home router battery backup
mark at tinka.africa
Tue Jan 18 15:11:57 UTC 2022
On 1/18/22 00:26, Jordan wrote:
> Wow, that's a nice program. Do you know what they keep the
> "reserve percentage" set to, the proportion of stored energy that
> will never be discharged for grid-support, but held back for
> island-mode use in case of an outage?
I don't use the Tesla Powerwall, but Li-Ion is generally the same
regardless of who packages it. The difference will be what the OEM
decides to set the low-voltage cut-off to on the inverter and/or BMS.
I'm not sure how much the owner can configure a Tesla Powerwall, but
with other installations, you can decide when your battery kicks in to
run loads, or when it hands back to the grid or generator. This assumes
evening time, when solar irradiation is unavailable, of course, as that
is generally the preferred source of energy.
I've heard that Tesla will monitor the weather in your area to
"pre-charge" the Powerwall to account for possible power disruptions.
While I find that rather invasive, it's a cool feature for folk who
"don't want to know". Then again, I also hear that Tesla will limit or
withhold support and/or warranty if you do not connect your Powerwall to
the Internet for them to "manage". The downside I hear, with that, is
that they can remotely adjust SoH (state of health) thresholds to
lengthen battery life in order to meet warranty promises. Not sure how
true that is, but I've heard it a lot.
In terms of "reserve" capacity, Li-Ion can go much deeper than Lead
Acid. Some inverters are setup to disconnect the battery anywhere
between 3% - 20% SoC, depending on the OEM. For LFP chemistries, the BMS
will usually turn the pack off at 2.50V, while for NMC, that will be
around 2.75V. But different battery OEM's may be more or less aggressive
with their BMS's, depending on who you choose to buy from.
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