Recommend me a fuse / battery disconnect

unkel

I use an automotive 250A megafuse, which is ok but not the most sturdy thing. I used to have a marine battery switch, but not using that any more

I want to combine the functions of the above in one physical unit. No need for it to be dual pole (on both negative and positive), just one will do. Only problem is that my main battery cables are 70mm2, so that would have to fit!

What would you recommend, preferably with a link to where to get it online?

unkel

OK, a DIN rail mounted DC circuit breaker is probably the best solution. It is also what I currently have for my supplemental power supply circuit

Surely it is enough to have a single pole one as the circuit is broken if either positive or negative side is disconnected? Or is there a benefit of dual pole?

A few options:

https://www.amazon.co.uk/dp/B0BRTYTJ1B?ref_=cm_sw_r_mwn_dp_R07WJ0QATZG4Y81D7D2B&language=en_US&th=1

https://www.amazon.co.uk/dp/B0BCX3FMRL?ref_=cm_sw_r_mwn_dp_HQPTCW6SBA3K2MHSKQ17&language=en-GB

https://www.amazon.co.uk/LOUIKA-%EF%BC%8CCircuit-%EF%BC%8CProtection-Automatic-Protector/dp/B0C7KVSRK3/ref%3Dsr_1_13?crid=1S2HJQ7KYVOR3&keywords=DC%2Bcircuit%2Bbreaker%2B250A&qid=1707172133&sprefix=dc%2Bcircuit%2Bbreaker%2B250a%2Caps%2C64&sr=8-13&th=1

SD_DRACULA

I am not sure any of them can take a 70mm2 cable.

Using 70mm2 cables myself with one of these but will probably have to order from UK

https://electric-solar.co.uk/products/keto-1-battery-disconnector-with-200a-fuses

They take M10 lugs.

unkel

Bought this

https://www.amazon.co.uk/dp/B0C7ZYZQ78?psc=1&smid=A30DC7701CXIBH&ref_=chk_typ_imgToDp

It looks to be identical to the second one in my list above. Another regular on the forum bought this Heschen one recently and confirmed it takes 10mm rings, which I need for my 70mm2 cables

gocfella

Hi,

Just browsing these threads and was wondering is there any data or testing around on the quality of those Amazon Heschen DC breakers? I can't find diddly squat info relating to them anywhere which doesn't give me confidence.

Ideally would like something from a known good brand but seems to be very difficult to source something without handing over an arm and a leg in exchange 😄

S'

I went with this. Well built study unit.

https://electric-solar.co.uk/products/jean-muller-fuse-switch-disconnector-keto-size-1-body-battery-isolator?_pos=8&_sid=03c7bca0c&_ss=r

gocfella

I'm sure that is good quality but not what I'm after. I already have a good marine disconnect switch but I am looking for a bi-directional DC breaker known to be of decent quality. I don't want to pay out stupid money for Schneider, ABB, etc. I'm finding it very difficult to find anything.

gocfella

Tomzn are supposed to be half decent from what I've heard for cheap chinese but none in stock in EU that I can find. It's quite possible that the Heschen ones are ok but there's no way to know without reviews or teardowns to watch. I'm tempted to order one. Any feedback on them from anybody?

SD_DRACULA

https://www.boards.ie/discussion/comment/121903498#Comment_121903498

Got one of them with 200a fuses, very sturdy and takes M10 bolts for multiple cables if you need

Will take 70mm2 no bother

gocfella

After further thought and reflection, I decided to get one of the Jean Muller Keto with 200a NH fuses. How did you guys mount them out of curiosity. There is a much greater force required to pull the release than I was anticipating 😁

GarlicBed

https://www.boards.ie/discussion/comment/121906751#Comment_121906751

Can I ask how big is your battery and how much current it can discharge ? I'm learning here......

Am I right in saying a 300ah battery (15kw @ 48v) discharging at 5kws makes 104Amps?

SD_DRACULA

https://www.boards.ie/discussion/comment/121942107#Comment_121942107

Yeah they are 305ah cells, two packs in parallel so 610ah so in theory you can draw 610a if you have some crazy inverter.

But yeah 100a is about 5kw, I have seen the inverter pull/push up to 190a which would be almost 10kw