As your picture shows (beautifully) the supplied "bus bars" are actually a pair of super-thin smaller ones, held together with shrink-wrap tape. The bend can help to handle a bit of expansion and shrinkage as the cells become more or less charged, but the cross section (looking from the end) is very small, perhaps the equivalent of AWG-8 wire. It's going to have increasing resistance above 40A, and all that heat goes into the battery. If you stay with only these Docan-supplied bus bars, you should definitely get more of them. With a small ring terminal also attached under the nut, and maybe a washer as well, the supplied posts can handle 4-6 of the thin ones.Just got the first part of my EVE230 shipment (UPS split it up for some reason, so some today, some tomorrow, weird). Opened the first box, packed super well. I was surprised however - no welded studs. Interesting. Maybe only the 280 or 304 has welded studs?
Also, the bus bars look to allow some flex based on the hump look. Any idea the current rating? They are two layers, evidently. My max DC load is expected around 200A. I'm expecting I'll probably need to get bigger ones, but I thought I'd see what showed up first before I bought more stuff.View attachment 87582
Chris, I won't have a big enough Inverter to "stress test" my own 4S battery pack until after Friday. I built with a "200A" BMS and the stacked bus bars in my previous post, but I cranked up the maximum current parameter in by BMS a bit. I will report back with my findings, using this concept: If the bus bars become more warm than the "12v+" terminal connector post, then even my stacked bus bar arrangement is insufficient to pull high current through the cylinder top (with a bit of current also going through the grub screw, assisted by contact with the nut at the top.I have the same cells and terminals, 120A bms, and comfortable with the supplied bus bars and grub-screws. I am also max 100A current on my system. I would want some input from the more experienced here for running 200A+ through them. From what I've heard and seen, those small-shouldered terminals were good for 100-120A. I think the busbars are okay, just not sure about the terminals for that kind of current output.
Are you building 12V or 24V pack? And powering a larger inverter?
I know it's been said before, but it is worth repeating: A 1/4" aluminum washer between the bus bar and the small post area greatly improves the contact area with the bus bar. Besides, dirty or oxidized surfaces and poorly tightened nuts will have a much greater negative impact to the electrical connection than the small surface area of the contact on the terminal.The flat contact area of the "welded post assembly", at the top of the cylinder, is very small. The long cut-outs within the Docan-provided bus bars further reduce that area, by a lot. You should apply high torque, to improve the electrical conductivity between the first bus bar and the top of the assembly cylinder. A washer, if you can find or cut one of the right size, might also help a bit.
A couple of small issues would arise by doing that. The surface area IS improved on the both sides of the washer, by avoiding the funny gap in Docan's over-long post cut on the "post", and by having more surface area on the bus bar side. But a comparatively thick layer of aluminum is much less conductive than the super-thin plating on these pure copper bus bars. Aluminum also rusts (and becomes much less conductive) very soon after you have cleaned it chemically, or sanded it clean with ultra-fine sandpaper (P-2000, or even smaller and tighter than that). The rust looks only a bit less bright than the clean metal, so it's hard to notice by looking at it. It's also held very tight to the original metal and prevents rust from penetrating further in.I know it's been said before, but it is worth repeating: A 1/4" aluminum washer between the bus bar and the small post area greatly improves the contact area with the bus bar. Besides, dirty or oxidized surfaces and poorly tightened nuts will have a much greater negative impact to the electrical connection than the small surface area of the contact on the terminal.
I agree mostly with what you've said. On the oxidation point (I would not call it rust, since that normally is used to refer to oxidation of iron), I've not had any problem with that because I clean / polish the surface and apply MG847 before tightening everything down.A couple of small issues would arise by doing that. The surface area IS improved on the both sides of the washer, by avoiding the funny gap in Docan's over-long post cut on the "post", and by having more surface area on the bus bar side. But a comparatively thick layer of aluminum is much less conductive than the super-thin plating on these pure copper bus bars. Aluminum also rusts (and becomes much less conductive) very soon after you have cleaned it chemically, or sanded it clean with ultra-fine sandpaper (P-2000, or even smaller and tighter than that). The rust looks only a bit less bright than the clean metal, so it's hard to notice by looking at it. It's also held very tight to the original metal and prevents rust from penetrating further in.
When bought from a store or shipped from Ebay, aluminum washers are 100% surface-rusted by the time you're ready to use them -they MUST be cleaned immediately before installing into a situation like this.
If you do add a washer on top, be sure to clean it and then clamp it tight with full torque immediately. Aluminum is very soft, the high pressure will help to form-fit the washer surface into the somewhat rough docan bus bar pair. And then, form fit with virtually no air exposure on the contact surface, it resists rust alot better.
Have never heard of 'lithicore' but appears to be the same address Docan uses for their TX warehouse. The same retail/industrial strip mall. A mini-warehouse - photo linked before, but here it is again below.
I put four LF230's in my cart, added 'primsmatic' coupon for free shipping, and have an option to checkout with paypal or credit card - no additional fees. Maybe you could call them to confirm inventory and shipping time.
It is possible this is the space Docan is renting or partnering with for US distribution - the other company was a 18650 cell retailer, but now looks like they're selling prismatic cells as well. Perhaps another web retail site.
The street address is in the back corner on the left of this strip:
Okay, for all the bus bars concerns, where is everyone getting their 200A rated bus bars?
Great case, I wish they would sell it without all their electronics though. I want to use my own BMSI'm planning on using the Seplos case that's specifically built for this.
you can order it without bms if you want.Great case, I wish they would sell it without all their electronics though. I want to use my own BMS
You can get it without the BMS - I was going to because I ordered JBD bms with my cells. But then, the seplos bms is also good, and it has a nice display and is well integrated with the case. So I decided to get the case with BMS, keep the JBD bms as backups.Great case, I wish they would sell it without all their electronics though. I want to use my own BMS
Where is that option?You can get it without the BMS
Because I already have my own BMS and I have requirements that their BMS does not meetyou can order it without bms if you want.
nit sure why you want though, their bms is of very high quality.
grantes they had 1 batch of the 200 amp version where were a resistor was bad, but they seem to have solved that
Just email them and tell them that is what you would likeWhere is that option?
wonder what those requirements are, purely out of curiousityBecause I already have my own BMS and I have requirements that their BMS does not meet
Feels a bit off topic here but I'll humor you. My main reason is I already own a Batrium BMS, so I'm not going to pay for another BMS when I already have one. I went with Batrium because they have some really nice ways to access data which I want to display in my Homeassistant and build automations off of. Batrium also integrates really well with my Victron system as well. I did a lot of reasearch many months ago and they came out on top. I'm not really interested in switching over to a new BMS system.wonder what those requirements are, purely out of curiousity