you'd like to have a chat about it, or even a demo unit or two. I'm in the Midlands.

I've not been on the forum for years, but noticed the article in Canal Boat magazine this month on Lithium battery systems and LifePO4. If you are looking for a DIY BMS - I've built/designed one thats proving to be quite popular. There is another forum where the discussion takes place. https://community.openenergymonitor.org/t/diybms-v4/11292

Hi John, no reason the display can't be separate - although you will need to disconnect the original - the replacement Arduino emulates the display so both together will get confused. The connection to the hour counter is over an i2c connection, so you do need to keep the cables as as short as possible, possibly with shielded cable as well.

Sorry, just get a 404 error on the link provided!