It worked... Then it didn't. Why?

[heirloom hamlet]

I have not done it myself but have read up on it when I discovered I had two flaky 174AH cells. (part of the ShunBin mess).
The procedure is not hard but time consuming. First to get the cells down to 2.50V then to slowly bring them up at low Amps and giving them "rest periods" to settle in between, as I recall the instructions said taking a break & rest at every 0.25V which seemed a bit much TBH but I can see some reasoning there due to the chemical reactions going on. There are different posts all over the internet and a lot of speculation as to what is best etc.... I'm sure there are ways to do so but it would really depend on the internal state of the cell in question and just what happened to it. Thing is, is One "recovered" cell worth putting into a good pack of cells ? That's only an answer the risk taker can make, entirely up to the individual.

Well, that's helpful. I'm all about time consuming. It actually probably wouldn't take much more time and attention than all my top balances.
I got two packs to top balance at 3.65 on the little 5a charger and am working on the third. First pack took 4 or 5 days but it had been used with the LV2424 without a balance for a bit. Same with the second pack, but to took 2 or 3 days. Now the third had been sitting on that charger for 3 weeks, with me checking it every morning and throughout each day. It's pretty ridiculous what we do for these things really.

I'm going to try what you said after I get my replacement cells in and all four packs top balanced. Thank you, again.

 

[heirloom hamlet]

There has been a lot of info about the BMS causing this, the quick test is to see whether your LV2424 actually switches off when the problem occurs. AFAIK, the LV2424 is powered from the battery, no battery, no display. If the LV2424 is staying on, then the likely culprit is that your LV2424 is actually disconnecting the load, maybe a thermal shut-down. Quick to test, and probably is the BMS, just offering an alternative perspective.

I'll find out. Because I intend to put someone on that saw and vac, while I stand by the unit with bluetooth BMS cell displayed in hand. We'll find out quick. Thanks for this.

And if it is the box thermal shutdown, any recommendations then? And how would that explain that it used to not cut out, through longer and thicker much more intensive rips, but now it does on 1/2 thinner material, 1/3 as long.
Thanks for this. You're a smart dude. You all are. Humbling.

 

[Steve_S]

LV2424

shnootz, just noticed that ! 2400W Inverter forget the surge values. a 120V/15A saw = 1800W That will certainly "WARM" the inverter, add more on top and the closer to 2400W you get the warmer it will get too. Thermal shutdown is quite possible on the inverter side. Watch the temps, I wonder if when you had no issues if it was cooler out and ambient temps were lower and now in hotter weather all of a sudden....

 

[heirloom hamlet]

shnootz, just noticed that ! 2400W Inverter forget the surge values. a 120V/15A saw = 1800W That will certainly "WARM" the inverter, add more on top and the closer to 2400W you get the warmer it will get too. Thermal shutdown is quite possible on the inverter side. Watch the temps, I wonder if when you had no issues if it was cooler out and ambient temps were lower and now in hotter weather all of a sudden....

So that could be it for sure. It's a 1200w/10a saw with a 1500w/12.5a HEPA Vac. Could it just be "worn" on some level now, and tolerating less?
The ambient temp definitely isn't the main issue. It was way hotter before. These past few days have been the mildest and most survivable in months. I replaced the little 14awg cord going 125' with an 8awg. Still black and out in the sun, though.

 

[heirloom hamlet]

shnootz, just noticed that ! 2400W Inverter forget the surge values. a 120V/15A saw = 1800W That will certainly "WARM" the inverter, add more on top and the closer to 2400W you get the warmer it will get too. Thermal shutdown is quite possible on the inverter side. Watch the temps, I wonder if when you had no issues if it was cooler out and ambient temps were lower and now in hotter weather all of a sudden....

I have realized that I need a 4th system, and am thinking about doing a "real" one, not an All-in-one this time like my LV2424s.
I don't really need this 4th system for a couple of years, but in light of my recent short term power needs for power tools, I may put this together sooner rather than later. I wonder if you have experience with a 24v inverter that you could recommend, one that could support my power demand we've been discussing. Perhaps a 24v 4000w? I have no experience outside of the LV2424s.

 

[Steve_S]

I have realized that I need a 4th system, and am thinking about doing a "real" one, not an All-in-one this time like my LV2424s.
I don't really need this 4th system for a couple of years, but in light of my recent short term power needs for power tools, I may put this together sooner rather than later. I wonder if you have experience with a 24v inverter that you could recommend, one that could support my power demand we've been discussing. Perhaps a 24v 4000w? I have no experience outside of the LV2424s.

I started out with a 3Kw Inverter/Charger & moved up to a 4Kw Samlex EVO which suits my needs. From what I know of MPP stuff it is stackable so therefore expandable in a modular fashion. I don't know what you have now, you say this is your 3rd system, so where to start what to do now ? I dunno. This is where long term planning and execution of it is pretty important, unless you happen to have a pile of extra, loose cash you don't want.

 

[heirloom hamlet]

I started out with a 3Kw Inverter/Charger & moved up to a 4Kw Samlex EVO which suits my needs. From what I know of MPP stuff it is stackable so therefore expandable in a modular fashion. I don't know what you have now, you say this is your 3rd system, so where to start what to do now ? I dunno. This is where long term planning and execution of it is pretty important, unless you happen to have a pile of extra, loose cash you don't want.

