300 AMP breaker for mid nite e-panel?

Started by ebenbayer, April 14, 2020, 12:04:06 PM

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ebenbayer

Are there any 300 AMP dc panel breakers available? I have a 250 Amp that is tripping on occasion (I'm using a DIY TSLA power wall, and lots of morning sun at 42 volts can trip the bank)
Offgrid;
25KW solar array
MicroHydro @ 150 ft of head w/ adaptive water sensing.
2000 AH 48 V ( Tesla Model S Battery packs in 2s1p format)
240 Gal integrated DHW / pressurized thermal storage

billmill

Hmmm,  Im just a newbie but it sounds like something is not wired correctly.  Post some closeup picts or diagrams of your system.  I cant imagine how a 250 amp break would trip like that?

ebenbayer

Yea, its tripping because its getting close 250 amps for medium periods of time and exceeding 250 in bursts. So it is working correctly. I'm just having trouble locating a larger amperage breaker.
Offgrid;
25KW solar array
MicroHydro @ 150 ft of head w/ adaptive water sensing.
2000 AH 48 V ( Tesla Model S Battery packs in 2s1p format)
240 Gal integrated DHW / pressurized thermal storage

Vic

Carling lists a 300 Amp F-Frame breaker.   May not be a standard,   stocking item,   and will NOT  be inexpensive (as are the MN Breakers):

https://www.carlingtech.com/sites/default/files/documents/F-Series_Details_%26_COS_010714.pdf

Check that the connections of the cables to the breaker are tight.   You might use an IR thermometer to check the connections/lugs.

Furthermore,   technically the cables that connect to the breaker may not be able to handle 300 Amps,   although inside the e-panel,   this may be considered to be in Free Air  ….   am notta code wizard.

FWIW,   Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

FNG

are you drawing more than 250 amps to power the house or charging at greater than 250 amps?

If you are charging at greater than 250 amps I would suggest a battery combiner and ore than one circuit feeding it. The combiner we have for example is good for 1000 amps and you would then feed charge controllers in to that not into a single 250 amp breaker

If you are tripping one of our 250 amp breakers from powering the house with AC then you are drawing around 300 amps at 42 volts or 12,600 watts. i can not think of any single inverter that is capable of that so it may be that you are asking multiple inverters to run through a single breaker.

Can you share a wiring diagram and specifics on the system? We can probably assist with some design ideas that will help with this issue

bee88man

First off, that 250 ADC breaker is for only vertical mount position for prper heat disapation.
And if all else dictates 300 ADC then know that 300 amp T fuses are common and not overly expensive.

ebenbayer

Hi all-- thanks for the feedback and references.

On topology, I have 5 outback VFX3658's that are all on independent breakers that run through a 350 amp contactor to the battery bank (which disconnects in fault condition, hi/lo battery etc). I've then put a manual 250 amp breaker in series here as a master shut off. Both charge controller and inverters run through this. I added this so in the unlikely event of multiple fail safes fails I only have to educate the other people in my house on a single operation (Pull master disconnect switch). I guess this is could also just be a DC disconnect.

the +250 amps only occurs in rare circumstances during charging (batteries empty and no AC Load).

The inverters are only ever at full load when all diversion loads are on and then all the electrons stay on the + bus bar w/ only ~20 amps flowing to battery.

Cables are sized appropriately. Everything is in E-panels and conduit. TSLA battery in fire safe cabinet.

I think I'm going to see if I can acquire the 300 AMP breaker that Vic listed. Otherwise I could split some of my charing loads into a separate 250 AMP breaker (or combiner? what is benefit to that ?) or just get a DC disconnect that panel mounts in an e-panel?

thanks!

E



Offgrid;
25KW solar array
MicroHydro @ 150 ft of head w/ adaptive water sensing.
2000 AH 48 V ( Tesla Model S Battery packs in 2s1p format)
240 Gal integrated DHW / pressurized thermal storage