I know of a few that have used it, not sure about common since I never did a poll.
Seriously, it doesn't take much, a one ounce tube will pretty much handle any size battery here.
Lishen 272 Ah Top Balance and Capacity Test
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Seriously, it doesn't take much, a one ounce tube will pretty much handle any size battery here.
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I used Ox-Gard I got at a hardware store on my battery build which I just fired up last night for the first time. I followed the instructions and scrubbed it into both sides (the battery terminal and the bus bar) using a green scotch brite pad. Then I left a thin layer of the residue on the battery terminal as the instructions don't say to wipe it off or anything. They say apply "liberally" but I didn't want to fill up my grubscrew threads with the excess, or let it spill down the sides of the raised terminal and contact the cell casing. So I left a thin layer. It's somewhat abrasive.
I saw about 81% efficiency in my first load test comparing the [uncalibrated] Overkill BMS power reading to a Kill-a-Watt plugged into the inverter output, when powering my ~900W shop vacuum. That seems a bit low for a Victron 24V/1200VA Phoenix inverter, which is 91% max efficiency, but I do have some cables, a BMS, a bus bar, a fuse, and an automatic transfer switch in the loop too.
I'm wondering if I should remove the bus bars and clean off the Ox-Gard and just go with bare connections. I might also look at the cell voltage drop when it's loaded vs unloaded, as ~40A from 280Ah cells is only 0.15C so there shouldn't be much drop at all I think. I would think most of the voltage drop would be attributed to the electrical connection to the terminals. Open to suggestions / second opinions here if anyone has one.
I saw about 81% efficiency in my first load test comparing the [uncalibrated] Overkill BMS power reading to a Kill-a-Watt plugged into the inverter output, when powering my ~900W shop vacuum. That seems a bit low for a Victron 24V/1200VA Phoenix inverter, which is 91% max efficiency, but I do have some cables, a BMS, a bus bar, a fuse, and an automatic transfer switch in the loop too.
I'm wondering if I should remove the bus bars and clean off the Ox-Gard and just go with bare connections. I might also look at the cell voltage drop when it's loaded vs unloaded, as ~40A from 280Ah cells is only 0.15C so there shouldn't be much drop at all I think. I would think most of the voltage drop would be attributed to the electrical connection to the terminals. Open to suggestions / second opinions here if anyone has one.
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If it "squeezes out", you used too much. Literally, less than a pea sized dollop wiped on with your fingertip. You should see a haze on the terminal and busbar, nothing more is needed. The objective is to provide a layer to protect from the oxidation by air. Once tightened down, there should be no excess oozing out.
I haven't had any problems using this method. I would certainly look at the voltage your BMS reports under load, that is how I found a cat hair had found its way into a connection.
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Yes, I used maybe 2 grains of rice worth of Ox-Gard on the scotch brite, then scrubbed it hard on the battery terminal, and a lot of it stayed on the scotch brite pad. There's no squeeze out at all; it's more of a thin greasy haze left on there before I assembled the bus bars. I think the grease actually stays in there; it's just conductive. Some people commenting about electric cars (or just conventional cars with their 12V batteries) talk about using insulating goop like petroleum jelly, and it just squeezes out from the pressure. I'm not sure this actually happens when you're only torquing the battery terminals to 35 inch pounds, so your goop needs to be conductive I think.
Anyway, I'm not convinced it's better than a flat bus-bar-on-terminal connection.
I posted a picture to "show and tell" if you want to zoom in and look for squeeze-out:
8s 280Ah 24V "Compact" Solar Battery Build
I thought I'd share some details of my current project which successfully powered on today. I'm currently learning about all the BMS and MPPT settings. It consists of an 8s 280Ah battery bank with MPPT and all electronics in a very compact box. This build tested the limits of what I could wire...
diysolarforum.com
I still have to replace that one bus bar with something longer; it hasn't arrived in the mail yet.
It's not a better connection. If you live in a high humidity environment, you should not notice any difference for a couple of years. Galvanic corrosion is real, and does take a while to reveal itself, my experience with house wiring in Florida says at 5 years, lights start flickering and the fire hazard is real.
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Wow that's nuts. I've lived in Colorado (extremely dry) and California (average to dry) and have never heard of such a thing.
They used aluminum wiring for only a few years in the mid 1970s, and stopped as soon as the fire hazard became known. Not because it was outlawed, but because nobody would buy a new house with aluminum wiring. Better than 95% of houses have aluminum as wiring from the pole to the panel, it's perfectly safe as long as precautions are taken.
Ox-Gard and Noalox use zinc as an ingredient, it's a sacrificial additive to corrode before the aluminum does. Aluminum oxide is a very poor conductor, and galvanic corrosion means it will be created rather than copper oxide (it's preferential, in other words any corrosion that would have occurred on the copper, will instead form on the aluminum, as well as any that would have occurred on the aluminum).
The purpose isn't to make a better contact, it's to prevent corrosion (in the future). Aluminum starts corroding pretty much as soon as it is exposed to air. I cleaned my terminals with a felt buffer pad and isopropyl alcohol using my Dremel tool (I used 99.5% IPA, simply because that's what I had). I'm not sure how regular rubbing alcohol would work with a significant water content. I also had to use the wire wheel attachment to clean off what looked like (maybe) glue from a couple of terminals from the manufacturing process.
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Oh I see, so only applicable to aluminum wiring, not copper. I thought you meant even copper wiring corrodes in Florida.
I have been wondering about this too. 35 inch pounds is equal to 700lbs of clamping force. I would think all the excess would squeeze out. Also these corrosion inhibitors are supposed to improve conductivity. I have been thinking about using MG carbon conductive grease. I haven't used anything yet but I would think anything is better than nothing to fill in the tiny holes and gaps between the busbar and cell terminal to improve conductivity and reduce corrosion. In my case corrosion is not a problem.
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I'll take your word for it, internet stranger! This excuses me from having to disassemble my bus bars, clean them, and reassemble. I think I'm still going to run a load test and feel if any terminals get warm though, as I would have expected a bit better efficiency than 81%. But, it could also be the BMS (or the Kill-A-Watt) are miscalibrated or the vacuum has a power factor which decreases the inverter efficiency.
Could be any or all of those. Maybe try a different load. I agree 81% isn't good. The deltas at the top and bottom and in between according to your BMS could be telling. A load test to check for heat would be telling as well. Like I said I haven't used anything yet.
Upnorthandpersonal has tested carbon conductive grease and all he has said so far is the results are good. But I question if using carbon conductive grease makes that much difference compared to using OX Guard and other similar products. Anyways I doubt it's the OX Guard causing the lower efficiency., but it's always good to note I could be wrong.
But the thing is many others are using it and have not noted any problems.Something else is the busbars that come with the cells have a slight burr left over from the holes being stamped out. It looks like you modified that one busbar to reach. Is there any substantial voltage drop going on with that interconnect? I am using a 6awg cable but will be replacing it with a 4awg cable in that spot.
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Yeah that's just temporary until my 3.5" 4AWG cable arrives later this week. I'll do some more load tests this week and report any findings. Need to get out there and install my panels today.
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Just thought I'd update anyone reading this thread and say I'm going to put my load test data in my own thread, linked above. I don't want to [continue to] hijack this thread which was originally about a different topic.
I have cleaned off and later reapplied Ox-Gard, the felt buffer with Alcohol on a dremmel works well.
I don't think that is the problem, or at least I haven't found it to be.
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