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SOLAX X1 series 2 Hybrid Inverter issue

Gray17

New Member
Joined
Jul 22, 2024
Messages
92
Location
Hull
Good Morning All.
Firstly let me introduce myself, i am an approved Electrician by trade and have worked in the industry for over 40 years, but am retired now.
i recently installed a Solar system on my Bungalow, it consists of:
Solax3.7kw hybrid inverter
16 x 250w solar panels
4 x 12v Lifep04 Lithium batteries
all of the work was carried out by myself to a high standard, but as retired got an approved electrician to certify it to part P after the install.
The system has 2 strings of 8 panels on same roof 287v per string, the inverter is set to comm which combines the strings production.
This brings me to the issues so far.
1. The lithium Batteries need to be charged to 14.7v full charge 4 in series is 58.1v but setting my inverter to this cut off voltage and 49v discharge voltage doesnt seem to do anything.
The batteries remain discharged even though the solar system is generating The batteries remain uncharged even though the system generating 3.7kw peak, my home use is small prob below 500w but instead of using energy to charge batts it goes to grid, even though ive set export value to 0w?
any ideas please?

Next ive tried connecting to the wifi, can connect direct to inverter itself and set up the wifi settings but even though ive downloaded Solax cloud app the options on it are pocket wifi, solax x inverter etc tried about 7 diff ones then input reg number just says invalid, thing is been in touch with Solax they say they can see inverter so should connect, any suggestions.

Finally i d like to get MCS certification if anyone local is interested in doing this in the Hull area Cost? i'm more then happy to help if needed.
 thanks
 
Hello there,
Have you had the chance to review the charging period settings? Many had problems with that when batteries were not charging.
Also, is the battery pack recognized? I had troubles with my pylontech setup, and had to go to inextricable contraption to make them work.
Cheers,
 
Thanks for reply, yes batteries recognised by Solax inverter at exactly same voltage as my fluke multimeter reads. Also inverter shows either a + in A for charge, or a - in A for discharge in charger settings in my case as soon as connected went into Discharge, despite my homes demand 300w approx being supplied by the 3.6kw being generated by solar?
I would have expected as set for self use priority is own use, then battery charge, any surplus to grid, but No my home demand was covered by inverter as was any extra demand kettle, immersion up to inverters max of 16A.
But batts not being charged, until all generation ceased on an eve, at which point fully charged batts should start discharging allowing your home to use the power from batts until cut off V reached at 49v at which point you use grid power. For some reason mine doesn’t work that way? Incidentally batts do not have BMS rs485 connection to inverter, Only the battery leads + and - but are supposed to have their own internal BMS for safety.
Im now thinking faulty inverter or possibly duff batteries as extremely light compared to others.
Theres another post on these Moseworth Batts that i replied to.
Comments anyone?

Update - decided Inverter may be faulty, contacted seller who agreed to swop inverter like for like.
This was downpowered and returned to seller, who upon arrival at his premisses had replacement inverter set up on test on his own batteries working correctly.
Returned home and re fitted replacement unit expecting all to be well upon start up, but after going through self check mode, with my Batts this time fully charged at 14.5v per batt. The inverter kicked in generating 3.3kw of solar, my home demand was 500w so a surplus of 2.8kw but for some reason the batts started giving power to the grid when it wasnt needed so 3kw going to grid? The grid setting is a max of 10w as dont want any going to grid so there was no demand, the inverter should have reduced yield to supply my home demand and any battery demand but didnt. Cant be inverter as its a replacement and unlikely 2 inverters with same fault. Batts faulty or something else?
Any suggestions?
Thanks
 
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Afternoon Guys, well Solax have had a look at all of the settings on the inverter and believe all is correct for my install. They have confirmed when inverter set to 0w export the inverter should reduce yield to cover my home useage and battery charging but little or No export to grid.
Yet the problem still remains.
I had thought i'd sorted it by chance as found the 3 CT clamps all next to each other so seperated them by 50mm,
(why 3 you may ask, 1 for Inverter, 1 for EV charger, 1 for house display) also checked cat 5 wasnt ran near any mains cables. It seemed to improve inverter phone app display but power was still going to grid despite home smart meter display showing the opposite? Im now wondering if CT clamp is faulty??
Any thoughts?
Thanks
 
Have you check the CT clamps are the right way round as they are directional.
 
