12 replies to this topic

[minipower101]

Hi everyone. I've come to the conclusion that my 45a alternator isn't good enough to keep my system charged. I'm going for the 70a replacement as it is actually cheaper than the 55 and the 65 for some reason.

I'd just like to know how you upgrade the wire that goes to the solenoid on the inner wing please. Not sure how you go about putting it in to the plug that goes in the alternator. And am I right thinking it needs to be grade 4? Thanks

[WiredbyWilson]

Grade 4 isn't a term i've heard before, but it's rating needs to be in excess of the alternator output. It also depends on the number of outputs from the alternator. Later pre-engaged setups have 2 outputs and a triggre wire so the load can be split across the two terminals.

 

I make this exact upgrade, so if you want the cable made with the terminals etc give me a shout.

[klivins]

I might be wrong on this, so correct me, if I am. I assume the alternator produces amps according to the demand. So I just swapped 45 A alt for similar shape 70 A one, renewing connections, what were somewhat corroded, and thats it. I havent noticed any ill effects from this modification.

[screech]

I've just downgraded mine to a 70a which uses a lug connection instead of the standard 3 spade terminals.

This way you can upgrade to 4awg or even 2awg if need be.

How have you come to the conclusion that you need a bigger one?

[MRA]

AWG or SWG maybe but not grade 4, as thet is wire wool

 

Wire sizes are better stated as CSA x strand count, as current travels on the outside of wire and not in the core. the more surface area you have the more current you can carry.

 

CSA is the cross sectional area (PIxd^2)/4

 

PI = 3.142.........

d = diameter in mm

d^2 = diameter in mm squared

 

This will allow you check you have the correct wire size/s

 

but I would go with 10mm2 total CSA and try to get higher strand count as this allows for more flexibility and reduced fatigue failures, also don't solder it as you will get "wicking" and it will quickly fail

[MRA]

I might be wrong on this, so correct me, if I am. I assume the alternator produces amps according to the demand. So I just swapped 45 A alt for similar shape 70 A one, renewing connections, what were somewhat corroded, and thats it. I havent noticed any ill effects from this modification.

 

Lets assume your wiring was designed to cope with 50A ie 45A + a bit for safety, you fit a 70A alternator and as soon as the demand goes above the 50A the wires will increase in temperature due to internal friction (resistance) then as the temperature increases so does the resistance and very quickly you could end up with a fire, now if all you changed was the alternator and didn't add any extra loads it probably won't make a difference or not enough to worry about, but start adding loads. big amplifier, heated front screen etc etc etc and you can expect a thermal event.

[klivins]

 

I might be wrong on this, so correct me, if I am. I assume the alternator produces amps according to the demand. So I just swapped 45 A alt for similar shape 70 A one, renewing connections, what were somewhat corroded, and thats it. I havent noticed any ill effects from this modification.

 

Lets assume your wiring was designed to cope with 50A ie 45A + a bit for safety, you fit a 70A alternator and as soon as the demand goes above the 50A the wires will increase in temperature due to internal friction (resistance) then as the temperature increases so does the resistance and very quickly you could end up with a fire, now if all you changed was the alternator and didn't add any extra loads it probably won't make a difference or not enough to worry about, but start adding loads. big amplifier, heated front screen etc etc etc and you can expect a thermal event.

 

Yes, all this is what I dont have:) Not even radio! If I was to add anything extra I was thinking to add separate wiring from the alternator via separate fuse box.

[screech]

What are you looking at adding to the car?

[MRA]

 

 

I might be wrong on this, so correct me, if I am. I assume the alternator produces amps according to the demand. So I just swapped 45 A alt for similar shape 70 A one, renewing connections, what were somewhat corroded, and thats it. I havent noticed any ill effects from this modification.

 

Lets assume your wiring was designed to cope with 50A ie 45A + a bit for safety, you fit a 70A alternator and as soon as the demand goes above the 50A the wires will increase in temperature due to internal friction (resistance) then as the temperature increases so does the resistance and very quickly you could end up with a fire, now if all you changed was the alternator and didn't add any extra loads it probably won't make a difference or not enough to worry about, but start adding loads. big amplifier, heated front screen etc etc etc and you can expect a thermal event.

 

Yes, all this is what I dont have:) Not even radio! If I was to add anything extra I was thinking to add separate wiring from the alternator via separate fuse box.

 

 

I should have said that demand on an alternator will reach the 100% mark, at any point the battery needs a top up, so it is still best to the job correctly, fit larger / higher capacity wiring

[klivins]

Point taken, thank you. I think I might add another wire from the alt to starter solenoid. From there the original wire back to the battery is beefy enough, isn't it?

[minipower101]

Thanks for the replies.

WiredbyWilson I might just take you up on that thanks. Would that just replace all the wires in the plug going to the solenoid then? I've got an inertia starter and the 3 spade connectors in a plug going into the altenator.

I think my alternator isn't working as it should as it's only reading 13.5 ish when running and when I turn on lights, heater etc it goes down to 11.8. I've got a few extra electrical things from standard and the biggest battery I could fit in the hole so thought it would be best to upgrade it. And my battery has been flat a couple of times recently.

[MRA]

Point taken, thank you. I think I might add another wire from the alt to starter solenoid. From there the original wire back to the battery is beefy enough, isn't it?

 

Yes the battery cable will take a lot more than your alternator will kick out, however try to get just one wire from the alternator to the starter terminal rather than a bundle,

[Ado1379]

For the time it takes to re-crimp a new wire into the circuit it really isn't worth risking a fire! If your having trouble then any electrical outlet store will advise you ie. Maplins (I don't usually rate their tech advice but this is something they should be able to help you with)