I am powering a ROV from a 4S LiPo battery (12.0 V minimum, 16.8 V maximum). The resistance of the battery is 36 mΩ, so that a maximum current of 470 A can flow through a short-circuit. In order to avoid risk of fire, I would like to implement short-circuit protection. The machine draws a peak current of 100 A (with a safety factor of 1.2 applied). Therefore the short-circuit protection device must trip at a current between 100 A and 470 A. I have been unable to find fuses that are rated at 12 V and a suitable Amperage. I have found the following product, intended for caravans and boats:


But I am unable to find a data sheet that confirms its specifications and timing. Could anyone please advise me whether a fuse or alternative circuit breaker for this application exists, and if so, if it would be sufficient to avoid damage to the vehicle?

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    \$\begingroup\$ I have been unable to find fuses that are rated at 12 V and a suitable Amperage Hmm, yet when I Google for "100A fuse" I get pleny of hits. Personally I would prefer a fuse as I consider a fuse to be more reliable (to break) than a circuit breaker in the event of an overcurrent. Circuit breakers for mains voltage have (require) all kinds of safety markings on them, the breaker you link to has none and that worries me. \$\endgroup\$ – Bimpelrekkie Mar 19 '19 at 12:08
  • \$\begingroup\$ You're not looking hard enough. A fuse with a rating above 16.8V will be fine. A quick Google quickly found a 32V 100A fuse from Littelfuse. \$\endgroup\$ – Simon B Mar 19 '19 at 14:54
  • \$\begingroup\$ @Bimpelrekkie I couldn't (and still can't) find a fuse that is rated for 100+ A and between 12 - 16.8 V, could you please link me to a product that you think meets that specification? I think I have misunderstood the importance of voltage rating here. \$\endgroup\$ – jholzer Mar 19 '19 at 15:32
  • \$\begingroup\$ @SimonB Could you please clarify what the purpose of the voltage rating of a fuse is? I think I haven't understood something basic. \$\endgroup\$ – jholzer Mar 19 '19 at 15:36
  • \$\begingroup\$ Farnell: uk.farnell.com/c/circuit-protection/fuses-fuse-accessories/… (32 models) Ebay: ebay.co.uk/sch/… more than 4000 hits. Are you specifically looking for 12 -16.8 V fuses? There is no need for that. Any voltage larger than 16.8 V will be OK. I challenge you to find a fuse that cannot handle 16.8 V. 16.8 V is so low, almost any fuse can handle that and at 100 A all of them will. \$\endgroup\$ – Bimpelrekkie Mar 19 '19 at 18:09

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