Large female blade or spade terminals

[superheat6k]

Occasionally I have trouble starting my engines due to voltage drops to the engine control supply whilst the starter is spinning, e.g. If the battery is slightly undercharged, or if as has more often been the case so called heavy duty battery switches are not up to the job (black body red key single pole type). If the control voltage drops below ~8 volts during the start the stop solenoid drops out, preventing the start required.

As an aside I have also noticed occasionally the engine will start and then cuts out as the alternator excites. If it does do this it then becomes a real pig to get to start again.

The problem hasn't been helped by a considerable volts drop across the battery single pole isolator switches (black body with red key type), so having changed these only recently I have now float tested the latest piece of junk in favour of a decent heavy duty switch.

The Corvette electrical distribution engineer was also less than clever with where he placed the 12 volt service distribution in a deep floor locker an extra 2m away from everything else electrical, so in a fit of pique yesterday I ripped the entire distribution panel apart and I'm now in the process of rerouting all the associated cables, heavy, medium and light, to a more suitable and indeed accessible position. The new switches Force 4 offered are rated for 1,250amps start current and are surface mounted so will be suitably mounted adjacent to the rest of the electrical distribution panels. The various distribution MCBs will be going inside the locker behind the helm where to my mind Corvette should have placed them in the first place.

So the cabin has a snakes' wedding in progress presently ! Fortunately I was calm enough to tag each wire as I disconnected it, and presently I only have two out of some 25 wires that I am not sure what they serve. Will soon have these chased out.

However, to better overcome this I want to draw the control power much closer to the battery rather than right at the starter connection, where the voltage drop at start up is at its most. plus I am going to fit cross over supply switches so the port engine control can draw its control supply from stbd battery or vice versa.

To do this I need some larger than standard spade terminals for my engine control power supplies. The standard large crimp spade terminal flag is 6.3mm wide. The ones supplying power onto my ignition switches (Cummins) are ~10 mm wide. I could cut the existing cable a few inches back and graft on the new supply cable but this seems messy for the want of the correct spade terminal.

Every search I use just leads me to a thousand listings for the larger 6.3mm yellow crimp style.

Anyone know where I might find the larger size I'm looking for ?

Also one of the distribution services is 'Maintained' i.e. Bilge pumps. What is the opinion on the supply source position for this - before the associated isolator i.e. direct to the battery or switched ?

It is simpler to feed it switched as there is a busbar serving the adjacent MCBs to other main services, but I guess a pre-switch feed would be better because then I can just turn off both Isolators to turn off the whole boat except the essential services. Due to the ridiculous position of the original Isolators they were never turned off.

BTW this thread fully complies with a thread I started a while ago asking if all electrical problems were poor connection related !

 

[rogerthebodger]

Is this what you are looking for

https://www.autosparks.co.uk/3-8-10mm-female-spade-terminal-to-suit-up-to-65-0-30.html

https://www.amazon.com/Yellow-Female-Slide-Terminal-10-12/dp/B00JWZEUEQ

 

[paulajayne]

1. Does the male blade have a hole in it?

If so bolt a connection on.

2. Can you solder a cable direct to it?

3. Can you change the Ign. Switch for one with standard connections?

 

[Big John]

https://www.ebay.co.uk/itm/Male-Tab...g:gJsAAOSwC~BcBqjY:rk:5:pf:0&var=512601992141

https://www.ebay.co.uk/itm/Large-10...tors-10-Pack-Alternator-Starter-/370592790873

https://www.ebay.co.uk/itm/10-x-Yel...h=item3ae9c5c15d:g:fPIAAOSwvjdZXXUb:rk:6:pf:0

 

[lw395]

Those 3/8 Fastons come in two blade thicknesses.
I would probably go for TE branded ones from RS
https://uk.rs-online.com/web/c/conn...les/?applied-dimensions=4294688289,4294688345

 

[matthewriches]

As mentioned above, the big yellow female spades are what you’re after as fitted to many Lucas style key switches. One point I’ve picked up on is to make sure they’re bloody tight as they do rattle about and eventually loosen which is exactly what happened to our forklift not so long ago.

