Broken battery terminal repair/work around?

[chriscallender]

I can't imaging wanting any of those fixes on my boat. As an insurer, I would say "nope." Exploding or leaking batteries are very bad.

My guess is that just inside the case the stainless post is crimped or cast or something to a lead terminal. I'm very comfortable with taps and drilling, but there is just too much unknown.

View attachment 196227

I'd sooner sail without power. If it is not the sole battery, can't you just combine until you can get a new one? I just don't see the risk benefit.

That's my take on it too, and I'm normally the kind of person that looks to keep broken things going and fix up whatever can be fixed. However, this is a high CCA battery capable of delivering a lot of current if something else goes faulty. Any bad connection can get very hot very quickly.

I had an engine fire on a car once when the starter solenoid jammed without me realising, it only took about 60 seconds after starting. Maybe I'm talking garbage here but annoying as it is I wouldn't want to use that battery, especially on a boat

 

[AntarcticPilot]

That's my take on it too, and I'm normally the kind of person that looks to keep broken things going and fix up whatever can be fixed. However, this is a high CCA battery capable of delivering a lot of current if something else goes faulty. Any bad connection can get very hot very quickly.

I had an engine fire on a car once when the starter solenoid jammed without me realising, it only took about 60 seconds after starting. Maybe I'm talking garbage here but annoying as it is I wouldn't want to use that battery, especially on a boat

I'm afraid I tend to agree. The current drawn by a starter motor is high, and the power dissipated goes up as the square of the current (RI²). So any significant resistance will get very hot, very quickly.

 

[Refueler]

I actually like the idea of a plate with hole in it placed tightly on to the broken stud ... if the stud can be tapered and the hole made slightly less than full stud diameter ... - it can be pressed so it makes good contact ..

The question is then how to secure the plate to the stud ?

 

[rotrax]

All this chatter about a job I have done before. I have repaired many battery posts. As a motorcycle dealer with many impecunious youths as customers it was a regular occurance.

In my now modest, but well equipped home workshop, it would be fixed-and fixed properly-by now.

It looks like a softish lead/ antimony alloy. Cut the thread down as far as possible, with the back side-ie non lead in-side of a die, or use, as suggested by William-H in post #34, a die nut. Then use an over length nut with a stud screwed in to make the connection. I would knock up a special nut on the lathe with a flange, reduced in the centre so the flange connected with the flat post base surrounding the stud to give as big an electrical contact as possible.

Just bloody do it!

 

[adamstjohn]

Can you wind the nut right down and then screw a piece of studding into the top of the nut?

My thoughts exactly

 

[adamstjohn]

I wouldn't rely on there being anything much to fasten to within the case, so whatever you use has to rely only on the material you can see. I'd be trying to get a nut on the remaining thread and then screwing a stud into the top of the nut. Not ideal, but there aren't usually strong mechanical forces on battery terminals. You might need to use washers to ensure that there's enough depth of thread for the stud to be secure.

Just seen the above posts. Can you tap the unthreaded part of the post?

good idea, gently run a tap/die, cant remember which is which now, to create more thread

 

[Refueler]

good idea, gently run a tap/die, cant remember which is which now, to create more thread

The problem I see with running a Die on that stub left ... its not that hard to break that stub off .... and a Die cutting a thread will be putting quite a bit of torque on it.

I think drill and tap internal thread would be much better.

Its funny actually - years ago - the solenoid on my Perkins gave up - one of the main power connectors broke ...

I took a small drill - drilled into the stub that was left ... used a small self-tapper to hold the power lead on ... worked a treat ... in fact I forgot about it and it was some months later that I replaced the solenoid .... my 'bodge' had worked fine without any hassle or heating up at all ...

 

[rotrax]

The problem I see with running a Die on that stub left ... its not that hard to break that stub off .... and a Die cutting a thread will be putting quite a bit of torque on it.

The residue of the fastning is a soft lead based alloy. I have no doubt that careful use of a die or die nut-probably turned by hand or with very little force-would cut the thread to the bottom of the remains of the stud.

One will not know until one tries., would one?

IMHO, based on repairing dozens of battery terminals, from Honda 50's to huge truck batteries, it is most certainly worth a punt.

 

[LittleSister]

. . .
In my now modest, but well equipped home workshop, it would be fixed-and fixed properly-by now.

. . .

Just bloody do it!

If I had a well equipped home workshop, plus your skills and experience, I probably would!

I can't imaging wanting any of those fixes on my boat. As an insurer, I would say "nope." Exploding or leaking batteries are very bad.

That's my take on it too, and I'm normally the kind of person that looks to keep broken things going and fix up whatever can be fixed. However, this is a high CCA battery capable of delivering a lot of current if something else goes faulty. Any bad connection can get very hot very quickly.

