home style breaker for ebike use

[rguy56]

I have a 500w hub motor and 48v sla batteries, and I thought a good way to combine switching and controller protection would be to use a panel style breaker between the batteries and controller...

So, I put in a 15 amp breaker, and it seems to blow randomly at less than high throttle loads... I'll just be merrily humming along at modest speed, and the thing blows.

Does anyone know if I should simply match the amps to the controller limit? Does a circuit breaker not care if it's handling 48 or 110 volts? Or is what I'm doing a waste of time, and should I just go with an automotive type blade fuse or some such thing?

Thanks,

Bob

 

[Rassy]

Wilderness Energy sells an optional breaker to use between the battery and controller (so you don't see the spark) and I am using several of them with 35 amp controllers. I also use 40 amp fuses, which have been blown several times, but the breakers have never tripped. I like the breakers because it saves having to unplug stuff to turn everything off. There is no indication on the breakers as to their rating, but others on this forum have suggested a breaker intended for DC use will be different than one made for AC use.

 

[Link]

I use a 50A house breaker on my stuff (rated up to 10,000A fault). It's never tripped with my 30A or 40A controllers. What's your controller rated for? It could be just drawing too many amps for the breaker.

I use fuses and the breaker, actually. Can't be too safe.

 

[rguy56]

This is the cheapest imaginable controller, Chinese, and the only information I have on it is 48v., 500w, and low voltage cut-out at 41v.

I'll check out the wilderness energy stuff. Thanks.

Bob

 

[RLT]

EDITED:

Dang, ZapPat was absolutely right, that IS only a switch.
I'm getting real tired of BG micro's less than accurate, to absolutely misleading descriptions.

Not the first time I've been stung by something they sold me, but this time it could have contributed to a disaster.

 

[ZapPat]

This is what I'm using now. So far, it is working perfectly. and you can't beat the price:
http://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=8954

Watch out, RLT, this "circuit breaker" sold by BGMicro is NOT a circuit breaker at all, just a regular switch! I bought four of these a couple years ago and only realised they were not circuit breakers when they were not triping when pushed over 100A. I bought a few real 20A DC rated circuit breakers (25A trip) from them at the same time, and these work great, even when connected in parallel to get 50A. Here they are, still there:

BGMicro circuit breaker

A great deal, specially for the mad scientists among us!

PS: While BGMicro have some good deals (like this breaker), they also sell stuff you could get cheaper elsewhere, even at digikey (specially the FETs!).

 

[TylerDurden]

Car-audio circuit breakers are cheap and designed for DC.

 

[fechter]

15 amps is too small most likely. I would use at least 30 amps.

I've used a number of different circuit breakers on my scooters. The trip point is not very accurate, but they have done their job on several occasions. Normally you'd want the breaker for protection against gross faults anyway, so accuracy is not a big deal. Just size it so it doesn't trip at the controller's maximum draw. A short will trip it and prevent any large fires.

On my Zappy, I used a pair of automotive self-resetting circuit breakers in parallel. The largest ones I could find at the auto parts store were 30 amps and I wanted 60 amps so I soldered two together. I wouldn't recommend these for anything over 48v.

 

[Lessss]

I use a 40amp breaker as the 20 aMp fuse I had in the bike was getting a tad warm on use. The 40 amp breaker hasn't tripped yet.
Also note most controllers regulate their own amp usage.

 

[rguy56]

You guys are brilliant. I spent hours in stores, automotive shops, and searching on google, and I was no further ahead...

Now, I really know some great options!

Thank you, thank you, thank you.

 

[RLT]

EDITED:

Dang, ZapPat was absolutely right, that IS only a switch.
I'm getting real tired of BG micro's less than accurate, to absolutely misleading descriptions.

Not the first time I've been stung by something they sold me, but this time it could have contributed to a disaster.

We need a cheap way to test circuit breakers and fuses WITHOUT putting our battery packs, controllers and motors at risk.

 

[vanilla ice]

I've got one of those car audio breakers. Theres also some neat stuff for multiple battery systems on big trucks and RVs.

 

[RLT]

Car-audio circuit breakers are cheap and designed for DC.

My turn for a warning, although it is the opposite of ZapPat's to me: I was using one of those... A 100A rated one...which would trip, quite reliably at about 65A.

Maybe because they are intended only for 12 V systems?

