Upcoming Solar/LiFePO4 project

[extrafu]

My bad, my understanding was that you are planning/designing the charge controllers around 24x265w panels you mentioned in this tread.

Well, I agree that I am throwing lots of numbers, no offense taken - thanks buddy!

[Iron Bran]

With the XW gear (easier to type than Schneider/Conext) you are really going to want a ComBox. It costs a bundle for what it is, but it does a nice job of logging and presenting data, And, you can use it to copy settings to a flash drive, and restore them
I don't think the inverter is overkill. (maybe because I loved an old video game called Overkill) The inverter is rock solid, nothing I've used makes it blink. 3Hp floor sander, 24V welder, pumps, workshop tools, it runs everything, And the Generator interface, while clunky to figure out, works great, which is going to be used a lot for 6 months of the year. In pure off-grid mode, it's pretty efficient, only in the hybrid grid selling modes, does it suck that 120watts .
In your combiner box, use DC breakers, not fuses, if you have the choice. I might go with 3 charge controllers and 3 PV strings. Not knowing what your gear replacement time is, loosing half your solar to a bad controller for 1,2 or 4 weeks waiting for replacement, could hurt more than buying a 3rd controller.
I don't see ANY surge protection gear (I suggest Midnight SPD) for either DC or AC lines.

Mounts
Roof or pole mount? Can you change angle for snow shedding in winter?

LFP & BMS:
Most BMS systems interface with the charge controller. you have at least 2 controllers. When the battery gets full the BMS normally signals the controller to shut off, Not sure how that works with this gear, does the controller interface with the MODBUS ?
Have you considered Bottom Balance on the battery bank, and no BMS. Use the controllers to shut down charge (they are programmable with the SCP/Combox) and the inverter has it's own programmable LVD. Battery protected, no extra wires, just a initial set up, 20 day checkup, and annual check of the balance of the cell pack.

The idea of balance boards with lots of wires, being able to shunt 50 amps around a bunch of cells as they fill up, scares me, Failure rate for 1 board might be low indeed, but when you have bunches of them, your chance one will die and take a battery pack out with it, puckers my sphincter.

Mike, I now have a custom firmware for the XW80-600 charge controller that would allow you to charge all 40 NiFe cells. Give me a call if you are interested. Your inverter will support up to 68VDC, and previoulsy the xw cc's would not reach this voltage. You are right on with the combox integration for lifepo4, easier to send modbus to combox rather than inject canbus onto xanbus. -b

[Mike90250]

I only have the XWD6048 inverter/charger, none of the Schneider charge controllers. If they have firmware that will allow the inverter/charger to charge past 64V, that would be useful to me, but from what i've heard, only for the solar charge controllers. In winter when I run the generator a lot, having the extended charge voltage from the inverter/charger would be great

[TommyDre]

That is a general rule of thumb, but for your batteries you can charge them at C/3 with no ill effects. You have Industrial batteries, and haved moved up quite a bit in quality. They are made for heavy use. One thin gI can tell you about them is not to charge to frequently with a generator in winter or short days. Wait until you get down to 50% before charging up on a generator. No sense in wasting fuel and a charge cycle if not needed. Your batteries will tolerate reasonable PSOC. Just make sure you keep an eye on Specific Gravity and water levels.

If I want use these batteries to drive my sister's CPAP machine for a week while I'm not there to watch over the situation. The question is can these Trojan IND batteries handle the PSOC for a week going down to 50% DOD without ill effect? There won't be any solar power feeding this battery bank.

[Mike90250]

If I want use these batteries to drive my sister's CPAP machine for a week while I'm not there to watch over the situation. The question is can these Trojan IND batteries handle the PSOC for a week going down to 50% DOD without ill effect? There won't be any solar power feeding this battery bank.

You should get a meter on the machine, and make sure you know what it's average draw for a night is. Humidifier on? 6 hrs, or 9 hrs ? Then we can better advise you

[TommyDre]

You should get a meter on the machine, and make sure you know what it's average draw for a night is. Humidifier on? 6 hrs, or 9 hrs ? Then we can better advise you

The current machine draws 80 watts/night total per the kill-a-watt without the heater being used. That was a 10 hour night, with a couple of hours where she turned the machine off to read before going back to sleep. My sister doesn't use the heater she just uses the humidifier with cold water.

The draw is so low that I had her run the CPAP off of a Samlex 12 volt, 300 watt, pure sine wave inverter using a Batteries Plus 100 amp hour battery to see if the cpap would operate off the inverter.

I just don't want my sister husband, the BIL, charging the batteries, because he doesn't pay that much attention to details, So having batteries that can operate in the PSOC without being destroyed is pretty important. I am debating on either two Trojan SPRE06 415 or two of the industrial SIND 06 610 or SIND06 920. Thats a fair amount of overkill as far as amp hours, but I'm also concerned with "mission creep" on my sister's part. She like a fan when it is hot and those draw 50 watts/hour.

I saw SK post on drawing the Trojan IND batteries down to 50% so as to maximize battery potential, receiving high charging currents, and getting a good mixing of electrolyte. Would the Trojan SPRE06 batteries fall in that same category of handling high recharging current, and living in that PSOC for up to 8 days without serious consequences?

these batteries would be getting recharged from my generator. Maybe in a year or two get some additional solar activity, but not right now.

I've held off on getting Trojan batteries while I learned on the cheaper batteries plus style and a temp controlled hydrometer

[Mike90250]

80Watt Hours ? Is that what you are intending to say ? or 80 watts per hour x 10 hours = 800wh I can't guess, you have to tell me.
80wh @ 12V = 6.6 amp hours consumed
800wh = 66ah consumed
If it's a simple CPAP, then you might just get by with the 80wh figure.

What I did with mine, I got 2 automotive Jump Start Packs, looked for one with a battery ah rating (most are between 10 - 20ah
You can only drain the pack 50%, without beginning to damage the battery.
Get one pack per night, EZ carry, easy to figure how to recharge, better than lugging 60# batteries around, clips & jumpers and such.

Any battery starts to suffer with partial discharge after 48 hours, the sooner you can recharge it, the better

also see this old thread of mine

https://www.solarpaneltalk.com/forum/off-grid-solar/off-grid-solar-panel-systems/16656-cpap-system-backup-camping-power

[Sunking]

If I want use these batteries to drive my sister's CPAP machine for a week while I'm not there to watch over the situation. The question is can these Trojan IND batteries handle the PSOC for a week going down to 50% DOD without ill effect? There won't be any solar power feeding this battery bank.

Yes, they are made for PSOS down to 80% DOD. Read Trojans test data. No other battery manufacture will let a 3rd party perform IEC61427 test.