Im 99% sure that your inverter needs comms with battery to work. That's your problem
 
Im 99% sure that your inverter needs comms with battery to work. That's your problem
[/QUOT
Thanks for reply, im hoping thats not the case as the 4 batteries whilst having their own internal BMS have no external means of connecting this to the inverter directly.
I also advised Solax of tbis and they haven't come back saying this could be an issue. You'd expect their Tech support to be on the ball on this.
However if it is how to resolve?
1. Replace batteries as were advertised and sold to work without this connection present, for Solar use.
2. Change setting from Lithium to Lead acid, using the same settings as now
Ie 58v max charge, 48v min cut off, 15a max charge and 25a max discharge. Of course not explored these settings so lead acid may not even allow the max voltage that high.
But assume no direct BMS connection needed as lead acid batts dont have this. Its also suitable for AGM batts too.
Alas this is my lack of experience i assumed that the inverter would just sense their state of charge through the Pos + and Neg - terminals similar to lead acid type. BMS connection only for safety. I note theres also a thermal sensor input on inverter, would fitting a thermal clamp to battery help? Assume this is just a thermister with a RJ45 plug?
Theres so much more to Solar then meets the eye thats for sure!
 
I thought you are already using it in Lead acid mode. If not change it to Lead Acid and set the voltages. Lithium mode is usually reserved to work with comms. I'm using Deye in lead acid mode with my 280ah Lithium battery pack
 
Have you check the CT clamps are the right way round as they are directional.
Thanks for reply, yes thought that myself and the app display was showing power going from grid to home but in reality was going the other way. Even though arrow on CT facing towards grid, which is correct for direct CT connection according to user manual, i tried reversing it, this caused app display to change power direction from Home to Grid which is correct, but then the other readings were all to pot so reversed it back. As its been extended with Cat 5 i tried reversing connections in case they were wrong, but that flagged up a CT fault on inverter so changed that back also. I have also made sure Cat 5 cable not run next to mains cable in case picking up transients. It isnt.
1 thing i did notice the CT has a split ferrite core to allow it to clamp around cable. The top section is fine, however the bottom U section looks like a piece has brocken off, so when closed doesnt create a full loop, im thinking this could well be the issue? As if it isnt a complete loop, it wont sense correct current transfer accurately.
Ordered a replacement 100a 33.3mv type. Thinking about it now inverter worked perfect on Solar alone, before batts were fitted and dont use the CT clamp in this mode.
Will fit upon arrival and post findings.
Thanks
 
I thought you are already using it in Lead acid mode. If not change it to Lead Acid and set the voltages. Lithium mode is usually reserved to work with comms. I'm using Deye in lead acid mode with my 280ah Lithium battery pack
Thanks for reply, guy i bought inverter from had it installed in his own home and upgraded to a larger inverter, he was using it with 4 eco- worthy lithium batteries but 12v 100ah, mine are only 12v 50ah but his didnt have direct connection to inverter either. He said i should use same settings.
However considering the issues I'm having and the fact that Moseworth themselves are now saying not suitable for Solar connection unless direct connected. Im reconsidering if Lead Acid connection is the better option.
Will give it a try
Thanks
 
Hi Guys, right well first off new CT clamp arrived correct type and current rating for Solax X1 Sk Su3700E series 2 inverter ie 100a 33.3mv, fitted this today, its hard to tell how its behaving as apparently the old Solax app im using only refreshes every 5 mins or so, your always viewing events in arrears even if refreshed. Solax say the new app for later ser 3 and 4 inverters far more accurate but wont work on my series 2 so im stuck using that or climb in the loft to view the inverter display.every time.
Next tried swopping Battery type to Lead Acid as suggested rather then Lithium. Solax themselves stated to get true reading from Lithium Batteries you need a direct BMS connection, my Lithium 12v 50ah Moseworth do not have this. Anyway swopped setting and watched batteries they started charging straight away but at a higher rate then set 15a? Temperature also climbed steeply to 68 deg C. Whilst watching the batteries i got a further email from Solax Tech support stating Not to change setting and should remain on Lithium. Otherwise the batteries may overcharge and could explode! Now that may well be overkill but i bottled it and changed setting back to Lithium just in case.
I also asked how the inverter sensed the voltage, current and temperature with no direct BMS connection. So far that has not been answered. I would have thought there should be 3 settings 1 for Lithium with direct BMS connection, 1 for Lithium without BMS connection and the 3rd for lead acid. But on my inverter theres only the 2 its Lead Acid or Lithium.
I will let you know how it behaves over the next few days for your info.
 
I also asked how the inverter sensed the voltage, current and temperature with no direct BMS connection.
Well the battery is connected to the inverter, so the inverters own Voltmeter/amp meter should see the battery volts/amps at the incoming battery wires. For the battery temp there should be a sensor at the battery with wires running to the inverter.

This all should be covered in the installation instructions.

Solax are correct, its best to run the lithium batteries in closed loop, ie the BMS sends the info to the inverter via RS485 or Canbus and tells it when to charge and not charge. Open loop is where there is no link and instead the inverter charges to a defined set of voltages and charging rates. As long as these are set conservatively then the BMS should not throw alarms.
 
Well the battery is connected to the inverter, so the inverters own Voltmeter/amp meter should see the battery volts/amps at the incoming battery wires. For the battery temp there should be a sensor at the battery with wires running to the inverter.

