diy solar

diy solar

Pylontech - The Right Buy for Me?

Mendoza

New Member
Joined
Aug 27, 2020
Messages
85
Location
Chile
The lead acid batteries I bought seem to be almost junk after 1.5 years of regular use and some hundreds of cycles.

I was thinking of replacing them with a lithium Pylontech UP5000; 4.8kWH (or maybe a Pylontech US3000C; 3.5kWH).

(EDIT Feb 16th: I bought US2000C x 2 as it was what was available.)

It seems to be a good beginner´s option, as well as one of the very few lithium batteries available here in Chile and within my budget. With 3.25kWP Risen panels (10 panels), does it seem to be an OK choice?

Would the UP5000 (and the US3000C) be compatible with my inverter Axpert MKS II 5kW? It looks like it might well be, but I couldn´t confirm for certain from google searches or manuals.

Batteries would be in an unheated area with brick walls, and a corrugated plastic roof. Winter night/dawn can be around 0C (32F) although the average winter daily minimum is >0C. I would be fine with say a 10% reduction in energy at 10C, and say a 20% reduction at 1C. However I need to make sure these cold temperatures won´t be damaging to the battery or have a big effect on its longevity. The temperature range is stated to be 0-50C. I know these batteries prefer 25C to 5C or 0C but not sure how big a deal this is. I read that in such a case the battery shuts down at 0C. Not sure if that´s true. As long as it would switch seamlessly to grid, that would be OK I think, as it would be a minority of days when we are asleep in the early hours.

If anyone can help with any of that, then thank you very much.

EDIT: End July 2022: We have now been through the middle of a slightly colder than average winter, including some days with slight frost and temperatures around zero. Batteries worked fine as far as I can tell.
EDIT August 2022: The thermometer in my car said -1C today and I looked in the software and the batteries registered a temperature of 5-6C and said temperature state "normal" and everything seemed fine. I put a thermometer on top of the batteries and it also said 5-6C.
 
Last edited:
The panels seem plenty and the inverter, if it's 48V and so is the battery, I can't think of a reason why it shouldn't be "compatible".

About the battery being outside, is there a particular reason to do that? I guess you kept the lead-acids out there because they "smell bad" ;·) but the Pylontech? It looks good, it has SOC and warning LEDs that give you an immediate general idea of what's going on, the rats are less likely to damage it :·) ...
-
 
Yes, both 48V. I think the issue of compatibility is whether inverter and battery can communicate.

Battery will be easier to install outside since that is where the inverter and the rest of the connections already are. Putting the battery in the office instead would require a hole to be put in the office wall, and maybe the cable going 8 metres around the walls and across the roof. Adds a bit to installation hassle, maybe some small efficiency losses with longer cable?

Is it worth it? Not sure. Outside space in winter averages temperature of 4C at dawn (daily low) and peaks at average 16C by afternoon, office in winter would be average 10C at dawn and maybe 18C by afternoon if I am in there with a heater.

Plus on a few colder than average days temperature may be 0C or lower, however I think the battery would turn itself off for self preservation. Not sure if this is an issue. In the office, temperature would never get down to 0C.

If the battery is outside it will probably be typically 10C-15C in the winter during the likely period of being charged the most (say 9am to 3pm) and perhaps 6C-12C when discharging (say 5pm to 10pm).

So typically the office will be about 5 degrees hotter than the outside in winter at all times of the day and the same as the outside (10-25C) in the rest of the year.

The temperatures range are specified at 0-50C for charging, -10 to 50C for discharging. 10C to 40C is described as optimal in the manual.

So given all that would being in the office would make the battery last significantly longer or give out much more energy, or is it negligible difference?

Note: this is a residential installation, when I say "office" I mean one room in the house that I use as an office as I work from home.
 
I just thought... I keep my (Pylontech, yes :·) batteries inside.
"Everything" else (inverter, breakers, solar controller... ) are in a "cupboard" outside. It's not quite closed, it has a door and a little roof, but just for the rain, it's quite ventilated.

Now, I have a thermometer, with the probe on the floor of it - supposedly the coldest point.
I thought I'd use it to measure outside temperature. Being close to the house, it shows some 8-10°C above actual outside temperature.

So, maybe your "unheated area" will never go below freezing. Put a thermometer in there and check.
You'll have to wait till winter (if you're in Chile ;·) but chances are, if it's close enough to a wall, it'll never go below 0°.
My house is quite well insulated, but no insulation can be perfect, and I have cables going there from the house, and judging from the thermometer, outside wall temperatures (and thereabouts) seems to be quite higher than out-in-the-field, open-to-dew ones.

That said, LFP doesn't really (seem to) mind below freezing temperatures - except as far as charging is concerned.
 
Thanks for this.
Before I consider putting the battery in the office, will it make any noise, beeping, whirring etc.
The office has a bed and can be used as a guest room, and I sleep in there as well when I am unwell as a kind of quarantine.
I am a light sleeper, so noise from the battery needs to be zero.
 
