LV5200 Battery Charge rate ?

[gbrdbry]

Hi
we have a new PV installation - Solis Inverter RHI 6K 48ES 5G with a Fox ESS LV5200 Battery.

we have seen some issues, but most resolved, however Solis support are stating that the Battery BMS is restricting the charge rate to be 12 A?

They say they cannot change this and by my calculation this means we can only ever charge the battery at 600w ?

The impact being that any excess yield over the charge to battery (600w) and house use (e.g. 400w) say on a Yield of 2kw would mean we "lose" 1kw to the grid rather than charging battery fully .

This does not make any sense to me as I believe the battery spec states it should charge at 100a and approx. 50 V = 5000W ?

Help would be appreciated.

[gbrdbry]

Additional info : we are sending most of the excess to the grid - battery WILL ONY CHARGE at 0.6kwh - this has to be wrong ?
yield 2.045 kwh
house consumption 0.417 kwh
battery 35% charged and charging at 0.659 kwh - charge limit is 12 a currently - I have seen this up to 50a at random times.
sending to grid 0.969kwh - this should be going to the battery ?

[gbrdbry]

Issue is where battery is installed - Loft space and temperature in that space at this time of year :

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.

so amps drop to around 12 when temp is low - when temperature rises through day amps charge goes up and more charge goes to battery ...

[Tpc5]

I too have a relatively new install and have been having recent charge rate issues on my FoxESS system. The overnight charge rate seems throttled at 1kwh, this then rises to around 1.5kwh over the 4hr charge period. Our battery and inverter are in the loft and we are having very cold nights. We were advised to place in the loft, and that performance could be affected by low temperatures, but not to this level.

Does anyone know whether the batteries unit can be insulated in some way to maintain core temperature?




FoxESS Inverter: H1-5.0-E, Fox Energy Cube - 8Kw

[Tpc5]

Hi, just another follow up question if I can. Is it the Inverter or the Battery that is determining the charge rate, based on the temp? As they are out of the way in the loft, I was going to look at options to build an insulation frame around the units but does this need to be 1 of them, or both? Thanks in advance for any info you can provide.






FoxESS system
Inverter Model : H1-5.0-EDevice, FoxESS Energy Cube - 8Kw

[Fiver]

Issue is where battery is installed - Loft space and temperature in that space at this time of year :

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.

so amps drop to around 12 when temp is low - when temperature rises through day amps charge goes up and more charge goes to battery ...

Does it make sense to place an isolation frame around the batteries in this case?

[Tim_q]

Interesting, I’m having a similar issue with low temperature charging, although the figures above don’t seem right as the LV5200 is rated up to 100A for charge and discharge.
My Solis inverter says the BMS is showing “status - low temp” and currently limiting the charge to 36A (about 1800W). I could understand that when it was 3 degrees C but today it is 13C and still says “status - low temp”!
That’s a big problem for me, I want my batteries fully charged overnight on my off peak tariff, I need close to 100A for that.
I’m discussing with my installer and will let you what we find out but would welcome any feedback if you have any information on this.

[Tim_q]

I had 3 engineers from Fox out today, so to be fair to them can’t complain about customer service! Unfortunately the charging behaviour is all by design though and no actual fault was found. Fox UK have had a number of complaints about this issue, I think the BMS setup is a bit over-cautious but whether they will change anything I don’t know, they will want to preserve their 10yr warranty. The latest firmware has been installed but I was told not to expect any different behaviour. At the moment the only answer is to keep them above a temp of about 15c or the charge rate will be ‘degraded’.

[calum]

I have HV2600 batteries (x6) in an unheated garage on the North side of the house, this should be good to stop overheating in the summer but it was not great during the recent cold snaps (our system was installed in early November last year).

I built a box out of 9mm OSB lined with sheet EPS (expanded polystyrene) and it's been very effective at keeping the battery bank at a good temp since I installed it in late January. Given that the slow charging is presumably causing you to be paying peak rates for power when you have the battery capacity to avoid doing so, the cost of the materials would probably pay itself back fairly quickly.

That said you would want to be able to at least partially dismantle it when you get to summer otherwise you risk overheating, which can of course permanently damage your expensive batteries...

[jerryhawkins]

I had the same issue with my LV5200 'bank'. Like other responses here, I made an insulated enclosure around my batteries and fixed reptile tank heating pads to the side of each battery (I found 28w pads that were the the right size to cover the side of the battery). These are controlled by an Inkbird thermostat that keeps the batteries between 21c and 25c. They seem very happy at this temperature and the charge rate is now not being temperature-limited. I'll have to keep an eye on this when we head into summer though!

Cheers, Jerry

[Tim_q]

I’m planning on building an enclosure before next winter. The heater pads are a good tip, thanks.

[bluemarvin]

Solis Inverter RHI 6K 48ES 5G with 2x Fox ESS LV5200 Battery in unheated garage
Hi - I've built a box with 50mm Celotex and added a thermostatic low power heater. Just wondering whether the required 30cm clearance all round is really necessary given that we're talking cold temperature problems? I've never really checked the batteries to see how hot they get or where they get hot - although I do have a 2 thermocouples in the enclosure for monitoring it's temp. Any thoughts?

Also, I'm puzzled by the systems behaviour in that sometimes when the charging limit drops, the state of charge goes to 100% and sometimes it doesn't - see pic from yesterday (heater was not on so ambient about 10degC)

cheers

[calum]

I think the directions for 30cm clearance on all sides are more for when these are being passively cooled in warmer climates than the UK. I don't know how you might get a data feed from the FoxESS BMS when using a Solis inverter, but ideally you'd monitor what the BMS is telling you about high and low cell temps.

[bluemarvin]

Thanks calum - I've scoured every screen on the Solis inverter and on the web-page - no indication of battery temp anywhere that I could find!

[calum]

From what I understand, the BMS uses Canbus to provide battery date to the inverter, but looks like non-Fox inverters may not display (or even read) that information. There is a thread on here somewhere about reading the CANbus directly....