Ammeter/fusible-links ......late model 40-series

[lostmarbles]

Excellent-excellent thread! I may have found some of my charging/power problems here. Thank you for posting this-very helpful.----- I love your style of writing

Glad you found it useful..

 

[Landpimp]

few things, I had to make my own fuseable links for my 82 Fj40 when I got it(10+ years ago), did pretty much what you show, nice work! be nice if Toyota would still sell them

amp meter never has moved(dont think it did on my other 82), ever, just sits in the middle, its the only thing that does not work I have been meaning to buy a new one and see what happens.

On my older 40's without a fusable link....the amp meters work.

But on the 81+ US spec 40's, the brake light is also a charging light(idiot) light, so maybe if you wanted a check light for the alt, this may be an option.

 

[peteinjp]

Well I just have to throw this in for the sake of discussion. Tom I totally understand what your point is but- is it not also true that one must actually test the circuit to be sure that the voltage is significantly reduced. Also we must remember that the majority of the current passes thru the fusible link when the engine is off and the alternator is not turning/supplying elec. And at least on my car this means that the only thing that will be getting current solely from the battery thru that fusible link is the starter and edic relay which if not pulling many amps should not cause much of a voltage drop. Right now my fusible link is blown and in its place is a 20 fuse as a temporary measure. And I have no problems starting and running my vehicle with just a 20 amp fuse. And as I said once its started current will be supplied by the alternator for the headlights, heater fans etc etc. I do have a spare and I will probably go to a 30 amp just to be o the safe side. Food for thought. pete

I'm just adding this in for future reference as I figure this thread is most related. 3 years to the day after I made the post below the 20 amp fuse that I had used in place of the fusible link decided to call it quits. From the look of it it had been deteriorating slowly. I replaced to with a 30 amp unit. In these years I have never had a fully drained battery however I have jump started other 24v vehicles with dead batteries on numerous occasions.

At any rate I would say that the 30 amp range is the minimum for me for a stock 24v late model in terms of the capacity of a fuse or fusible link.

Pete

 

[lostmarbles]

I'm just adding this in for future reference as I figure this thread is most related. 3 years to the day after I made the post below the 20 amp fuse that I had used in place of the fusible link decided to call it quits. From the look of it it had been deteriorating slowly. I replaced to with a 30 amp unit. In these years I have never had a fully drained battery however I have jump started other 24v vehicles with dead batteries on numerous occasions.

At any rate I would say that the 30 amp range is the minimum for me for a stock 24v late model in terms of the capacity of a fuse or fusible link.

Pete

Right... So for someone with a 12V version and standard 40A alternator I think we can assume from this that a 40A fuse (as a replacement for the main fusible link) would perform just like your 20A fuse. (ie. Probably fail after a few years service.)

Although perhaps I may get away with 40A (if I were ever to swap from fusible link to fuse) because my alternator on my 79 is rated at only 35A.

Looking through my engine FSMs (covering 40-series cruisers with B-series engines)

• 1977 B-engine FSM98082 shows the alternators as 12V 30A and 24V 15A
• 1977 B, 2B Engine FSM98260 gives them as 12V 35A (mine) and 3 options for 24V of 15A, 20A and a whopping 65A
• 1980B-series FSM36047 gives them as 12V 40A and 24V with 20A and 25A options

I'm assuming here that your 24V alternator would be the 20A version Pete..

 

[peteinjp]

I have to amend my previous post- it turns out that there was a short in the backup light circuit and in the fuse box I found a 30amp fuse where a 20amo should have been. Surely it makes since though that the fusible link should handle more current that any individual fused line should. Therefore I'll stick with my minimum of 30 on the fusible link. And yen my alternator is a 25amp unit.

Also for future reference the place that I am buying the new link wire from lists an amperage rating for each of the four wires

.5mm cross section 16a
.85 21a
1.25 26a
2.0 31a

They do not sell larger gauge links. The wire is Yazaki flwx.

Pete

 

[lostmarbles]

I have to amend my previous post- it turns out that there was a short in the backup light circuit and in the fuse box I found a 30amp fuse where a 20amo should have been. Surely it makes since though that the fusible link should handle more current that any individual fused line should. Therefore I'll stick with my minimum of 30 on the fusible link. And yen my alternator is a 25amp unit.

Also for future reference the place that I am buying the new link wire from lists an amperage rating for each of the four wires

.5mm cross section 16a
.85 21a
1.25 26a
2.0 31a

They do not sell larger gauge links. The wire is Yazaki flwx.

Pete

Aha! Your 20A fuse sacrificed itself to protect your loom wiring from short-circuit current. So it was just doing the job you expected of it.

But I agree with your decision to upgrade it to 30A regardless.

Besides the point you make, I think it's unwise to have an alternator output higher than your fuse rating because your battery could conceivably demand all your alternator's output following a jump-start if your battery was dead flat.

 

[GLSisk]

Tom,

Awesome write up! Where did you get that electircal plug kit!? I need one for when I do my resto as I have some of the plastic that is in bad shape.

BTW... Breaks is not a colloquialism here in the states... It is purely the wrong word. Same as some use Loose as opposed to Lose. You lose your keys, but only when the ring is loose. Sorry, pet peeves!

"Advise" instead of the correct "advice" and "downfall" in place of "drawback" etc. And my personal favorite..."exponential" in place of "explosive." Okay, I'll stop. Apologies...

 

[waiting for time]

"Advise" instead of the correct "advice" and "downfall" in place of "drawback" etc. And my personal favorite..."exponential" in place of "explosive." Okay, I'll stop. Apologies...

Last entry in this tread was in 2013.

 

[fjc-man]

That’s thread, not tread.

 

[waiting for time]

I’m Dutch.

 

[GLSisk]

Last entry in this tread was in 2013.

I've been busy.