Ya and once I went to a lifetime replacement alt. about once a year I took an hour and installed their replacement for free. That hour included a couple of brews.

 

Lifetime replacement parts are fine, but they do not cover consequential damage.. which in the 6.0s case, is batteries, FICMs, to start.

 

Did you upgrade the wires as well? And if so which ones?

I just ordered the 185amp alt and talked to a guy who said my best bet would be to simply upgrade the alt-primary batt wire to a 2/0 with a 200-250amp fuse and a 1/0 from primary to secondary batt. Thoughts?

 

Fuse way bigger than theoretical max output?

I wouldn't do it that way as an engineer!

A fuse does it job by tripping.

Can you get a 200amp fuse?

http://bluesea.com/files/resources/r...se_Holders.pdf

I would personally go with a 175amp ANL fuse -- and take the risk of it being under rather than oversized.

 

Yes I only upgraded the wire from the alt. to the pass side battery with 2/0 and a 200amp fuse. I will upgrade the others when weather permits.

 

I like this:

200 AMP DC Breaker Disconnect

O'Reilleys has this:

http://www.oreillyauto.com/site/c/de...1177&ppt=C0172

 

The breaker disconnect looks like a real good product.

If you think you are ****... LOL

I would put a 175A fuse in front of it.

 

I hear ya - an electrician friend of mine just told me a story about almost burning his house down because a circuit breaker stuck and did not trip. Burn't up quite a bit of wiring in the wall.

 

duplicate (I hate it when that happens)

 

Circuit breakers, in an auto app.... get corrosion.. ice.. extremes of heat and cold... that is why the Factory uses so few of them --- and it is not just because maxi fuses and fusible links are a lot cheaper all the time.

It is because of the certainty of action is much better --- as a passive device that is non mechanical.

I tend to get panic attacks when stuff is fused at above the max. out.... knowing that there is a even bigger threshold that the circuit breaker goes above before it trips, so I am quite conservative.

 

What about folks that have a 250A alternator? They will most likely have a 250A fuse. If it is OK for that size alternator, why would it not be OK for a 200A alternator? I understand it doesn't "feel" right, but isn't it the same amount of protection either way?

Also, I know we discussed it, but can't recall. Do you feel it is necesary to fuse the wire going to the driver's battery (from the passenger battery) if the alternator wire to the passenger battery is fused?

 

i would stay away from the ultima brand altenator. i am on my third one since august. when this one goes i am going to get my money back from oreilly's and go elsewhere.

 

OK, first, High ordered the 185 amp alternator.

The idea is to closely match the fuse with the maximum output (with no trouble) and to kill it as soon something that just shouldn't / can't happen like it sees a 200amp current --- kill it fast.

So a fuse that is slightly below its max output (175a) is probably OK.

My theory is he will not achieve that output unless he has a power drain hog running at the same time as flat batteries, everything electrical running.

So safer to go a tad below its "cold" rating, assuming the "hot" rating of the alternator is way below --- probably 150amp hot.

If it is 150 amp hot... 175 cold (allowing for a bit of poetic exaggeration under real life conditions, resistance of wires,etc.)... and normal deterioration of components over time...

A 175 amp fuse is ample -- should not blow with a 185 rated alternator... it is within 5%... but I want it to blow fast if he exceeded 190amp.. which is where that fuse is actually tested to blow at.

Note as a fuse age, the amp it blows at decreases -- not increase. So safety margin and hassle is added over time --- if it blew for no reason.






Short answer: No.

Longer answer:


We are talking about 2 things.

A) the wire from the alternator to the battery / starter solenoid (which output is limited to the maximum output of the alternator. (185 amp in HB case)

B) the wires from the battery to the starter solenoid.

Demands on that wire is limited only by how much the truck can draw at max. load with starter cranking, and all the electrical gadgets running.

That is a whopping 400 amps or so.

Do the math --- 3 kilowatt starter... add 600 watt baseline load, add glow plugs, fuel heaters, ghetto blasters, seat warmers, your extra headlights.. and at a nominal 12V, it can easily be pushing 400 amps.

If you were to fuse that cable --- from both batteries to starter solenoid, it needs a fusible link of 350 to 400 amp range.

Now... lets look at the individual batteries and what they see:


You have 2 batteries wired in parallel. So at the "outboard" end, the battery furthest away that sends its juice via the battery ahead of it to the starter should see 1/2 the current of the theoretical max.

Assuming both batteries are working properly.

The problem becomes, if one battery (the one in front) is bad, then the current draw goes disproportionately to the remaining good battery.

So you cannot assume it is 1/2 --- it can be carrying the whole show --- the whole freaking 400 amp load our trucks put on the batteries on one battery and one cable.

A 200 amp fuse would, under those circumstances, blow.


Hence, the standard practice is to just fuse the 2 parallel batteries --- with one fusible link.

Plus fuse the alternator output wire with a smaller one (matched to alternator output).

I would almost say there is more risk of trouble fusing individual batteries in parallel.

Because if the fuse blew.. how are you going to find out? You would just run it on one battery until the thing died.


Think of the other common failure --- internal short in some cells of one battery.. leading to very low "pull down" of voltage of the entire system.

That is one of the primary causes of batteries failing / needing replacement in pairs.


In real sophisticated battery arrays, normally, batteries are individually disconnected, tested and monitored apart from an array... cell by cell (not even battery by battery)... and then replaced one by one..

That is what they are doing with the hybrid buses I see running around me.

No way to judge health of whole battery system easily --- and too expensive to tooss out the whole array for a few bad cells.

 

Hey guys the guy I talked to at DCPower said that the higher amp fuse was recommended to catch a spike, not so much as to be used as a method of limiting amps to the battery. I'm a mech engineer and only took EE204 so my electrical engineering is sub-par.

 

10-4
Rep'd ya