is a larger alternator a no brainer?

Joined
Sep 23, 2017
Messages
433
hey guys! here in alberta we get really cold winters and most of my trips are very short trips. i have a 03 hummer h2 with a 6.0l v8. for example i drive 2-3 mins to work. shut off vehicle and then in evening drive 2-3 mins home and shut off vehicle. last winter i was lucky because my battery was relatively new but i noticed that my battery sulfated a bit and it must have been because of it not charging properly. i also do drive on weekends so it obviously charges up on the weekned but sometimes i drive a diff vehicle. i suppose the better way is to just trickle charge the battery whenever i can but i am for sure veyr lazy and i would always forget and just feel like it is a hassle

my alternator is also due for replacement very soon, do you think a larger alternator would be better or does it not make a difference?
my theory is a larger alternator would keep my battery charged quicker and at a higher level which would mitigate any problems from low charge levels?
or would the larger alternator not really make a diff? thx
 
I don't think it'd make a difference. I would add a trickle charger, and also think about how to run it longer, for longer drives, to get the fluids warm and to prevent other issues.

2 to 3 minutes of driving? Is that like 5 minutes of walking? Seems like a very short distance to bother with driving.
 
The battery gets charged at a certain level of voltage no matter how powerful your alternator is. As an alternative you can get an AGM battery. AGM batteries can be charged at a lower voltage and at a lower ambient temperature. My lead-acid battery is charged only to 65% level if I don't charge it manually and I drive more then you. Low level of charge kills lead-acid batteries quickly.
 
I don't think the larger alternator would make a significant difference in charging your battery for such short trips. Not enough driving time for that larger alternator to do its thing.

I have a CTEK battery charger. Had it for a year and am very satisfied with it. You can leave it plugged in. It will act as a trickle charge once the battery is fully charged.

CTEK
 
Originally Posted by supton
2 to 3 minutes of driving? Is that like 5 minutes of walking? Seems like a very short distance to bother with driving.

OP is from Alberta, Canada but doesn't state where.
Wintertime temps regularly get into the below 0°F range in that locale.
I'd prefer to drive just to stay out of the wind in those conditions...
 
My S600 gets cranky if it sits for more than a week or two. Nature of the beast. It's got an enormous AGM battery and a liquid cooled 200amp alternator, but even that can get low if it sits.

So, though yours isn't sitting, your short tripping is likely as bad as sitting, perhaps worse.

I got a battery tender. https://www.batterytender.com/Battery-TenderR-Plus - (cheaper on Amazon by the way).

Then, installed the terminal rings for a quick disconnect. I plug it in if it's going to sit.

In your case, plug it in overnight once in a while and keep the battery healthy.

If the car sits outside, get the extension cord so that the charger sits inside.

https://www.amazon.com/Battery-Tender-081-0148-25-Disconnect-Extension/dp/B000FW2MWW
 
Last edited:
Originally Posted by Imp4
supton said:
I'd prefer to drive just to stay out of the wind in those conditions...

+1
Driving everywhere is just a part of life in that part of Canada.
As a result, obesity also seems to be prevalent.

correlation?
maybe
 
Why not just take the long way to work/home each day? Short trips aren't good for the engine.. condensation build up in the crank, etc.
 
Originally Posted by apollo18
i suppose the better way is to just trickle charge the battery whenever i can but i am for sure veyr lazy and i would always forget and just feel like it is a hassle


Do you have outlets where you park? Get one of those quick connects that hangs out the grille and it won't take any time at all. You can wire in a block heater as well, which is a topic also worth considering.
 
In southern areas I would be thinking about adding a solar charger to a vehicle that was constantly under-used. But up North any solar charger would have to be seriously upgraded to take into account the reduced amount of sunlight and the poor angle that that sunlight arrives at.

OP, I do not know, are you far enough north that you get days with no daylight in the winter? If so even a seriously upgraded solar array would not work.

One thing, a Hummer would have enough hood space to put a solar array on, and it would be at a height that would make it easier to clean the snow off of. Though all that cleaning might be a PIA, and even if you clean it, it could snow again before the solar array did its job. But a solar array would not have to work every day in order to still be effective.
 
The above is correct, the battery will only accept so many amps. Your alternator is not too small either, as it's likely a fairly righteous 145 Amp unit.

Batteries will take a lot of amps for a few seconds after start, after that the "rate" of charge tapers down. A healthy battery might look like this:

Right after start 90A
20 seconds after start 30A and dropping fast
60 seconds after start 10A or less
3 minutes after start 5A or less

As you can see, a 200A alternator won't affect that.
 
Originally Posted by Imp4
Originally Posted by supton
2 to 3 minutes of driving? Is that like 5 minutes of walking? Seems like a very short distance to bother with driving.

OP is from Alberta, Canada but doesn't state where.
Wintertime temps regularly get into the below 0°F range in that locale.
I'd prefer to drive just to stay out of the wind in those conditions...

Fair enough--but that's not every day conditions. Surely there are many days where walking is an option. Rainy days, not so much, but shave a few days of the week off and it's all the easier on the vehicle in question.

Not my decision to make, just tossing out the concept. Sometimes possible solutions get overlooked.
 
Originally Posted by JimPghPA
He could run the engine for 20 to 30 minutes before he gets in the vehicle to both pre-heat the inside of the cab and charge the battery.

Great idea. This way he'll save on the cost of the more expensive alternator.
 
ahh thx for the replies and input everyone
i guess im just gonna trickle charge it with my noco g3500 every couple days or whenever i am short tripping. with quick disconnect it shouldnt be too hard to do
 
It seems as if there are some pretty obvious solutions here:

1. solar panel while outside (does OP park in garage at home or work? This hasn't been answered yet?)

2. Hookup a charger as frequently as the OP can bear. If the OP has a garage or accessible outdoor outlet at home?

3. Drive longer distances...while gas is cheap. I can't imagine the OP, with his driving style is getting even double-digit MPG's

Originally Posted by kschachn
Originally Posted by JimPghPA
He could run the engine for 20 to 30 minutes before he gets in the vehicle to both pre-heat the inside of the cab and charge the battery.

Great idea. This way he'll save on the cost of the more expensive alternator.


In a few years, he will have burned enough gas to buy a new battery...Idling isn't IDEAL for the engine, either.

Assumptions:

0.3 GPH at idle (is it higher for this large of an engine - probably)
0.5 hrs/day warm-up
5 days/week
26 weeks/year (half the year)

//

Regarding walking instead of driving for the sake of the engine: ridiculous! This thing is a machine designed to operate for the owner, not the other way around.

//

Again, WHY does the OP think he needs a new alternator??? He doesn't mention WANTING a replacement, but says that it's "due".
 
Originally Posted by JimPghPA
He could run the engine for 20 to 30 minutes before he gets in the vehicle to both pre-heat the inside of the cab and charge the battery.


If the battery is significantly run down, it could take several hours or more for the battery to charge up. Twenty or thirty minutes extra time would be beneficial, but not enough to recharge an already low battery. That's due to the chemistry of lead acid batteries, not the output of the alternator.

If this was my car and I lived in the Great White North, I would seriously consider installing both a block heater and a battery tender and plugging it in overnight. The battery would be a lot happier and it could reduce the negative effects of short trips.
 
Putting it on a low amp smart charger is the best thing between trips.

Neither your alternator or a larger one will ever fully charge that or any 12V battery, no matter how long the trip - where a smart charger will.

A larger alternator becomes a no brainer when you have a second bank you have to service, like an RV with a starting battery and a house bank, or when the vehicle is used commercially powering auxiliary lights or electric loads.



UD
 
Back
Top