MULTIPLE CONNECTIONS TO PYLON TECH 2.4 KW BATTERIES

[AlBargey]

I checked going back to 8th Jan. We've been down to minus 6 overnight and minus 3 through the day. There is only 100W or so variance in the charge rate. Its 3.4kW constantly until the battery hits 88% and then it slows down to 3kW but that is by design as confirmed by Pylontech a few years back.
The green line is soc while the purple is charging btw. Maybe i'd see more variance on a 5kW system but mine is 3.6kW. Maybe its a Victron thing?

It's most likely your battery internals aren't as cold as outside.

If your actual battery cells are -3°C and charging with any substantial current, then either Pylontech allows it (unlikely) or the internal temp is higher, otherwise the Pylons internal BMS should disconnect or throw a fault alarm if their own call for stopping charge is being overridden by external chargers.

As Tinbum says, it's a good system and works well to look after LFP cells, which normally shouldn't be charged below 0°C, but can be discharged albeit with reduced current down to -20°C or so.

[Tinbum]

Victron Energy
https://www.victronenergy.com › live › battery...

Just looked at that link and the whole tread just shows a distinct lack of basic knowledge, enough said.

[Marcus]

As to how the futureneegy controller manages without a dump load: my guess is that it shorts the generator - effectively using the generators resistance as a dump load; this causes the (windturbine) aerofoils to stall, and the power needing be dumped drops off.

That's not going to work with a waterwheel though, so if my guess is right i'd look into a separate overvoltage control mechanism: a 200w dumpload and controller is quite easy to make, or possibly a voltage sense control of the water sluice gate.

I must admit i would be looking for a different generator and controller - partly 'cos I'm a cheapskate* and futurenergy stuff looks overpriced to me, but also as the datasheet for the 48v generator looks to have a 48v d.c cut-in speed of about 500 rpm - I'd be looking for something nearer 200rpm, or lower if i could find it to reduce the necessary gearing.

*and proud of it.

I did wonder if the OPs wheel rpm estimate was under 200w load or free running (guessing the former), but i guess they'll figure all that out one way or another - sometimes it's easier to cobble it together and see what it actually does - then re-do it better, rather than to try and to get it right on paper and just get bogged down in technical details. Another reason for not spending too much money on the 1st go.

[Joeboy]

I checked going back to 8th Jan. We've been down to minus 6 overnight and minus 3 through the day. There is only 100W or so variance in the charge rate. Its 3.4kW constantly until the battery hits 88% and then it slows down to 3kW but that is by design as confirmed by Pylontech a few years back.
The green line is soc while the purple is charging btw. Maybe i'd see more variance on a 5kW system but mine is 3.6kW. Maybe its a Victron thing?

It's most likely your battery internals aren't as cold as outside.

If your actual battery cells are -3°C and charging with any substantial current, then either Pylontech allows it (unlikely) or the internal temp is higher, otherwise the Pylons internal BMS should disconnect or throw a fault alarm if their own call for stopping charge is being overridden by external chargers.

As Tinbum says, it's a good system and works well to look after LFP cells, which normally shouldn't be charged below 0°C, but can be discharged albeit with reduced current down to -20°C or so.

I agree, most likely the garage remains +0 degs even in multiple days. I'm not saying it isn't worth looking into (all for it actually) but dumping on a new members system when he said he's new and non tech and which he has already bought seemed needlessly cruel and I'm not into that.

Never have been. Even worse, to do it using 3rd party info which even mentions it is itself anecdotal?

Anyhoo, I now have Victron graph envy AL. Not only living the barge life but with sexy graphics! Where will it end?

[richbee]

My Sunsynk setup is definitely affected by temperature, but maybe not as much as I thought it might be.
The battery temperature readings haven't dropped below 5 degrees during the recent cold snap - they are in the loft so will get some heat rising up from the house.
I now charge them overnight between 2 & 5am on Flux. You can see them fully charge to start with, and then tail off once above 85ish%.
Strange sometimes that they don't reach the full 99%, sometimes 97 or 95, even though there is time left before 5am to keep charging.
The only common point seems to be this happens if the batteries were 'empty' at 20% so not discharging before charging started.
If they were at 25-30% or higher and still discharging, they will reach 99% every time (will also be interesting to see if they come back to reaching 100% once the weather warms up, or if they have lost their first 1%?

