I'm a "Yank", so always think in FarenheitNeither will plywood. But IMHO it's far superior to plywood for this application, and it's non-conductive.
BTW, the MSD on it says melting point is 126 to 135C.
Cause of Battery Fire
- Thread starter ndrober
- Start date
When we use plywood in any environment that is not heated 24/7 the inside get epoxy / 4oz cloth / epoxy. The outside get 2 coats of epoxy.
Heat shrink is soft. Threaded rod will cut through it.
I'm a "Yank", so always think in Farenheit
Me too. But I'm getting better. Back in high school they kept telling us everything was going to switch over to metric. Gee, that was fifty years ago!
Post #2 here......
My slab of UHMW-PE has too much warp.
I purchased a .75x24x36 slab of, TIVAR 1000 Natural Plate, UHMW-PE to make a FDA compliant cutting board for a customer. Unfortunately, it has over 1/2" of warp; more curl than I can take out when screwing to it's support frame. I made a similar table for the same customer about 15 years ago...
www.practicalmachinist.com
12VoltInstalls
life passes by too quickly to not live in freedom
Ya, but it takes more temperature to boil water in FahrenheitI'm a "Yank", so always think in Farenheit
Hedges
I See Electromagnetic Fields!
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People produce videos of "dendrites" growing across a PCB in real time.
I'm following "creepage and clearance" rules for a PCB I designed that will provide some EMI filtering of mains power. It needs to work for 120/208Y and 230/400Y. I first selected 0.156" pitch connectors rated for 600V, but realized I couldn't meet "creepage" rules for distance across surface of PCB unless I either used a higher grade of material than FR4, or had slots milled between all pins. I was able to use 0.25" pitch connectors instead and stick with FR4.
The creepage and clearance table covered some common material types (graded by "tracking index"), but didn't extend down to "Marine Plywood"
PCB Line Spacing, Creepage, and Clearance | Sierra Circuits
PCB creepage and clearances depend on CTI, pollution degree, working voltage, insulation, and altitude of the system.
www.protoexpress.com
Lt.Dan
Solar Wizard
The heat shrink I used is 1/8" Thick, much thicker than the threads of the rod. But thanks for the concern
MrM1
I'm Here, But I'm Not All There
@Browneye ,Hard to tell. Is that 3 lugs coming off the BMS to the battery or 3 cables in 1 lug?My biggest fear with lifepo4 in the RV...
I'm surprised HDPE 'starboard' isn't used more often. Impervious to everything and non-conductive. It's used a lot on boats and I suspect that many are unaware of its existence due to that.
I liked this build so much I'm copying its overall design parameters with a few modifications.
Thread link:
560ah 12v Battery with Clean, Modern Case
This is my first post here, but I wanted to share my DIY battery bank. This forum and Will's videos were so helpful that I wanted to share a few things I learned, as well as a few things I created that I haven't seen before (specifically the asthetics of the case). I'd also appreciate any...diysolarforum.com
If 3 wires into 1, Any issues with that? NEC code ?
I'm about to build 2 16s packs. Wanting to do it "Code-ish" (not inspected) . Will have 2 cables each side of the BMS. Can't decide if I want 1 lug or 2 per side. Issue is the cable is 7 awg. 1 fits too tight in a #8 and loose in a #6. But I do have a hydro crimper. If I go 2 cables in 1 lug a #4 is just right before crimp.
Hedges
I See Electromagnetic Fields!
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I know code doesn't allow two wires in one lug/terminal. Except for lugs/terminals listed for two wires. Like split-bolt? I've found ferrules for two wires, not sure they are listed.
I never could see what was wrong with it.
There are a variety of lugs for two wires. Maybe mostly screw type, not crimp, except battery terminal?
I've also threaded a wire through a single lug (wire stripped in middle and both ends) to connect two circuits to a single lug (output of knife switch.)
I never could see what was wrong with it.
There are a variety of lugs for two wires. Maybe mostly screw type, not crimp, except battery terminal?
