Insulating battery terminals - electrical load ?

[sarabande]

http://www.ybw.com/forums/showthrea...ng-terminals&p=5947120&highlight=#post5947120

I've not added this to the above thread cos it's a drift.


The quick release terminals have arrived from ebay.

My question is: can I use them as part of a (permanent) wired system on board and in a charging system on the farm ? The concern is the load that they can take.

The dimensions of the "brass" stamped metalwork at the narrowest part just by the screws and bolts are 15mm by 1.5, giving a cross-sectional area of 22.5 mm². According to Wiki that is rateable for 95 -115A, which may be a bit small. That figure also relies on me identifying the strap as the narrowest part of the structure.

The wire clamp looks to have a dia of just under 10mm, so say 80mm², which seems to take a battery cable up to 450A. Far more than the alternator can produce.

The importer of the terminal (from China) has not got a clue !


What do the members think please ? It would be very handy to quick clamp a battery into my charging system on land, but perhaps not on board.


TIA

 

[savageseadog]

The conductive path in the contact area is very short, it's not a length of cable so voltage drop and heat generated will be small. They are plated steel at a guess so will need to be well greased for anything to do with boats. This type of connector is being used on lots of cars.

 

[pvb]

Yes, voltage drop will be miniscule, not a problem. However, these clamps aren't brilliantly made and will corrode in outdoor use, leading to resistance at the contact with the battery terminal.

 

[stevie69p]

These sorts of terminals are used as standard on many (French in particular) cars. They are well able to handle the current draw of a 1kw starter motor. The rest as the above posters have mentioned...

 

[blxm]

I have used these on a car and they are fine in terms of clamping ability and contact area so no real issues with voltage drop. i fitted them as the car is often left unused for weeks at a time and wanted to isolate the supply quickly. However, they corroded badly, despite good greasing. Removed them and put in a a proper battery isolater. Unless you need to disconnect the banks on a very regular basis I would just use standard clamps and have a small spanner handy.

 

[Lon nan Gruagach]

Totally agree with the previous replies. (So whats the point of another one?)

Well, do you see, its like this:

The rating you found via Mr Google et al relates to a length of insulated cable (technically an infinite length) What this means for the rating is that any heat generated in any part of the cable has to be dissipated by that part and not rely on the rest of the set up. Now, for your battery clamp, you have on one side a rather large chunk of lead, and the other side a run of cable. Provided the cable isnt maxed out, it can help, the battery will do as well. Also you dont have quite such a snug fitting plastic overcoat as a cable does.
All in all the rating for cable is rather pessimistic compared to a very short section of bare metal.

 

[superheat6k]

You do not say if you simply want to disconnect quickly for isolation purposes or to allow the battery to be removed.

I fitted an extra battery to my domestic bank recently, but it wasn't identical to the other battery, so I wanted to be able to leave it mostly disconnected, so I could turn it on as and when required and for an occasional charge.

I have used one of these ... http://www.ebay.co.uk/itm/Battery-I...id=100005&rk=1&rkt=6&mehot=pp&sd=252186337196

 

[Lon nan Gruagach]

You do not say if you simply want to disconnect quickly for isolation purposes or to allow the battery to be removed.

I fitted an extra battery to my domestic bank recently, but it wasn't identical to the other battery, so I wanted to be able to leave it mostly disconnected, so I could turn it on as and when required and for an occasional charge.

I have used one of these ... http://www.ebay.co.uk/itm/Battery-I...id=100005&rk=1&rkt=6&mehot=pp&sd=252186337196

Tidy. Would be almost perfect if it had clear indication of switch position, not too hard to add though.

 

[VicS]

http://www.ybw.com/forums/showthrea...ng-terminals&p=5947120&highlight=#post5947120

I've not added this to the above thread cos it's a drift.


The quick release terminals have arrived from ebay.


My question is: can I use them as part of a (permanent) wired system on board and in a charging system on the farm ? The concern is the load that they can take.


What do the members think please ? It would be very handy to quick clamp a battery into my charging system on land, but perhaps not on board.


TIA

My concern would be their corrosion resistance if used outdoors on the farm or in the marine environment.

 

[oldharry]

My concern would be their corrosion resistance if used outdoors on the farm or in the marine environment.

I've had the same pair on my boat for the last 5 - 6 years, now starting an old MD7A so not particularly high starting current. Not had a problem either with overheating or corrosion, and it makes it dead easy to release the terminals in a battery box which is difficult to wield a spanner. Ive had them on previous boats too, and only if seawater splashes directly on to them have I needed to replace them. They are no all that expensive, so I replace them as a throw away item as soon as they show signs of deterioration. Its onlyfive minutes with a screwdriver. I have had a set for 8 years on the domestic batteries of my motorhome too, but of course there they are fully protected inside the vehicle. So far they are as good as new. I'm not sure I would trust them to start a big heavy diesel but they seem to be good for the 3-500amps of the average car starter. The probably wouldnt do in an open boat though as they are just pressed steel and do rust easily. But who keeps batteries out in the open anyway, particularly at sea? I got a meter reading of 4 - 5 volts on the casing of a dirty damp battery of an old banger when I was a student! Cleaned off, it held its charge again....

 

[sarabande]

You do not say if you simply want to disconnect quickly for isolation purposes or to allow the battery to be removed.

I fitted an extra battery to my domestic bank recently, but it wasn't identical to the other battery, so I wanted to be able to leave it mostly disconnected, so I could turn it on as and when required and for an occasional charge.

I have used one of these ... http://www.ebay.co.uk/itm/Battery-I...id=100005&rk=1&rkt=6&mehot=pp&sd=252186337196

Two usage patterns, T, as you suggest.

1...On board, to have a contingency battery, kept as near as dammit up to 100% charge, then isolated from service and engine batteries. So a permanent part of the system, but needs isolating.

2...At home, to make it easy and quick to bring in a farm lighting or fencer battery, and attach it to the solar panel set up on the shed, which keeps 1 - 4 batteries topped up and ready for rotational use.

I like the look of that isolater you linked, and will get one. Ta !