Pre-Order Discussions

I asked the question too he said they are copper, well I asked for the 6K but from how he said it sounds both inverters are getting nickle covered copper terminals.  Here is a link to the forum post I asked about them. 

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2 hours ago, AquaticsLive said:

Yeah would be handy if they could read a CAD drawing there is no language barrier with those normally.  I ordered a cabinet from China and they got it perfect first try so its possible just hard to find. 

Ha, if only 😉

I do send them not just CAD drawings & renderings, but also actual CAD files (DXF, etc.) which require zero translation effort to send to the cutting machines.

Some things come out perfect the first time (like the heatsinks).  And others...well...don't.  Busbar manufacturer didn't use the DXF cutting file I sent--they recreated their own, but misread a measurement that wasn't too clear on my PDF drawing...resulting in a busbar that was about 55mm too long.  I'm not blaming them per se, as the measurement clarity issue was my fault, but still...I had provided a ready-made DXF cutting file....

1 hour ago, dickson said:

IT take a while for the worker to  figure why no  wires  inside  and  PJ  will probably  copy  in the  future  for their  PJ inverter . 

Nope, not gonna happen.

Wires are FAR cheaper than the custom busbars.  I'd still be using wires if the resistance of the busbars wasn't design critical.

1 hour ago, Carlos said:

One question are the battery terminals made of tinned pure copper like the bus bars or are they brass. It seems that all the battery terminals coming from China are all made of of brass.

Terminals SAY they're pure copper...but I have some here.  <a contenteditable="false" data-ipshover="" data-ipshover-target="/profile/16-carlos/?do=hovercard" data-mentionid="16" href="/profile/16-carlos/" rel="">@CarlosDo you have a quick test to determine if something's copper or brass?  (I could probably Google it...)

@Sid one way is to do a resistance test but best way is to cut one in half. Brass is no good only conducts 28% of what pure copper does. Pure copper bar looks way different that brass. 
Brass is way cheaper than copper as it’s an alloy not pure like copper. You are correct that sticking to wires is way cheaper that pure copper buss bars also bending copper bars is expensive compared to crimping wires.

If you google image brass vs copper pure copper will be more of a red orange color and brass will be more of a yellow gold color. Best way is to cut in half.

I am sure there is a fancy way to figure it out. 

Old school ways.  One way is file down the edge coating and look at the color I have a set of the plastic and metal pieces on a large key ring so may want to buy one of those little sets they are handy.  Brass is much brighter yellow.  Well the other that I know of the real world heat testing the brass ones will get warmer faster. Cheap brass is about 1/4 as conductive as copper, so they will get fairly warm with 100 Amps so doesn't take a whole lot before you notice the problem.

The ones that I got from Amazon looked really nice but with a quick scratch it was obvious and returned them saying false advertising wish Amazon would actually remove the bad products.  

I ended up making my own but that won't work commercially. I have a lathe and 3D printer.  Well could have the factory make them.  Copper is not cheap right now so it won't be cheap no matter how you get them.  I guess that could be a way to tell too if they are too cheap they are most likely fake.

Well, it does look like they might be (ahem) brass.  I guess I got duped a bit, thought "that looks nice", plus seeing listing stuff saying their terminals were so much better than the competition.  But right there on the listings I picked...says brass.  Didn't even think to check that.

I did find a different listing that said T2 RED COPPER instead of brass--costs ~$2.50 more than the brass ones.  Problem is, it's a completely different design, and I'd have to redesign the busbars to fit...

Sorry for the bad news as I had a feeling that this was going to happen. I have not found one supplier in China that sells pure copper battery terminals. Also for the 12k it’s even more of a problem not so much for 48v as only 300 amps are going to pushed through them but a big problem for 24v system. With 24v systems you are pushing 600 amps through those buss bars and battery terminals but you already know that. 
 

I am just glad you caught it on time before committing to a production run. As for the terminals it must be done custom just like your buss bar design you don’t have any other choice unless you want to go back to wires and use Anderson 350 connectors then you would have to limit the 12k inverter to only 48v systems.

From memory T2 red copper is pure copper it’s just China’s version. Be careful as many sites list it as T2 copper and it is not when you receive it. I have searched and contacted many companies and they all told me that they can custom manufacture it minimum order was like 1000 units.

The problem with brass is that it sucks as a conductor 28% of what copper can put out with same size. Also brass is going to put a lot of resistance and heat. You have to go with pure copper and you will have to also ditch the 24v option for for the 12k and the 12v option for the 6k

300 amp buss bar is not that thick however 600 amp buss bar is and will be very expensive that same with the pure copper battery terminals.

Is it even worth using copper over just using Aluminum?
Aluminum is far more conductive than Brass. And costs a lot less than copper. Pretty sure it costs less than brass too, actually.

There's good reason we use it on power lines.

Not to mention oxidation...

Aluminum would work too however you need to select the correct alloy which from memory is about 78% as conductive as copper. Still it’s a lot better than fake copper AKA brass which is 28%.

The old PJ one are Aluminum so not too bad, but I think the plan was to improve safety.  The PJ ones you need all 4 to handle the amps for 12V.  I tried using just two of them at 225 Amps the terminals were over 300F.  So I use all 4 now they still get to about 140F but that isn't too bad.  I am in the process of switching all my other connections to copper to reduce the heat.  Any heat you can reduce is a ton of energy savings. 

Aluminum used for bus bars is about 50% conductivity of copper, the version that they use for aluminum bus bars is an alloy.  100% aluminum is a little better, but the threads are too weak.  Googling 100% aluminum its 61% of copper, but the alloy they use is a bit less.

Aluminum terminals...that'd be pretty soft for snugging down some big bolts into.

I'll just have to see if I can find copper terminals...that's what I thought I was getting.  The 12kw terminals are very simple: a 30mm diameter cylinder with an M10 thread down the middle (think it's 45-50mm long).  Should be very easy to do in copper.

Looked at a listing diagram I downloaded, and the title indicated "Thickened Square Copper Nose"...I didn't look further down to see the actual composition material.  "H62 BRASS".  That indicates a mix containing of 62% copper, and 38% other materials.  I have not been able to find specifics as to what the electrical resistivity of that mix is.

That is normal brass.  Brass is a copper and zinc alloy.

It’s been a long time since I have used aluminum as bus bars as I always use copper. For marine use if I do a custom install I always use copper tinned buss bars.

Brass has been tested to be 28% of copper conductivity which is really bad.