Hey all, wondering if anyone around Australia is having the same issue as myself in Melbourne with my FoxESS batteries and inverter outside on a south-facing back wall.
Earlier this week the temperature dropped down to about 6-7C and the battery temp got so low that the "frost" indicator was shown in the android foxcloud v2 app. I didn't think too much of it until 11am rolled around and the batteries were only charging at 3.7kW, which for the three hours with Globird is not enough to fully charge my ~42kW.
Now, it would have been really nice for the sales people or installers to mention this heavy down-side to outdoor battery placement, as I likely would have installed in my garage instead, at least I could have considered the options and done some research on how often this limiting factor might occur in Melbourne, etc., etc.
So now I'm looking to perhaps build a cover with insulating material, polystyrene with aluminium sheeting or something similar, and possibly use a heater pad and controllable switch to turn on the pad when the temperature drops too low, etc. I have a Homey Pro home automation system set up for my house and I have built an app/device to pull the FoxESS data from the cloud, so I can see the internal BMS-reported temperature.
By the looks of things online forums, etc., this API-reported temperature is NOT the same as the lowest batt. temp value which no doubt actually drives the BMS to slow charge/discharge to prevent damage, but I figure I can probably calibrate one to the other over time, i.e., if the BMS API temp says 12C, then the lowest temp is likely to be 6-8C or something like that. Either way, turn on the heater pad until we see the BMS report 20C or whatever, then switch it off.
Chances are I'd only have this flimsy enclosure installed over the battery during winter, or I could potentially add a fan to the top of it and drive that when too hot, sucking cooler air from the bottom...future improvement maybe.
Anyhow, the questions are:
1. Has anyone built something similar and can offer advice on materials, etc.?
2. Does anyone have any particular knowledge on the relationship between the BMS temp via API and the actual lowest one likely used to drive BMS throtting? Or perhaps other method to get a close approximation, e.g., physical temp sensor attached to the bottom-most battery?
NB:
- I see that it appears the lowest batt temp is probably exposed via MODBUS, but I'm not in that space...yet.
- I see that there's plenty of UK users who install covers / insulation to their units, usually in the loft, but I guess I'm looking for something more Aus-based, at least as far a materials are concerned.
- No, my unit doesn't have a warming function in the BMS; again, if I had of known about this fairly heavy drawback, I'd have probably asked for that model / upgrade.
Any help or comments would be most appreciated, cheers.
Ok, not a lot of feedback / comments on this one...maybe it's only me that is having this issue...dunno. I'm tempted to delete the post out-right, but I guess I'll leave it in case someone notes the same / out of interest, not a big deal.
As a side note, I don't think I'll spend any money on construction of said enclosure as it's likely false economy; it 'cost' me about $1.50 in lost credit on the Globird ZeroHero plan from not feeding to grid 6-8pm that day - and any others that might occur later, so...who cares, really.
As a side note, I don't think I'll spend any money on construction of said enclosure as it's likely false economy; it 'cost' me about $1.50 in lost credit on the Globird ZeroHero plan from not feeding to grid 6-8pm that day - and any others that might occur later, so...who cares, really.
Hi. If any of this helps for my setup in the UK. I have batteries in the garage but still were throttled for charge and discharge when below 10 degrees c. So built square cover from Kingspan 50 mm insulation which has a thin aluminium cover. Don’t forget to leave recommended 300 mm all round. I then use Home Assistant to turn on a small greenhouse type heater that is about 90w per hour, below 11 and off above 14. I also have an automation that warns me to remove cover if high temp goes above 30 and to fit below 14. The smart plugs are Zigbee and very simple to pair in Home Assistant. My inverter is connected using Modbus so no experience of api.
John
John
In pictures from another user here
viewtopic.php?p=12714#p12714
An old video from Will, with a chart of Temperature vs. charge rates (chart around 5.5mins in roughly)
A post of mine of charge Amps at the various Temperature points
viewtopic.php?p=16070&hilit=charge+rate#p16070
viewtopic.php?p=12714#p12714
An old video from Will, with a chart of Temperature vs. charge rates (chart around 5.5mins in roughly)
A post of mine of charge Amps at the various Temperature points
viewtopic.php?p=16070&hilit=charge+rate#p16070