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Well, in general the PV system is achieving great results - i.e. only using about 1 kWh per week of grid elec. since the install ( 7 weeks ago )

However there is a persistent and sporadic Alarm being reported by the Solis Inverter
BMS 2015 . . . . . described as a "Hint Alarm"
It self-corrects after some variable period of time.
Below is the lower-level error - presumably passed up from the battery . . . . . .
InnerErr.BMS(33293) & Low.Temp.BMS(33293)

I have asked the Installer to notify and get advice from Pylontech. ( I have expectations of a very slow response, )

Anyhow, I have read about various ways of creating a less-hostile environment for the batteries in the loft & remember previously asking the installer if I could locate them in the "electrics corner" in the kitchen. This was dismissed because of "lack of air-flow".

Distance between Inverter and Batts would then need 4 or 5 metres for new cables . . . . . Wha'dya think ?
. . .

What are the loft temperature highs & lows in your house? (how does that tie in with kits operating parameters? ..any de-rating occurring from gusty winds taking it below regular design limits?
What options to increasing airflow are there now it is already installed (minimising more disruption & cost potential)

Did the installer have much experience with batteries, pylontech especially?

I'm really wary of the extremes lofts can cycle through, dust etc, maintenance & removal / upgrade access every time I hear of it chosen as a site of install.

Whats the problem re airflow in the kitchen he cited? ..didnt want to spend time creating some extra if needed through what look like they could be solid walls?

Have you got a temp sensor up there that transmits the temp to you so you can log when it go's off & what temperatures kick it off?
Is it boarded out & dust free up there? (anything clogged with 100 yrs loft dust) ?

Have you checked solis website error code list?

is "hint" actually High Internal Temp ?
https://usservice.solisinverters.com/su ... lete-list-

Joeboy has his pylons in the garage, so I'm sure can set you at ease there, if only to get a broader perspective.

Is ned yu (pylontech) still around on the victron boards?

1) You have to move the inverter and the batteries. You can't shift just the batteries. Keeping the distance between inverter and batteries as small as possible trumps all other design considerations.

2) The Pylontechs are happy in a wide range of environments. An attic is a perfectly reasonable place for them. If the cell temperature get's below 0℃ then the charge rate will drop. However this is cell temperature not ambient temperature. The cells will be warmer than ambient if they're in use (charging or discharging) and will take a long time to cool down thereafter. Even if the low-temp is triggered they soon warm up while being charged at the lower rate and allow full-rate charging.

3) A far simpler option is to put some insulation around the batteries in winter to help them stay warm.

Only thing i would say is that kitchens can be humid and a corner like that could be cold so think about condensation.

What’s under the floor?
Do you have suspended timber floor with depth?

My long term plan is to do this under my hallway where I have about 1.5m depth, tidy up a bit down there, and have a heater on a frost stat for any chilly days….

AGT wrote: ↑Sun Mar 26, 2023 6:31 pm What’s under the floor?
Do you have suspended timber floor with depth?

My long term plan is to do this under my hallway where I have about 1.5m depth, tidy up a bit down there, and have a heater on a frost stat for any chilly days….

Thats where mine are and I have less than 0.5m depth, nicely out of the way and the temperature is very stable, typically 10 degrees in winter and 15 degrees in summer.

Mine are in my roof - with the inverter/chargers that drive them. The cables are no longer than 2m each, I could probably shorten them if I really wanted to.

There’s no issue with airflow, but temperature is an issue especially as I went down from a stack of 5 to a stack of 3. If the attic is less than 10c then they charge at a lower rate. This was masked when there were 5. The discharge rate isn’t an issue, but the charge rate is. As we have come out of winter things have improved- but I’ll be adding a 4th battery to the stack when funds permit. I have two stacks of 3, so will need to go to two stacks of 4. Hope that make sense.

I would be more worried about them getting to hot in summer in the loft
As Stinsy says move both inverter and batteries doubt they will overheat the kitchen

Mine have been in the roof since 2019 with no problems at all, until I went from 5 x 2 to 3 x 2 batteries & got the cold problem I outlined before …

Thanks to all for your contributions. Comments noted. I'll concentrate on this one :-

Stinsy wrote: ↑Sun Mar 26, 2023 5:33 pm 1) You have to move the inverter and the batteries. You can't shift just the batteries. Keeping the distance between inverter and batteries as small as possible trumps all other design considerations.

Thanks : This is the critical info. I'll waste no more time on the "electrics corner" plan.

2) The Pylontechs are happy in a wide range of environments. An attic is a perfectly reasonable place for them. If the cell temperature get's below 0℃ then the charge rate will drop. However this is cell temperature not ambient temperature. The cells will be warmer than ambient if they're in use (charging or discharging) and will take a long time to cool down thereafter. Even if the low-temp is triggered they soon warm up while being charged at the lower rate and allow full-rate charging.

This is important for managing my expectations. { I would prefer my expensive, shiny, new, toy to NOT produce Alarm messages }.

3) A far simpler option is to put some insulation around the batteries in winter to help them stay warm.

Stage 1 :
Methinks I need to get a remote Temperature sensor up in the attic, with a DayHigh & DayLow recording - as a minimum.
Better still if I can store regular, periodic readings in a data store for plotting / analysis.

Stage 2 :
Anticipate possible cooling requirement in summer & a mild heating facility in winter . . . e.g. typical reptile / fish tank controls . . . .