Pylontech x Sofar - battery in standby mode far too early

[Tinbum]

Other than cost, pretty much this entire post is a good summary of why I'm going completely DIY.

I'm not completely convinced that the Pylontechs are as hands-off as most would hope - they need just as much tinkering with as a DIY stack in order to perform well sometimes. If the built-in BMS isn't doing its job properly out of the box and you have to hold its hand like this, I might as well build my own, save some money, learn a few things about how it all works, and be in a much better position to replace parts of it cheaply if anything fails.

It looks nigh-on impossible to replace a single cell in the Pylontechs for example. I opened one up recently and the cells are 3 packs of unidentifiable black blocks. I didn't take the tape off an unidentifiable black box but I rather doubt they were 18650s or anything off the shelf in there. And if the BMS failed in a Pylontech well.. its pretty much going to the recycling.

The tinkering I have done, as I said in my post to quote "I can't say that this is an improvement in the balancing over what the BMS actually does though" , doesn't mean it has to be done. I like to see exactly what is happening and needed to because my set up isn't anywhere near standard.

Winter is going to be the time when any imbalance is going to show, and none of these packs have failed.

The packs are very much fit and forget- it's more than often the setup that isn't correct, due to not reading the manual properly. The number of times I read about people saying to set the dip switches shows exactly what I mean.

If you do a search you will see exactly how the packs are made up. Also note they come with a very long warranty.

This thread actually shows that the batteries are good.

[Tinbum]

The battery that won't charge past 95 is indeed going to idle mode once it gets to 95%, so I don't think it's trying to balance its cells?

Battery temperature has been pretty constant at 13C, they are indoors so never get too cold.

I suspect it probably doesn't matter if the 2 batteries appear unbalanced at full charge, due to the tiny difference from 95 to 100. After a few more cycles I'll see how they compare at 50% or thereabouts.

The current taken to balance is so small that the battery will go into idle and then charge then idle.

Re Temp- as I said before the bms reported battery temp goes up when balancing. You need bateryview or similar to see that. (or sniff the CAN messages).

Sure they will get their, but it may take some time, as during winter unless you do grid charging, they never get up to the voltages required for balancing.

Below gives an idea of the settings for balancing.

[Tinbum]

Of course this is all a bit of a revelation to me but I do understand the management of LiPo batteries is somewhat more technical than charging Lead Acid.

Which will bypass this data exchange.

Yes, lead acid will just bubble away happily being overcharged but LiPo do need controls or posible

'connections between my new panels, charger and battery.' ???

'Which will bypass this data exchange.' ???

I use Eltek chargers to charge mine but as Ive mentioned before I intercept the CAN messages- convert them and send them to the charger.

https://camelot-forum.co.uk/phpBB3/view ... f=14&t=221

[nowty]

This info is good to know Tinbum, my Pylontechs now go full every night because I charge without BMS connection to a slightly higher voltage but less than the lower 'C' versions upper limit. So they charge till they go into standby so their balancer should get exercised every night.

The new 'C's seem to be a lower spec than the 'B's as the voltage range is not as wide. They are supposed to be the same at the bottom end but I've noticed my new 'C's shutdown on discharge at a higher voltage than the official spec and before my 'B's used to complain.

[Tinbum]

Yes, they can start to balance at 50.4v but they need a 30mv difference. At that voltage they really would have to be out of balance a lot. It's only when you start getting up to the high voltages that balancing really starts on good packs.

I would assume that pylontech know what is good for their batteries! They do seem to have a good reputation.

[nowty]

Yes, they can start to balance at 50.4v but they need a 30mv difference. At that voltage they really would have to be out of balance a lot. It's only when you start getting up to the high voltages that balancing really starts on good packs.

I would assume that pylontech know what is good for their batteries! They do seem to have a good reputation.

Yes I read a few years ago when I gought my first ones that they are a fully vertically integrated company,

Pylontech is an unique company with vertical integration of all technologies needed for ESS (Energy storage system), including cathode material, lithium cell, BMS and system integration.

If true, I can't imagine many companies can boast that.

[Oldgreybeard]

Our six Pylontech batteries have just past their second birthday and, with the exception of finger trouble by me causing one slight scare seem to just work without drama. They've been worked harder this last week than at any time since we've had them, this cold weather has meant running the MVHR heat pump 24/7 as well as extending the hours of the main ASHP that runs the UFH (that normally only comes on overnight, then only for a short time during normal winter weather). Minus 5°C here this morning, coldest we've seen here in a long time, but at least a hell of a lot warmer than for those much further North.

Instead of the normal 5kWh to 10kWh per day we use this time of the year we've regularly been pulling over 20kWh/day for the past week or so. Looking forward to us getting back to normal in a few days, when it's forecast to warm up a lot (should be up into double figures by Sunday/Monday).

[Fintray]

Our six Pylontech batteries have just past their second birthday and, with the exception of finger trouble by me causing one slight scare seem to just work without drama. They've been worked harder this last week than at any time since we've had them, this cold weather has meant running the MVHR heat pump 24/7 as well as extending the hours of the main ASHP that runs the UFH (that normally only comes on overnight, then only for a short time during normal winter weather). Minus 5°C here this morning, coldest we've seen here in a long time, but at least a hell of a lot warmer than for those much further North.

Instead of the normal 5kWh to 10kWh per day we use this time of the year we've regularly been pulling over 20kWh/day for the past week or so. Looking forward to us getting back to normal in a few days, when it's forecast to warm up a lot (should be up into double figures by Sunday/Monday).

Got a bit of a thaw up in my area of Aberdeenshire, a balmy 1C this morning.

[ducabi]

I dropped my SOC to 90% 2 days ago and yesterday it discharged batteries to 16% and then (first time I've seen it) topped it up to 17% and went static (DOD set to 90%). I haven't done any balancing recently, just changed the SOC in time-of-use. I recall that when i changed it previously (from 90% to 100%) it also worked better but only for a day or two.

[dangermouse]

It's only been a couple of days but since my attempts to balance my 2 batteries (charging individually to 70% then letting them balance while disconnected from the inverter) I haven't had any unexpected behaviour.

I'll report back after another week or so.