Solis RAI not charging Fox-ESS LV5200 correctly

[ScottishBadger]

Hi all, hoping someone can shed some light on this.
My Solis RAI charger is programmed to charge the battery from the grid for 4 hours every night on cheap-rate electricity, but it is not getting much of a charge. Software I have on the computer shows 640W going out to the workshop, where the charger and battery are, and there are no other power demands during the night. When I go and check it in the morning, it appears to have taken in around 2.4kWh, which more or less tallies with the power flow figure.
Here's the thing - this means it's only charging at around 11Amp! The battery type (FOX) is selected correctly on the charger menu, and it is indeed charging for the full 4 hours. The battery is rated for charging at up to 100A, the manual charge current setting on the charger says 60A, but when I go to Advanced Info>BMS, it tells me the charge current is set to 12.5A, and I can't see any way to adjust it? I do not know if this is a charger limit or a BMS limit that is stopping it charging correctly, but I do know it's as much use as an ashtray on a motorcycle as is......
I have informed the installer and despite initial emails saying someone will contact me, there has been no contact to discuss the problem or suggest a solution since reporting it 6 days ago. Seems a lot of these companies are quick at taking your money but not so good at customer service afterwards - maybe just as well I haven't made the final payment (and won't until it's working correctly)! If there's a simple solution, I'll do it myself rather than have the hassle of waiting for the installer.
Any help appreciated, thanks.

 

[SeaGal]

Interesting, I was just responding to this post below and stumbled upon yours - seems same issue within day of each other

Solis RHI 6K 48ES 5G Inverter Fox ESS LV5200 Battery - Charging limit ? and export to grid ...

Hi All Not an electrician and some of this is now going over my head, but new PV install with Solis inverter and Fox battery as above... Issue is according to Solis cloud data we are seeing energy production but battery is only charging "slowly" and at times most of the energy produced is...

diysolarforum.com

 

[ScottishBadger]

Hmmm.... as you say, interesting! I have been trying to get my installer to respond to me for 7 days now, all I keep getting is emails from the receptionists saying "I've passed this on to our installation manager and they will call you", but I never ever get a call! Absolutely wishing I'd gone with a different company, it's just been one thing after another - however they were informed today that they will not be getting any further payment from me until they resolve this!

 

[SeaGal]

Hmmm.... as you say, interesting! I have been trying to get my installer to respond to me for 7 days now, all I keep getting is emails from the receptionists saying "I've passed this on to our installation manager and they will call you", but I never ever get a call! Absolutely wishing I'd gone with a different company, it's just been one thing after another - however they were informed today that they will not be getting any further payment from me until they resolve this!

It's pretty disgusting how unprofessional these businesses are. Best 'different company' is yourself = DIY. You better keep badgering ? them until they call back .

 

[ScottishBadger]

SeaGal, I'm getting very close to the point of going to Trading Standards over this bunch in Central Scotland. I do keep at them, but they just don't respond.....! Thing is, I'm not stupid, I'm an engineer by trade with a reasonable grasp of electrics - I rewired my house, I designed the whole of my solar additions and installed my Puredrive 10kW AC-coupled system myself, yet I'm left dealing with donkeys that can't even do simple basic electrics properly during an install, such as moving circuit breakers along the bus-bar in a domestic consumer unit to keep the highest rated breakers nearest to the mains master switch.... no, too easy, let's just add a pair of 22A breakers at the far end of the bus-bar, beyond the 6A lighting breaker!

Take a look at the attached diagram, you can clearly see that any demand within the workshop that is greater than the total solar production will result in power flowing from the house consumer unit to the workshop one - this being detected by the Puredrive's solar CT clamp as "negative solar". Now, this is purely an indication that has absolutely no effect on the system operation - the Puredrive is quite clever, it knows that a combination of Grid CT <0 and Solar CT >0 means charge battery, it also knows to ignore a negative solar value, but try telling that to the utter donkeys that are employed as "customer service" at Puredrive and won't let you speak to an engineer about a BMS needing a system reset after it loses comms with one of two batteries.... Absolute idiots that haven't a clue what you are talking about, they shouldn't be answering phones, it's almost as if they are deliberately put there to fend off any issues!

 

[SeaGal]

So you have two issues. The RAI not charging the Fox and the Puredrive not handling the workshop power.

With regard to the first issue; have you tried connecting the Fox battery to the RHI, rather than the RAI? To me that would make more sense as you will avoid DC->AC->DC conversion losses, though wouldn't, obviously be able to charge the Fox from the Fronius output. If only temporary test, it could help pinpoint the Solis->Fox incompatibility issue.

We looked briefly at Puredrive.. glad we didn't use them.

On a separate note (and not related to your issues) what mains cable size do you have for the 30m to the workshop?

 

[ScottishBadger]

The Puredrive handles workshop demand just fine and has done so perfectly for well over 18 months, it's as if the newly-installed Solis RAI is trying to kick-in and meet demands too quick and attempting to deliver more than its rated output - I would have thought it wouldn't try to produce more from the battery than it was rated to?

The other Solis is a solar inverter only, no battery ability. It's an S6(?) not an RHI, my mistake sorry, I'll amend the schematics!

