Cable ends, homade better than store bought!

[nothing to lose]

Hey all,

We talked about this before, and many people say store bought is not that expensive so why bother making cable ends ourselfs. But yes store bought is expensive when you not many of them!

Well here is a point of interest not mentioned in the past that I know of.

I left 3 walmart deepcycles sit for awhile, did not need them then or the 5K inverter.

They went dead from sitting and inverter draw over time, was charged once or twice perhaps, this sat for about a year I geuss since connected, used a bit but mostly sitting.

Yesterday I went to the old trailer, fixing up a shop and gonna live in it part time, so I check the batteries right. Gonna be offgrid mostley so I will need them.

3. deep cycles in parralel, 6 posts, the ONLY post that did not have a giant large coating of goop was the only post that had only my homemade cable end on it.
   
4. posts had that crusty cystal like build up, major large formation I could not even see the wing nuts hardly! Other post had a nasty gooey brown goop. My homemade cable end is tarnished a bit but otherwise nice and clean, nothing on the post at all.
   
   

I will try to post the pictures I took later, camera not here right now.

My cable end was just a piece of cleaned copper tubing, one end hammered flat, hole drilled for the bolt, rounded with a file to prevent a sharp corner. Hammered down and set tight onto the cable. No corrosion!

The posts with corrosion were Walmart bought ends (more costly and the worst), large cables with ends that came with my inverter, some auto cables with factory ends like would be used on a soloniod.

I takes me about 1" of scrap copper tubing and less than 3 minutes to make an end, total cost about 5 cents, you can bet I will make my own and never buy another 50cent to $1 end again! I only bought a few anyway when I first started needig them. As for those already on cables, I will be cutting most of those off and putting my own on!

 I have better things to do than clean correded terminals any more than I have to.

[jimjjnn]

Some after4 market cables are not solid copper. Some are aluminum with copper plating. These were eliminated from most store staocks as the caused lots of problems including fires. I worked for an auto parts store for a short period and ran across these. They can be used if you cut off the ends and make your own such as you did on the one cable. Scratch the bare wire and see if it is a shiny white color.

If it is , make your own end and use that goop for aluminum wire.

Better yet, if aluminum, THROW THEM AWAY.

[ghurd]

Wondering.

If the CU were solder plated, will the resistance to corrosion be better?

Also, my cables do better if the terminals are soldered on allowing the solder to crawl up the wire on the insulation side.

G-

[wind pirate]

NTL - I agree with you. Most of the stuff needed to make good cables resides in the bowels of Ebay or can be scrounged locally. I bought cable and shrink tubing on Ebay, and bought the cable ends from a real good electrical house store for 65 cents ea. I did solder and shrink wrap the ends, and after six months, they are still fine.

The part about hammering copper pipe and drilling a hole is valid, I have done that alot in the past. I just came up with a solution that fit me well and to each their own. I wouldn't pay the money they ask for cables on the web or anywhere else when you can make a real professional cable on your own for a fraction of the cost.

WP

[Ungrounded Lightning Rod]

Two comments:

1. I hope the negative terminal used is on the upper-left battery.
   
2. It would be a good idea to space the batteries out a bit (maybe an inch or so) to let air circulate between them.  Otherwise the ones in the middle get hotter than the ones around the edges, run at a higher voltage for a given state of charge, and you have an imbalance that can reduce your battery capacity and lifetime.
   

[wind pirate]

Ungrounded

#1-Yes the Neg is connected at the other side of the string. They are grouped 4 per bank in series, and paralleled in 3 banks.

#2-That is a good suggestion about the spacing, I never thought about that. They are in my basement that stays about 55'F year round and I have never noticed any heat differential - but I wasn't looking for it either

I am reconfiguring to 48V - 3 strings of 8 (48V x 540AH) and I'll need to move these around a bit (probably rack mounted), so thanks for the advise - I'll keep that in mind when I get them together.

WP

[TomW]

NTL;

Now that you bring it up, I noticed the same thing, kind of.

My system uses a fair bit of cabling I got when a local farm supply store went out of business. I bought up pretty much all the cables that had a "ring" connector on at least one end. Many of these had the lead battery post clamp on the other end. I cut those off and put on my own flattened copper tube ends on them.

Since your post, I looked at things in my battery box and, sure enough, the factory ends all have some green on them while the home brewed ones seem clean in comparison. However, the ends I bought from the electrical salvage place near by which I soldered on a couple cables seem to have faired the best. Not sure if these are copper or brass but they are the cadillacs at least from what I see.

Anyway just some observations from both a tightwad and scrounger.

Cheers.

TomW

[ghurd]

Those cheap 'Green & Red' felt battery washers actually work.

G-

[katman]

Actually, you should run equal lengths of cable to each bank and use a block to attach each of those to your feed cable. Hooking up your feeds on diagonal corners, causes uneven charging and uneven discharge.

[Ungrounded Lightning Rod]

Actually, you should run equal lengths of cable to each bank and use a block to attach each of those to your feed cable.

That WOULD be better since it would reduce the total resistance.  But ...

Hooking up your feeds on diagonal corners, causes uneven charging and uneven discharge.

Actually, no it doesn't.  While each of the series strings is sitting at a slightly different voltage above ground, they each see

 1) the same voltage from end to end,

 2) the same TOTAL resistance to the load, and

 3) the same induced voltage from other-series-strings' current in shared wiring.

Different strings see 2) and 3) divided differently between their + and - side wiring, but they always see the same total.  So the bank is balanced.

It's the same hack that is used when stringing parallel street lights down a road or across a bridge to keep them all at the same brightness despite progressively longer paths to the power source.  You string THREE wires:

 - Neutral

 - Lamp hot

 - hot.

(My terminology.)

Neutral is tied to the neutral side of the power source at the near end.  Lamps are between neutral and lamp hot.  Hot is tied to the power source at the near end and to lamp-hot at the far end.  Then all the lamps see the same voltage and the same voltage drop.

In this case "Neutral" is the - wiring from the block through the daisy-chain to the last negative battery terminal, "lamp hot" is the section of the + wiring daisy-chaining the battery posts, and "hot" is the section of the + wiring from the block to the first battery post.

[katman]

Please check out this page. I thought the same as you until I read this page.

http://www.smartgauge.co.uk/batt_con.html

[Ungrounded Lightning Rod]

He's right, I was wrong.

Different tie-across-the-ends jumpers get different loads and thus different voltage drops.  While it's far better than feeding one end, there is still an imbalance if you have more than two paralleled strings.  Then the ones nearer the end work harder then the ones in the middle.

You can fix it by running separate, equal-length feeds from a terminal block to each string.

Alternatively you can double-up on the jumpers across the paralleled ends of the strings:

 - The jumper farthest from the kiddie-corner feed point gets one thickness.

 - The one next-closer gets two thicknesses (two jumpers, two hunks of wire, or drop the wire three gauges)

 - The next one gets three thicknesses

 - and so on until the one nearest the feed point gets N-1.

A third approach is a hybrid of the other two:  Use the kiddy-corner posts as the tie points and run a separate wire to each of the other strings.  Insure that the length of the tying jumper on the + end of a series-string plus the length of the one on the - end total to the same amount for each string.  (This is equivalent to the previous suggestion but a lot easier to construct.  It also makes it easy to unhook a single string for maintenance.)