| << . 1 . 2 . 3 . 4 . |
| Author |
Message |
gcrank1
Member
|
# Posted: 21 Nov 2025 11:32am - Edited by: gcrank1
Reply
An LVD at 11.7 isn't really low as the BMS is a safety trip, not supposed to be a regular 'run until it drops off' kinda thing (they do wear out I hear). That low it gives the bat the ability to have its voltage drop under load in the lower knee of voltage and not switch off early yet save the bat from dropping too low into the danger zone.
I know the LVD on the inverter is even lower so mine hasn't been shutting down since getting the LFP's; it did when I ran the old LA bats down too low (guess that effectively tested the inverter safety switch too).
|
|
paulz
Member
|
# Posted: 11 Feb 2026 09:54am
Reply
Let’s see, where were we.. I’m still using the old Valence bank, new ones sitting. 95% generator charging, small bit of solar. One Meanwell charger.
Lately even after an hour or two on the charger the bank would show 13.6, quickly down to 13.2 once charger off, 13.0-1 by morning, lasting all day until evening charge.
Yesterday I checked the meanwell unhooked from the bank. 14.1 where last set. I cranked it up to 14.6, hooked back up and the bank rose to 14.6 quickly., down to 13.8 shut off, down to usual 13.2 and 13.0 this morning.
So, as Steve has told us, the extra charge voltage really doesn’t help much. I forgot to mention the charge amperage is about the 40 amps the meanwell puts out, either way.
|
|
gcrank1
Member
|
# Posted: 11 Feb 2026 11:36am
Reply
That is pretty much my experience too, the settled/resting voltage is where we start drawing power from so I guess if we want more time to run or bigger loads what we need is more battery bank (now that Is the Same as with LA).
We have a Feb thaw now so for V-Day we are going to cabin (happy dance!), my LFP there should be ready to run the fan(s) to mix the heating air, at least it was when we were last there (it have no charging going on). I also have the little portable LFP (Ecoflow?) and the inv/gen there. My notes on that cabin bat are there; ie, how many hrs at what load I was getting so I could track its real-world capacity.
|
|
Steve_S
Member
|
# Posted: 11 Feb 2026 01:27pm
Reply
@Paulz, I just wanted to add a wee detail here. I have both a Meanwell setup that can push 50A at a 24V Battery Pack but I also have a proper Lab grade charger for cells that can push 40A @ 3.650V per cell. I upgraded the charging wires after some hair pulling to 6-AWG Ultra-Fine stranded pure copper in silicone jackets which pretty much eliminated all line loss & resistance. Wire from Charger to Pack/Cell can be such a royal PITA and even coarse stranded wire is of little help...
My oldest LFP cells are "Bulk Grade" and 7+ years old now (gee time flies) and they've worked but never strained at any time. I can charge these up to 3.450V per cell / 27.600V and let them settle to a point where they take no more than 1A and shutoff. They will within 20 minutes (without load) settle to 26.9 and once I add even a tiny load they will hit 26.7V or 3.3375V per cell with a slight imbalance usually below 0.010V between cells.
Now these are earlier LFP and "BULK" grade meaning they did not qualify as B Grade & certainly not A-Grade.
ON THE FLIP !
I have 3 Packs of A-Grade Matched & Batched cells and I can charge those teh same way but they settle at a much higher voltage (3.395 /3.400) without load and will only drop another 0.010 with a light load which is right on target and that is also at 15C/59F temp. * Remember, I keep my powerhouse/pumphouse heated to 15C in winter. In the summer they settle (lose) less because temps are closer to the optimal of 25C/77F.
NOTE: The 6-AWG wire I use had to be imported from one of my industrial suppliers in China as I could not find anything close at domestic suppliers & I searched hi/lo. The "Utra-Fine" pure red copper wire is essentially "Angel Hair" thin and if my recollection is correct, there is something like 600 strands in that wire... I mean it is REALLY thin ! Interestingly, the wire is rated for 800VDC ! It is not stuff you will find easily.
|
|
paulz
Member
|
# Posted: 11 Feb 2026 05:52pm - Edited by: paulz
Reply
Thanks Steve. Wondered about wire gauge too, since I rewired for the Victron SCC. I have 4 awg from meanwell to splitter, 8 awg to each battery.
Bank holding pretty well today. Wife has been watching Walker Texas Ranger all day on the 40” big screen while I make firewood, bank still at 13.15 at 3pm. Maybe yesterday’s 14.6 charge jolt woke them up a bit.