I've also threaded a wire through a single lug (wire stripped in middle and both ends) to connect two circuits to a single lug (output of knife switch.)
When I worked with acrylic we would score it with a knife and snap it. The pieces broke if dropped and fastening was a nightmare. Quarter turn to much would break so we started to use foam washers.
I assume so. Check out the thread - it's not my build.
The Overkill bms does have two or three feed wires to it from neg post - I guess you're supposed to crimp them into a single lug for output. I dunno. I ordered mine with two screw posts on each side - -B and -C on the board - I made up two 6awg wires into a 4awg lug and crimped them, double shrinked. Seems solid. It was tough to get all the strands into the lug, but I managed. The other ends can have a lug on each lead, put them together on the outer negative post to connect the neg cable to ground. I actually have a shunt to install, so that will be my outer battery post. The plus side has a huge class T fuse - I had no idea those things were that big!
The acrylic rod/tube I got is just to protect threads on the compression rods. They don't have to be tight between the end panels, and they'll have no stress on them.
I also got 1/8 medium density rubber sheeting for the bottoms to rest on. I'm still trying to decided if I'm going to turn my cells on their narrow side - under the sofa in the motorhome doesn't have much vertical clearance. It's probably still going to work out okay with the lugs up.
I'll link over to finished pics in one of my build threads when I get done. In the meantime, I'm STILL waiting on the top-balance - they're taking forever to come up to full charge. I had the power supply on 3.4 for two days, then on 3.5 for a day, and the cells are still sitting at 3.359 and not budging. I may shut it down, let them rest for a day, then try again at 3.6V to complete the top balance. The power supply says it's putting out a few amps, but gee, seems like I've pumped a couple of hundred amps into them, and they're only 230A cells!!
Class T...
_IMG_4193(1).HEIC?width=960&height=720&fit=bounds)
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edcoopered
New Member
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Remember if you have 16 230Ah cells paralleled up thats a 3680Ah pack, a power supply at 2A could take two months to fill that up.
S Davis
Solar Addict
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Yes but you have four at 230ah cells so 960ah charging at 3.6 volts.I assume so. Check out the thread - it's not my build.
The Overkill bms does have two or three feed wires to it from neg post - I guess you're supposed to crimp them into a single lug for output. I dunno. I ordered mine with two screw posts on each side - -B and -C on the board - I made up two 6awg wires into a 4awg lug and crimped them, double shrinked. Seems solid. It was tough to get all the strands into the lug, but I managed. The other ends can have a lug on each lead, put them together on the outer negative post to connect the neg cable to ground. I actually have a shunt to install, so that will be my outer battery post. The plus side has a huge class T fuse - I had no idea those things were that big!
The acrylic rod/tube I got is just to protect threads on the compression rods. They don't have to be tight between the end panels, and they'll have no stress on them.
I also got 1/8 medium density rubber sheeting for the bottoms to rest on. I'm still trying to decided if I'm going to turn my cells on their narrow side - under the sofa in the motorhome doesn't have much vertical clearance. It's probably still going to work out okay with the lugs up.
I'll link over to finished pics in one of my build threads when I get done. In the meantime, I'm STILL waiting on the top-balance - they're taking forever to come up to full charge. I had the power supply on 3.4 for two days, then on 3.5 for a day, and the cells are still sitting at 3.359 and not budging. I may shut it down, let them rest for a day, then try again at 3.6V to complete the top balance. The power supply says it's putting out a few amps, but gee, seems like I've pumped a couple of hundred amps into them, and they're only 230A cells!!
Class T...
Hedges
I See Electromagnetic Fields!
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Tin whiskers.
One looks like an insect leg in the air, other like "alien" coming out.
This one, well, I'll refrain from saying what it looks like:
Now those were "tin whiskers" growing in the air.
As for dendrites where voltage across PCB is too high (and there is surface contamination & moisture), this is what I was talking about:
That's something a vendor shows us a few decades ago. Easy to find now on YouTube if you know what to look for.
And finally, "Treeing" high-voltage failure in insulators.
Nice looking build you have there. Did you run the washing machine unbalanced with the battery on top as a shakedown test?
