Alternator charge wire???

[DennisG01]

What size are the wires?

I think my alt wire is 4 ga. I'll have to double check tomorrow. It might be 1 gauge like my battery cables, I just don't remember offhand what I did last year.

 

[RadioMan]

Google DC wire ampacity. Keep in mind that most charts are for a standard day, the ampacity has to be derated for under hood temperatures.

 

[DennisG01]

OK, let's see if I'm on the right track. I want a fusible link/mega fuse that is rated higher than what the load would be, but lower than the ampacity of the wire. I know the max output of my alternator is 125 (even though it would probably never actually get that high).

However, looking a bunch of the charts, I'm not seeing a consistent rating for the wire ampacity. I see anywhere from 105a to 140a. One table says the ampacity goes up as temperature goes up, another says it goes down.

I'm confused.

Even if the 140a ampacity rating is correct, isn't that awful close to the load rating? Too close? How can the 105a rating be correct with a 125a alternator?

Sorry for all the questions, but I'm just not figuring this out completely. I want to put the protection back in the wire, but I also want to do it correctly.

 

[jbsaxman]

What *I* would do is run straight fusible link between the battery and the alternator. You *could* run then run a length of fusible link on each end of the connection between batteries, but that is probably not necessary.

IIRC it will provide plenty of protection between the battery(ies) and the alternator.

 

[Turbine Doc]

IIRC the charging wire from alt the fuse link would be on is about 10 or 12 ga, 4 ga is light battery cable sized wire, check to be sure as RM says not safe to guess wrong here.

 

[packratt]

Took another look at Mitchell's wiring diagram. They don't list the gauge of the charging wire (can be either black or red). It just shows a 10 gauge fusible link for base setup or the 175A Maxifuse for the uplevel setup. No definition give for the uplevel.

 

[hereismylife]

So since there is alot of differnt ways of looking at this what would be the right way of doing this? So your saying don't use a waffle fuse? What to do?

What about a 4 gauge bat cable with 100 amp fuse? Is the fuse to big or small?

 

[DennisG01]

Joe, take a look at this link: http://www.electricvehiclesusa.com/category_s/52.htm it's about the mega fuse. These are a replacement for fusible links - seems to serve the same purpose, just easier to install/replace. They are the same price, regardless of amps. Just gotta figure out the appropriate size.

 

[Turbine Doc]

Joe we are talking about the alternator charging wire correct ???,

Going to heavier ga wire is wrong action, the object is to properly size it and fuse to be enough to carry the normal load, but small enough so it wont take on too much current if something goes wrong with the volt/charge regulator part of the alt, and let it go overcurrent to point of meltdown/elect fire.

The one called for by GM has been calculated to meet that requirement based on what devices/loads on the vehicle, so best plan is to replace with exact same rating GM provided for it, if you are failing the charge wire/fuseable link you need to find out what is causing the failure, rather than upping the size of the wire to handle extra load that is causing the OEM sized wire to be insufficient.

 

[Turbine Doc]

Joe, take a look at this link: http://www.electricvehiclesusa.com/category_s/52.htm it's about the mega fuse. These are a replacement for fusible links - seems to serve the same purpose, just easier to install/replace. They are the same price, regardless of amps. Just gotta figure out the appropriate size.

Word up :thumbsup:

 

[Turbine Doc]

I was looking at my charge wire on my alt ( alt to the batt wire). I was thinking of upgrading it so it has a better flow to the batts. Well I do remember seeing somewhere that there is a resistor in the wire.

What does that resistor do? Can I replace the wire without it?

thanks

I went back to 1st post, I know you probably gonna hate to hear this, but clean gnds also imperative for proper charging and maintaining tron flow to batts, and since you have 2 batts the cross tie hot lead to the other batt needs to be spiffy, the 1 wire as supplied by GM on mine and most other is up to task if you are having charging issues, need to find out why, is charge wire corroded under the insulation, I've seen that diminish alt charging output before.

Do you have a load cell, 1 dead cell in a pair of batts will diminish entire charging/electrical system capabilities?

 

[Turbine Doc]

IMO anybody with a modern vee-hickle needs a load cell tester, the puters want good healthy tron supply quick easy test with load cell to know fast if you have batt issue they are on sale all time at harbor freight, must have part of your diagnostic kit looks like these, last one is carbon pile tester good for loading a batt to 500 amps, most load to about 100 amps, same thing more/less part store use to check a batt but you dont have to leave the house in 2nd vehicle to have it tested

 

[jrsavoie]

IS that cheap Chicago Electric Load tester any good? Most of the Chicago Electric stuff I've seen was crap.

 

[Turbine Doc]

Would I fly to the moon with it's data, no; as a field test to determine if I need a new battery, yes.

Very basic device, you have a 12V heating element, depress the switch 10 seconds it gets red hot and loads battery in process, if batt is healthy enough to keep it hot the meter says battery good, kinda like turning all glows on at once and having ammmeter in circuit reading the current,

hey now another gage idea just popped in my head :drool5:, ammeter hooked up in the cab to monitor output of the glow relay,:grin: 2 birds 1 stone is glow relay werkin, and how much juice is the battery bank pushing

 

[DennisG01]

Going to heavier ga wire is wrong action

As long as I put the appropriate fuse in, am I correct in thinking that would satisfy the system?

Maybe I can find a wiring diagram that would show that 175 Mega Fuse that Packratt was talking about. I'll stop by a local garage that I'm friendly with - they have Alldata, maybe that will help.

 

[Turbine Doc]

As long as I put the appropriate fuse in, am I correct in thinking that would satisfy the system?

Maybe I can find a wiring diagram that would show that 175 Mega Fuse that Packratt was talking about. I'll stop by a local garage that I'm friendly with - they have Alldata, maybe that will help.

it would the fuse would be the thing to protect it, bigger wire than necessary would be extra cost (more copper)
I hadn't had full coffee on yet amps is amps, if wire is up to the load that is all you need, protected by fuse or link of proper rating

I loaned out my manuals they havent made it back yet, or I'd check myself thanks for getting all data info

 

[Veg_Out]

This sure would be nice to have a standardized "upgrade" available. I think all our rigs could use a little more charge.

 

[RadioMan]

ammeter hooked up in the cab to monitor output of the glow relay

2 would be even more cool - 1 for each bank....
Looked up DC Amp Meters on Mouser - WOW - Big $$$
But there are several on eBay for reasonable money.

Sounds like a great idea to me!

If you're serious - I'd find out the initial surge current on 1 glow first. For all 8 figure 80A after the surge - Could be an outrageous start kick though. Enough to wrap up an analog movement, or rip the pointer right off it's little bearings.

Might should be in it's own thread though - I like it

 

[Turbine Doc]

I had some analog specials made to monitor the battery bank on my solar rig at my hunting camp. I'll have to dig up the paperwork to see if they can build me something, but were panel meters

 

[hereismylife]

Joe, take a look at this link: http://www.electricvehiclesusa.com/category_s/52.htm it's about the mega fuse. These are a replacement for fusible links - seems to serve the same purpose, just easier to install/replace. They are the same price, regardless of amps. Just gotta figure out the appropriate size.

Thanks you:thumbsup: