Whoa! I'd like to renew my appeal for standardization. Good to know, and thanks for the info.
Jason On Wed, Aug 26, 2026, 8:30 PM William Bryce <[email protected]> wrote: > All > > The Sol-Max (MidnitePower) batteries work fine with the Midnite Inverter. > You just have to make sure you correctly wire them. If you do it wrong, > then you can blow up the BMS and or the Inverter. You only need 2 wires so > DO NOT plug in a RJ45 with all the wires connected or you WILL have > problems. You can reach out to [email protected] and Ryan can help > you make sure it is correct. > > On Wed, Aug 26, 2026 at 6:06 PM Bill P. Battagin <[email protected]> > wrote: > >> Zeke and Jason, >> >> And so with all that said would a Midnite *Power* MNPF16 >> closed loop with a (any) Midnite *Solar* inverter (EG: Little Rosie). >> Zeke, you know where I'm going with this but seemed like a good question >> for all wrenches. Since the Midnite divorce, are the now two "Midnite" >> parties programming their respective brains (BMS/MNGP2/Whiz bang Jr.) to >> play nicely together? Oh yeah and now MidnitePower is Sol-Max. >> >> Bill >> >> Feather River Solar Electric >> 5575 Genesee Rd >> <https://www.google.com/maps/search/5575+Genesee+Rd?entry=gmail&source=g>.(billing, >> USPS, UPS, FedEx) >> 4291 Nelson St >> <https://www.google.com/maps/search/4291+Nelson+St?entry=gmail&source=g>. >> (freight delivery) >> Taylorsville, CA 95983 >> 530.284.7849, 530.258.1641 cell >> CA C10 Lic# 874049 >> Solar Powered since 1982 >> >> ------------------------------ >> *From: *"Jason Szumlanski" <[email protected]> >> *To: *"List for professional installers of home-scale renewable energy >> systems" <[email protected]> >> *Sent: *Wednesday, August 26, 2026 1:23:41 PM >> *Subject: *Re: [Re-wrenches] Wacky FNDC behavior >> >> Zeke's last paragraph says it all. The AIOs from Sol-Max and EG4 are >> pretty good at reporting an accurate SOC, regardless of charge and >> discharge rate, as long as the manufacturer-matched batteries reach 100% >> reasonably often. Even when the batteries sit in the mid-range for >> several days, the SOC seems to remain pretty accurate. When they hover near >> the low end for extended periods is where they will drop to zero without >> warning. >> >> I find it hard to trust external shunts for Lead Acid over time for the >> reasons Zeke mentioned, and for the reasons I mentioned previously >> regarding aH capacity depending on rate of charge/discharge. And for LFP, >> it generally makes more sense to rely on the battery BMS stated SOC, even >> though that can't be completely accurate, either. It's pretty wild to watch >> the discrepancy between a large EG4 rack-mounted bank versus what a Sol-Ark >> 15K reports in open loop. I have watched this pretty closely at a few >> sites, and the Sol-Ark seems to be all over the map. >> >> I have pretty limited experience with the Victron shunts, so I can't >> speak to those. I am getting ready to do a small Multiplus installation >> where SOC is going to be important due to tight margins between solar >> production and load, so I will be interested to see how well it does. >> >> Jason >> >> >> >> On Wed, Aug 26, 2026 at 4:09 PM Zeke Yewdall <[email protected]> >> wrote: >> >>> I did not expect this to be such a controversial topic... but since it >>> is... here goes :P >>> >>> I consider having an AH counting SOC meter absolutely vital on most LFP >>> projects -- at least on any older equipment. Voltage is just way too flat >>> on LFP to make any reasonable decisions based on it, except below 25% SOC >>> maybe, and above 90% SOC. But that entire range in between there is very >>> difficult to tell where you are based on voltage. And most of the older >>> LFP had no display for SOC (or at best a couple segment bar graph), and no >>> way to do comms to them for many of them either. So to allow the customer >>> to actually know what their batteries are doing, and make decisions on >>> operation, they need to know SOC -- especially at middle levels where >>> decisions can still be made (other than it's full, or it's empty, start the >>> generator asap). >>> >>> Even on lead acid batteries, I would almost always do an AH counting SOC >>> meter rather than relying on voltage, as it was just too complicated for >>> about 75% of customers to grasp voltage -- that's it's non-linear, 0 volts >>> is no 0% charged, and that it changes at the same SOC depending on whether >>> you are charging or discharging. >>> >>> I've used the FNDC, Victron Smartshunts, and Trimetrics on LFP >>> batteries. And even a Schneider conext battery monitor thing once or >>> twice. For the most part, I've been quite happy with how they've >>> functioned. >>> >>> Thats not to say that there aren't a number of issues with AH counting >>> SOC meters, whether on lead acid or lithium batteries, and there are some >>> cases where they just don't work. >>> >>> With lead acid, the biggest issue was usually declining battery capacity >>> over time lead to the SOC being unreasonably high compared to reality. So >>> it worked great to begin with, but 4 or 5 years later, it would start >>> kicking the generator on (or shutting down) at much higher indicated SOC >>> than it used to. >>> >>> For lithium, SOC drift can definitely be a problem. I do tell people >>> they need to get the SOC to 100% once every two weeks minimum, in the >>> winter, to prevent this -- 1% accuracy error per day doesn't sound bad... >>> till you go a full month without recalibrating.... >>> >>> Many BMS's built into the batteries experience the same issues with SOC >>> drift too. Most internal BMS's are blind to currents less than 1 amp or so, >>> so people who are very good at conserving electricity, reducing their loads >>> to less than an amp per battery for large portions of the day or at night, >>> seem to have bigger issues with SOC drift than heavy users. >>> >>> The new heated batteries are a big problem with AH counting, and can >>> cause the SOC meter to be completely wrong and useless at times. I have >>> not figured out a way around that yet (other than not using heated >>> batteries in cold climates... they have many other drawbacks IMO, compared >>> to a separate heating system that's not internal). >>> >>> SOC meters that reset to 100% if they lose power, rather than retaining >>> SOC, can also be a problem if you ever trigger the emergency protection on >>> the lithium battery. Battery shuts off from low state of charge then SOC >>> meter resets to 100%, then customer is super confused. The Victron shunts >>> are the only ones I've found that can be programmed to keep the same SOC >>> over a power outage. Batteries that disconnect just the charging FET due >>> to cold temperatures, can also cause a unintended reset, by making it >>> appear the battery rises to absorb voltage with very low amperage while >>> charging, when really it's just the charge FET is off. >>> >>> For any new systems, I am coming around to using closed loop batteries >>> of the same manufacturer as the AIO inverter, and everything is just built >>> in... the BMS reports to the inverter, everything is based on the BMS >>> control, and the same monitor shows SOC along with everything else. My >>> first attemps at closed loop control were disasters, and I stayed away from >>> that for several years, but recently I've been much happier with it and the >>> level of control it gives you. So that's a different case, and eventually >>> that'll be all the systems out there. But for now... there's a lot of >>> legacy systems still out there, and first gen lithium batteries on legacy >>> equipment -- no SOC display on batteries and no comms. So, that's where I >>> still believe that AH counting SOC meters are critical for system >>> operation, as long as the customers know the potential trip-ups and don't >>> view the SOC meter as gospel. >>> >>> Zeke >>> >>> >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> Pay optional member dues here: http://re-wrenches.org >> >> List Address: [email protected] >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> There are two list archives for searching. 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