I did consider a volt drop along that length of cable, but there's only around 2.5v difference from house consumer unit to workshop consumer unit as a heavy load (compressor start or vehicle ramp start) is applied in the workshop - and actually, the mains coming into the house takes a 1 to 1.5v dip as the initial load goes on, recovering after around a second!
Question - do you know if the Accrel meter sends grid voltage data to the inverter or just power flow? You've got me thinking now.... I wonder what would happen if the Accrel sent a voltage reading higher than the Solis RAI was connected to, as the load was applied? Could that cause the Overcurrent surge? I'd still have though the power production would be controlled internally from within the RAI unit in the first place though?
The cable between house and workshop is 6mm SWA 3-core rated at something like 40-odd Amps, the sparky that did the job when the workshop was built said 4mm would do but I up-specced it to 6mm. It's buried for approx. 15m of the total 30m run.

 

[ScottishBadger]

Update.

Spoke with an extremely helpful tech at Fox-ESS today, a bit of an eye-opener. It turns out the published figures in their own manuals are not worth the paper they are printed on! Yes, the battery can discharge at 100A, but the quoted figure of 100A for charging is only for a PAIR (or more) in parallel - a single unit is limited to a maximum 50A charge rate by its internal BMS. Not only that, but its internal BMS will not allow a charge below 0 deg. C, between 0 and 5 deg. C it's limited to 10A, from 5 to 10 deg. C it's limited to 15A, 10 to 15 deg. C is 25A, rising to 50A by 20 deg. C and above.
According to him, the installers are given this information at the time of setting up purchase contracts and as part of ongoing product support, so it seems it's some installers that aren't being open and truthful with their customers - no surprises there, really!

Based on these figures and the average overnight temps we've been seeing recently, it appears the charging rates I'm seeing are fairly correct for the ambient temperatures the BMS will be picking up, as the battery is mounted on the internal face of a concrete block wall in an un-heated workshop! I may have to consider an enclosure with some heating if I want a decent charge rate in the winter months.....

 

[SeaGal]

That fits the info just posted from "the-other-thread-about-the-same-issue".

100A makes sense to be for 2+ batteries, otherwise you'd be charging at 1C, which is high for longevity. A charge rate of 0.25C is much better (i.e. 25A for a 100Ah battery).

It's a pity FOX's engineers didn't implement the type of algorithm I created for our DIY batteries ?‍?- see info I posted on that here..

Science based discussion on charging LiFePO4 below 32°F

It wouldn't be hard for an engineer designing a BMS to scale charge current with temperature and state of charge. Seems like it could be done in firmware. For example: 10A@-10°C, 15A@-5°C, 20A@0°C, 30A@5°C, 40A@10°C, 100A@20°C. This would allow them to better protect the battery from damage at...

diysolarforum.com

Jumping directly from 15A to 25A at a single temperature point doesn't make sense (apart from saving 1 hour of coding time)!

A charge rate of 0.1C for cells that have > 70% SOC at 5 degrees is correct for EVE cells.

 

[SeaGal]

I did consider a volt drop along that length of cable, but there's only around 2.5v difference from house consumer unit to workshop consumer unit as a heavy load (compressor start or vehicle ramp start) is applied in the workshop...

Agree... 16A @ 230V will be about 2.7V drop/rise with 6mm2 cable.

Question - do you know if the Accrel meter sends grid voltage data to the inverter or just power flow? You've got me thinking now.... I wonder what would happen if the Accrel sent a voltage reading higher than the Solis RAI was connected to, as the load was applied?

Yes it does. BUT, I don't think it does anything useful apart from being displayed on the 2nd or 3rd info page of the Solis. The Solis measures its own voltage. Which, interestingly reads higher than it should and the Acrel is even worse!

Could that cause the Overcurrent surge? I'd still have though the power production would be controlled internally from within the RAI unit in the first place though?

Don't see how or why. I find the Solis takes a few seconds to ramp up or down its production (whether from solar or battery) so sudden changes in house load will result in little spikes of grid import or export.

The cable between house and workshop is 6mm SWA 3-core rated at something like 40-odd Amps, the sparky that did the job when the workshop was built said 4mm would do but I up-specced it to 6mm. It's buried for approx. 15m of the total 30m run.

Good you increased it. 4mm2 is fine for current capacity, but not voltage rise. The bigger the better and less losses on the way. 6mm2 handling 16A will loose about 40W over that 30m length. Dammed physics ?‍?

 

[GBRDBRY]

@ScottishBadger you me and @coolcarper1 all have the same issue.
Installations in low temp environments - Loft spaces...
we are all seeing the same charging issue at low temps and I also spoke to a very helpful chap at Fox this afternoon - probably the same guy !

Options it seems are installers come back and move to a different location or provide some form of heated enclosure with temp control...

 

[ScottishBadger]

@ScottishBadger you me and @coolcarper1 all have the same issue.
Installations in low temp environments - Loft spaces...
we are all seeing the same charging issue at low temps and I also spoke to a very helpful chap at Fox this afternoon - probably the same guy !