I prefer the key switches as fitted to the likes of the Beta panels which use ring terminals with split washers.

Which Corvette do you have?

 

[superheat6k]

Thanks for the links. I've ordered a pack from Ebay, but this will be crimped and soldered.

My boat is a Corvette 32 Classique 420 1991, one of the last built in Nottingham.

 

[JohnGC]

Thanks for the links. I've ordered a pack from Ebay, but this will be crimped and soldered.

My boat is a Corvette 32 Classique 420 1991, one of the last built in Nottingham.

Be careful! Crimping a soldered wire can lead to poor joints for a couple of reasons;

1. Soldering makes the cable stiff up to the point the solder stops. That point may flex a lot and break. Additional strain relief should help.

2. If you solder the wire end and then crimp; high currents soften the solder (just I2R heating as the joint always has a little resistance) and the crimp can loosen. Loosening leads in turn to a higher resistance joint which softens the solder even more. I've seen this run away and completely burn out. I wish I'd kept a photo of this but we are talking black and hot enough to melt the copper wire in a 30A circuit and a potential fire starter.

Personally, I would crimp only and do some practice crimps with a good quality and well adjusted crimping tool - they needn't be all that expensive.

 

[PuffTheMagicDragon]

Be careful! Crimping a soldered wire can lead to poor joints for a couple of reasons;

1. Soldering makes the cable stiff up to the point the solder stops. That point may flex a lot and break. Additional strain relief should help.

2. If you solder the wire end and then crimp; high currents soften the solder (just I2R heating as the joint always has a little resistance) and the crimp can loosen. Loosening leads in turn to a higher resistance joint which softens the solder even more. I've seen this run away and completely burn out. I wish I'd kept a photo of this but we are talking black and hot enough to melt the copper wire in a 30A circuit and a potential fire starter.

Personally, I would crimp only and do some practice crimps with a good quality and well adjusted crimping tool - they needn't be all that expensive.

+1

Get a proper ratchet crimper like this one:

not like these cheap ones:

p.s. The images used are only to illustrate the different types and have no relation to the brands that are indicated.

 

[PaulRainbow]

Be careful! Crimping a soldered wire can lead to poor joints for a couple of reasons;

1. Soldering makes the cable stiff up to the point the solder stops. That point may flex a lot and break. Additional strain relief should help.

2. If you solder the wire end and then crimp; high currents soften the solder (just I2R heating as the joint always has a little resistance) and the crimp can loosen. Loosening leads in turn to a higher resistance joint which softens the solder even more. I've seen this run away and completely burn out. I wish I'd kept a photo of this but we are talking black and hot enough to melt the copper wire in a 30A circuit and a potential fire starter.

Personally, I would crimp only and do some practice crimps with a good quality and well adjusted crimping tool - they needn't be all that expensive.

+1

A properly crimped connection is perfectly adequate. Some heat shrink adds extra support, which reduces flexing at the crimp.

 

[superheat6k]

Be careful! Crimping a soldered wire can lead to poor joints for a couple of reasons;

1. Soldering makes the cable stiff up to the point the solder stops. That point may flex a lot and break. Additional strain relief should help.

2. If you solder the wire end and then crimp; high currents soften the solder (just I2R heating as the joint always has a little resistance) and the crimp can loosen. Loosening leads in turn to a higher resistance joint which softens the solder even more. I've seen this run away and completely burn out. I wish I'd kept a photo of this but we are talking black and hot enough to melt the copper wire in a 30A circuit and a potential fire starter.

Personally, I would crimp only and do some practice crimps with a good quality and well adjusted crimping tool - they needn't be all that expensive.

I appreciate the advice about crimping and soldering, but I will as well be covering the joint and connector with heatshrink. I will also cut off the yellow insulation and direct crimp with a heavy duty hydraulic crimper, and this will be hefty 4mm2 cable, and in an area where there is virtually nil free movement of the cable. The cable itself will also be tied to the entire grouping to the engine control panel.

