Shunts

Bill 112

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I have an Aims 12v 3000 watt pure sign wave inverter/charger installation diagram shows a DC shunt between the inverter and the battery on the neg. cable. It does not show the amperage of the shunt. Anyone know what it should be rated at ??? It also shows breaker or fuse inline on the positive line...also no value given for it.
 

cosmicosmo4

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3000 watts at 12v is 250 amps. The inverter is 90% efficient so that bumps it up to 278 amps. Usually it's prudent to size fuses about 20% larger than your expected max load, or 20% smaller than the safe current for your wiring, whichever is lower. You haven't told us anything about your wiring, but based on the loads, I'd fuse at 325 amps. Sizing the shunt for the same would work fine.
 

Short_Shot

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3000 watts at 12v is 250 amps. The inverter is 90% efficient so that bumps it up to 278 amps. Usually it's prudent to size fuses about 20% larger than your expected max load, or 20% smaller than the safe current for your wiring, whichever is lower. You haven't told us anything about your wiring, but based on the loads, I'd fuse at 325 amps. Sizing the shunt for the same would work fine.
Is it 90% efficient at 3000w though?

Even the victron units are only 86% at full load.

This bumps your figures up a bit.
 

mikefitz

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diagram shows a DC shunt between the inverter and the battery on the neg. cable.
This is optional should you wish to monitor the current. typically the shunt will be rated at 500 amps.
It also shows breaker or fuse inline on the positive line...also no value given for it.
As suggested at full power the inverter will pull approaching 300 amps, nearer 300 amps with lead acid batteries a little less with lithium.

The inverter will be wired with AWG4/0 cable and fused at over 300 amps (stock values are 300, 350 or 400 amps).

Mike
 

Will Prowse

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Typically shunts are sized at 60% of their max current capacity.

They get get really hot if you pull their full current in a continuous duty fashion.

So a 500A shunt can safely carry 300A all day long without issue. It can handle and measure surges up to 500A, but the continous current should be 60%.

A 500A shunt should work given the current figures above. Just ensure you use the proper thickness of conductor.
 

Bill 112

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Jul 28, 2021
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Tks for all the help. I have a 500 amp shunt laying around.
As far as the wiring ...this is a new install on my new camper.
So wiring can be whatever I need. Thanks to Will and watching
about 200 hrs of his youtube videos...I bought 3 200 watt 12v
solar panels, a 40 amp 12v Epevers SSC, an Aims 3000 watt 12v
inverter/charger, and finally 2 SOK 12v 206ah Lithium batteries.
So I am trying work out the putting all together part. Thanks so
much for your videos Will.
 

Bill 112

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Thanks everyone for all the help. I have decided that since I already have the 3 ...200 watt panels...and i'm getting the 2 ...206 ah Lithium batteries today ...and planning on getting 1 more 200 watt panel and 2 more 206 ah lithium batteries .....I just went ahead an bought another epevers solar controller...this time I got a 100amp 12v controller. Think that will solve all my problems...lol at least I hope so.
 

Bill 112

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So what do you think Will... I value your input so much. A 300 amp fuse between the battery and my Aims 12v 3000 watt inverter charge. And what size fuse between the battery and the knew 100 amp Solar Controller. I have the Mt 50 for the controller and the Aims Inverter charger has remote LCD monitor. On the install diagram I don't see a smart shunt for either one..... what do you think ????? Oh by the way, I'm going to use 4/0 wire
between the 2 ..200 ah SOK batteries and then AWG 6 between the controller and the batteries and to run to my fuse/breaker panel. Sound good...???
 

Will Prowse

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So what do you think Will... I value your input so much. A 300 amp fuse between the battery and my Aims 12v 3000 watt inverter charge. And what size fuse between the battery and the knew 100 amp Solar Controller. I have the Mt 50 for the controller and the Aims Inverter charger has remote LCD monitor. On the install diagram I don't see a smart shunt for either one..... what do you think ????? Oh by the way, I'm going to use 4/0 wire
between the 2 ..200 ah SOK batteries and then AWG 6 between the controller and the batteries and to run to my fuse/breaker panel. Sound good...???
You need 2 gauge minimum for that solar charge controller.

4/0 is good for inverter.

Yes smart shunt is easy to install. Just throw it on the main negative supply conductor on the battery bank. It comes with a nice manual with easy to follow pictures. You can put the shunt on at any time very easily.
 
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