Idiot's guide to a self build battery

[nowty]

Oh wow, just in case I was ever interested in removing all the Pylons and going completely DIY, just discovered this: https://github.com/juamiso/PYLON_EMU

So basically pretend to be a Pylontech from a Python script so you can tell the inverter how much amps to charge/discharge at etc. Quite interesting just to see what information the BMS sends back to the inverter looking at that. Although there's a proviso in the README that it isn't tested with real hardware

What does that give you over running in simple lead acid mode ?

I still get full control over charging parameters in the inverter, my Pylontech's run stand alone and do not have any comms to my inverter. The only thing I don't get is an accurate SOC level but I work off a simple voltage level monitor to work out the SOC.

[Caesium]

What does that give you over running in simple lead acid mode ?

I still get full control over charging parameters in the inverter, my Pylontech's run stand alone and do not have any comms to my inverter. The only thing I don't get is an accurate SOC level but I work off a simple voltage level monitor to work out the SOC.

That's a good question, the main thing I'd want is being able to tell the inverter precisely what voltages to charge/discharge to. From a quick skim through that Python script there's a couple of other parameters it would be nice to be able to control too - although for my current needs just setting a 21:30-02:30 charge window on the inverter is ok, if in future I wanted to dynamically enable/disable charging on an half-hourly basis, I could toggle that as I liked. Agreed that SOC is really just a nice-to-have.

My inverter appears to let me set a Lead-acid low voltage discharge cutoff, but nothing for charging. So without trying it, it's anyone's guess what a Luxpower inverter will try and charge what it thinks is a Lead-acid battery up to. I'd bet some money that it wouldn't be right for a 15S LiFePO4 pack though.

All in all I probably wouldn't buy Lux again. It's been ok, reliable enough, does the job, but their support is absolutely appalling, I've never had a reply to an email to them, despite asking for firmware upgrades a few times, and they completely refuse to give any documentation about APIs for it. For local control I ended up reverse engineering packets it sends to China, painstakingly. I might be asking about recommendations for hybrid inverters in a few years, particularly interested in the ability to keep solar generating and charging batteries and supplying at least an EPS load in a grid outage .. but maybe they all do that now.

[Tinbum]

Oh wow, just in case I was ever interested in removing all the Pylons and going completely DIY, just discovered this: https://github.com/juamiso/PYLON_EMU

So basically pretend to be a Pylontech from a Python script so you can tell the inverter how much amps to charge/discharge at etc. Quite interesting just to see what information the BMS sends back to the inverter looking at that. Although there's a proviso in the README that it isn't tested with real hardware

What does that give you over running in simple lead acid mode ?

I still get full control over charging parameters in the inverter, my Pylontech's run stand alone and do not have any comms to my inverter. The only thing I don't get is an accurate SOC level but I work off a simple voltage level monitor to work out the SOC.

Can't see that it achieves much as it doesn't calculate SOC which is the important one.

[Joeboy]

Oh wow, just in case I was ever interested in removing all the Pylons and going completely DIY, just discovered this: https://github.com/juamiso/PYLON_EMU

So basically pretend to be a Pylontech from a Python script so you can tell the inverter how much amps to charge/discharge at etc. Quite interesting just to see what information the BMS sends back to the inverter looking at that. Although there's a proviso in the README that it isn't tested with real hardware

What does that give you over running in simple lead acid mode ?

I still get full control over charging parameters in the inverter, my Pylontech's run stand alone and do not have any comms to my inverter. The only thing I don't get is an accurate SOC level but I work off a simple voltage level monitor to work out the SOC.

I seem to remember messing about with l/a mode on the goodwe hybrid, got a fright though when the soc dropped out and went back to pylontech stack of two back then. As you say, if all you lose is the soc it's no big deal. I'm sure there are voltage monitors that can be networked and app'd back to phone?

[Caesium]

I'm sure there are voltage monitors that can be networked and app'd back to phone?

I thought about looking for something to do this, including all the cell voltages, but figured the entire stack voltage will very quickly match the Pylontechs (since it will be paralleled to them, after all) which I can already see through existing monitoring, and if the balancer is doing its job then the individual cell voltages won't be very interesting (all of them stack/15 hopefully!). So I resisted spending yet more money on a bluetooth-enabled 15-way voltage monitor

The occasional check with a multimeter should suffice to check the balancer is working I reckon

[Joeboy]

I'm sure there are voltage monitors that can be networked and app'd back to phone?

I thought about looking for something to do this, including all the cell voltages, but figured the entire stack voltage will very quickly match the Pylontechs (since it will be paralleled to them, after all) which I can already see through existing monitoring, and if the balancer is doing its job then the individual cell voltages won't be very interesting (all of them stack/15 hopefully!). So I resisted spending yet more money on a bluetooth-enabled 15-way voltage monitor

The occasional check with a multimeter should suffice to check the balancer is working I reckon

True, was thinking next step ahead on the off-chance that the hybrid inverter throws a wobbly and we have to revert to l/a manual settings. Won't happen, just my mind seeking a fallback for a fallback.

[Caesium]

According to alibaba my cells are being prepared for shipment, I have a DPD tracking number and everything Exciting!

[Joeboy]

According to alibaba my cells are being prepared for shipment, I have a DPD tracking number and everything Exciting!

Excellent news! You might be able to get the vessel name and track its progress on marine traffic?
My ampclamp arrived yesterday. Not quite as momentous admittedly.
Making final payment for cells a month today.

[Caesium]

Excellent news! You might be able to get the vessel name and track its progress on marine traffic?
My ampclamp arrived yesterday. Not quite as momentous admittedly.
Making final payment for cells a month today.

Yep, the alibaba seller I used (Jenny Wu, apparently very reputable) said I can ask her for more information once it's on a ship. Which hopefully is within the next few days. But fortunately I'm heading off for a holiday week in Wales today with some family so I'll be distracted from thinking about it for a while, will see what the status is on my return

I have a growing pile of parts here:



Pylon long interconnects, 25mm cable, 100A mega fuse with holder and spare fuse, chunky DC isolator.

[Joeboy]

Excellent news! You might be able to get the vessel name and track its progress on marine traffic?
My ampclamp arrived yesterday. Not quite as momentous admittedly.
Making final payment for cells a month today.

Yep, the alibaba seller I used (Jenny Wu, apparently very reputable) said I can ask her for more information once it's on a ship. Which hopefully is within the next few days. But fortunately I'm heading off for a holiday week in Wales today with some family so I'll be distracted from thinking about it for a while, will see what the status is on my return

I have a growing pile of parts here:



Pylon long interconnects, 25mm cable, 100A mega fuse with holder and spare fuse, chunky DC isolator.

That's great, I am very much looking forward to seeing/reading about your progress. Absolutely love Wales, such a beautiful country. Happy hols!