Pylontech 5000 batteries GOOD or BAD??

[FlyingScot]

Well planning on installing a battery system and met a few clowns one today was rather upsetting.

So here is what I have and what I want to do

I HAVE 3.75Kw of solar 15 250W panels with Solar Edge Optimisers and a Solar Edge HD Wave inverter. (that was a TFU installation by total cowboys the only good thing was that it included workmanship insurance which I did have to claim on :-(

I WANT to run the house on Battery Power (As I build solar systems for yachts in the Caribbean and about 7 years ago built my own LifePO4 600Ah House bank using LifePO4 Prismatic Cells designing and installing the whole system myself and being a multidisciplined engineer I am for sure not a numpty.)

Today I got treated like one :-(

SO my plan was to put in what would become a hybrid system. My preferred batteries are going to be the Pylontech 5000 and initially I will just charge them with my existing Solar and Octopus off-peak energy phase 2 eventually I am going to put as much solar on the roof (now a 15/20 degree flat pitched roof) of my just about to be built garage that should give me initially 30 sqm and with the attached car port another 30 sqm for probably a DC system with VICTRON ENERGY MPPT controllers feeding the house system.

I was going to use a Solis AC inverter charger but being a VICTRON ENERGY guy I thought I could use a Victron MultiPlus-II 48V/10000VA/140A-100/100/230V Inverter Charger with three inputs two AC one from the grid (off-peak) and one from my solar and one DC from the new solar on top of the garage (there is no room on the house roof for a decent amount of new solar)

NOW this morning I had a highly recommended solar installer come to see me (recommended by the local solar wholesale supplier)

Sadly he was bad mouthing my proposed systems and recommending a Givenergy system NICE and EXPENSIVE. That was OK until he started telling lies about the Pylontech batteries telling me that they were NOT reliable were dangerous had no UK back up and very silly boy that they were not Lithium Iron Phosphate and were liable to catch fire!!!

Now have done lots of research before deciding that this was the battery for me and finding not a lot of bad reports about them, I thought I would ask here.

Many thanks for all your feedback

David

​

 

[Horsefly]

The main negative that I have heard / read about the Pylontech batteries is that they are 15 cell rather than 16 cell. So they are cutting corners and to give you what they are calling a "nominal" 48V battery, but it's charge and discharge will be one-cell short of what everyone else in the business is doing. Makes them cheaper to manufacture, but for me I would much rather go with the 16-cell standard everyone else is selling.

 

[rpdom]

I've got a couple of the US2000C units, half the capacity of the 5000. I've had them just over a year and haven't had any surprises. I would love to upgrade with a couple of 5000s, but that's outside my current budget.

 

[SeaGal]

I have Solis too but with DIY battery. With your skills why not DIY your battery or choose a more standard 16 cell one such as the pack from Fogstar as you're in the UK? Or even the Fogstar Seplos kit with cells looks good value too.

Edited to add: The only bad thing I've heard is as @Horsefly mentioned. Only 15 cells, so less voltage and hence less output from a Solis as the output power reduces as voltage reduces. Also, you won't be able to expand later with a 16 cell pack as that will run at a higher voltage.

 

[FlyingScot]

I was contemplating building my own using the same cells as I use in the Caribbean 200Ah Prismatic cells

BUT while that is dooable it does not now seem like a cost-effective solution

Previously I purchased cells from an American Aircraft Tug manufacturer in Los Angeles, California at seriously silly prices

That was easy to do, but that supply dried up many years ago and cell prices have got seriously silly in an expensive way now

And i want a quick solution spending my money and not my time

will have a look at your suggestions re Fogstar

Any and all subsequent battery expansion will be by adding MORE Pylon 5000's IF I went for a quick and cheap Solis inverter and one 5000 then I may swap the inverter for a VE one as I upgrade the battery numbers.

QUESTION can the Solis /Pylon 5000 system export from the battery when energy prices are high?

thanks

 

[rpdom]

QUESTION can the Solis /Pylon 5000 system export from the battery when energy prices are high?

The Solis can export from battery, but that is using a timer. It doesn't know anything about energy prices.

It's possible that HA could handle that automatically if connected via Modbus to the inverter. The registers used to set the timers for charge/discharge from/to grid are documented.

 

[SeaGal]

while that is dooable it does not now seem like a cost-effective solution

I'd say it depends on the amount of storage you are looking at. For 5kWh it would not be much more cost effective by the time you've added all the bits (BMS, housing, fuses etc). But if you are looking at 15kWh+, then yes, still cost-effective. I have a 280Ah (14.3kWh) system, which worked out about 2/3 of the price of buying 3 x 5kWh racks. And for me having better control over the system is more important, so I'd go DIY even if it cost a bit more ?‍?.