IMG_6497.jpeg
| 
IMG_6495.jpeg
|  | |
|
|
paulz
Member
|
# Posted: 2 Mar 2026 10:16am
Reply
Article today on EV battery life. Better than expected. Never had one, couple neighbors with old Teslas still going. They didn’t interview me about my 12 year old cabin bank, still hanging in there…
https://www.npr.org/2026/03/02/nx-s1-5706658/electric-vehicle-battery-lifespan
|
|
gcrank1
Member
|
# Posted: 2 Mar 2026 11:24am - Edited by: gcrank1
Reply
I just charged my depleted to 10.5v #1 bat (12v 100ah) for 3 hrs on the Mean well set at 13.9. It got to 13.6 with no readable amps on my old cheap automotive meter by 8:30 last night and settled to 13.5v after sitting all night. I think that is a better HV settle than Ive ever had 0n #1 and comparable to #2.
Of course that 13.5v will burn off quick at cabin to the normal 13.2ish where the real meat&taters of the charge lives but Im pleased with the settle.
Btw, my hashmarks show this is only the 9th full recharge Ive given that bat since I bought it and put into service. It has never been on a solar system to keep topped, we just take and use until it needs recharging.
|
|
paulz
Member
|
# Posted: 20 Jun 2026 10:16am
Reply
12v
|
|
|
gcrank1
Member
|
# Posted: 21 Jun 2026 03:01pm
Reply
That looks like a pretty generic, maybe even AI, page of questionably (to me) 'info'.
I dont think Ive ever seen a 3S pack with a 9-12.6v rating and believe that would result in early device shut down due to Low Voltage Disconnect on the '12v' stuff we run in cabin.
The 4S I believe is what our typical 12v LFP's use and they settle in voltage quickly to ~13.3/13.4v so no worries about that paper's 'high voltage warning'.
What Steve says will be definitive 
|
|
paulz
Member
|
# Posted: 21 Jun 2026 04:07pm - Edited by: paulz
Reply
Yeah hope he chimes in.
What I’m messing with: The cabin TV has extra speakers near my ears so I can hear over the wife’s blabbing. They are USB powered, but put out static plugged into the cabin bank. I thought I had a usb noise filter but can’t find. So I put the 18650s in series and plugged into that. Static gone.
The speakers work on either 3 or 4 batteries in series but I was worried that plugging into the bank to recharge after use might overheat and explode them at 3s, the bank can hit 14s on solar.
|
|
Steve_S
Member
|
# Posted: 21 Jun 2026 04:21pm
Reply
LFP versus NMC/NCA chemistries follow different config rules due to their voltage curves. That AI generated twaddle is best left ignored. LFP is the closest "proxy" for FLA voltages & power delivery curves. For example: 24V systems 30.0V charge is acceptable for both FLA & LFP as is 15V for a "12V" system.
Cheapo "buck converters" will 80% of the time will fail due to over-voltage because they rarely can handle a proper charge voltage, such as they will not take more than 13.0V. for a 12V system. The "Good Ones" take into account a higher potential source voltage and regulate a precise output voltage and can compensate.
I actually run 24V & 12V DC devices with proper regulated converters that deliver precise voltages. That runs Ether Switches, Modem/Router and even a couple of Raspi's - none of which have tolerance for screwy voltages. I quite literally melted down a few buck converters (1 terribly scary one caught fire) but they were those cheapo's that folks buy without realizing it.
Image of the Most Evil types...
|
|
Steve_S
Member
|
# Posted: 21 Jun 2026 04:36pm
Reply
With LFP, be they prismatic Block, Pouch or Cylindrical for 12V we always use 4 Cells, 24V uses 8 Cells and 48V of course 16 Cells. For High Voltage things change up a bit as that takes us into Series/Parallel configurations that can hit 800VDC.
I am now looking into EVE, BYD & CATL Sodium-Ion cells which are in production for Energy Storage but also into several brands on EV's (BYD, Nio, Geely & SAIC) being the first to export these as well as well into their own market (they've had them on the roads for a while already).
Sodium ION is only available in "bulk" (meaning cells for public sale) from a few lesser companies as the Big Players are focusing on EV's & ESS systems and ramping that up before making cells available for buyers. My wholesaler is in-line on the list and they should be getting them as early as September but possibly later. I do not bother with the smaller players, just not worth it.
I won't be replacing my LFP Bank nor building any more batteries for myself or sale to others anymore, I've shut that down but I am still keeping a close eye on things... Life Changes have a way of happening and I have a sneaky feeling that changes are coming for me again (not bad ones) and I have to make some decisions this summer... a possible 12,000km move to spend the rest of my life in a sanctuary haven.
|
|
paulz
Member
|
# Posted: 23 Jun 2026 07:40am - Edited by: paulz
Reply
Thanks Steve. Speaking of volt converters our 40” TV uses one. Same old TV i used to run on AC until last year when I realized it used a 19vdc power supply, so I bought one of those cheapo converters like you pictured, 12 to 19 volt. Now it runs right off the bank, no inverter. So far so good. Its a flat screen LED, doesn't use much juice.
|
|
Steve_S
Member
|
# Posted: 23 Jun 2026 09:10am
Reply
The devil is certain in the details (specs). Those"Buck Converters" are trixy ! I went through 3 (last one caught fire) the first 2 burned out, and one of those passed along the "24V" to 12V which fried the motor on the RV Furnace in the powerhouse. Boy I was emitting a lot of "Blue Words" because it was -20C outside then, fortunately I had backup options.
