Would appreciate any assistance. I have had solar for 1.5 years now but I didn´t install it myself and still feel very much a beginner.

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).

It seems to be a good beginner´s option, as well as one of the very few lithium batteries available here in Chile. 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?

(EDIT February 16th: Bought 2x US2000C instead of 1 x UP5000 due to the UP5000 being unavailable at time of purchase. However total capacity is same/similar.)

Batteries would be in an unheated area; average winter minimum daily temp is about 4C, about 0C can happen on a minority of days. How big an issue is that?

Edited February 17, 20223 yr by Green Power

11 hours ago, Green Power said:

Would the UP5000 (and the US3000C) be compatible with my inverter Axpert MKS II 5kW.

They are, but you can't connect the BMS directly to the inverter. You can connect the BMS to a monitoring program, and have the monitoring program act as an intermediary, or just not connect the BMS to anything. In the latter case, if one cell gets over- or under-voltage, the BMS can't tell the inverter to back off with charging or with loads, so it might have to disconnect itself. But hopefully those cases should be quite rare.

12 hours ago, Green Power said:

average winter minimum daily temp is about 4C, about 0C can happen

Batteries don't like extreme cold or hot environments. That is very cold for a battery. The battery might deteriorate faster than normal. Ideal battery operating temperatures are between 15 and 35 °C.

2 minutes ago, Don said:

The battery might deteriorate faster than normal.

LFP battery chemistry has a special problem with charging at low temperatures, usually 0°C and below. I forget the issue, but degradation is certainly possible, and the battery BMS may refuse to allow charging (or only allow very low current charging) if the temperature is low.

4 hours ago, Coulomb said:

They are, but you can't connect the BMS directly to the inverter. You can connect the BMS to a monitoring program, and have the monitoring program act as an intermediary, or just not connect the BMS to anything. In the latter case, if one cell gets over- or under-voltage, the BMS can't tell the inverter to back off with charging or with loads, so it might have to disconnect itself. But hopefully those cases should be quite rare.

Again, feel out of my depth here. Don´t know what that monitoring program would mean, or even whether that means some additional  hardware to be purchased or whether it´s just software. If it´s very easy for an amateur to do, and cheap, I could learn more about it. Otherwise maybe just plug and play and see what happens? And maybe revisit this topic if I get disconnections later?

On the temperature, I can think of three options.

1 Just put the battery next to the inverter and get on with it, and accept some performance reduction and degradation over time.

2 Put the battery in the cupboard  next to the inverter. Means leaving the battery in an enclosed space, no air flow. Could its own heat production heat up a cupboard enough? Or try and rig this up with an incandescent bulb or some other tiny heat source in there. Or maybe this is just a mad idea.

3 Put the battery in my office next to the outside area. Temperature would rarely be below 10C and would be on average 5C higher than the outside in winter, the same for the rest of the year. Requires drilling a hole in the wall of the office and putting 5 - 10 metres of cable/wire between battery and inverter. I´m guessing some small efficiency losses fro the length of cable/wire but not as much losses as leaving the battery in the cold?

9 hours ago, Green Power said:

Don´t know what that monitoring program would mean, or even whether that means some additional  hardware to be purchased...

I use my own, so I'm not familiar with what's out there. But I believe that most of them run on a Raspberry Pi, and are not free software.

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or whether it´s just software.

There was a version of ICC that ran under Windows, but it was before lithium batteries with BMS.

Quote

Otherwise maybe just plug and play and see what happens? And maybe revisit this topic if I get disconnections later?

That sounds like the option for you. Use the settings that this forum has settled on (though we don't all agree), e.g.

9 hours ago, Green Power said:

2 Put the battery in the cupboard  next to the inverter. Means leaving the battery in an enclosed space, no air flow. Could its own heat production heat up a cupboard enough? Or try and rig this up with an incandescent bulb or some other tiny heat source in there. Or maybe this is just a mad idea.

Batteries contain lots of material, so they are dense, and have a lot of thermal mass. So self heating and tiny heat sources aren't going to make a significant difference, unfortunately.

9 hours ago, Green Power said:

3 Put the battery in my office next to the outside area. Temperature would rarely be below 10C and would be on average 5C higher than the outside in winter, the same for the rest of the year.

That's great so far, as long as it doesn't get too hot in summer when the office isn't in use. I have no idea about your climate, sorry.

Quote

Requires drilling a hole in the wall of the office and putting 5 - 10 metres of cable/wire between battery and inverter. I´m guessing some small efficiency losses fro the length of cable/wire but not as much losses as leaving the battery in the cold?

Long battery cables aren't ideal. Apart from the slight losses from the cable resistance (you can reduce this by using thick cable, e.g. at least 35 mm² or even 50 mm²), I worry about inductance and the spikes caused by sudden changes in battery load. But I suspect that this is your best option. If you can juggle things to minimise that cable length, so much the better.

