48V system but 48V "parts?" sometimes yes sometimes no? Newbie confused

[cyberfed]

Hey folks,

As many of you know who read my posts I run several 48V rack mount style packs. Awhile back I learned (even though some large companies had it wrong) that you shouldn't use ANL style fuses since they are not rated for 48V, instead use their twin the CNN/ANN style fuse (or t-fuse) rated for usually 80VDC. All of that has been swapped out a long time ago.

I was looking and my bus bars say the same, rated for 600A 48VDC. Now I have used them in the past without issue, what exactly is the risk here of when a full pack lets say 56VDC is flowing through these bus bars? I noticed Blue Sea Systems only has one bus bar that is 70-80VDC and that is like their ultra mega super crazy bar. They have some rated at 1000A that are a giant block of copper and it says rated for 48VDC. So.....can you use them or not?

I could understand there could be a problem if you were running crazy high voltages (hundreds) through them, but does it matter at 53-58VDC? If it does then who exactly are those 48VDC bus bars targeting? 36VDC packs?

Just confused.

Cheers

 

[hwy17]

I believe the 48VDC Max products were aimed at 12V and 24V systems as is common in Marine applications.

You technically are not supposed to use them but I use them in my <60VDC system and I'm not worried about it.

 

[sunshine_eggo]

I'm just blabbering...

It may be a power limitation, i.e., whatever heat gets generated/dissipated at 600A/48V is the max. If you run under 600A, you could exceed 48V.

I'm with @hwy17 . I have a Blue Sea 300A/48V cut off switch on my ~55V battery that never sees more than 100A.

 

[wpns]

56VDC is flowing through these bus bars

Voltage does not flow through bus bars, current flows through bus bars. Voltage only cares about the gap between positive and negative, so that you can’t short them out and start an arc.

 

[hwy17]

Voltage does not flow through bus bars

Objection your honor, unnecessary theoretical linguistics.

 

[Robbert]

With regards to busbars 48v is fine as long as you stay well below the stated amperage.

However wrt fuses, that's different and you should get a fuse that is rated at 60v or higher.

 

[littleharbor2]

These are really well made 64Vdv max 300 amp bus bars. Nic price too.

300A 4-Stud Bus Bars - Distribution Block w/Cover - Red/Black

Designed to streamline and organize electrical connections, our high-performance 300A 4-Stud Bus Bars are suitable for a wide range of applications!

www.currentconnected.com

 

[blenderbender]

These are really well made 64Vdv max 300 amp bus bars. Nic price too.

300A 4-Stud Bus Bars - Distribution Block w/Cover - Red/Black

Designed to streamline and organize electrical connections, our high-performance 300A 4-Stud Bus Bars are suitable for a wide range of applications!

www.currentconnected.com

Perhaps a dumb question, but why would a single cost $20 and a pair cost $45?

 

[RussNM]

I dont now if he fixed it but single is $22.50 now AND these are brass
buss bars not copper.

 

[sunshine_eggo]

Brass is 28% as conductive as copper.

 

[littleharbor2]

$22.50 single. Isn't the rating what it is, 300 amps? If it were copper would it be 1000 amps or more?

 

[robbob2112]

Depends on the quality of the brass. Junk brass is 28% as conductive, best brass is around 78% as conductive.... the thing is you can't really tell which are which without a file or some other tests... the yr-1035 is at the edge of its limits measuring the difference with short pieces. You can run a known current and measures voltage drop as well.

I bought a bunch of the speedy metals 1/4" x 4" and 5" wide bars. I am going to cut it up to make bus bars as needed. Electrically separated copper verse generic copper so slightly better conductivity.

 

[cyberfed]

Thanks folks, I must say this thread generated way more responses than expected, but it makes sense. Yeah when it comes to fuses all of them are rated for around 80VDC (CNN/ANN style) t-fuses are usually 80VDC I think? I don't know I've bought so many of different amperages to match my different inverter sizes I've lost track. But yes all are greater than 60VDC.

I also will NEVER come close to drawing 100 amps. I think the most I will ever see is actually when the MPPTs do their magic I'll probably get to about 60 - 70 amps going to the batteries.


W.R.T the copper/brass discussion, I honestly thought about just for fun and to see if I could make something usefull looked at buying pure silver in a rectangle type shape and drilling holes for turning them into busbars. Silver isn't that expensive (I've been buying/selling silver for fun for years). Just because its the most conductive of the common metals. I thought about melting a few oz down and making bars, but then I realized 1. I'm not handy at all and I'll likely screw something up and burn the crap out of myself! 2. I have no way to melt silver other than buying a small blow torch and I dont know if that would work and 3. I have no molds so I gave up on that idea

Thanks all!!

-------stop reading here----below is a random rant----those who know me know what I'm talking about, read if you want-------

Shameless random plug for the Bi-facial Hyperion Solar panels 400 watt. The other day I got 1800 watts (for quite some time) out of a 1600 watt (4S) array. I know they are still new and all so they are going to perform as good as they can and slowly go down hill over the years but I was happily suprised when I saw that! 112% not too shabby, now I want to hit the documentations "max" of 25% gain haha, that's just one chunk of the PV array I'm running, the other half is so close to coming online. Over the xmas break, I got the ground rod into the ground, and ran the ground cable, waiting on the connector bits to attach them firmly to the panels. Outside Emergency disconnect box is done and ready. Inside the house I have everything nicely fitted to a 2ft x 4ft red cedar plank with all the inside disconnect switches, SCCs, fuses, busbars, automatic fire surpression, breakers, all nicely routed, custom sized/cut wire. It looks sharp I even found a place on Etsy that prints metallic signs and I had them print me a warning sign that has custom instructions on how to properly turn the sytem on and off. For a guy who's not good with his hands I feel pretty good!

Oh and I bought my 5th rack mount box, I say box because its a DIY kit and I supply my own batteries. I think I'm going use this pack to feed the fridge. We'll see I need to measure 24hrs worth of wattage using the kill-a-watt so see how much juice the fridge actually uses, it has a sticker saying 966watts, I hope that doesn't mean constant or else the pack wont work for long at all!

My office is fully powered with a pack that some on this thread helped me rebalance, its been going strong and I am getting the full amp rating (minus minor normal loss) of the batteries. I already have top balanced 16 batteries for the DIY box for when it arrives. Drained it and charged it again and the numbers match for that pack ahead of time so hopefully no nonsense like before. Thanks again for your help! I even took part one that I thought "might" be unbalanced and re-balanced it and its doing great too.

I really want to DIY a 48V system with some of those large 300AH+ EVE cells but I'm scared to buy them, everytime I think I've found a reliable vendor I read about someone getting fakes or B-grade or dented/bloated cells. Not to mention the cost, its honesly becoming more cost effective to buy a few UL rated EG4 rack mount packs that are 100AH and just parallel them, heck even throw them in their own EG4 cabinent!

This has never really been about cost for me but the difference is pretty large that it makes me re-think. Plus those EVE batteries look huge! As a renter I'm limited in what I can do! I could build a custom box for them out of wood. My wood working skills are bleh, I have all the equipment though. I was hoping to get a deal during black Friday but either I missed them or there were none (when I looked).

Now I'm seeing these 12V batteries for like trollilng motors that are 100ah - 400ah some decently priced but brands I've never heard of, but free shipping and protection plan from Amazon could be tempting to pick up 4 and throw em in parallel with some t-fuses, they are already BMS'd and in a plastic (bleh prefer metal) enclosure. Those I could see myself throwing in the garage. The struggle is real! as for those who know me, here is another long rant!

Happy Holidaze!