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You can also restrict charging to only solar by setting config item 6 to “OSO” (“only solar”). Then if you see charging you can be sure it’s PV.

This turns out to be an issue also when the AIO’s inverter is operating - discovered when I forgot to turn on the input breaker after adjusting that wiring. I’ve started putting together a microcontroller to handle startup and shutdown sequencing: an esp32c3 running Micropython measures...

Ignoring the infrequent bursts, it sounds like you’re looking for (200A x .5 x 1h + 50A x .5 x 1h + 25A x 22h) = 675Ah/day or about 33Kwh/day. So maybe 36Kwh with a bit of reserve? That’s EV territory- at 140-150Wh/kg you’d get from lightest off the shelf LFP you’re talking 275kg or more for...

Further testing confirms that charging during m250 bootup will consistently trigger the DC Resistance error. I bet a fully isolated charger would be fine, but my AIO and it sounds like most chargers don’t isolate DC from AC— so I’ll just ensure the two activities don’t overlap. In other news...

I think @kundip's got me beat in terms of success & scale! Agreed. I predict we'll see plenty of used m215/m250's on the market as people update systems, but a $25 micro that's complicated and unreliable isn't such a bargain. Safe travels!

You've got it. I split the measurement into two parts - from the + mc4 connector to batt+ bus in between the batteries and main fuse; and from - mc4 to the negative battery bus. Sum of those values was 89.1mV at 9.47A, == 9.4mOhm. The remaining 50mOhm is my estimate of the batteries' internal...

I'm running from batteries (3 prebuilt in parallel) attached to an existing off-grid hybrid inverter charger. The 60mOhm figure (+/- ~40mOhm) did factor in estimated BMS and cell internal resistance alongside measured cabling, breaker, main fuse, etc. Measurements were via V drop at known...

It turns out I’d tested earlier at 200+60=260mOhm not 150+60=210mOhm. No MPPT lock at 210. At 235, I could see the inverter hunting for for a long while (~60sec) before eventually locking on; normally it’s instantaneous.

This afternoon I had some time to test operation without a "run" resistor (only the 60mOhm in my batteries/cables/etc): Envoy On? Boot R Run R Boot mOhm Run mOhm Boots MPPT Amps (DC Meter) I^2R inline Pwr Loss Watts (DC Meter) AC Amps Watts (AC VA) m250 DC/AC Efficiency Overall DC/AC Eff. N...

The SmartESS cloud monitoring (uses a dongle like this to connect rs485 to wifi) is adequate. You can monitor production, consumption, etc. and also control a few parameters remotely. I’ve heard good things about Solar Assistant which has a far richer set of data capture and control features.

I spent time this weekend testing various values for the two resistors I'm connecting between the batteries and the m250: Rboot, connected only during m250 startup and initially 4 Ohm; and Rrun, connected at all times. The following diagram depicts the path from battery to m250: I'm tracked...

From the system side of the main battery shutoff (behind which are only the batteries and main fuse), 110mOhm. That's with main battery switch open, main breaker closed, MC4 shorted, and a wire bridging the SSR. Batteries are connected in parallel: 2xprebuilt 24V (AmpereTime/LiTime) and one...

I decided to go through this itemization exercise myself to understand the role of the extra resistors I’m adding. Most values from data sheets except for the bolted connections which is a WAG. And as noted in my earlier message, there are other 24V devices operating in parallel with this...

Last night I discovered something odd w.r.t my AIO connected to the same battery bank: when AC and DC breakers are both off, DC positive (either side of breaker) and negative both show 1MOhm+ to ground. But ~20 seconds after either AC or DC is enabled and after initial AIO bootup, my meter...

Common heat sink for the 3 power resistors, then just natural convection I hope. Cutoff is relevant should the SSR die or the switch/controller fail to enable it- either way the 4W resistor might be on at 25W for an extended period. (After 3 hours @ 9.5A, the two 100mOhm resistors hit...

Thanks for sharing your calculations - it's great to see model and reality line up so closely.! Far too low, alas - I'm using the Thornwave 24v 80A ssr which consists of a driver and 6 parallel NTMFS5C604NL MOSFETs (60 V, 1.2 mW, 287 A). Measured voltage drop of 0.2mv at 10A == 0.2mOhm aligns...