Thanks for the inverter settings. I would like to do that in between buying the battery (assuming I do go ahead) and installing it, so let´s come back to that topic at that time.

If the cable length is a problem, perhaps putting the battery inside the cupboard could work. To be clear, by "tiny heater" I am talking about heating the air in the cupboard, not the battery itself. I wondered if we could put the battery in a closed cupboard and then on winter nights some very tiny (i.e. low power) heater such as perhaps a 40W incandescent bulb in the cupboard to provide enough heat to keep the temperature overnight in the cupboard where the battery is to a better level. And just turn it on when I go to bed and turn it off sometime the next morning. That might mean using 10% of the battery capacity to heat the cupboard though.

The office will not be too warm in summer.

Have you written about your experience of your Leaf´s battery degradation in 7 years and the battery change. I would be interested to know a bit about that, but just curious (battery degradation after 7 years, costs, what happened to old battery). Good that you managed 98% solar powered, I reckon I`ve manage about 90% for the car. I have a first generation Ioniq 2017 model.

9 hours ago, Green Power said:

If the cable length is a problem, perhaps putting the battery inside the cupboard could work. To be clear, by "tiny heater" I am talking about heating the air in the cupboard, not the battery itself. I wondered if we could put the battery in a closed cupboard and then on winter nights some very tiny (i.e. low power) heater such as perhaps a 40W incandescent bulb in the cupboard to provide enough heat to keep the temperature overnight in the cupboard where the battery is to a better level.

It depends on how well insulated the cupboard will be. It will have to be fairly big, so for a 40 W heater (for argument's sake) to maintain the temperature at a relatively constant level throughout the night, it would have to lose a maximum of 40 W to the surroundings; that seems optimistic to me, but I haven't done any calculations. Perhaps if it was lined with Styrofoam sheets some 10-25 mm thick, it might work.

9 hours ago, Green Power said:

Have you written about your experience of your Leaf´s battery degradation in 7 years and the battery change.

Yes, here: https://ozleaf.proboards.com/thread/1286/sudden-loss-range-replacement-battery .

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I would be interested to know a bit about that, but just curious (battery degradation after 7 years, costs, what happened to old battery).

I don't have those details, because the former owner had the warranty replacement done. I know it was free (I have the invoice for zero dollars), and I believe that they keep the old battery, mainly for the shell to recycle into other cars, and that they have a recycler for the old cells.

Quote

Good that you managed 98% solar powered, I reckon I`ve manage about 90% for the car.

I guess I should update my signature. I estimate that my EV motoring was 98% solar powered when it was just the Leaf, but now that we have the MG as well, it's probably more like 90%. Still pretty darned good, especially since when I use power from the grid, I don't pay for it. I have a small grandfathered solar energy system with a AU$0.44 per kWh Feed In Tariff, i.e. they pay me 44¢ (about 5R today) for every kWh I export from that system. The battery system means that we rarely use grid power, so the credit from the Feed In Tariff pays for the electricity we do use, and for the fixed costs (so much per day "connection fee" plus so much per day for the solar meter). Our account has been in credit for years, except for one quarter when the FIT inverter failed and I didn't notice. I repaired it myself, and next quarter we were back in credit.

Edited January 17, 20223 yr by Coulomb
Added "(about 5R today)"

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. Coulomb, is that the issue you meant when you said "you can't connect the BMS directly to the inverter"?

Edited January 20, 20223 yr by Green Power

On 2022/01/21 at 7:38 AM, Green Power said:

I googled that and I see RS485 and RS232 are different communication standards. Coulomb, is that the issue you meant when you said "you can't connect the BMS directly to the inverter"?

Yes, exactly. You also need some extra firmware, but that comes with the RS-485 port.

This document might put your mind at rest a little. It's from MppSolar, another reseller of Voltronic Power inverters; the PIP-5048MG is equivalent to the Axpert MKS II (last column of the table on PDF page 4). A bit long and technical, but it basically says you can use a Pylontech with an MKS II.

Thanks for that.

OK, so maybe the shop didn't want to sell me the battery to avoid me coming back with novice issues and complaining...maybe they thought it wasn't worth the hassle.

I did actually email Voltronic Power in Asia (coincidentally before you mentioned it as they are the one other manufacturer I found with a reasonably priced lithium battery for sale in Chile) 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".

I also emailed Pylontech but no reply yet.

And emailed another shop in Chile that sells the batteries, 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." "Yes, you can configure however that inverter doesn't have communication with battery. So the configuration must be done manually".

My friend who did my original solar install for me, who works as a professional installer, also thinks it will be OK.

Any thoughts anyone on Pylontech vs Voltronic Power?