Using the 12V examples. The detail to look for is the Input Voltage that they can take (in the spec fine print) where some will only take 24V, while others may take 30V, and of course, my being 24V-based it means I charge my battery bank @ 28V, so the input has to handle that. I then chose to buy a slightly more expensive ($30 USD) converter/regulator, which always outputs a clean 12V regardless if input voltage is 28V or 23.0V (my cutoff).
Those "Potted" ones are a nasty piece of work and if you ever tear one down you'll understand.
A digital device like a TV, Router/modem/Rapsberry Pi, have no surge draws and are light power-wise is one thing but anything that has a surge draw will fry these little buck converters, they just aren't designed for that. IE: Never try to run a 12V fridge with one of these !
|
|
gcrank1
Member
|
# Posted: 23 Jun 2026 11:03am
Reply
Steve, can I trouble you to post an Amazon link to a buck converter (for 12v stuff) that you could recommend?
|
|
Steve_S
Member
|
# Posted: 23 Jun 2026 02:40pm
Reply
gcrank, I've deployed a few different ones but they are Step-Down converters from 24V/48V.
One I use that I am very happy with is similar to this link... make/model but I get this stuff through my direct suppliers in Shenzhen, China. I do believe these can be had on Amazon but avoid them like the plague.
https://www.alibaba.com/product-detail/Kuerl-high-quality-30A-car-step_1600439063568. html
If you want really top quality, never have to worry ever again stepdown converters then look at the link below this BUT this is Tier-1 not cheap goodies but they provide peace of mind which is priceless.
https://samlexamerica.com/product-category/dc-dc-voltage-converters/
Sorry but they got got tariffed to hell even though they are Taiwanese.
Hope it helps, Good Luck.
|
|
MtnDon
Member
|
# Posted: 23 Jun 2026 03:38pm
Reply
The Samlex is excellent. We have one.
I do know that a direct lightning strike will kill them, but other than that, they are trouble-free.
|
|
Steve_S
Member
|
# Posted: 23 Jun 2026 07:48pm
Reply
Not much will take a lightning strike. My system has Midnite Solar SPD's which will take the hit and cutoff preventing systematic damage.
#1 Rule of Crisis Management is Prevention.
|
|
MtnDon
Member
|
# Posted: 24 Jun 2026 11:44am
Reply
Quoting: Steve_S system has Midnite Solar SPD's which will take the hit and cutoff preventing systematic damage
Our strike was before Midnite made their SPD's. We now have a few as well as other improvements. Midnite SPD's are great. We have had two rendered ineffective by strikes. They were covered under warranty
|
|
gcrank1
Member
|
# Posted: 24 Jun 2026 04:26pm
Reply
Wow, covered under warrantee....seems like a device like that is supposed to be sacrificial in a L-strike
|
|
MtnDon
Member
|
# Posted: 25 Jun 2026 12:45pm
Reply
Let me re-address my experiences with Midnite Solar SPD's. Things have changed over time.
The MN SPD's were introduced in the spring of 2012. It was perfect timing as it coincided with our lightning strike. The old Delta units blew up.
I found the MN SPD's at NAWS and bought three. At that time they had a lifetime warranty. A few years passed and one day after a big storm I noticed the blue indicator led on one was non lit. I sent it in after getting an RMA. They said it had been killed by a big surge or two and gave me a new one at no charge.
Several years later another stopped showing the OK led. I got another RMA and sent it in. They replaced that one as well ,but noted that the warranty on new purchases was 5 years, not lifetime. (I had bought two more for use at home).
Today I looked online and the warranty is worded to only cover fefects. So they changed, from a superb warranty, maybe first used to generate sales? Not a big deal as those surge suppressors do the job they were designed to do.
|
|
Steve_S
Member
|
# Posted: 25 Jun 2026 01:42pm
Reply
Midnite has changed (more greedy & grubby) over the past 5 years and is reflected in warranties & more. The majority of their products are still top notch in comparison to others but not as good as they used to be, as well.
I have Classic Controllers, breakers, fuses, SPD's, E-Panels etc from them (none of their new AIO's etc, won't touch them).
If I was to start over building a new offgrid solar system, it would be all Victron and again NO AIO's (All In Ones, which have Solar Controller(s), Inverter/Charger all in one box).
|
|
gcrank1
Member
|
# Posted: 25 Jun 2026 03:53pm
Reply
Why no aio's, Steve, too much internal overhead?
|
|
| << . 1 . 2 . 3 . 4 . |