No. No noise, no heat, no problems.

But as I said, you may not have to. We're having an unusually cold spell these days. This morning broke all records with -6°. Water pipes froze.
Temperature in the outside box was above 5°.
-
 
I quite like to have them in a place where I can see them.
Once you get the hang of the LEDs, they can be quite informative.

pytch.jpg
-
 
In my case, I think if I leave the battery next to the inverter it will basically be the outdoor temperature or maybe 1 or 2 degrees higher because:

It is near the far wall of the outside area, not adjoining the house.
It is a large area, maybe 3mx7mx2m.
The outside area has many air gaps to the outside totalling several square metres.
It is next to the office and the kitchen, neither of which is heated in the evening, so the temp in adjoining areas already drops in the evening.

Possibly it could help to just put it in the cupboard and have the cupboard door open in the day to heat the cupboard and closed at night.

If the system is running well they'll probably come a time when I hardly ever look at the battery, but to start with and if I'm having power cuts or other problems I'll probably be constantly checking it.

I will have someone else help with the installation, so I'll see what they think.
 
I went to the shop today to buy a Pylontech battery and they asked me what inverter I had and when I told them they said the batteries would not be compatible, that it may not work when I turn it on, and that I would need to buy a different battery or change the inverter.

They showed me the Pylontech US3000C and I took a photo of it. It has 6 ethernet ports (or something that looks very similar) and they are labelled "Contact" "A/CAN" "Linkport 0", "Console", "B/RS485" and "Linkport 1".

My inverter, the Axpert MKS II 5kW, only has one such port and it has RS232 written on it.

I googled that and I see RS485 and RS232 are different communication standards. I'm not sure whether or not the difference between these two is the issue.
 
From the Pylontech US300 manual:
"Console Communication Terminal: (RJ11 port) follow RS232 protocol (Baud Rate: 1200), for
manufacturer or professional engineer to debug or service.
"

So maybe that would work, with a suitable cable.
Still, my batteries do not communicate with my (all-in-one) inverter. I honestly wonder why they should, or if I'd actually want them to.
They seem to make enough of a mess cope quite well individually ;·)
 
I emailed Voltronic Power and I did actually get a reply from someone in Taiwan. They said "Yes, it is OK to use it without bms communication." I also asked: "Is it still safe, and will it still work, with normal battery life, and warranty still valid?" and they replied "yes". The reason I contacted them is they have a similar battery available in Chile with the same communications standard mismatch.

If I go with Pylontech, there's a chance I may go with two US2000C rather than one UP5000 battery. The total capacity is the same, so I assume it doesn't matter either way. I also emailed Pylontech, but no answer yet. For the smaller US2000C, the reccomended discharge current of 25A looks a bit low for my needs. However if I buy two of them then I will have a recommended discharge current of 50A?

I emailed another store about using Pylontech with my inverter and they said "si se pueden configurar sin embargo ese inversor no cuenta con comunicación con baterías. Por lo tanto la configuración debe realizarse de forma manual." which should mean something like "Yes, you can configure however that inverter doesn't have communication with battery. So the configuration must be done manually".

Any thoughts on Voltronic Power LIO4810 vs Pylontech US2000C/US3000C/UP5000?

At the moment the store doesn't seem to have stock, so it may come down to which product comes into stock first this week or next week.
 
Last edited:
Pylontech replied to my email: "We don't encourage our customers to use our batteries without communication, and it will not be under warranty."
 
On the cold temperature thing, discharge is less of an issue than charging. You do not want to be charging at cold temps, definitely not below 0°C, and preferably not below 5°C. Discharging at 0°C is perfectly fine. A good BMS with low temp cutoff would protect your battery.
 
So after some delay I got the batteries US2000C x 2 and currently scheduled to be installed Friday. Will be installed with Axpert MKS II 5kW and 3.25kWP Risen panels (10 panels) as mentioned previously.

Here are some of the settings as they currently are (majority of the rest are at default setting):

Do these settings look OK? My main focus at the moment is to have the system work smoothly in its initial days with the new battery with no power cuts, and to chose safe settings that can´t damage or degrade the battery, inverter, or anything else. Let me know if any other advice for installation day or immediately after.


1. Output Source Priority: SOL (after installation is complete will change to SBU; during installation might set to Utl?)


2. Maximum charging current: 30A


5. Battery Type: USE


11. Maximum utility charging current: 30A


12. Setting voltage point back to utility: 48V
EDIT: Changed to 47V to stop it using grid electricity in the morning.

13. Setting voltage point back to battery mode: 51V
EDIT: Changed to 49V/48V to make it switch back to solar more quickly after it switches to grid.

