Amp size for 2 lead acid batteries

[mtt04]

We are adding another battery to our forestry camp setup. (2 batteries now)

It's 12 volt and we are adding another to make a parallel Battey bank for more storage.

They 120AH each. Any idea what inline fuse size would be between the controller and the batteries ?best?

Also wire size recommendations.

They are attached to a 40A pwm charge controller.

Thanks

 

[Craig]

Well the most you will get into the batteries from PWM is 40 so I would use a 50 amp fuse.

 

[mtt04]

Awesome thanks
We were gonna use 0 gauge but I thought I would check with you guys.

It's got a 40 amp now.

 

[HighTechLab]

What are you powering with the batteries? First figure out what the load is, then size your wire appropriately, then size your fuse based on the wire and load. If you have multiple things connected (E.g. inverter, PWM Controller, etc.) that have different amp requirements, you may need multiple fuses.

I suggest you read this post below as this is covered pretty extensively in the electrical code and can be difficult to grasp:

How to know what wire to use

Selecting the proper wire gauge can be tricky. In the US, the National Electrode Code (NEC) specifies the rules around wiring including gauge, grounding, and even color. For the most part when you need wire for inside or to be buried underground you'll figure out the distance and number of...

www.diysolarforum.com

^^^^^^This thread should be pinned^^^^^ @Will Prowse

 

[Craig]

What are you powering with the batteries? First figure out what the load is, then size your wire appropriately, then size your fuse based on the wire and load. If you have multiple things connected (E.g. inverter, PWM Controller, etc.) that have different amp requirements, you may need multiple fuses.

I suggest you read this post below as this is covered pretty extensively in the electrical code and can be difficult to grasp:

How to know what wire to use

Selecting the proper wire gauge can be tricky. In the US, the National Electrode Code (NEC) specifies the rules around wiring including gauge, grounding, and even color. For the most part when you need wire for inside or to be buried underground you'll figure out the distance and number of...

www.diysolarforum.com

^^^^^^This thread should be pinned^^^^^ @Will Prowse

He was asking between PWM and battery not load side , I'm pretty sure . The load size would be a completely different issue.

 

[mtt04]

He was asking between PWM and battery not load side , I'm pretty sure . The load size would be a completely different issue.

Yeah it's just 3 - 5 watt LED DC lights. We have inverter for a few ac things. Very vary basic.

Thanks

 

[mtt04]

What are you powering with the batteries? First figure out what the load is, then size your wire appropriately, then size your fuse based on the wire and load. If you have multiple things connected (E.g. inverter, PWM Controller, etc.) that have different amp requirements, you may need multiple fuses.

I suggest you read this post below as this is covered pretty extensively in the electrical code and can be difficult to grasp:

How to know what wire to use

Selecting the proper wire gauge can be tricky. In the US, the National Electrode Code (NEC) specifies the rules around wiring including gauge, grounding, and even color. For the most part when you need wire for inside or to be buried underground you'll figure out the distance and number of...

www.diysolarforum.com

^^^^^^This thread should be pinned^^^^^ @Will Prowse

Yeah thanks Will. It's a rough country forestry camp with a few rv DC lights. Less than an amp or two

 

[HighTechLab]

He was asking between PWM and battery not load side , I'm pretty sure . The load size would be a completely different issue.

Missed those couple words, whoops ?

 

[eddie1261]

They are attached to a 40A pwm charge controller.

Multiply that by 1.25. 50 amp fuse.

 

[mtt04]

Multiply that by 1.25. 50 amp fuse.

Thanks Eddie

 

[mtt04]

On another note. Since we are gonna add another 12v 130AH battery I'm curious about battery cabling.

Total is 260Ah.

We have a crapload of 2/0 welding cable here in the shop. Would this work between the batteries or is strands an issue?

Welding cables have far more strands than typical battery cables.

Does anyone use welding cable for battery connections?
It's whitetail season soon and my workers are getting cranky. So I have to get moving
Thanks in advance