Re exporting: As well as the 2 methods @rpdom has mentioned, there is also the possibility to MITM the RS485 grid-export power meter readings to force the Solis to charge or discharge from battery at will - take a look at @peufeu's postings for more info.

 

[FlyingScot]

OK thanks guys & girls

I looked at the various YT videos on the Off-Grid-Garage on the Fogstar Seplos kit with cells that does look good so I think this is the way I will go Battery wise. Thanks for that heads-up. Probably go for the higher capacity 304 kit rather than the 280 kit and i would imagine that will be more than enough battery capacity for me for some time I am contemplating a fully electric house (battery powered) and getting rid of the Gas C/h and H/w but that won't be next week and probably not even next year

I want to do online monitoring not only Bluetooth or hard-wired but remote so i need to do a lot more investigation there as well as what inverter charger to purchase Solis or the VE multiplex with the necessary bits to do remote monitoring and control

I can feel a sore head coming on :-(

thanks again

David

 

[FlyingScot]

The Solis can export from battery, but that is using a timer. It doesn't know anything about energy prices.

It's possible that HA could handle that automatically if connected via Modbus to the inverter. The registers used to set the timers for charge/discharge from/to grid are documented.

Can you explain all of that better to me please and what is HA?

 

[SeaGal]

Can you explain all of that better to me please and what is HA?

The Solis has a time-of-use setting (TOU) so you can force it to charge from grid or discharge to grid at a configurable, but fixed current. That is only accessible via multiple key presses on the clunky Solis screen, so not very user-friendly or flexible.

HA is Home Assistant in this context.

Some people have built interfaces from a PC / RPi to communicate with the Solis's RS485 comms port to write to some ModBus registers to automate the process of setting Solis variables.

Do check out these 2 threads as a starting point if that's something you are interested in...

Solis S5: Various issues

Previously the fan was set to start when inverter self-reported temperature exceeds 40°C and stop when it cools down to 30°C. In this inverter, most of the heat comes from the battery DC-DC. So I also set it to run the fan when battery power exceeds 2kW. This gives it a head start, as it...

diysolarforum.com

Modbus Register Backflow Power for Solis Hybrid Inverter

I currently have the Solis RHI-6K-48ES-5G hybrid inverter which I am connecting remotely from a Raspberry PI via the Modbus. I want to be able to automate the power exported to the gird, depending on the state of charge of my battery. i.e. 0 export when battery State of Charge (SOC) is

diysolarforum.com

 

[FlyingScot]

OK more questions, INVERTERS!!!

I was planning to either use the Solis RHI-(3-6)K-48ES-5G AC Charger Inverter OR spend lots more money and get the {more clever and user adjustable} VE Multiplus II one

But someone suggested using the Solis Hybrid Solar Inverter 5kW SOLIS-RHI-5K-48ES-DC 5G since I expect to be using more power at times than the RHI-(3-6)K-48ES-5G can supply. If that were a long term issue and I had gone ahead and purchased a 3.6K Solis inverter, then if i was buying lots of energy at peak times then the options for a Phase two upgrade would be to upgrade to the VE Multiplus OR add another RHI-(3-6)K-48ES-5G

Thoughts on using the Solis Hybrid Solar Inverter 5kW SOLIS-RHI-5K-48ES-DC 5G for just a non-solar battery solution with the Fogstar Seplos DIY 15.5 battery kit OR even a twin RHI-(3-6)K-48ES-5G installation

 

[SeaGal]

I'll give my 2p.

First, the name "RHI-(3-6)K-48ES-5G" is the generic name for the RHI range from 3 to 6kW. I assume you actually mean the RHI-3.6K-48ES-5G model which is 3.6kW (yes, confusing).

As well as the RHI range, there is a newer EH1 range. Virtually identical, but the EH1 has newer firmware and supports a slightly larger PV input current. I have the RHI running at the moment, @rpdom (who replied earlier) had his RHI swapped out for an EH1 to fix some issues with high PV current (IIRC!). So, I'd look at the EH1 range right now.

Next up is DNO approval - both Solis's are approved. Up to 3.6kW is inform DNO, over 3.6kW is get approval first and you may need to configure the inverter to limit output (but that feature is build-in, so not an issue).

I am in the process of upgrading, so yes, would advise to go for the larger one for future expansion - there is little difference in price anyway and the EH1 range has a 6kW model.

If you only want an energy storage solution you can use the Solis RAI. Otherwise, yes can use the RHI / EH1 with battery an no solar AFAIAA.