Having had this problem repeat itself several times with the voltage drop stopping the engines from starting I am determined once and for all to be rid of the issue once and for all.

 

[JohnGC]

I appreciate the advice about crimping and soldering, but I will as well be covering the joint and connector with heatshrink. I will also cut off the yellow insulation and direct crimp with a heavy duty hydraulic crimper, and this will be hefty 4mm2 cable, and in an area where there is virtually nil free movement of the cable. The cable itself will also be tied to the entire grouping to the engine control panel.

Having had this problem repeat itself several times with the voltage drop stopping the engines from starting I am determined once and for all to be rid of the issue once and for all.

It's up to you of course and I understand your desire to remove the current problem, I would. The additional heatshrink and support should be good whether you solder or not. So long as you don't create too sudden a transition from stiff and supported to free.

But it won't mitigate concern 2 at all. This manifests as a small and slow extrusion of the solder out of the crimped joint as it heats and cools; vibration plays no part so the additional support doesn't help.

I would only remove the yellow cover from a few test joints to enable inspection.

Just for my own interest; do you have a figure for the current though and voltage drop across the switches?

 

[rogerthebodger]

If you plan to crimp and solder this type may be better.

I used these at some time. I created the inner flags near the connector then soldered. I waited for the solder to cool then crimped the outer flags over the wirf insulation before adding heat shrink to insulate the lot.

 

[superheat6k]

It's up to you of course and I understand your desire to remove the current problem, I would. The additional heatshrink and support should be good whether you solder or not. So long as you don't create too sudden a transition from stiff and supported to free.

But it won't mitigate concern 2 at all. This manifests as a small and slow extrusion of the solder out of the crimped joint as it heats and cools; vibration plays no part so the additional support doesn't help.

I would only remove the yellow cover from a few test joints to enable inspection.

Just for my own interest; do you have a figure for the current though and voltage drop across the switches?

This is power to the engine ancillary circuits including the starter secondary solenoid, which is the highest load. I reckon at most ~ 4 amps, so through 4mm2 wire, the volts drop should be negligible. But when this problem occurs is when the starter solenoid as well as the massive starter motor current is flowing. I don't think even 30 amps through 4mm2 cable would get anywhere close to melting the solder. The main starter solenoid control power is fed from the main feed cable via a secondary start relay.

Also my idea to go direct from the battery to the re-positioned isolator switches, higher quality switches, then a far shorter run to the ignition switches removes ~ 4-5 m from the run for the ancillary power had before and across a crap isolator switch. The same crap switch was providing the power to the starter itself with the take off to these ancillary supplies right at the main power connection to the engine starter main solenoid, itself ~ 4m from the crap isolator on what looks like 35mm2 wire. The replaced engine main power runs will end up about 1m shorter.

I am replacing the engine feed cables with 50mm2 flexible fine cored welding cable. Every lug will be replaced and hydraulically crimped. I am also replacing the awful battery lugs with the screw style clamps, in favour of lug connected clamps.

The battery charger feeds also routed to the floor locker and connected on the battery side of the isolator switches, so with a couple of ancillary feeds to the voltmeter and maintained (bilge pump services) a veritable Christmas tree of connections at these switches.

The whole affair was made worse because the mess of cables, heavy medium and light was mounted to the hinged panel, so each time it is accessed all the cables got moved / strained.

I have now reduced the connections at the battery isolator switches to three on each output side - engine 50mm2, services (P) / windlass (S), and engine ancillaries. The port input side has two - Battery and Maintained power (bilge pumps), the stbd has just one input cable. Each battery will have two cables to +VE - Main power and charger power (the stbd has an additional feed direct to the miniature CB to the VHF)

For now I am re-using the original battery feed cable which is marked 40mm2, but if I have enough spare 50mm2 then I will replace these short sections also.

The alternator wiring is not altered and so will continue to put its power back to the batteries via the start man feed cable.

