This Busbar config ok?? (Pic included)

[johnnysolar]

This is about the busbar placement and configuration. Hi all, I'm doing random configuration before design. I like this best. Two 6500ex with three batteries. *Obviously not mounted to the batteries* but a few inches in front on a bar/casing/etc, please share your thoughts on this configuration of the busbars that are (checks notes)...... Brand name "mofeez" from Amazon. While I know it's a bit of a pain to remove the batteries.... once set they don't get removed often and when they do this is less than 20 mins more of disassembly and 30-ish mins more reinstalling/torquing/etc.

 

[DIYrich]

Batteries should connect to large bolts, not small ones.

 

[johnnysolar]

Batteries should connect to large bolts, not small ones.

While I get that by looking at it, it's severely oversized on the large lugs. The small ones provide a proper torque and there is lots of contact. I have larger ends but they are for 2/0 and they fit those large lugs but not the battery ?. It's worth noting the screws that are flush mounted on the very ends are the ones fastening the plastic and the busbar together, not the small ones I have connected here.

 

[Warpspeed]

Current flows through the copper lugs, not the bolts.
Provided the bolts are done up REALLY tight, and there is good contact, should be fine.
If its not, you will know, because the lugs might begin to run a bit warm.

 

[johnnysolar]

Looking into it, I can get 8ga 3/8" cable terminals so ima do that sooner than later. Man, I had not considered it that deeply because the contact is actually quite good, but this will just give that bit more contact and far more squeeze. Tks for sharing all the thoughts, all. I'll follow up with pics when progress is made.

 

[Warpspeed]

I suppose it depends what you are doing with this.
If there are to be massive short term discharges, something more robust might be a good idea.
If all those stored amp hours are mostly for hours rather than amps, should be o/k.

 

[Rocketman]

The mofeez bus bar is brass - a copper bus bar is much better. Brass has more resistance. If you notice the batteries are not charging equally that may be part of the issue.

Good Luck

 

[Steve_S]

Do watch the above video, it is pretty self-explanatory.
Ideally, a Busbar setup with 5/16 bolts is optimal for our types of installations.

 

[Will Prowse]

I think it's fine if you torque to proper spec.

 

[Warpspeed]

Its mostly about clamping pressure.
Small high tensile bolts and a steel washer will beat larger "soft" bolts that have a very coarse thread.

 

[Will Prowse]

Batteries should connect to large bolts, not small ones.

Every server rack bus bar being sold today has the same size screws to connect batteries to it. I would argue that in this configuration, the large bolts are better for inverters. Each battery is pulling a max of 100A. An inverter will pull a lot more.

 

[rhino]

Bigger issue would be if it is brass as @Rocketman suggested. Brass is about 1/4 the conductivity of copper.

 

[Will Prowse]

I would put large load across bus bar diagonally and put clamp meter on each battery supply conductor. Equal length conductor, so I think they will feed current equally. Those washers hold well when they are torqued to spec.

 

[Warpspeed]

Load her right up, and start measuring millivolt voltage drops around the whole system.

Anything that is truly awful will soon stand out.

Nothing wrong with using lower cost lower performance materials (aluminium, brass, copper) as long as there is enough of the stuff to provide a low enough resistance. We do not always need to make absolutely everything out of solid silver !!

 

[rhino]

Load her right up, and start measuring millivolt voltage drops around the whole system.

Anything that is truly awful will soon stand out.

Nothing wrong with using lower cost lower performance materials (aluminium, brass, copper) as long as there is enough of the stuff to provide a low enough resistance. We do not always need to make absolutely everything out of solid silver !!

It looks like this busbar or this one both of which state it is brass. Yes, you can use brass but as Steve_S's link to that video shows which measures them they are ridiculously undersized for claiming to handle 250A.

 

[Warpspeed]

Chinese amps are much smaller.

 

[johnnysolar]

Thanks again all for the input. I did notice it's brass when I bought it. What I am more closely seeing now is the claim (in the description) that its 20 amps max per connection for 1 min, which contradicts the overall max. I foresee a busbar upgrade soon. This will get the system going for now. Thanks again guys, lolz from some of the posts. I appreciate the video link too.

 

[Steve_S]

There are alternate methods to interconnect rack-style batteries.
See here for 3 examples, maybe Will can do evaluation & tests etc...

Request fo Will Prowse: Video/Evaluation of best way to interconnect "Rack" battery packs.

Good Day @Will Prowse , Recently some questions have been posted to me that would make for a really Good Video & Guide regarding interconnecting "Rack Style" battery packs. We see several variations with their connectors, to busbars or "daisy chained" cabling and so on... Interestingly...

diysolarforum.com

 

[johnnysolar]

There are alternate methods to interconnect rack-style batteries.
See here for 3 examples, maybe Will can do evaluation & tests etc...

Request fo Will Prowse: Video/Evaluation of best way to interconnect "Rack" battery packs.

Good Day @Will Prowse , Recently some questions have been posted to me that would make for a really Good Video & Guide regarding interconnecting "Rack Style" battery packs. We see several variations with their connectors, to busbars or "daisy chained" cabling and so on... Interestingly...

diysolarforum.com

on my limited knowledge, I think the daisy chain and busbars connecting to the batteries directly subject the battery terminals to far more amperage than they are designed for, yeah? This doesn't quite have to be tested to be known. but, in a low power consumption situation those ways may be fine.

 

[John Kelly]

Thanks again all for the input. I did notice it's brass when I bought it. What I am more closely seeing now is the claim (in the description) that its 20 amps max per connection for 1 min, which contradicts the overall max. I foresee a busbar upgrade soon. This will get the system going for now. Thanks again guys, lolz from some of the posts. I appreciate the video link too.

Those look similar to my bus bars from Current Connected.... in the description the small screws you have attached to on those are only rated for 20amps, the bolts are rated much higher.