I'm afraid I tend to agree. The current drawn by a starter motor is high, and the power dissipated goes up as the square of the current (RI²). So any significant resistance will get very hot, very quickly.

I thank you for your concern/warnings. I am a (usually!) cautious soul.

I appreciate all the various suggestions people have made which have certainly given food for thought, but (in part due to lack of tools and skills) am still leaning towards a 'non-invasive' solution where an additional external contrivance holds and presses a ring-type wire terminal onto the remaining flange of the battery terminal, and the stub of the post just locates it laterally.

Your comments do lead me to question whether there would be adequate area of contact under this arrangement. It would have the same contact area underneath the ring, but would be missing the connection from its top normally via the washer, nut and threaded post. I am guessing that taking into account both the smaller area of contact above and several additional connections between the parts that would be effectively something like perhaps 50% or 70% of the underside connection, i.e. a reduction of maybe about a third from what the manufacturers regard is adequate for the claimed potentially 500 CCA.

Importantly, it strikes me that the adequacy or otherwise of this solution could be readily checked by feeling whether the terminal gets significantly warmer than the negative one when used to start the engine.

In the meantime, my plastic vernier caliper has emerged from hiding, and I find that
- the diameter of the base flange is 11.5mm (standing 1.4 mm above the plastic surround);
- the diameter of the stub of the post is (of course) 6mm; and
- the height of the stub is 2.5mm.

The area of the flange is 104 sq mm, less the area of the stub at 28 sq mm, leaves a contact area of 76 sq mm (equivalent to a circle of 10mm radius). That area would certainly be an adequate cable size (with no length to be considered for cumulative resistance), but of course the contact between the wire terminal and the battery terminal will not be anywhere as good as that within the continuous material of a copper cable. That calculation doesn't tell me anything with certainty, but it does suggest to me that it is not beyond the realms of possibility that it would be adequate.

I think the answer is to suck it and see!

 

[rotrax]

Go for it-what have you lost?

If you cant fix it, the battery is Donald Ducked anyway.............................

 

[AntarcticPilot]

Go for it-what have you lost?

If you cant fix it, the battery is Donald Ducked anyway.............................

But a repair that appears to work could end up with a fire?

 

[rogerthebodger]

But a repair that appears to work could end up with a fire?

That is why any repair however done must be monitored to ensure no heating of the repair

I'm with rotex just fix it the way suggested by roex and Willam_h

 

[Paddys milestone]

I actually like the idea of a plate with hole in it placed tightly on to the broken stud ... if the stud can be tapered and the hole made slightly less than full stud diameter ... - it can be pressed so it makes good contact ..

The question is then how to secure the plate to the stud ?

As I explained, use 3 or 4 self tappers,They are there not to be conductors but to hold the brass plate tight enough to the flange ,which will be a big area and conduct the current,. Clean the surfaces and use terminal paste to keep it going.

 

[billskip]

But a repair that appears to work could end up with a fire?

Only once though....

 

[LittleSister]

But a repair that appears to work could end up with a fire?

Only once though....

Shame. If it happened often, think of the potential savings in bottled gas!

 

[AntarcticPilot]

Shame. If it happened often, think of the potential savings in bottled gas!

I don't know - I guess they need to put a few bob in the meter at the crematorium!

 

[billskip]

I don't know - I guess they need to put a few bob in the meter at the crematorium!

That's a given eventually anyway.....

 

[LittleSister]

In the extraordinarily unlikely event that I am fried in a conflagration caused by using an alternative means of securing a wire against a battery terminal than the missing stud, I am sure the nation would be only to pleased to put a few bob in the crematorium meter early to save the cost of my future pension and demands on the NHS. I should also be keeping the boating community happy by taking a boat out of circulation and vacating a mooring and shore storage space, thus helping sustain boat values and driving down running costs.

You should all be encouraging me down this route and thanking me in advance!

 

[billskip]

In the extraordinarily unlikely event that I am fried in a conflagration caused by using an alternative means of securing a wire against a battery terminal than the missing stud, I am sure the nation would be only to pleased to put a few bob in the crematorium meter early to save the cost of my future pension and demands on the NHS. I should also be keeping the boating community happy by taking a boat out of circulation and vacating a mooring and shore storage space, thus helping sustain boat values and driving down running costs.

You should all be encouraging me down this route and thanking me in advance!

Now you have stated all the up sides, just get on with fixing it....

Ps, don't lose th soh.

 

[IanCC]

I would guess that as long as the threaded stud you put in seals in the threads - and add a nut with soft washer to further seal ... ??

Prope tight fit as you just screw the threaded bar into the drilled hole. Quite tough to get it started, if i remember right, but not a drop of leakage.