This all should be covered in the installation instructions.

Solax are correct, its best to run the lithium batteries in closed loop, ie the BMS sends the info to the inverter via RS485 or Canbus and tells it when to charge and not charge. Open loop is where there is no link and instead the inverter charges to a defined set of voltages and charging rates. As long as these are set conservatively then the BMS should not throw alarms.
Thanks for reply, yes your right it should all be covered in the manual unfortunately it isnt in mine which i had to download myself. Fine if your a seasoned solar agent but not great for a novice like me. Yes im a retired approved Electrician, but not Solar so all new, lots to be learned!
I guessed that the inverter sensed the batteries from the + and - terminals and assumed the capacity % is measured from whats gone in and out based on voltage, the Temp not so sure as mine doesn't have a battery temp sensor although there is provision for one, yet the temp still changes up and down without. Again assume this uses inverters own internal/external temp sensor. obviously not having the external BMS connection is a problem for accuracy, but unless i replace the batteries which are brand new it wouldnt be cost effective at this stage, also theres only certain types of battery that share same protocol, Solax own, Pylontech may be others too. Another option maybe to install an external BMS board to monitor the 4 batts, & connect that to inverter, but which would work?
At the end of the day i just wanted a solar system to run home load about 500w daytime use, charge batts during day discharge on an eve when not generating to reduce grid power import. Export is set to 0w as dont get paid so try and use up what i generate by putting Washer, Dishwasher or immersion to use up any surplus.
Unfortunately it hasnt worked out that way so far
 
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At the end of the day i just wanted a solar system to run home load about 500w daytime use, charge batts during day discharge on an eve when not generating to reduce grid power import. Export is set to 0w as dont get paid so try and use up what i generate by putting Washer, Dishwasher or immersion to use up any surplus.
That should be achievable but you need to first set out your requirement s and then buy only kit that meets that requirement and also works with each other. Its this bit that the time and effort is best spent on, my solution meets all those requirements but I had it planned out before commiting to any purchase.

Your task now is to reverse out the cul-de-sac and change direction with least cost.

PV panels can stay as is.

Any Solax later than G2 needs Solax High Voltage batteries which are not cheap. As the Solax G2 is probably the most expensive part of your current setup so plan to keep that.

The batteries are a dead end in their current form. Four 12V batteries in series never work long term. I would take them apart and build a 16 cell DIY LPO battery from the cells and dump the 4 current BMS's and replace them with one JK PB Series BMS. That talks Pylontech Canbus so if the Solax G2 also talks Pylontech Canbus then you should have a working solution.

I see my Solax X-1 Boost G3 data real time in a browser using this solution.

https://blog.chrisoft.io/blog/2023/...-un-pincho-alternativo-para-inversores-solax/

It may also do your inverter ?
 
Thank you for reply, i would totally agree the batteries are the weak link, hadnt realised that when i bought the system. The guy i bought off upgraded his system and sold me the old equip, minus batteries which he used on his new setup. Ironically his were also 12v but 100ah again no external BMS connection but his worked fine, so thought mine would too.
His were similar chinese lifepo4 batteries but made by eco worthy, rather then Moseworth. I was about to but the eco worthy ones when clicked Ebay buy it now price doubled? I enquired why they said price changes daily? Anyway did a search and Mosewrth came up. Wished hadnt bothered now! This is the learning curve. I have contacted battery supplier and told them of the issues, they told me to check several settings which were all ok, then said they need the BMS direct connection to work correctly. I said but you advertise them for Solar use if they cant connect to BMS then their not suitable for purpose. Havnt heard back so may get refund as misadvertised however.
Are you suggesting i cut the cases open and re distribute the individual cells into 1 battery then fit the new BMS? Not sure if im up for that as may end up destroying all 4 batteries. Clearly you have a lot more experience on this then me. But never opened up a battery def not a Lithium one.
Anyone know whats actually involved to do this?
Thanks
 
Its has been done and not for faint hearted but I bought my cells direct, two sets of 16 to make two 15kwh batteries.


500w overnight is 6kwh so you could go to say a 7.5kwh battery so 140AH.
 
Thanks again for reply, think the whole Solar scene is an awful lot more technical then i thought thats for sure and im electrically biased so heaven help total novices, guess they make even more errors!
Going back to batteries 500w is daytime use, nightime a little more up to 10.30pm then drops to about 300w overnight. Initially wasnt even having batteries but seller said if youre considering them in the future then buy a hybrid inverter rather then a none hybrid which would mean buying another at some point. Good advice, however the batteries were an after thought, perhaps with hindsight should have waited until more funds available and bought a larger batt pack, however my reasoning, parallel another 4 up to double AH. Its this BMS issue causing the problem!
Think if im.offered a return and refund i'll take it and buy a proper solar lithium.battery pylontech etc.
Or if not bite the bullet and try your option but may end up ruining them???
Decisions!
 