[Tinbum]

My Sunsynk setup is definitely affected by temperature, but maybe not as much as I thought it might be.
The battery temperature readings haven't dropped below 5 degrees during the recent cold snap - they are in the loft so will get some heat rising up from the house.
I now charge them overnight between 2 & 5am on Flux. You can see them fully charge to start with, and then tail off once above 85ish%.
Strange sometimes that they don't reach the full 99%, sometimes 97 or 95, even though there is time left before 5am to keep charging.
The only common point seems to be this happens if the batteries were 'empty' at 20% so not discharging before charging started.
If they were at 25-30% or higher and still discharging, they will reach 99% every time (will also be interesting to see if they come back to reaching 100% once the weather warms up, or if they have lost their first 1%?

With my Pylontech they sit at 89% for ages and then rocket up to 100% in no time at all, as is common and the expected behaviour.

However when I set the max charge voltage at 52.5v instead of 53.2v the time taken to go from 90 % to 100% increases markedly.

SOC1 is 53.2v and SOC3 is 52.5v



Sure yours will come back to 100%

[Joeboy]

There might be variance in settings within inverter control units over the batteries. By this I mean manufacturers programme which kicks in before any onboard bms throttling from the battery itself. Pure guesswork based on nothing at all.

Maybe cabling effect too as no two systems will be identical?

[Tinbum]

There might be variance in settings within inverter control units over the batteries. By this I mean manufacturers programme which kicks in before any onboard bms throttling from the battery itself. Pure guesswork based on nothing at all.

Maybe cabling effect too as no two systems will be identical?

Was this to me?
Not in my case as the voltage setting is done by my Teensy that adapts the CAN messages sent to the inverter so I can show the same on one set up.

( I limit my Max voltage to 52.5v except for on one day of the week when it is 53.2v (or the pylon battery request). If the battery doesn't get to 100% on that day then it will do it the next day etc. until it does get to 100%).

[Joeboy]

There might be variance in settings within inverter control units over the batteries. By this I mean manufacturers programme which kicks in before any onboard bms throttling from the battery itself. Pure guesswork based on nothing at all.

Maybe cabling effect too as no two systems will be identical?

Was this to me?
Not in my case as the voltage setting is done by my Teensy that adapts the CAN messages sent to the inverter so I can show the same on one set up.

( I limit my Max voltage to 52.5v except for on one day of the week when it is 53.2v (or the pylon battery request). If the battery doesn't get to 100% on that day then it will do it the next day etc. until it does get to 100%).

Not to anyone really, just a thought for thought on why some see charging drop off and some don't. If the batteries are all the same my thought would be environment or control?

[resybaby]

My Sunsynk setup is definitely affected by temperature, but maybe not as much as I thought it might be.
The battery temperature readings haven't dropped below 5 degrees during the recent cold snap - they are in the loft so will get some heat rising up from the house.
I now charge them overnight between 2 & 5am on Flux. You can see them fully charge to start with, and then tail off once above 85ish%.
Strange sometimes that they don't reach the full 99%, sometimes 97 or 95, even though there is time left before 5am to keep charging.
The only common point seems to be this happens if the batteries were 'empty' at 20% so not discharging before charging started.
If they were at 25-30% or higher and still discharging, they will reach 99% every time (will also be interesting to see if they come back to reaching 100% once the weather warms up, or if they have lost their first 1%?

With my Pylontech they sit at 89% for ages and then rocket up to 100% in no time at all, as is common and the expected behaviour.

However when I set the max charge voltage at 52.5v instead of 53.2v the time taken to go from 90 % to 100% increases markedly.

SOC1 is 53.2v and SOC3 is 52.5v



Sure yours will come back to 100%

Well this has got me very 8nterested after todays experiences.

My Pylontechs charged by my Sunsynk inverter have been doing exactly this for a few weeks now - charging like a good one all day until they get to 89% then flatlining and not going higher even if a few more hours of good sunshine left in the day.

In fact this afternoon i phone Sunsynk Texhnical line and asked them why this is.

Guy on the phone (john) was no real help, logged into my system but kept saying its "just coincidence" that the 89% has been flatlining partway through a sunny day. I told him to look back through my SOC history and see just how many times the 89% issue happened, as its been 12 times in four weeks. Never at a different % always 89%. He agreed the 12 instances but kept saying its "just coincidence". Mine havent got to 100% as yet since this issue.

Ive even rewired the stack to use different batteries as master to check, and different numbers of batteries, but always the same % no matter what, so im thinking inverter fault. John says 'oh no, not an inverter fault'

Now im def8nately no expert, but he was pulling all sorts of excuses out.
Todays reason was because the "sun must have gone in at 3pm as you only was producing 30amps from your panels then" - quite why 30amps didnt lift the SOC% at all in over an hour he just couldnt explain. I was also on the roof at the time and it was as sunny all the way through till well past 4pm.

To be honest, it was a total waste of time talking to him, but he kept trying to convince me for half an hour!

He wants me to keep monitoring them, i want a replacement inverter, as this wasnt an issue previously.