Options it seems are installers come back and move to a different location or provide some form of heated enclosure with temp control...

Bloke I spoke with was Martin, really helpful. Yes, I went out to the workshop and had a look at where my battery is, for feasibility of building some sort of insulated enclosure myself. My issue is height - it's mounted on the workshop wall, up above the roller door, so anything heavy being moved around at that height becomes awkward. It's either that or I take the battery and charger unit out of the workshop and shift them into the house somehow, but that will not go down well with the "local planning department" and may cause other issues as this system would then be operating directly in parallel with the 10kWh AC Purestore that's already in the house. At present, the purestore simply sees anything coming from the workshop (whether it be from solar panels or battery) as a "solar input" and uses it to charge - that balance may be affected by moving the Solis and its battery.

 

[CJack]

Update.

Spoke with an extremely helpful tech at Fox-ESS today, a bit of an eye-opener. It turns out the published figures in their own manuals are not worth the paper they are printed on! Yes, the battery can discharge at 100A, but the quoted figure of 100A for charging is only for a PAIR (or more) in parallel - a single unit is limited to a maximum 50A charge rate by its internal BMS. Not only that, but its internal BMS will not allow a charge below 0 deg. C, between 0 and 5 deg. C it's limited to 10A, from 5 to 10 deg. C it's limited to 15A, 10 to 15 deg. C is 25A, rising to 50A by 20 deg. C and above.
According to him, the installers are given this information at the time of setting up purchase contracts and as part of ongoing product support, so it seems it's some installers that aren't being open and truthful with their customers - no surprises there, really!

Based on these figures and the average overnight temps we've been seeing recently, it appears the charging rates I'm seeing are fairly correct for the ambient temperatures the BMS will be picking up, as the battery is mounted on the internal face of a concrete block wall in an un-heated workshop! I may have to consider an enclosure with some heating if I want a decent charge rate in the winter months.....

This is very interesting. I'm relatively new to solar and have been trying to work out why my battery only charges at a max. 12A. Solis RHI and Fox ESS LV5200. Battery is mounted on a block wall in an unheated garage, so guess that is the problem! I have built an enclosure with an 80W bar heater in it and that is now maintaining a toasty 15-20 deg C in the enclosure. BMS charge rate will not go above 12A regardless, so with limited winter sun the battery doesn't get fully charged but power is being exported to the grid rather than topping up the battery. Inverter shows max. 100A charge rate so it is a BMS limit but it doesn't seem to be improving despite the temperature improvement. :-/

 

[Tomcik]

Hmmm.... as you say, interesting! I have been trying to get my installer to respond to me for 7 days now, all I keep getting is emails from the receptionists saying "I've passed this on to our installation manager and they will call you", but I never ever get a call! Absolutely wishing I'd gone with a different company, it's just been one thing after another - however they were informed today that they will not be getting any further payment from me until they resolve this!

I've got 2 batteries and one is charging slowly and the other one doesn't at all. My installer is taking a micky as well - called Invictus Electrical Ltd. I wish I never heard about them either.

 

[Drewjh]

Hi, I'm not a diyer but have purchased a system. Panels were installed in 2011 with a Fronius inverter. Last Sept, with the threat of rising bills I decided to add a battery to my system. The original installers who are based in my town quoted and I was happy with the price and proceeded. There was a three month delay before installation on 4th Jan. New Solis inverter installed with Fox battery in my garage. However, battery lost charge within two days and did not charge. Fox engineer visited and said it was faulty battery and ordered a replacement but within two days changed his mind and said it was the inverter. Installer and Fox again visited and new battery installed but still does not charge. I was informed that the BMS switches off the battery at minus 10c. I was informed this issue became apparent during the December cold spell but looking at this forum it seems the issue was known prior to this. Is this peculiar to Fox batteries? If so, are there recommendations for other suppliers? My installer tried to suggest that the problem is the battery has never been warm and at the moment, I haven't heard from them for two weeks. Not sure if they are waiting for the ambient temperature to improve to see if that resolves the issue but that begs the question as to whether it will work next winter!!

 

[SeaGal]

... I was informed that the BMS switches off the battery at minus 10c. I was informed this issue became apparent during the December cold spell but looking at this forum it seems the issue was known prior to this. Is this peculiar to Fox batteries?

Welcome! No, it's not peculiar... it is a limitation of all LiFePO4 based batteries. It should switch off discharge at -10C and switch off charging at 0C. Furthermore charge current should be (and will be, with Fox) reduced below +10 to +15C degrees.

My installer tried to suggest that the problem is the battery has never been warm and at the moment, I haven't heard from them for two weeks. Not sure if they are waiting for the ambient temperature to improve to see if that resolves the issue

Fox reduces charge current below 15C which is normal and expected. From other's feedback, Fox also inform their installers not to install in low temp environments. Call the installer's back and get them to relocate the equipment as they should not have installed it in an unheated garage in the first place.

Waiting for the weather to warm up is not addressing the key issue - i.e. that they put it in the wrong place and against the advises of Fox.

but that begs the question as to whether it will work next winter!!

There will still be charging issues if it is below 15C.