Edited January 24, 20223 yr by Green Power
Updating to add reply from shop in Chile

The Voltronic battery I might be able to get in Chile is LIO4810.

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. 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, right?

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.

Edited January 24, 20223 yr by Green Power

20 hours ago, Green Power said:

The Voltronic battery I might be able to get in Chile is LIO4810.

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. 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, right?

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.

The temp problem is easy to solve. Make a smaller partition in the cupboard. Leave 15cm space between battery and 40W incadescent bulb. Wire this type of thermostat in series with bulb but say a 15 deg C unit. This is NC so it switches off at desired temp. They cost less than $2 and will extend the life of the lithium which cost $800 or more. This switch is good for 5A AC/DC load. Just look on ebay. Can be driven from the 48V or the grid.

 

Edited January 25, 20223 yr by Scorp007
Spelling

Pylontech replied to my email: "We don't encourage our customers to use our batteries without communication, and it will not be under warranty."

 

16 minutes ago, Green Power said:

Pylontech replied to my email: "We don't encourage our customers to use our batteries without communication, and it will not be under warranty."

Ooh. That's the first time I've heard that sentiment. Interesting.

1 hour ago, Green Power said:

Pylontech replied to my email: "We don't encourage our customers to use our batteries without communication, and it will not be under warranty."

 

can you share the email address of the person who told you that? 

See 6 on page 3;

https://en.pylontech.com.cn/download.aspx?id=169

4 hours ago, hoohloc said:

can you share the email address of the person who told you that? 

[email protected]

I emailed sales@ but reply came from service@

1 hour ago, Tinbum said:

See 6 on page 3;

https://en.pylontech.com.cn/download.aspx?id=169

Thank you for this. That is helpful. It looks like you are referring to (copy and paste from the above)

6. Exclusions of Warranty
To the extent permitted by law, Pylontech excludes all liability for the Product to the
extent that any damage or defect has been caused or contributed to by the following:
1) Inverter or charger failure;
2) The Product being installed with inverters or charger which have not been certified by
Pylontech;

According to the document, this applies to US2000, US3000 or US3000C

It doesn't mention US2000C, which is the one I am looking to get, although perhaps it is the same situation.

The above document also includes a card you would fill in with some details, and one of the details you are asked to fill in when making a claim is the inverter.

I just wanted to highlight that the wording means the warranty has been invalidated if the inverter "caused or contributed to" the failure. It does not say that using an inverter that isn't certified automatically invalidates the warranty.

Edited January 26, 20223 yr by Green Power

5 minutes ago, Green Power said:

[email protected]

 

I emailed sales@ but reply came from service@

contact technical support and you will get a different answer. The battery's BMS does not rely on any inverter for the BMS to function or to protect the battery in any way. [email protected]

Contact jeff for more information on this 

3 minutes ago, Green Power said:

Thank you for this. That is helpful. It looks like you are referring to (copy and paste from the above)

6. Exclusions of Warranty
To the extent permitted by law, Pylontech excludes all liability for the Product to the
extent that any damage or defect has been caused or contributed to by the following:
1) Inverter or charger failure;
2) The Product being installed with inverters or charger which have not been certified by
Pylontech;

According to the document, this applies to US2000, US3000 or US3000C

It doesn't mention US2000C, which is the one I am looking to get, although perhaps it is the same situation.

The above document also includes a card you would fill in with some details, and one of the details you are asked to fill in when making a claim is the inverter.

I just wanted to highlight that the wording means the warranty has been invalidated if the inverter "caused or contributed" the failure. It does not say that using an inverter that isn't certified automatically invalidates the warranty.

The inverter causing the battery damage is another story on its own. My issue is this statement, Pylontech replied to my email: "We don't encourage our customers to use our batteries without communication, and it will not be under warranty." 

1 minute ago, hoohloc said:

The inverter causing the battery damage is another story on its own. My issue is this statement, Pylontech replied to my email: "We don't encourage our customers to use our batteries without communication, and it will not be under warranty." 

When you contact support they even have recommended settings when you do not use BMS coms, so! someone there is confused 😂

Bottom line, lack of BMS comms with the inverter will not void your warranty, contact them and get the recommended settings and keep the email of those settings that they gave you as evidence. Just incase

21 minutes ago, Green Power said:

Thank you for this. That is helpful. It looks like you are referring to (copy and paste from the above)

6. Exclusions of Warranty
To the extent permitted by law, Pylontech excludes all liability for the Product to the
extent that any damage or defect has been caused or contributed to by the following:
1) Inverter or charger failure;
2) The Product being installed with inverters or charger which have not been certified by
Pylontech;

 

It does not say that using an inverter that isn't certified automatically invalidates the warranty.

Does it not? - I read it as it does.