Sorry if this has been covered but I want to know asap. The jaycar guy just sold me a 20amp circuit breaker for my dual battery setup. My maximum draw should only be around 15amps ( with a couple of lights and a fridge ). I was about to put this between the isolator and the aux battery, but I see that the isolator is 140amp. Will a 20amp circuit breaker be big enough to allow the aux battery to charge ? Won't my alternator's charge be too much for it and trip it constantly ? He told me to put it as close as possible to the isolator also. I think that part is right.
Cheers for any info. Turbz.
Notice: We request that you don't just set up a new account at this time if you are a previous user.
If you used to be one of our moderators, please feel free to reach out to Chris via the facebook Outerlimits4x4 group and he will get you set back up with access should he need you.
If you used to be one of our moderators, please feel free to reach out to Chris via the facebook Outerlimits4x4 group and he will get you set back up with access should he need you.
Recovery:If you cannot access your old email address and don't remember your password, please click here to log a change of email address so you can do a password reset.
circuit breaker, what size ?
Moderator: -Scott-
The current it will carry is more a function of your charging system, the battery and the setup.
Although your isolator is rated for 140A it cannot carry more than the alternator can generate.
Your alternator may be rated for a large current, but it is unlikely to deliver that to your second battery.
A 20A breaker is rated to carry 20A indefinitely - 21A may take an hour to make it trip, it may carry higher current for a minute or two.
Personally, I would've selected higher rating (I have a 60A fuse) - but, as you've now got it, run with it and see how it goes.
Cheers,
Scott
Although your isolator is rated for 140A it cannot carry more than the alternator can generate.
Your alternator may be rated for a large current, but it is unlikely to deliver that to your second battery.
A 20A breaker is rated to carry 20A indefinitely - 21A may take an hour to make it trip, it may carry higher current for a minute or two.
Personally, I would've selected higher rating (I have a 60A fuse) - but, as you've now got it, run with it and see how it goes.
Cheers,
Scott
Hi Turbz, what type and size of an auxiliary battery are you going to be charging.
I find a 30 amp circuit is about right fo 90% of single auxiliary battery set-ups.
Your 20 amp circuit breaker will handle around 30 amps for about an hour and a 30 amp will handle about 45 for an hour.
There’s a lot more to it but let us know your battery details and I’ll give you some ideas.
As for the circuit breaker needing to be close to the isolator, not so, it should, for safety reasons, be as close as practical to the battery.
Cheers.
I find a 30 amp circuit is about right fo 90% of single auxiliary battery set-ups.
Your 20 amp circuit breaker will handle around 30 amps for about an hour and a 30 amp will handle about 45 for an hour.
There’s a lot more to it but let us know your battery details and I’ll give you some ideas.
As for the circuit breaker needing to be close to the isolator, not so, it should, for safety reasons, be as close as practical to the battery.
Cheers.
2007 TDV8 Range Rover Lux
2009 2.7 Discovery 4
2009 2.7 Discovery 4
Interesting. My aux battery is a 75 amp hr. Total amps going to be used from that aux bat is no more than 15amps/hr ( that is including an initial 5-10amp spike from the fridge starting up, and 2 spotties that get turned on every now and then. )
As long as the 20amp breaker can handle the charging system ( 55amp alt ) it should be ok. Fridge uses like 2.5 max and 2 50watt spotties would use ( 110/12=9.2amps ) 9.2 amps ?
I guess I can just try it. Whats the easiest way to check amp draw ? Can you buy gauges that show current draw from a battery?
Cheers. Turbz.
As long as the 20amp breaker can handle the charging system ( 55amp alt ) it should be ok. Fridge uses like 2.5 max and 2 50watt spotties would use ( 110/12=9.2amps ) 9.2 amps ?
I guess I can just try it. Whats the easiest way to check amp draw ? Can you buy gauges that show current draw from a battery?
Cheers. Turbz.
Hi Turbz, with that small a load, you shouldn’t have any problems but if the loads do go higher, the circuit breaker will simply trip and no harm done.
As for measuring amps, for currents up to 10 amps, a $10 multi meter will do the job but for anything over 10 amps probably the cheapest way to go would be a simple automotive amp meter, like what you can get at places like Supercheap Autos.
Cheers
As for measuring amps, for currents up to 10 amps, a $10 multi meter will do the job but for anything over 10 amps probably the cheapest way to go would be a simple automotive amp meter, like what you can get at places like Supercheap Autos.
Cheers
2007 TDV8 Range Rover Lux
2009 2.7 Discovery 4
2009 2.7 Discovery 4
Who is online
Users browsing this forum: No registered users and 0 guests