DC breaker tripping on high charge (100A)

jasgrif11 · 17-09-2023 03:27PM #1

I noticed (twice) that my DC breaker has tripped when on a high charging load at 100A. The breaker gets very warm and trips. The model I have is the "DIHOOL DZ47B-125 125A", so in theory, it should be able to handle the 100A load. As a test, I've set my battery to charge at 50A to see if the issue repeats.

I have 35mmsq cable coming from the battery to the breaker and 25mmsq from the breaker to the Sofar 6000HYDEP inverter. Given the thickness of the cable, I don't have any Ferrules on the battery cable going into the breaker. I assume this is fine, the connection is very solid.

Has anyone seen this issue?

graememk · 17-09-2023 04:20PM

Are you sure its a DC breaker?

Its not an exact match but this one sounds very similar : http://www.cncspv.com/DZ47-125-Series-63-125A-AC-Mini-Circuit-Breaker-MCB-pd41356179.html

(I also dont trust the No brand DC breakers, They are quite hard to find)

You could fall back to the old faithful Mega type fuse and a DC isolator.

jasgrif11 · 17-09-2023 04:36PM

Here is the link to the one I purchased.

https://www.amazon.co.uk/gp/product/B09VYLYJMV/ref%3Dppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&th=1

What brand names are others purchasing?

graememk · 17-09-2023 04:48PM

https://www.boards.ie/discussion/comment/121122571#Comment_121122571

~~That's an AC breaker~~

Ah I see DC ones there now

Projoy is the one on my dad's solis.. I think, I'll check tomorrow

fael · 17-09-2023 07:58PM

I would replace it, based on my own experience. I wanted to get a Projoy from midsummer for my install but they were out of stock with no ETA. Ordered Dihool DC breaker from amazon instead.

Had the same issues as you. Tripped twice but could not find fault anywhere. While doing some troubleshooting it then failed again and got very hot, cable sleeve melted and some soot on breaker but it did trip. I noticed when tightening cable the housing comes apart slightly. Swapped it out for a GivEnergy from midsummer (they finally had something in stock). Immediately noticed how much sturdier it was when installing. If I had compared the two side by side before installing I would have dumped the Dihool straight away.

I cannot rule out my own stupidity but I've seen some reports on the dihool with similar experiences.

Goes without saying but make sure there is no strain on the cables in or out of the breaker.

jasgrif11 · 17-09-2023 08:57PM

Great advice @fael thank you. I noticed it was very hot so disconnected everything and removed the breaker from the enclosure and the plastic is all stained from the heat.

I’ll try Solartricity and Midsummer in the morning for the Projoy

irishchris · 17-09-2023 09:10PM

https://www.boards.ie/discussion/comment/121123664#Comment_121123664

Using the projoy 125a dc breaker in my so here too and no issues whatsoever with regular 100A charging.

graememk · 17-09-2023 09:30PM

Found it online here : https://cosypower.ie/projoy-battery-isolator-125v-125a-dc-mcb1.html

SD_DRACULA · 18-09-2023 01:54PM

You could go with one of these https://www.ebay.co.uk/itm/305118069081?chn=ps&norover=1&mkevt=1&mkrid=710-169260-534375-3&mkcid=2&keyword=&crlp=670833748941_&MT_ID=&geo_id=&rlsatarget=pla-293946777986&adpos=&device=c&mktype=pla&loc=9040163&poi=&abcId=&cmpgn=20488672762&sitelnk=&adgroupid=155578564071&network=g&matchtype=&gclid=CjwKCAjw6p-oBhAYEiwAgg2PgrxGxcx9EwiSjqqT60AY5tzUQp19tfP6ubTlzCjkzdaDPfVQhDq_9hoCGREQAvD_BwE

Very sturdy and no chance of the cables ever moving as they go onto lugs with M10 bolts.

10-10-20 · 18-09-2023 02:46PM

https://www.boards.ie/discussion/2058314174/dc-breaker-tripping-on-high-charge-100a

If you over-torqued the connector you may have severed some of the strands. That's the benefit of the bootlaces/ferrules, stops strand loss. You'd see that if you examine the cable. Another potential cause could have been thermal expansion on the connector causing the screw-torque to lower over time. Did you notice whether the connections were less tight when you checked them?

jasgrif11 · 18-09-2023 04:38PM

The connection seemed tight and no broken strands. Although I do prefer the use of ferrules myself. Does anyone know if they automatically come with the Projoy? If not are there specific types required for the 25mm2 and 35mm2 battery cable?

SD_DRACULA · 18-09-2023 06:41PM

https://www.boards.ie/discussion/comment/121126811#Comment_121126811

You'll need 25mm2 ferules for the projoy I used that too but you will have a hard time finding ones which are 8-10mm in length as longer will stick out too much of the projoy.

Just buy what you can and slice off the ends to make it fit.

jasgrif11 · 19-09-2023 05:54PM

Projoy breaker arrived today. Crimped on the 25mm2 ferrules and have the battery back up and running.

I will run a few high charge loads over the coming days.

Thanks everyone

DC breaker tripping on high charge (100A)

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