Mpp lv2424 not turning on..

[John Frum]

24 volts is a good cutoff point for an 8s lifepo4 batttery.
I guess the "easy button" solution if you have access to a generator or shore power is an rv style ac to dc converter.
The unit should power right up when exposed to even "float" voltage.
Probably only needs to be on long enough for the all in one's own charger to start propping things up.

 

[steve_bc]

i am guessing that the battery sagged under load below the lvd, then once disconnected it rose back up. But the easy trouble shot would be to check if there is voltage and the wire ends. If there is it may be in the AIO. If not then it's the battery/bms

 

[John Frum]

I've said it before but I will say it again.
A BMS should have a momentary switch and an led so that even my grandma can easily check for a bms trip.
For bonus points the bms should be easily reset.

 

[heirloom hamlet]

Have you tried shutting off the breaker on the BYD and letting it sit (the voltage eaks up some)...then flipping it back on after a while?
The BYD won't come back on (thus neither will the LV2424) unless at 22.4, in my experience. Sometimes it was minutes before the voltage would organically come up enough, sometimes days. But you have more than enough voltage on the BYD apparently, that's what makes me wonder if you should simply try the breaker. I also never had one just come on on it's own, I had to manually flip the breaker.

 

[John Frum]

Have you tried shutting off the breaker on the BYD and letting it sit (the voltage eaks up some)...then flipping it back on after a while?
The BYD won't come back on (thus neither will the LV2424) unless at 22.4, in my experience. Sometimes it was minutes before the voltage would organically come up enough, sometimes days. But you have more than enough voltage on the BYD apparently, that's what makes me wonder if you should simply try the breaker. I also never had one just come on on it's own, I had to manually flip the breaker.

What is the lvd disconnect voltage for the BYD?
What is the lvd reconnect voltage for the BYD?

 

[heirloom hamlet]

What is the lvd disconnect voltage for the BYD?
What is the lvd reconnect voltage for the BYD?

I don't have these anymore, I'm speaking from past experience. These figures didn't matter...they come with unalterable figures in the built-in BMS with the BYDs.
That was set higher than my LV2424.
When they dip below 22v, they shut down. In my experiences, I never saw them come back on until they were at 22.4v.
I learned to shut it all down, including that pre-installed breaker. I'd wait and let the voltage come back up a biy on it's own. It always did eventually. Then I'd flip the breaker and everything was live. But I'd only do it if the sun was shining and could begin to charge immediately.

It wasn't a brilliant system, but that's how it worked.

 

[John Frum]

These figures didn't matter...they come with unalterable figures in the built-in BMS with the BYDs.
That was set higher than my LV2424.

Yes they do matter.
If we knew what they were we could set the LV2424 higher or vice versa depending on which one is more easily recoverable.
Knowledge is power.

 

[heirloom hamlet]

Yes they do matter.
If we knew what they were we could set the LV2424 higher or vice versa depending on which one is more easily recoverable.
Knowledge is power.

Yes, you're right about that. I apologise, I didn't mean that it didn't matter ever, I meant that it didn't matter while that thing is off and can't be turned back on.

 

[erik.calco]

@Mirandya can you describe your battery bank? Is it just one DIY 24V battery?

 

[Forbisher]

@Mirandya can you describe your battery bank? Is it just one DIY 24V battery?

Her battery ia not diy.
It is a.3.7kw grade b BYD battery bank with a meter.

 

[erik.calco]

Her battery ia not diy.
It is a.3.7kw grade b BYD battery bank with a meter.

She needs to confirm she can charge the battery. If the LV2424 will not power on, and she has panels, one option is to get a cheap $20 SCC that can handle 24V, and plug in panels to charge the battery. Not all the panels. If 12V panels, then just two in series. Because a $20 SCC can't handle much. I have a $20 one that I've had zero issues with a 100W 12V panel running every day since Dec.

If the battery takes a charge, then when it is higher, 24-25V, see if the LV2424 can turn on. If it can, then once running, change the setting to raise the cutoff for low battery higher than where it is to ensure the LV2424 cuts it off before the BMS does. Will confirmed in another thread that if it cuts off via the LV2424 instead of via the BMS, it should still be able to charge it.

One reason I asked about the bank, though, is the times mine cut off was because my bank got out of balance, which can lead to a BMS in one battery cutting off even though other batteries in the bank have plenty of juice. Some have pointed out that you can often reset the BMS and boot the LV2424 without any load and charge it. I can't say I tried that because in my cases, I chose to try to balance a bit before reconnecting the LV2424.