Cheap Dual Battery Setup

[gshannon]

You are absolutely right - we talked about fuses, but didn't mention breakers.

I'm not sure they make breakers larger than 30A - I have 30A thermal resettable breakers in mine, located about 20mm from the battery (electrically, about 100mm from the battery post).

But Darren said:



and that's more than a 30A breaker can handle, so I went the fuse route.

If you know a source for higher capacity breakers (100A, even 150A or 200A) then let us know, because I'm sure some of us could find them useful!

Its my understanding that a circuit breaker will only trip out when the accessories are drawing more than what the breaker is built to handle, or if there is a short circuit somewhere.

I know anderson plugs are rated to handle 175 amps, but will aux accessories connected to a cars 12v system going to draw this much? Let alone 30 amps? I would much prefer having a 30A circuit breaker than a 100A fuse protecting my car and accessories.

 

[will]

I would much prefer having a 30A circuit breaker than a 100A fuse protecting my car and accessories.

Me too on the circuit breaker, as fuses can maintain double their rated amperage for 6 seconds. Therefore anything short of a dead short may not cause a 100A fuse to go.

 

[reel-sensation]

Circuit breakers are readily available up to 50amp. They are even available to replace blade fuses. That is they fit in the fuse holder.

You are absolutely right - we talked about fuses, but didn't mention breakers.

I'm not sure they make breakers larger than 30A - I have 30A thermal resettable breakers in mine, located about 20mm from the battery (electrically, about 100mm from the battery post).

But Darren said:



and that's more than a 30A breaker can handle, so I went the fuse route.

If you know a source for higher capacity breakers (100A, even 150A or 200A) then let us know, because I'm sure some of us could find them useful!

The Sure Power instructions specify either 50amp or 80amp depending on the length of wire and the amount of draw. The idea is it matches the maximum current draw and they only throw when there's a problem ie short circuit or severe overload. If you use a 150amp circuit breaker the damage could be done long before the circuit breaker activates.

Alan

 

[reel-sensation]

Your alternator is only 70 amps max.

Alan

 

[KraftyPg]

Factory Alt (in my 09 STX atleast) is 80A. But 80A is max so the chances of getting 80 when so much else is running as soon as the ignition is turned on is fairly slim.

 

[Leprechaun]

Factory Alt (in my 09 STX atleast) is 80A. But 80A is max so the chances of getting 80 when so much else is running as soon as the ignition is turned on is fairly slim.

Wow, the Thai trumps a Spain build, 120A in mine!

 

[KraftyPg]

That's why your economy is so bad, the Alt is too heavy

 

[Old.Tony]

I thought mine was 120A or 130A, not sure which. Let me check the Manuel.

For the YD25, it's a Mitsubishi A3TG2681ZE 130Ah and for the VQ40 it's a Hitachi LR1110-730 110Ah.

Page 44, SC.PDF.

 

[KraftyPg]

Yeah that would be right, I was thinking about something else when I wrote that post. When buying it took me 4 dealers to actually find out what size the alt was and the one response I did get said 80A.

When I put the isolator on I confirmed it was 130A thats why I went with the 100A Projecta and not the 150A.

 

[Old.Tony]

Only shame is the manual says (this is translated into English):

"In order to develop over 122A, you need to develop over 5,000rpm"

I've never, ever not even ONCE had mine that high. I'm not even sure it's safe to go that high in the diesel.

Just because it's rated to be ABLE to do it, doesn't mean that we're going to.

 

[KraftyPg]

Peak output figures are the main reason I've never been bothered enough to test mine at any rev range by the time you take out all the crap that's running when the ignition is on a 100A isolator that can peak at 130A short term is more than adequate for my liking.