Inverter occasionally goes into high voltage disconnect

[ericfx1984]

Don’t worry he has two BMS to keep that all in check! ?

I mean there's nothing to worry about really... Everything's been running for over a year now and we're fast approaching the house being finished which means we'll be disassembling this temporary system as we start to build a 48 volt system for the house

 

[ericfx1984]

Bingo! That was too high.

Yeah I think I was foolishly relying on the BMS to handle the shut off not thinking about how jarring that disconnect would be... After all the power has to go somewhere

As long as you're consuming the power it's never really a noticed issue... But it's when you're not consuming the power that things get a little wonky

I feel happy that I was able to recognize the issue... And then correctly deduce that the issue was related to the disconnect on the top end of the battery charge

Honestly if we're not learning something new it's kind of boring... So I'll take it well worth it lots of fun

 

[740GLE]

It's the entire battery that's heading disconnect... I looked in the BMS to double check everything and it never recorded a a high cell... They all stay pretty darn close to each other. I've never seen them more than 0.00X volts out of balance

high voltage disconnect, for the pack is set to 14.6v on the BMS

Charge voltage for the MPPT charge controllers is set to 14 volts now but previously was set to 14.6

So you’ve never seen any cell reported by the BMS hitting 3.65?

Very very very common for cell voltages in the 3.3-3.38v range to have zero delta but still have vastly different SOC between cells but soon as voltage climbs above 3.4 you’ll get a runner start to shine.

 

[740GLE]

I mean there's nothing to worry about really... Everything's been running for over a year now and we're fast approaching the house being finished which means we'll be disassembling this temporary system as we start to build a 48 volt system for the house

If you’ve been running for a year, when was the last time you top balanced? Otherwise there’s a high chance your cells are just unbalancing themselves. As it unbalances You’ll eventually need to drop charging voltage again and again.

Once you build you’re 48v system a proper top balance maybe in order.

 

[ericfx1984]

So you’ve never seen any cell reported by the BMS hitting 3.65?

Very very very common for cell voltages in the 3.3-3.38v range to have zero delta but still have vastly different SOC between cells but soon as voltage climbs above 3.4 you’ll get a runner start to shine.

No I've watched them even as they climbed past 3.4... never said that they had not hit 3.65... But rather that they do so at the same time

Think a lot of it has to do with that I actually spent time doing a top balance on all these cells when I first assembled this temporary pack

One thing I will say I found annoying about this pack being so large is the battery management system does not have a proper way to report anything over 650 amp hours... But that's simply reporting error so it doesn't really affect anything...

 

[ericfx1984]

If you’ve been running for a year, when was the last time you top balanced? Otherwise there’s a high chance your cells are just unbalancing themselves. As it unbalances You’ll eventually need to drop charging voltage again and again.

Once you build you’re 48v system a proper top balance maybe in order.

Absolutely I plan to... I have another set of 280 amp hour cells that will be going into 16S that I'll need to do a top balance on

At that point I'll be able to decommission this system...

It won't be a total decommission but it will be a major scale back

Currently I have 16, 304 amp hour, Eve cells set up in 4P4S running on a single 200 amp BMS


Then I have eight, 230 amp hour, Eve cells running in 2P4S also on a single 200 amp BMS

Basically the plan is to take the 304 ah cells , give them a good top balance, reconfigure them into 16S, and put them on a 16S, 200 amp BMS

The RV will be pushed down to a pair of 4S, 230 amp hour batteries


So basically when the house is done we will have a 16S, 304 amp hour battery and a 16S, 280 amp hour battery

 

[740GLE]

No I've watched them even as they climbed past 3.4... never said that they had not hit 3.65... But rather that they do so at the same time

Think a lot of it has to do with that I actually spent time doing a top balance on all these cells when I first assembled this temporary pack

One thing I will say I found annoying about this pack being so large is the battery management system does not have a proper way to report anything over 650 amp hours... But that's simply reporting error so it doesn't really affect anything...

Ahh maybe the multiple SCC are still trying to shove 170a as you get closer and don’t ramp current down enough before HVD is hit.

What SCC do you have again?

 

[ericfx1984]

Ahh maybe the multiple SCC are still trying to shove 170a as you get closer and don’t ramp current down enough before HVD is hit.

What SCC do you have again?

(1) Victron 100/50
(1) EP ever 40 amp
(3) EP ever 60 amps

They're just kind of loafing along

 

[740GLE]

Btw according to my math that adds up to 150a not 170a ?

 

[ericfx1984]

Btw according to my math that adds up to 150a not 170a ?

Well actually you missed something

There are a total of 3, 60 amp charge controllers... 1, 40 amp charge controller and 1, 50 amp charge controller

Which is actually 270 amps... Although I never see that type of amperage...

I typically see around 170 amps

But I also have no practical way to really consume much more than that anyway

Although I suppose there is some advantage to the fact that the equipment is just kind of loafing along since I rarely drop below 70% state of charge...

The big advantage I see to having these panels and charge controllers is that I start making power pretty early in the morning

By the time we're at full sun I'm already at a reasonably high state of charge even if I've been running both air conditioners all night

As a result I don't think that the batteries present an opportunity to really push the charge controllers... As a result I typically don't see more than 170 amps between all five charge controllers