Dual Alternator Setup
- Thread starter p38
- Start date
p38
Caught the Bug
Well, as my wife says about shopping - "It's never a question of need - it's want." Actually there's a couple reasons. Redundancy is one, convenience is another. There are a number of electrical components on my jeep besides the basics of fuel pumps, engine fans, lights, etc. There's a Luna fridge/freezer, my espresso maker (yes), FLIR, Lowrance, radios, SAT phone, and a large inverter to power cameras and battery chargers. My dual batteries and single alternator system handles the load, it's more about not having to stop what we're doing to change one if/when it goes out. I can keep going and change it at a more convenient time. It's sort of like my redundant fuel pumps - if I'm going to carry them as spares - I might as well mount them. I don't have to allocate space for them somewhere on the jeep.
My Ford F350 Superduty has both dual batteries and dual alternators.
p38
Caught the Bug
Thanks, but I think you missed my reason - it's not about output, it's about not having to stop and change one. Plus, if I'm going to carry it as a spare - I might as well mount it - like I did the fuel pumps.
Before you guys get carried away with, "why not have dual tires, dual drivelines, etc - components like fuel pumps and alternators are "nuisance" items. It's not a major issue if they fail, like an axle or a driveline - but they will stop you. If I was just cruising a trail - no big deal, but I'm talking about situations where that would be a pain in the butt I'd like to avoid.
Note: I can go at least 100 miles with no alternator and just battery power - but I can't run all the equipment I need to power.
Spazbyt
Hooked
I don't see a big advantage of having two. The most common reason for having two isn't redundancy its because manufacturers couldn't fit a larger single unit.
It's not hard to swap an alternator.
Carrying a brand new spar is reasonably easy.
Alternators don't normally randomly die completely.
Unless you add multiple voltmeters you won't know if one alternator is dead.
Every second your not using the energy from the second alt it's would only be wearing itself out and consuming fuel.
If the 2nd alts failure mode is a bearing then having two won't help anyway.
I agree with Brute. Maybe a HO alternator from Mean-Green would work for you.
It's not hard to swap an alternator.
Carrying a brand new spar is reasonably easy.
Alternators don't normally randomly die completely.
Unless you add multiple voltmeters you won't know if one alternator is dead.
Every second your not using the energy from the second alt it's would only be wearing itself out and consuming fuel.
If the 2nd alts failure mode is a bearing then having two won't help anyway.
I agree with Brute. Maybe a HO alternator from Mean-Green would work for you.
p38
Caught the Bug
Good points, thanks for taking the time to respond.
True - on my rig an alternator is probably one of the easiest components to change
We are in the process of redesigning and building storage compartments - I'll make sure there's a spot for an alternator
True - but if/when it dies, I'm done until it's swapped (more details below)
That is a very good point - dual voltmeter or lights - but just more crap to add
True - but in my application it's expendable
Agreed - I'd still have to change it, and replace a belt.
The alternator on the rig can handle the load, that's not the issue. If the alt fails, I can power down all the equipment and either drive back to my support rig or stop and swap it for the spare. What I was trying to avoid is either of those options for something as trivial as an alt failure.
A good option - I thought, but it seems it produces more problems than it solves.
I spoke with an alternator guy today, he said many of the same things and added a very significant point - dust is a major cause of alt failures. And I am spending a lot of time in dust. So an additional alt would most likely fail as well.
So, thank you for helping me sort this out. I'll stick with the single alternator and carry a spare and protect it from dust.
OverlanderJK
Resident Smartass
I have had one alternator fail in 20 years. And it was a ten year old truck at the time.
TrailHunter
Hooked
Right... also an alternator for a SBC can be bought at any local auto parts store and swapped in about 20 min.
p38
Caught the Bug
The
Not disagreeing - but it has to be the correct bolt pattern for the mount; and sadly, parts houses aren't stocking parts like they used to.
Thanks for the input guys, but that's not the situation I'm talking about. I like the failure rate of one in 20 years; I don't know that I've ever had one fail - until this one, and it was installed new 2 years ago.
It's not a question of carrying a spare or driving to town to buy a spare - I have plenty spares. I was just trying to come up with a way to avoid having to stop and change one while the jeep was working. If I'm just cruising or running a trail, stopping to change an alt is no big deal.
I'm hoping this failure was a fluke and it doesn't happen again, at least not for awhile.
TrailHunter
Hooked
Brute
Hooked
I’ve had two fail me…one was on an F150, close to ten years old…and I replaced the alternator on my 2015 Anvil …
jorgelrod
Hooked
This, I had the original one in my JK fail at 6 years, but 4 of those the Jeep lived in Puerto Rico where I mudded and forded silty water more than most members here. I think you are overthinking it.
HighwayTrout
Hooked
Napa Valley AK or Napa Valley Ca lol?
Why have two and whytf would you even consider carrying a spare? It’s not a hard part to buy or replace if it fails.
Why have two and whytf would you even consider carrying a spare? It’s not a hard part to buy or replace if it fails.
p38
Caught the Bug
Napa Valley CA
I think we've resolved the question of two and supported the case for having the spare close by; if not on the jeep, at least in the support truck or trailer. Shouldn't be hard to buy, but I run a high output - and try to buy anything these days. It's either out of stock, back ordered, or the sales people don't give a crap.
If I snap a drive line or an axle, pop the motor, put a hole through the radiator, etc - I'm done, and no - I don't have those as spares. That's "major" and we're going to plan B. An alternator and/or belt falls under the "minor - pain-in-the ass" classification and as you stated, not hard to change.
p38
Caught the Bug
Yes - and thanks for the suggestion. I have a smaller version, but we are looking to increase capacity. We are replacing the inverter with a higher output as well. The cameramen carry extra batteries, but the ability to charge them is a definite plus.
bobfriesenhahn
Hooked
In the late '80s I had an alternator start to fail in my CJ-5 while in Canyon Lands. It was really hard to find another. We encountered a kind couple who lead us to an unmarked warehouse and sold us an alternator at a good price. They even helped me install it when they noticed how deeply my tools were buried.
Unfortunately this new alternator had a bad regulator. While we were between nowhere and nowhere in northern New Mexico, it was like a giant hand stopped the jeep. After ten minutes or so it just magically fired up and we reached civilization. Later on the giant hand stopped me on IH-10 in a bad place. Luckily it just fired up not long after a kind police officer called for a tow-truck.
I eventually realized that the alternator was sometimes producing far too much voltage and it fried my ignition module.
Sometimes it is not as easy to find something as trivial as an alternator because there is no convenient store and no one to help.
TrailHunter
Hooked
Bummer. Do you carry a spare now?