The Solis RHI and EH1 ranges don't inherently support twin operation out of the box. To achieve that you would need to implement external control systems as discussed in the other threads and also mentioned here..

Solis S5 / Fox Battery not discharging

Hi I have a complicated system (?) as I dont have roof space for 12 panels so they have been split over the garage roof and house roof. Each string on panels having a dedicated Solis S5 invertor and Fox 5200 battery (therefore I have 2 independant but connected systems - one on garage roof and...

diysolarforum.com

HTH.

 

[rpdom]

The Solis has a time-of-use setting (TOU) so you can force it to charge from grid or discharge to grid at a configurable, but fixed current. That is only accessible via multiple key presses on the clunky Solis screen, so not very user-friendly or flexible.

As well as the front screen, you can access the TOU settings from the Soliscloud App or website if you have a datalogger connected to the inverter. This does mean your inverter data is stored on Solis' servers.

 

[SeaGal]

... in China

(which is why I don't have the datagrabberlogger and forgot about that option !)

 

[FlyingScot]

I'll give my 2p.

First, the name "RHI-(3-6)K-48ES-5G" is the generic name for the RHI range from 3 to 6kW. I assume you actually mean the RHI-3.6K-48ES-5G model which is 3.6kW (yes, confusing).

As well as the RHI range, there is a newer EH1 range. Virtually identical, but the EH1 has newer firmware and supports a slightly larger PV input current. I have the RHI running at the moment, @rpdom (who replied earlier) had his RHI swapped out for an EH1 to fix some issues with high PV current (IIRC!). So, I'd look at the EH1 range right now.

Next up is DNO approval - both Solis's are approved. Up to 3.6kW is inform DNO, over 3.6kW is get approval first and you may need to configure the inverter to limit output (but that feature is build-in, so not an issue).

I am in the process of upgrading, so yes, would advise to go for the larger one for future expansion - there is little difference in price anyway and the EH1 range has a 6kW model.

If you only want an energy storage solution you can use the Solis RAI. Otherwise, yes can use the RHI / EH1 with battery an no solar AFAIAA.

The Solis RHI and EH1 ranges don't inherently support twin operation out of the box. To achieve that you would need to implement external control systems as discussed in the other threads and also mentioned here..

Solis S5 / Fox Battery not discharging

Hi I have a complicated system (?) as I dont have roof space for 12 panels so they have been split over the garage roof and house roof. Each string on panels having a dedicated Solis S5 invertor and Fox 5200 battery (therefore I have 2 independant but connected systems - one on garage roof and...

diysolarforum.com

HTH.

OK MORE QUESTIONS

IF i do NOT want to export and Just use AC from my Solar Edge solar system and from Octopus cheap overnight electricity to charge my batteries AND do ALL the installation myself then I do NOT have to contact anyone??

IF I install a 5k or 6k inverter, I need DNO approval to export to the grid (will there be issues since I will have built and installed all of this myself?) OR should I get an approved installer {or just a qualified electrician} to put it in for me {I will build the SEPLOS 15.5K DIY Kit battery} to make the DNO approval easier?

EXPORTING Energy. Assuming I get DNO approval to have a battery system with a 6k inverter, and I am exporting to the grid IF I add lots more solar on my soon to be built garage roof will I then need to apply for more DNO approval for that upgrade and if I change inverters like from the Solis to a VE one will that require more DNO approval.

 

[FlyingScot]

WOW found a Victron Energy MultiPlus-II 48/5000/70-50 230V at almost 50% discount with a free Cerbo GX for only £1,100

Victron MultiPlus-II 48/5000/70-50 Promo 230V(PMP482505010)

Victron MultiPlus-II 48/5000/70-50 230V(PMP482505010)Victron MultiPlus-II 48/5000/70-50 230V combines the functions of the MultiPlus and the MultiGrid. It has all the features of the MultiPlus, plus an external current transformer option to implement PowerControl and PowerAssist and to optimize...

nomadicleisure.co.uk

​

 

[SeaGal]

OK MORE QUESTIONS

IF i do NOT want to export and Just use AC from my Solar Edge solar system and from Octopus cheap overnight electricity to charge my batteries AND do ALL the installation myself then I do NOT have to contact anyone??

That is not correct. If you are grid-tied in the UK, you need G98/G99 compliant and need to inform your DNO for G98 installations and get approval before installing G99 equipment.

IF I install a 5k or 6k inverter, I need DNO approval to export to the grid (will there be issues since I will have built and installed all of this myself?)
OR should I get an approved installer {or just a qualified electrician} to put it in for me {I will build the SEPLOS 15.5K DIY Kit battery} to make the DNO approval easier?