I had some time last night to play around with the M250's; here's what I've discovered: They will power up when connected directly to a battery, HOWEVER: These models (and iq series) perform a DC resistance check at startup, and if too low they mark themselves offline (solid red LED) which...

( Thanks @fafrd for the expansive summary above! I'm tied up with work/etc for a few days but will report back. Capsule version of my goals: I've got 6kw of AC coupled solar via enphase iq7; 7kwh of storage charged by an SRNE 3kw 24v AIO; hoping to set up 1-1.5KW of m250's to dynamically load...

I recently picked up a bunch of used m250’s for ~$15 ea, am eager to test out some of the PWM ideas in this thread. They were cheap enough that I’m not too concerned about frying one or two or five in the process. An m250 teardown video from a few years back shows 4 input caps which appear...

No personal experience, but Victron specifies 3kw continuous duty for their 24v multiplus-ii at 25C. That’s if you can keep it at 25C- with 94% efficiency, 3kw = ~180w exhaust heating; a large cool basement might be a sufficient heat sink. (Or if you’ve got the budget, parallel 2 for 3.4kw...

SRNE (OEM for PowMr, Midnite Solar, and a host of others) has ul1741 certification for their budget all-in-one units; see: https://www.srnesolar.com/blog/srne-solar-charger-inverters-get-etl-certification This thread discusses a version of their 24v HF2430U60-100 recently going for $320. That...

I believe CRD-PCS refers to the ul1741 utility Power Control System - if your system responds to export/import controls from the utility, storage is unlimited. Otherwise, restricted to 10kwh or below. This seems generous of PG&E — afaik SDGE requires PCS to ensure absolutely no sell-back of...

I’m in the same spot, am considering gutting a $21 AC panel and just using the shell. The Carling breakers don’t quite fit a BR opening so a bit of dremel work will be needed.

Quick on the heels of their Ebay fire sale, LiTime's launched a new, smaller 12V/100ah battery apparently with a new BMS and now suitable for use in "Any direction mounted, even upside down.", on sale for $319, shipping 3/13...

Thanks for the extra details! It appears your system has a max VOC of 80V and should accommodate 2 of your panels in series. You might try connecting just one pair of panels in series and see if the charging behavior improves.

A few questions: first, can you link to the Amazon listing for the inverter? There are only a handful of OEM manufacturers (Voltronic, SRNE, etc) which can often be identified from the specifications, with each such base model having its own quirks. Your reference to “Watchpower” didn’t click...

200ah 12&24v are still available for $500-550, just picked one up. https://www.ebay.com/itm/354324893534

Unused - purchased for $180 last year for a project that fell through. Willing to take $75 venmo/zelle/etc or PM me an offer; will split (US) shipping with you.

(these have been sold) I ended up going with 150A fuses which use a smaller block. Both 5502 fuse block and 5117 225A fuse are unused. Asking $50 for both including shipping within US, or make an offer.

Sounds like they want a battery listed as UL9540 when paired with your Sol-Ark. Pytes is in the same rough price range as SOK/Jakiper and recently announced approval such: https://www.pytesgroup.com/news-detail/&5380 C$2600 for 5.12kWh from...

119075c “Any electrical generator, other than a generator designed to run in parallel with the system of the serving utility and approved by that utility…” must have a transfer switch. But if that approval applies to the model, and not the specific installation…

@Ampster for California, there do appear to be criminal penalties (misdemeanor) for connecting a parallel generator without utility approval and permission: https://leginfo.legislature.ca.gov/faces/codes_displayText.xhtml?lawCode=HSC&division=104.&title=&part=15.&chapter=5.&article= I don’t...

Ref: http://www.paigewire.com/wire_resistance-prop.aspx My primary concern when choosing cable size is minimizing voltage drop during surges, and minimizing power loss (aka heat) from average current. Both are related to the cables’ resistance. 16 feet of 2awg cable will measure about 3mOhm...

I wonder if the MPPTs or inverters are periodically thermally throttling, then recovering. If you trim back the number of active strings - and thus total power through the system - do you go back to an expected parabolic power curve? Also— are any loads connected via the inverter, and do R+S+T...

Some have reported success pairing a 230v/50hz european quattro/Multiplus with Victron’s autotransformer, yielding US style split phase 120+120. I believe the adjustment to 60hz, 240v only involves a software tweak. It might be worth reaching out to Victron or a competent dealer (alte, naws...