Was going to replace it with a 140A one of the same type to see if it would handle my amperage needs but it was mechanically defective, so I gave up on that idea.

Seems to me, they ought to rate circuit breakers for Wattage, rather than amperage

 

[disadvantage]

I have questions on this topic.

The only place I know of to get these "car-audio circuit breakers" is PowerWerx.com:
http://www.powerwerx.com/product.asp?ProdID=3323&CtgID=1774

Where else can these be purchased online?

I like the Buss circuit breaker shown above. I read somewhere it can be used as an on/off switch. I assume the red button cuts the power, and turning the lever turns the power back on.

Also, do we really need magnetically activated circuit breakers?
Or is thermal activation quick enough?

Thermal breakers are cheaper than magnetic, but magnetic are faster reacting. A faster circuit breaker might help protect our expen$ive controllers and batteries better.

TYVM for bringing up this topic and sharing.

 

[RLT]

The only place I know of to get these "car-audio circuit breakers" is PowerWerx.com:
http://www.powerwerx.com/product.asp?ProdID=3323&CtgID=1774
Where else can these be purchased online?

There are a couple of eBay stores that sell them; Sorry but I don't have links or names for them.

I think that Scoshe and one of the other car audio manufacturers make them. The 100A and the 140A ones that I have aren't branded,----- I'd definitely go with the Buss brand though, In general, I have found their quality to be better.

I've also seen similar things at a couple of the online solar and wind power stores, and also at a marine (boat, not military ) supply store. and I think I remember seeing breakers for 24V systems at the marine supplies place. More expensive there though.... I think they were about $50-$60

And indeed that red button is pushed to open the circuit.

 

[TylerDurden]

found a few here:

http://www.cardiscountstereos.com/Accessories.asp?Catagory=AS&Sub_Catagory=CB

 

[RLT]

P.S.:
Thanks for potentially saving me from disaster on that switch sold as a circuit breaker, ZapPat.

 

[ZapPat]

P.S.:
Thanks for potentially saving me from disaster on that switch sold as a circuit breaker, ZapPat.

I'm happy to have been your guinea pig, RLT! Maybe you should thank the FET's that gave their lives in my lab though, since they are the ones who really let me know about BGmicro's misprint!

For anyone looking for a really heavy-duty DC breaker check this out @ 13$! 100A airpax DC breaker Be aware though that this thing is HUGE, about one pound heavy.

 

[rguy56]

So, I bought some BG micro breakers, and went from that original 15 amp home breaker to a 20 amp DC breaker from them.

Unfortunately, it's even worse for blowing. Pain in the a*s*s... The irony of the circuit breaker is that when you need the most power, "POP", you have no power.

Fortunately, I bought higher amperage breakers from them!

I'll swap it out tomorrow.

Bob

 

[marty]

I have questions on this topic.

The only place I know of to get these "car-audio circuit breakers" is PowerWerx.com:
http://www.powerwerx.com/product.asp?ProdID=3323&CtgID=1774

Where else can these be purchased online?

I like the Buss circuit breaker shown above. I read somewhere it can be used as an on/off switch. I assume the red button cuts the power, and turning the lever turns the power back on.

Also, do we really need magnetically activated circuit breakers?
Or is thermal activation quick enough?

Thermal breakers are cheaper than magnetic, but magnetic are faster reacting. A faster circuit breaker might help protect our expen$ive controllers and batteries better.

TYVM for bringing up this topic and sharing.

Look here to see lots of circuit breakers http://www.bussmann.com/pdf/383c094e-15c9-4c38-953c-6033b67204d0.pdf
See page 5
To see who sells? Search for part numbers with http://www.google.com/

 

[rguy56]

I'm using the bg micro d.c. breaker 50amp. (and cheap) recommended earlier in this thread now... and problem solved!!! You guys rock!!!

No more coasting to a stop just when I need power the most.

Bob

 

[thoxbui]

Maybe you guys can clear up something that I was told:

I was told that circuit breakers are not fast-acting enough to protect FETs and would put most controllers at risk.
Because of this, I usually put a circuit breaker with lower rating (say, 20amp) in series with a higher rated fuse (say, 30 amp).

The breakers I use is usually one of these:
http://www.electricscooterparts.com/circuitbreakers.html

The idea here is using the higher value fuse to protect the controller, and a lower value breaker to protect the battery from too high of a discharge rate (I use D size NiMH).

Comments?

Tho