Electrical question please

[Figaro]

My new Fogstar battery wouldn't fit in the seat base so I've had to relocate it to under the bench seat, extending the battery cables by about 700mm.
Do I need to fit a new fuse next to the battery or can I rely on the existing one which is still in the seat base ?
If I need a new one, any recommendations for an easy fit one ?
I used 10mm2 70amp cables
TIA

 

[Pausim]

I would want a fuse next to the battery.

 

[Jev88]

Fuse as close to the battery. It's the cable you are shielding from fire risk

 

[Figaro]

Would this be suitable ?
50 amp version ?

30-300Amp Waterproof Circuit Breaker Fuse Reset 12-48V DC Car Boat Auto UK Stock | eBay

Cars Racer. This is an automotive self-recovery fuse holder that features a multi-type circuit breaker and an automatic switch. It is available in different amperages, ranging from 30A to 300A, and is suitable for use in various vehicles, including cars, boats, and trucks.

www.ebay.co.uk

 

[autorouter]

If it's a lithium battery probably it's not got a terminal post like a lead-acid battery. Maybe one of these would be OK.

Mrbf Terminal Fuse Block Kit with Fuse 5/16" (M8) Compact Marine Rated Fuse | eBay

Design: Small and compact in size, can greatly save installation space. It's just take you 1 minute. We'd like to settle any problem in a friendly manner. Because the unpaid dispute will not be closed automatically, and we may ignore it.

www.ebay.co.uk

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[Lenny HB]

Would this be suitable ?
50 amp version ?

30-300Amp Waterproof Circuit Breaker Fuse Reset 12-48V DC Car Boat Auto UK Stock | eBay

Cars Racer. This is an automotive self-recovery fuse holder that features a multi-type circuit breaker and an automatic switch. It is available in different amperages, ranging from 30A to 300A, and is suitable for use in various vehicles, including cars, boats, and trucks.

www.ebay.co.uk

A t that price it will be a pile of poo, if you want a reliable breaker 12v Planet do them about £65.
When buying fuses always buy from a reputable supplier best to avoid ebay.

 

[AdrianChen]

Do the 10mm battery extension cables join to the same size existing cable?

 

[Figaro]

Do the 10mm battery extension cables join to the same size existing cable?

The existing battery cables are probably a little smaller, I didn't really take a lot of notice.
Is it important ?

 

[Figaro]

If it's a lithium battery probably it's not got a terminal post like a lead-acid battery. Maybe one of these would be OK.

Mrbf Terminal Fuse Block Kit with Fuse 5/16" (M8) Compact Marine Rated Fuse | eBay

Design: Small and compact in size, can greatly save installation space. It's just take you 1 minute. We'd like to settle any problem in a friendly manner. Because the unpaid dispute will not be closed automatically, and we may ignore it.

www.ebay.co.uk

Interesting, I've not seen a fuse like that before.
I take it the fuse part is the plastic block with the rating on ?
Are replacements readily available ?
Yes, lithium without conventional terminals.

 

[AdrianChen]

The existing battery cables are probably a little smaller, I didn't really take a lot of notice.
Is it important ?

Only that 10mm² isn't a huge cable, but if they go onto existing cables they may already be fused and at a smaller or larger rating.

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[BouncyBoatFolk]

Fuse size would be related to cable size , but for a 35mm2 cable, what should be the optimum?

 

[NPea]

Lookat a cable calculator and also work out your loads. If you are just feeding 12v you might be ok but if going to an invertor then 10mm could be inadequate, and yes battery close to the battery.

Cable Size Calculator - Cable sizing and selection | 12 Volt Planet

Cable Size Calculator - Read our guide to selecting cable of the correct type and size for your automotive, marine or leisure wiring application. Auto and Marine Electrical Components from 12 Volt Planet

www.12voltplanet.co.uk

 

[Figaro]

Only that 10mm² isn't a huge cable, but if they go onto existing cables they may already be fused and at a smaller or larger rating.

There is a factory fit Hymer 50amp fuse that was next to the leisure battery, but now 700mm away.
I'll get one of those terminal fuses recommended by @autotrader

 

[Figaro]

Lookat a cable calculator and also work out your loads. If you are just feeding 12v you might be ok but if going to an invertor then 10mm could be inadequate, and yes battery close to the battery.

Cable Size Calculator - Cable sizing and selection | 12 Volt Planet

Cable Size Calculator - Read our guide to selecting cable of the correct type and size for your automotive, marine or leisure wiring application. Auto and Marine Electrical Components from 12 Volt Planet

www.12voltplanet.co.uk

Only 12v loads, no inverter

 

[autorouter]

I take it the fuse part is the plastic block with the rating on ?
Are replacements readily available ?

Probably hard to find in garage shops, but available at the places that sell the big fuses like Mega and Midi fuses. The fuse is in a cubic block. MRBF = Marine Rated Battery Fuse

Link Fuses (Mini/Mega/Strip) | 12 Volt Planet

Midi, mega and strip link 'power' fuses for higher current automotive & marine applications. Available in various ratings up to 250A.

www.12voltplanet.co.uk

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[Lenny HB]

The existing battery cables are probably a little smaller, I didn't really take a lot of notice.
Is it important ?

When wiring Lithium's should wire each battery to a buss bar with cables exactly the same length and size & individually fused..

 

[Insider]

Blue Sea do a battery mounted fusing system(single or dual) that is easy to fit and very safe as you can't get any closer to the battery terminal. Be aware you also need to buy the fuse as well. I used the dual version and fused 150A directly to my invertor and 80A to the bussbar for the reset of the camper. Not cheap but top notch stuff.

Blue Sea Systems 5191 MRBF Terminal Fuse Block 30-300A

Space-saving, ingition-protected MRBF 5191 fuse block for high amperage circuits such as DC main feed, inverter, windlass, bow thruster etc. 58VDC, 300A rated.

www.12voltplanet.co.uk

 

[berni109]

If you go the mrbf route get yourself some spare fuses. Probably never need them but you won't find them in many places if you do.

 

[Figaro]

When wiring Lithium's should wire each battery to a buss bar with cables exactly the same length and size & individually fused..

I've only got one battery and no inverter, what's the advantage in wiring to a busbar please ?

 

[Lenny HB]

I've only got one battery and no inverter, what's the advantage in wiring to a busbar please ?

I thought you were fitting a 2nd Lithium.
A Busbar still has the advantage of making multiple connections easier.

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[Figaro]

No just the one seat base 230 that doesn't fit in the seat base.
I wish I'd gone for the 280 now it's having to go under the bench.
Ah well