PS2DC Shunt

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Iceboxjar
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PS2DC Shunt

Post by Iceboxjar »

As we were hooking up our solar panels to the DC - Bus bar in our PS2DC we noticed that it looks like there is a shunt on the - branch between the battery cable and the cable to the inverter. can this shunt be used with additional equipment like a battery monitor?
Kent Osterberg
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My RE system: SMA Sunny Boy 2500 with eight Mobil Solar Ra 180 modules
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Post by Kent Osterberg »

The shunt is there for exactly that purpose.
Iceboxjar
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Another Shunt/Busbar question

Post by Iceboxjar »

The power from our solar array comes in on 2/0 wire we have the wire terminated into screw on lugs (ones with a set screw) one lug (the +) is attached to the Circuit breaker for the array and the other (the -) is connected to one side of the shunt in the PS2DC. however it has dawned on me that we connected it to the wrong side of the shunt if we are to use the shunt for a battery monitor the only catch is that the bolt on the other side of the shunt does not seem long enough with the battery cable and the bus bar connector to add the lug for the solar array. Can this bolt be replaced with a longer one or is there a better way to connect the 2/0 wire to the - bus bar? If the bolt can be replaced does it matter the compisition of the bolt (e.g. stanless, brass, other)? and also what is the size/thread of the bolt included with the shunt?

thanks,
Ken
Kent Osterberg
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My RE system: SMA Sunny Boy 2500 with eight Mobil Solar Ra 180 modules
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Post by Kent Osterberg »

There are a couple ways out of this circumstance:

1. Use a barrel splice to reduce the 2/0 wire down to 1/0 or #2 so that it will fit in the into the bus bar. Here's a link to one product, your local electrical distributor can probably get you a similar item.

2. Use a longer screw on the shunt. If you have two inverters already connected to the shunt, it's probably best not to go there with a third lug. I'd use a brass bolt to avoid thermal expansion issues. If you aren't fortunate enough to have a well stocked hardware store with brass bolts nearby, try the bolt from a ground rod lug (acorn nut). Many of those are the same diameter and pitch but 1/4" longer than the stock bolt.

You must have a very large PV array to be using 2/0 wire. Because of the difficulty of using 2/0 wire in the PS2DC and in the PSPV, you have to be really motivated to use 2/0 wire.
Iceboxjar
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Post by Iceboxjar »

Thanks for the info. We only have one inverter at this time but will have 2 in the future. the 2/0 wire was specified for the array wiring for 2 reasons

1. We have to run about 200 feet from the array to the system and

2. so we can grow from our current 12 EC-115 pannels to 24 or 36 and use the same wire.

I think I'll look for a longer bolt as we can easily get them in town.

thanks!
kevin
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Location: Nevada City, CA

Trimetric OK on shunt?

Post by kevin »

Just wondering if there are any gotchas with connecting a Trimetric onto the PS2DC shunt?
PS2 w/2 VFX3648s MX60 MATE HUB 2700W/PV
8 Absolyte IIP 100A29s
jkirkebo
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Re: Trimetric OK on shunt?

Post by jkirkebo »

kevin wrote:Just wondering if there are any gotchas with connecting a Trimetric onto the PS2DC shunt?
None, my system does exactly that. Just remember to set the Tri-Metric for the correct shunt size (500A).
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