No, no cash to waste. But I'm building a bit of a village. The 3 systems are not a progression, they are independent systems. Each supplying power to 3 separate locations. All are 2.4kw LV2424s with a 24v 280aH Lifepo4.
I have most of what I'd need for a 4th separate system, minus the SCC and Inverter. If I am going to create another, with the knowledge I now have, I feel like I could out together a custom system that could easily support this new power need that has arisen for me. Of course, I have the internet, but I was just looking to avoid a mistake and regret by seeing if there were any tried and tested SCC / Inv that meet the description of the need. Just a finger pointed in the right direction.

 

[tictag]

If it is a thermal shutdown (or any other LV2424 initiated behaviour), firstly the unit will stay powered i.e. they'll be a display (that will tell you whether or not this is a BMS-initiated shutdown), and then it should tell you what it has done i.e. some error code will be displayed, you'll have to check the manual for this (I am not familiar with these all-in-ones).

Looking forward to the results of your further troubleshooting - don't leave us hanging!!

 

[GVSolar]

I have nothing but good things to say about the Schneider Conext SW4024. I've had one running my whole house for almost 4 years now. On or Off-grid hybrid inverter - good surge - DC and AC coupling - excellent integration with the Conext Charge controllers - software monitoring thru Combox & System Control Panel. Programming may be a little complex sometimes - but that is the cost of flexibility. Pricier than any of the all in one stuff - but real (although sometimes slow) tech support - and a company that's not likely to disappear. Might be worth a look-see. Best.

 

[heirloom hamlet]

If it is a thermal shutdown (or any other LV2424 initiated behaviour), firstly the unit will stay powered i.e. they'll be a display (that will tell you whether or not this is a BMS-initiated shutdown), and then it should tell you what it has done i.e. some error code will be displayed, you'll have to check the manual for this (I am not familiar with these all-in-ones).

Looking forward to the results of your further troubleshooting - don't leave us hanging!!

I feel like I have read that these LV2424s can be stacked somehow, paralleled. I have a dormant one. I wonder if I should try and figure out how to stack two units, if it would get me over the hump for now, increasing the threshold of my inverter. Have you any knowledge of if this is feasible.

 

[John Frum]

I feel like I have read that these LV2424s can be stacked somehow, paralleled. I have a dormant one. I wonder if I should try and figure out how to stack two units, if it would get me over the hump for now, increasing the threshold of my inverter. Have you any knowledge of if this is feasible.

Suggest you solve your problems before you start complicating things.

 

[tictag]

As I understand it, and according to their datasheet, it can be paralleled with up to 9 units. It doesn't look like it strictly speaking AC-Couples because you need a communications cable between each unit.

 

[tictag]

Suggest you solve your problems before you start complicating things.

Well, at least identify the source of the problem. If it is your MPP overloading then stacking another would, presumably, fix that problem. But if this is indeed a BMS issue, stacking another unit won't help with that.

 

[heirloom hamlet]

Well, at least identify the source of the problem. If it is your MPP overloading then stacking another would, presumably, fix that problem. But if this is indeed a BMS issue, stacking another unit won't help with that.

Its the MPP. It's stays powered on, and the cells stay together.

 

[tictag]

Might be worthwhile getting one of those energy monitors to independently measure how much power is being drawn. If what is being drawn is inside the specs of your MPP then you might have a warranty claim. If above, then you're either looking at paralleling up or upgrading.

 

[heirloom hamlet]

Might be worthwhile getting one of those energy monitors to independently measure how much power is being drawn. If what is being drawn is inside the specs of your MPP then you might have a warranty claim. If above, then you're either looking at paralleling up or upgrading.

View attachment 19611

I have that exact one. Pretty sure it's my fault, I'm asking more of a 2400w inverter than it was designed for. 1500w 12.5a Hepa Vac combined with a 1200w 10a Track Saw.
If it is possible to parallel what I already own and have it get me by for now, I'd rather. Then I could get a larger system when I actually need it, in a couple of years.
So you do think that paralleling these will give me twice the AC output, right? I should be able to have a 4800w draw? Not that I want to do that, but while building it appears my tools do need 3000w.

 

[schmism]

After struggling for years on trying to use shop tools on not-large-enough gas generator, I can tell you that inductive loads from brushed motors are no joke.

Its disappointing to see the number of reviews of inverters and reviewers pull out their space heaters and heat guns. Congrats guys, you ran a 1500w restive PF 1.0 load. Lets see it start 1500w of air compressor or table saw.

 

[schmism]

If it is possible to parallel what I already own and have it get me by for now, I'd rather. Then I could get a larger system when I actually need it, in a couple of years.
So you do think that paralleling these will give me twice the AC output, right?

yes if they support the parallelling feature, and your not currently useing them to 220v split phase, then yes parallel them so they can load share that startup load.

 

[Bob B]

In all my years of troubleshooting, my first question is always ... what has changed. You identified those things in your first post.

I'd go back and eliminate those changes one at a time starting with the easiest one first.