| Author |
Message |
Jerry (152.163.188.227)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 04, 2003 - 11:59 am: | |
Batteries, weight, connecting bar question, and glad I now have a bus
A STORY:
I do a lot of dry camping and hate generator noise so even with my old class “A” RV (that I sold to buy an even much older 4106) a battery system and inverter was the best way to go for me. But by the time I added all this and other stuff I wanted (larger fuel tanks, tools, and other ‘stuff’) when all was full it was about 3000# over GVWR!
Next to my town in the St Louis metropolitan area, there is a battery supplier that manufacturers their own brand of golf cart batteries and I put a set of four in my last RV. They worked out well – got 8 years out of them with - what I would guess to be – heavy use. They fulfilled my electrical needs fairly well and when they got low a large inverter/charger would make short work of charging them back up once plugged in or if the generator was started. I especially liked the seemingly large reservoir of electrolyte over the plates – I could have probably gone almost a full year before the level approached the top of the plates but had better have several gallons of distilled water available when it came time to top them off.
So...when I began designing the battery system that is going in my ‘06 I’m using the same system. I’ll put in at least 6 batteries but the battery box and tray has room for 8 (I moved the ‘06 original battery box back wall back, filled in the empty space – the 8D starting batteries go on the lower shelf and house system on the upper; the inverter/charger goes on the other side of the back or inboard wall and the 12VDC distribution panel and controls goes in a closet designed above the battery box — this arrangement keeps all the heavy DC cables in one area and close to the engine generator). As much as I like metal working I’m getting short on time so I decided to splurge and buy a ready made slide out and just build my own battery tray that would go on top. By the time just the tray was all done it was 110#! And each battery weighs about 64# x 8 = about 625# (glad it’s the bus and not me that has to carry that around) but compared to my Class “A” RV I still have LOTS of room left before I get anywhere near the GVWR of the ‘06 (which I check actual weight regularly during the conversion process).
THE QUESTION:
During the temporary installation of the invertor, prior to the “new and improved” battery box , I had a very short distance to cover between the ‘06 12v+ tie block and the special class “T” fuse block for the large amp fuse required for the invertor. Only a few inches – to short use a typical a battery cable so, since I had a roll of ½" copper tubing around, I hammered some of it flat, cut it into strips and made 4 layers (guessing – using the “T”LAR method - that much copper looked about the same in 0000 cable and would be enough to carry the current – “T”LAR = That Looks About Right), drilled the appropriate sized post holes in each end of the sandwich and used this to cover the gap. I’m using 0000 cable to tie most of the installation together but I’m thinking of using this same system to cover the short distance to series each set of 6V golf cart batteries together. Good or bad idea? Easier and certainly less expensive than making up the 0000 cables for the short distance but how could I get more scientific about how many layers to use to safely carry the current. I’ll be reviewing ANSI & the electrical code at least I think some of this may have to be insulated. |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 04, 2003 - 8:31 pm: | |
As a "seat of the pants" hint, try running your copper pipe thing under full load for a half an hour or so, and then feel it to see if it gets warm or hot. If the answer is no, you're in there and working fine. If it does get warm or hot, it's probably not thick enough.
That said, when you hammer pipe flat you are "work hardening" it, making it much more vunerable to breaking under vibration... and solid copper of any type isn't the best thing for a vibrating installation in the first place. If I were you and could do it, I'd at least heat the whole thing up to red with a torch and slowly cool it (ie don't stick it in a bucket of water, just let it cool on it's own), to anneal it after your hammer job, and that will make it soft again.
Again, it's probably OK to tie batteries together with the stuff, but the one hitch is that there's no "give" to soild copper, and if the batteries shift or move, you'll likely break a post at best, or break the top of the battery at worst.
If the mechanical stuff doesn't bother you, and the lack of insulation doesn't either, go for it!! (but do anneal it)
Cheers
Gary |
Tom Caffrey (Pvcces) (64.114.233.155)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 04, 2003 - 10:00 pm: | |
Jerry, I think you ought to check on the right way to anneal copper. I know it's a long time ago, but from what I remember of my shop class, to anneal copper, you had to get it hot and then quench it.
The way I remembered the rule was that it was the opposite of steel. Hammering steel makes it soft, quenching it makes it hard. Reverse for copper.
I do think that you ought to consider some way to use cable, even for that short of run. Solid copper will never give you the safety, and there's the insulation problem, as well.
If you're going to split the source of inverter power from your house batteries, you can split the guage as you do. The rule is for each 3 gauge sizes, you change the cross section by double or half. This means that if the whole bank was 4/0, if it's divided once, 1/0 should work.
Since you're splitting it twice, perhaps 2 gauge would be good enough after the second split. Go larger to satisfy any safety factor you like, and you're in business.
Good luck.
Tom Caffrey PD4106-2576
Suncatcher |
mel 4104 (208.181.100.30)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 04, 2003 - 10:07 pm: | |
Jerryyou can use welding cable and copper pipe that is the same size as thebare copper wires in the welding cable or just slightly largerthen open your vice a little ot about 1/2 the wire thickness and useing a dull chisel make your own connectors cut off the extra length pipe and flatten out and drill the hole to fit the barry lug bolt and make your own jumper cables at a fraction of the cost of store price and a lot better, this way they are theright length and are safer and look great. mel 4104 ps..solder the home made connectors to the cable with rosin core solder DO NOT use acid flux on any electrical joints.. |
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