I will check the -VE heavy cabling from the engines back to the batteries and may replace this, or at minimum re-lug the main connections.

The new layout schematic is here (I know it is marked 2.5mm2 for the ancillary, but this will be 4mm2)

https://www.dropbox.com/s/z39gc4bvpubd682/Boadicea Batteries to Services.PDF?dl=0

 

[JohnGC]

This is power......................

I think everything you are doing is sensible except soldering the crimp terminals.

Just to be clear;

It isn't the wire which causes the heating (initially) and the solder doesn't melt (initially). The potential problem is caused by having the solder in the crimped joint. When correctly crimped, the stranded copper wire forms a solid mass surrounded by the crimp. This joint is stable and can easily be achieved with a moderately priced tool and good quality crimps.

By soldering the copper wire strands before crimping, you get a soft metal layer between the crimp and the copper strands. Because the solder is soft it continues to flow, even at moderate temperatures. That flow of solder out of the crimp reduces the pressure within the crimp. That reducing pressure increases the resistance - more power dissipation - more heating - faster solder flow and if you are unlucky it gets rapidly and suddenly worse until there is enough heat to melt copper.

NB. There isn't an issue with manufactured tinned copper wire because the tinning layer on individual strands is very thin.

 

[superheat6k]

I think everything you are doing is sensible except soldering the crimp terminals.

Just to be clear;

It isn't the wire which causes the heating (initially) and the solder doesn't melt (initially). The potential problem is caused by having the solder in the crimped joint. When correctly crimped, the stranded copper wire forms a solid mass surrounded by the crimp. This joint is stable and can easily be achieved with a moderately priced tool and good quality crimps.

By soldering the copper wire strands before crimping, you get a soft metal layer between the crimp and the copper strands. Because the solder is soft it continues to flow, even at moderate temperatures. That flow of solder out of the crimp reduces the pressure within the crimp. That reducing pressure increases the resistance - more power dissipation - more heating - faster solder flow and if you are unlucky it gets rapidly and suddenly worse until there is enough heat to melt copper.

NB. There isn't an issue with manufactured tinned copper wire because the tinning layer on individual strands is very thin.

I would always crimp first before soldering.

However, I have another issue. The available crimp lugs for 4mm2 cable are the yellow shrouded crimp style, and are very skinny, and after the crimp is pressed give very little effective support to the cable, especially with a 10mm hole (4-10). So can I double the bared cable end then use a 10mm2 crimp which are a far more substantial crimp (isolator switch end). Again I would expect to solder after crimping, especially as there will be some spare space within the crimp, plus add a heatshrink layer or two over the joint.

I think this will be a stronger joint than the yellow shrouded crimp alone.

 

[PaulRainbow]

I would always crimp first before soldering.

If it's correctly crimped, solder adds nothing[/quote]

Again I would expect to solder after crimping, especially as there will be some spare space within the crimp.

If the crimp is done correctly, there will be no extra space.

plus add a heatshrink layer or two over the joint.

I think this will be a stronger joint than the yellow shrouded crimp alone.

That's what i said in post #10

 

[superheat6k]

If it's correctly crimped, solder adds nothing

Again I would expect to solder after crimping, especially as there will be some spare space within the crimp.

If the crimp is done correctly, there will be no extra space.



That's what i said in post #10

What is your opinion about using the larger heavier 10mm2 crimp with the cores folded back. ?

The yellow shrouded crimps look too flimsy.

 

[PaulRainbow]

What is your opinion about using the larger heavier 10mm2 crimp with the cores folded back. ?

The yellow shrouded crimps look too flimsy.

I see no reason not to, i sometimes do it with the red crimps and smaller wires, stops the crimp deforming. If you add a layer or two of heatshrink, covering the whole terminal, you should have a pretty robust connection.

 

[lw395]

What is your opinion about using the larger heavier 10mm2 crimp with the cores folded back. ?

The yellow shrouded crimps look too flimsy.

Buy a 4mmsq crimp that isn't flimsy.
And/or secure the cabling so the crimp is not under stress.