Nice looking build you have there. Did you run the washing machine unbalanced with the battery on top as a shakedown test?
Thank you for your patient help Jim. You were a big inspiration to go for it. @time2roll too, you guys and the old guard here are a wealth of information. Three months ago I had never even heard of lifepo4 batteries.
I winced when I turned the cutoff switch on...the silence was deafening. LOL
Overkill bms BT app is just killer. It's in and working. ?
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12VoltInstalls
life passes by too quickly to not live in freedom
I imagine
An electrical code inspector made me throw and reconnect a humongous spring loaded legacy 1971 800A three phase disconnect that my electrician had “field repaired” once. I was quite scared especially when the two state inspectors suddenly backed up ten feet as I reached for the disconnect release.
I’ve imagined playing with batteries would have a similar scary gut.
Did you ask the inspectors to hold your beer? LOL.
That's a nice build. With the length of the plexi there won't be an issue with the PE bending.As promised...a twelve hour build session yesterday - Eve LF230's with 120A Overkill for the RV house:
It lives under the sofa:
Countersunk screws and hole saw holes in plexi isn't the best....here's some info.
Repairing a Crack in Plexiglass
Your Plexiglas is cracking. You're thinking... hey, it's the Plastic Genius, there must be a solution to this! Well, there is and here's the...
....fuse goes after the disconnect
...a double cable crimp on the battery neg vs. two single crimps on the shunt?
That's a nice build. With the length of the plexi there won't be an issue with the PE bending.
Countersunk screws and hole saw holes in plexi isn't the best....here's some info.
Repairing a Crack in Plexiglass
Your Plexiglas is cracking. You're thinking... hey, it's the Plastic Genius, there must be a solution to this! Well, there is and here's the...www.plasticgenius.com
....fuse goes after the disconnect
...a double cable crimp on the battery neg vs. two single crimps on the shunt?
Thanks!
My thoughts...as a noob:
It's lexan - polycarbonate, three times stronger than acrylic. I can replace it with non-countersunk if it becomes an issue, but wanted a flush appearance. It would have been just as easy to use round-head screws, considered it. I build a lot with wood - boats, cabinets, etc., and it's natural to countersink and plug. Old habits die hard.
Everywhere I searched said fuse comes before switch. Everywhere. It was a quandary. I even asked and got no replies. It's really there to protect the battery, and really that's the BMS's job. The only other thing on that leg is the charger and it has it's own 70A fuse. If the feed wire shorts when the battery switch is off it will blow the fuse to the charger if it's on, I suppose.
Yes, double crimp. Fits better on those smallish 6mm posts. I bought SS 8mm adapters but they're too tall and didn't like the way they fit over the very small contacts on the cells. Overkill/JBD actually recommend TRIPLE crimps to the cells.
I was going to buss the two posts on the bms and use a single 4awg wire, then decided it would be easier and cleaner to utilize two 6awg leads. Spec calls for 3@10awg or optional 8awg. Pos is 2awg all the way to distribution blocks. BMS build options are: no wires, 3@10awg,3@8awg, 12 or 24" leads, or 6mm screw posts. I figured I could make my own custom leads, hence....Remember, this is a 120A bms, a 600w inverter is the highest load - the rest is lighting, fridge board, water pump, furnace blower. It replaces two GC2's.
Adapters from Pegasus racing I didn't use:
12VoltInstalls
life passes by too quickly to not live in freedom
>grin<
The senior electrical inspector used to be a master sparky for a big commercial electric outfit who knew me from years before. Big guy, 275ish.
The guy with him wasn’t an electrician but when big john moved so quick he jumped back.
Comical in hindsight but I honestly was more than a little scared.
The last recorded disconnect was something like 1987 when the powerco threw it and it wouldn’t reconnect. A brilliant electrician disassembled it and fixed it. Coincidentally his son was my electrician- he said “do not open that! If you hit that you’re on your own.” And hurriedly left. I had no choice… needed the CO signed off for Level 5 compliance.
I lived.