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Afternoon Guys, well good news, as stated in previous reply new CT arrived and fitted, but made very little difference or so i thought. Then at 10pm inverter goes into sleep mode and everything shuts down, assume thats normal. Has done this all the time ive had it. Anyway woke up this morning to no Solar? Unusual as usually generating from 6am, opened phone app into inverter big red notification CT fault! Also inverter yield 0w, batts 0w home 0w WTF? It was all ok upto shutdown.
Went to CT connection where it joins onto cat 5, split wires and swopped them around, then cleared fault and re started inverter, after checks started up as normal no CT fault and Solar generating again. Turns out when i swopped CT it used diff colours no indication which is + or - on supplied data sheet. Obviously id got them wrong way around whats supprising is that the inverter continued to work as normal giving generation right up to shutdown, then flagged up fault. Now know to re start inverter after CT tinkering on the plus side the app readings are a lot more accurate, best of all it now charges batteries and supplies home as it should, and reduces PV yield to minimise export to grid. So seems to be working as it should now.
Cannot believe all this due to a faulty CT never mind the 300 mile round trip journey back to sellers to swop inverter. Lesson learnt.

Solax suggested I'd be better served with a Chint meter and CT connected via Modbus RS485 now these are expensive, however i've seen Modbus own meters using same connections and protocols, as Chint Anyone know if these will work on Solax as much cheaper?

Anyone experiencing similar issues to me def check their CT clamp.
Thanks
 
however i've seen Modbus own meters using same connections and protocols
Are you sure, not only do they need to be RS485 RTU but the register map, ID no, baud rate etc all need to be the same.

Rather than limit production I divert to immersion to get free hot water.

The one I use is no longer available but this should replace it.

 
Ah yes thanks i've seen others like that, thats another option, as do still have an immersion. The only difference is i do it manually ie turn it on when generating did same this morning with Washer, tomorrows Dishwasher etc.
But like the idea of it being automatic.
In my case as it now reduces PV yield when not needed would have to reverse settings back to get max generation again.
Def worth considering.
As for protocol on Modbus, the one i'd seen is the GEM120CTM which uses the modbus protocol which can be altered for baud rate etc, as the Solax one uses the same modbus protocol assumed they'd be compatible
Thanks
 
You need to confirm the register mapping is identical, you will need pdfs of the registeru from both and compare.
 
Morning Guys, well spoke to soon, new CT has been working several days perfectly, going in to idle mode then waking up as normal, assume doing its CT check then powering up, supplying home, batteries and reducing yield to minimise export to grid exactly as it should work. Not this morning awoke to same Red CT fault on inverter again and locked out.
So fault definately on the CT.
i have checked the RJ45 cat 5 extension connections all the way to the point where it joins to the CT clamp all ok no shorts and good resistance.
I have re made the connections and tried them both ways round same result. I know original Solax CT states on lable 100a and 33.3mv and uses red and green, the new one is exactly the same although the colours are different white and black. Obviously somethings making the inverter go into CT fault, but why run for 2 days perfectly then not makes no sense. Also why read correctly and re act to load by increasing inverter yield as it should if its faulty?
Any suggestions guys or what more to check as im running out of ideas?
Thanks
 
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Your cat5 cable is carrying a max of 33.3mv when you are drawing 100A, a typical peak draw for me of 5kw means it would only see 6 to 7 mv so a very small V that can easily be disturbed especially over long distances. Not all ethernet cable is made the same, I found issues with Cat5 cable that was made from copper coated solid aluminium wire. Cured by going to 27awg stranded copper wire Cat 5. Plus if your Cat5 is passing next to an AC cable if its not shielded then other currents could be induced. Alternatively you have an internal wiring issue developing inside the inverter.
 
Thank you for reply, yes i understand the load maybe very small, my distance is only 20m as inverter in loft, CT in external mains box, but only has 5m of cable so theres a joint under kitchen kickboard where the CT cable ends and cat 5 begins. It is solid core low smoke cat 5 no shield but ran seperate from mains cable, obviously where it is drilled through wall into mains cupboard theres a closeness to mains but very short and not alongside perhaps crossing. What i cant quite
understand, if its faulty, or wiring an issue why does it work all day long ok and only when goes into idle pick up the issue the next morning, even then not all the time.
The guy who supplied inverter sent a Growatt 100a but 100ma CT which didnt flag up the fault, but didnt read correctly, this was prob because a chunk of the core was missing was advised to use a genuine Solax which are 100a 33.3mv which i bought. But now got this issue unless theres something im missing?
Does anyone know if that CT is correct for the series 2 SK-SU3700E inverter and its rating etc what resistance does it give on the connections. That way i can test it against mine.
Thanks
 

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