An absolutely fuseinating question

[Ellis]

Hi all, am looking around for the various bits and bobs that we need to go LiPo, and naturally, we need fuses. The batteries we're getting can do 100a continuous and 150a burst. I figure a fuse in the region of 125a is suitable, or around there at least, but I am struggling to find one that is perfect. I would be easy and go for a 100a but I think, at least in Tormenta 2, we'll be blowing them constantly.

Where do you guys get your fast failing fuses that aren't typical sizes? The types are confusing (see what I did?), and it's a safety feature so, naturally, we want the right thing.

I suppose another question is whether you think a 125a (ish, +/- 10) is suitable for a 150a burst pack.

Thanks.

[mattsdragons]

http://uk.farnell.com/jsp/displayProduc ... price=true

Not sure if its any use but taadaa

[Ellis]

That's a slow blowing one mate, which I don't think will save any batteries.

[plargen]

if you go for a 100a midi fuse its rupture point is 200a

if its the same with other fuses then you probably want a 75a

[plargen]

found a 70a midi fuse

http://www.ebay.co.uk/itm/Midi-Fuse-70A ... 3cce163d85

[Ellis]

Tormenta 2 will definitely pull 70a at times, and something about pulling power through a fuse that will limit the performance of things, whilst getting hot and potentially blowing prematurely, doesn't sound ideal! But interesting though, if they reliably blow after a short burst of say 120a and not 70a then they may be an option.

Has anyone had any positive experience with putting several smaller fuses in parallel?

[razerdave]

I err on the side of caution. The fuse in Satanix is only 60A, reason being that its the continuous rating for my speed controllers. If my robot somehow draws 60A, then there is something drastically wrong and I'd rather sacrifice a fuse than almost £200 worth of speedos.

[Max]

I would say you want a normal 100A fuse as this will be fine with a burst of 150A like the battery is, but it will blow if you are drawing more than 100A for a longer period of time. You could also buy a range if fuses and expirment to see what is the lowest fuse you can get away with without it blowing in normal use.

[Mouldy]

blow times relative to fuse types can be found in 17th edition wiring regulations.

For automotive fuses i very much doubt tormenta will blow a 75a automotive style fuse....

In the wiring regulations book it talks about diversity of wiring, which can also be taken into account when building robots, your unlikely to stall all 3 of your motors at once, causing a fuse to blow....

Long story short ive got a 100a auto fuse in 720 which pulls over 300a... havent blown one yet.

[Ellis]

Right. It does make sense to buy some and just try them. Of course the likelihood of more than one motor stalling is very low, but for example the lifter motor is an unknown quantity, for all we know it's pulling bucket loads, as it is similar in scale to a s900.

Think we'll buy some 80a and 100a ones and see how we go!

Thanks all.

Also, fusetrating. I just needed to say that.