16. Charger source priority: OSO (Only solar)


26. Bulk charging voltage: 52.5V


27 Floating charging voltage: 52.5V


29 Low DC cut-off voltage: 47V
EDIT: Changed to 46V to stop an alarm going off, but for most people 47V may still be most secure.

The ones in bold are from an email from Pylontech that I told the system specs.

EDIT: As above, made some edits on March 7th to update to the settings I´m currently using.
EDIT: These settings are for Pylontech 15 cell battery, and voltages would likely be different for the more common 16 cell batteries.
 
Last edited:
It appears from what I'm reading that the Pylontech BMS is made to not simply ensure the battery is operated safely, but to also ensure it lasts long enough that you don't get to replace it while it's under the ten year warranty. Because, you know, efficiency. Apparently its BMS will limit you to 25% of the charge current to extend the life of the battery at times.

An interesting tactic if true. If they limit you to only charging or discharging 1% of the battery's actual capacity they could advertise a 1000 year warranty. Maybe we'll see that in an advertisement soon.

From what I'm also reading, if you have their BMS directing your charge controllers, it will limit the charging current below 64F which I find mind boggling. And it will apparently "severely" limit the charge current to the batteries under 50F. Yes, they advertise the normal operating temps you'd expect and charging down to 32F but it appears their BMS has its own temperature schedule which they won't publish.

If you kick out their BMS and its temperatures (which apparently assume you are storing your batteries on the sun rather than trying to store energy from the sun -- 64F!) then they apparently say you'll void the warranty.

Having just purchased 8 x US5000 after relying on their specs (which said nothing about this insane BMS) and after sizing my PV and my SCCs to store as much sunlight into the batteries during the 4 hours of sun we get on December 21st in ALASKA, I was not pleased to learn this. We designed our battery room 6 feet underground and insulated to ensure it stays above freezing even in our winter time. I had thought that would be enough as it has been with the lithium batteries we own and our current small solar setup. With some more insulation of the batteries themselves inside the culvert I imagine we can keep them happy with their tropical requirement of 65F for full charging. But I will be eagerly awaiting whether or not they limit our charge current to extend their warranty the life of the battery.

In our case, for about 8 months of the year we will have very limited charging and discharging of the batteries because we will generate so much solar power. But we sized the system for the remaining four months when we need it to work to the max. It will be interesting to see what that BMS does and we will log everything. If after its BMS sees that the batteries are used very lightly for 8 months it decides to let us use them to their full potential for the four months we need it, then cool, we'll be fine with this limitation. Since I'm guessing its BMS is calculating the ten year period efficient life of the battery and ensuring you don't use the battery too much so that it lasts longer by not being used when you need it, that might happen.

We will log and track this from the beginning when these batteries are delivered and if they don't give us the advertised specs during those four winter months, we'll put in a warranty call to get our money back because they do not meet their specs. I'm sure that will be a fun process that will result in us just taking their BMS out of the equation during our 4 winter months and voiding the warranty. But we'll see.

We haven't used the batteries and they might be awesome. The dealer (great guy who has been very helpful and generous with his time, although I wonder whether he gets the full story from his company on how the BMS operates) has told us these limits will NOT apply to the US5000. So who knows how they will operate. Maybe the Soup Nazi BMS I've read about won't show up and they will behave as advertised. If so, we'll probably buy eight more.

We'll share what we learn in detail regarding these batteries.
 
Last edited:
Having just purchased 8 x US5000 after relying on their specs (which said nothing about this insane BMS) and after sizing my PV and my SCCs to store as much sunlight into the batteries during the 4 hours of sun we get on December 21st in ALASKA,
US5000 is 4.5kWH so 8 of them is 36kWH, is that right? You can charge up with 36kWH in 4 hours, that´s 9kW charging rate? Even in the middle of winter? What is the KWp of your total panels? Must be huge? Are you living completely off grid?

By the way, are you going to register the batteries on the Pylontech site? Is is worth it?
 
US5000 is 4.5kWH so 8 of them is 36kWH, is that right? You can charge up with 36kWH in 4 hours, that´s 9kW charging rate? Even in the middle of winter? What is the KWp of your total panels? Must be huge? Are you living completely off grid?

By the way, are you going to register the batteries on the Pylontech site? Is is worth it?
Yes, 36KW. We'll see how the math works out, but we have 22KW of bifacial panels optimized perfectly for the 4 hours of sun on 21 December. No shade, no trees. We won't know until we try how much power we'll get but since it will be cold outside and snowy, it's possible they will produce more than 22KW of power each hour on that day. But we'll see.

We bought two 450/200 charge controllers to operate in parallel to send 19KW of power to the batteries. Part of the reason I am going to be very unpleased if their BMS limits the charge when we need it.

Yes, we are totally off grid and we're setting up our system as soon as the snow melts. We've ordered all the equipment, panels are on the barge up, but batteries have not shipped to us quite yet. I haven't thought about registering the batteries on their site and haven't looked into it yet.
 
Back
Top