Alternator replacement

[great white]

no

Get a second battery if you don't have one already and upgrade the ground/alternator cables.

Actually, it is.

External rectifier bridge, external voltage regulator, larger case, improved bearings, twin internal fan assemblies (one front, one rear).

It all equates to longer service life, cooling running and higher average output.

A cooler alternator means more amperage. As they get hotter, the amperage drops. This is why an alt rated at 140A can often be measured closer to 200A when it first kicks off. As it heats up, it comes down to its rating. As it gets hotter than its rated output temperature, the amperage drops lower than the rating. Even though a cs140 and an ad244 are both rated at 140A, if the ad244 is running cooler it will have more output. Might be talking 5-10 Amps, but 5-10 amps is significant.

If the op needs more than an ad244 puts out then an aftermarket higher amperage or dual alternators are called for.

Dual batteries are good for extra "hold over" time with high draw electronics, but you need to recharge them once the load has dropped. A single or lower amperage alt is going to take twice as long to charge two batteries in parallel as it will one.

For example: one 700 CCA battery will take an alternator (on average) 8-10 hrs to replenish a deep discharge (is: heavy winch). That same alt is going to require 13-15 he's to recharge two 700 CCA batteries in parallel (1400 CCA).

Higher amperage alternators (or dual) can put out more amps, but there's a limit to how much and how fast you can cram it back into the batteries. If you don't exceed the amperage capabilitybof the alternator with your loads, you're good. At least while the engine is running that is.

This is why I run dual alts on my truck. I have a high enough amperage load that it draws my dual batteries down at the worst time, right at start. Mine function to put the charge back into my batteries so I can start that big diesel once I get to where i'm going. I also have heavy heating loads. My washer heater pulls 60A all on its own. The glow plugs for starting kick the living crap out of the 1800-odd CCA.

Dual alts give me a potential 210 amps when on speed. If I were to go to dual ad244's (bolt on for my ce130d's) I'd be looking at 280 amps. Overkill for my situation but pretty good for OEM parts you can by at any parts store instead of having to wait for a custom apt to replace a bad one.

Vehicles subject to high loads and short drives are best put on a trickle charger once a week to maintain battery heath. Short drives don't give any alt enough time to replenish the batteries.

If going with a higher amperage aftermarket alternator and high amperage draw items (like a winch), up sizing cabling is always a wise decision. Just make sure the fuseable link in the alt wiring is not bypassed....

 

[aarolar]

So talk to me about how you would do the dual battery setup for my uses great white. I don't need extra cranking like you so I was going to use an isolator on the second battery and dedicate one to cranking and the other to running the accessories. Is this better or should I just run two in parallel? Also if I do use an isolator could/should I use a deep cycle marine battery for the accessory batter to get better service life?

 

[great white]

Sorry, don't know a lot about isolated systems.

Best to check out some of the cruising/boat sites.

They deal with battery banks, charging and isolation circuits a lot.

I set up dual systems in parallel and have the extra amperage available all the time. Same with my dual alts. I prefer it this way as instead of only having 700-800CCA available I have the full 1600CCA. It also means more Ahrs, but CCA is easier to talk about as most guys see that number on the top of thier battery.

I do set up isolated systems if a guy wants them, but I'm not the guy to talk to. I pretty much just follow instructions that come with the isolator of choice...

Boat sites also address multiple alternators and multiple battery banks.

 

[great white]

Double post, please delete.

 

[aarolar]

So basically you feel a true dual battery setup is more effective?

 

[great white]

So basically you feel a true dual battery setup is more effective?

For my dollar, yes.

But it all comes down to what you want it to do.

Mine is for starting, charging and running accessories in cold/crappy weather. I also have a few items that are high draw that I use when out on ground SAR or squadron exercise. Lots of times my truck ends up being base camp since its fairly multirole. I sort of built it that way half on purpose.

The extra capacity kind of loafs along the rest of the timr except for supplying charge for the trailer on long hauls.

It keeps my big batteries nice and fresh though. They're over 6 years old now and going strong.

I also have an on board battery tender (schumacher) that plugs in with the block heater every night in the winter (no block heater in summer, just the charger) which helps the batteries live a long and happy life.

If you plan to run your batteries until they are below starting reliably, isolating the second battery might be a good idea. I prefer to have as many AHrs as possible and recharge or shutdown before its too low. I have a monitor and alarm on mine for this purpose when used as base camp.

Soon, it will have an autostart monitor hooked up for the same purpose. Although I've never run into a no start condition because of the batteries, no harm in one more layer of protection.

When I'm base camp, not being able to run/charge lights or radios is not an option.

Hmmm, maybe a twin set of ad244's wouldn't be a bad idea after all......