You need DNO approval for connection to the network, irrespective of whether you intend to export any power or not. No issues with self-install as far as DNO is concerned. You will obviously need all wiring to be done to BS7671 standards by a competent person and meet building regs Part-P requirements - see also my posting with more detail here...

Octopus Energy will no longer require MCS certification in the UK

https://gtec.co.uk/clause-5-8-octopus-opens-up-the-solar-pv-market-with-a-paragraph/ I'm not sure how exactly the UK's permitting and approval process works but this sounds like a major win for DIY.

diysolarforum.com

EXPORTING Energy. Assuming I get DNO approval to have a battery system with a 6k inverter, and I am exporting to the grid IF I add lots more solar on my soon to be built garage roof will I then need to apply for more DNO approval for that upgrade and if I change inverters like from the Solis to a VE one will that require more DNO approval.

The approval is based on the compliance of and export capacity of the inverter. The number of panels connected to the inverter is irrelevant wrt. DNO approval. So, changing inverters will require liaison with DNO, changing panels will not.

 

[LeeOliver]

The main negative that I have heard / read about the Pylontech batteries is that they are 15 cell rather than 16 cell. So they are cutting corners and to give you what they are calling a "nominal" 48V battery, but it's charge and discharge will be one-cell short of what everyone else in the business is doing. Makes them cheaper to manufacture, but for me I would much rather go with the 16-cell standard everyone else is selling.

Why is this considered bad?

The Pylontech batteries have a nominal voltage of 48v, which is 3.2v x 15. The Fogstar batteries have a nominal voltage of 51.2v, which is 3.2v x 16.

The only technical difference I see between the batteries is that the Pylontech batteries will discharge at 6.6% higher current for the same power. Maybe slightly thicker/shorter cables would be required. I don't see any other difference. It's not like 16 is some magic figure that makes LiFePO4 battery chains work better?

I do see a cost difference. The Fogstar rack is cheaper:

£8000 - 6 Fogstar 5.12kWh batteries in a rack = £8000 / (5.12 * 6 * 0.8) = £325 per kWh @ 80% DOD
£6000 - 4 Pylontech 4.8kWh batteries in a rack = £6000 / (4.8 * 4 * 0.8) = £390 per kWh @ 80% DOD

 

[SeaGal]

Why is this considered bad?

The Pylontech batteries have a nominal voltage of 48v, which is 3.2v x 15. The Fogstar batteries have a nominal voltage of 51.2v, which is 3.2v x 16.

The only technical difference I see between the batteries is that the Pylontech batteries will discharge at 6.6% higher current for the same power. Maybe slightly thicker/shorter cables would be required. I don't see any other difference. It's not like 16 is some magic figure that makes LiFePO4 battery chains work better?
...

Bad for 5 reasons, IMHO...

1) Industry standard is 16 cells, not 15. Hence, you will not be able to mix-and-match different battery packs in future as they run at different voltages.

2) You are getting 1/16th less storage than an equivalent 16 cell unit - which wouldn't be so bad if they were 1/16th less expensive!

3) Inverters will typically charge / discharge to a given current, not power, so with less voltage available they will charge / discharge at a lower power.

4) Some inverters such as the Solis I have will also deliver less power from battery as the voltage decreases. My inverter will deliver 3000W until the battery voltage gets down to about 52V, at 51V it will only delivery 2900W and at 50V only 2800W. So, if you are starting 3.2-3.3V lower, you will never get your full 3000W.

5) When the industry standard for so-called "48V battery racks" is to use 16 cells, then it is a bit sneaky (IMHO) for a company to sell a product with only 15 cells in it. Obviously their sales brochures state 4.8kWh, rather than 5.12kWh, but to the newcomer the difference is not that obvious or clearly stated in their sales brochure. I feel it is a bit like a few producers of milk in the UK who sell bottles of 1 litre, whereas most sellers sell bottles of 2 pints = 1.136 litres. They look roughly the same size, but it's not till you get home and run out of milk sooner than you expect do you realise you've been diddled out of 13% capacity

 

[Horsefly]

It's bad mainly because they are taking advantage of people who are not as smart as you. People may go out and look at different 48V 100Ah batteries and think they all have the same power, but in fact you are getting less power from the Pylontech. The fact that they are the ONLY company that is doing this (15S instead of 16S for a 48V battery) makes me think they are hoping people don't notice when they are making purchase decisions. You recognize the lower Wh from Pylontech, so at least you are going in with your eyes open.