Alternator upgrade

[Drunner97]

I've searched around a little bit, but really haven't found anyone who's actually done this. With the dual batteries and a fridge running full time, it's almost looking like my alternator can't keep up the charge on both batteries. I think this was actually the cause of all the problems I was having in my other thread and the main battery just wasn't charging good enough to start consistently.

I have the Expedition Portal cheap isolator setup. 80 amp isolator, connected to a switch that I can flip to either connect the batteries or leave them isolated. I recently installed a dual voltage panel so that I could monitor the batteries and I was surprised to say the least.

When the batteries are isolated, I get a 13.6 - 14.0 charge to the main battery depending on load.

When the batteries are connected, I get 13.4 - 13.6 on the main battery, and 13.0 - 13.2 on the second battery.

If the fridge is running, I get 12.6-12.8 on the second battery, and 13.2 - 13.4 on the main battery.

This leads me to believe that the stock alternator can't keep up with the charging needs of the dual battery system. I'd hate to see what happens when I switch 4 LED pods (2 white, 2 amber) along with the CB over to the secondary battery.

From searching around I found this link:

Toyota 4Runner High Output Alternators

Which has a 240 amp and a 320 amp alternator. I'm thinking a 240 would handle my needs, but not sure if I'd need to upgrade the belts, the wiring, and the isolator system. Either way I'm pretty sure if I keep trying to push the stock alternator, I'm going to kill it because it's working too hard to keep up with the loads I'm putting on it. Has anyone actually upgraded?

 

[J053619]

[MENTION=77955]jdkilroy[/MENTION] might be able to shed some light on this. I was reading his post because I'm about to do my dual battery setup as well this summer to run my fridge without any issues. Below is the link to his post on upgrading his alternator.

Alternator Upgrade

 

[Brian3676]

I am not sure about a aftermarket higher output alt off the shelf, but a good alt rebuild shop can usually get a little more juice out of yours. I know I have had the local alt shop rebuild a couple for me over the years from different cars and a few I have had up the output. It just slightly downgrades there life is the side affect.

 

[Drunner97]

That answered a couple questions, mostly if I should upgrade the isolator to a 200 amp for the dual battery system, since it looks like he did (vs using the 85 from the kit he's using) Wonder if I'm going to need a belt upgrade.

 

[Drunner97]

I am not sure about a aftermarket higher output alt off the shelf, but a good alt rebuild shop can usually get a little more juice out of yours. I know I have had the local alt shop rebuild a couple for me over the years from different cars and a few I have had up the output. It just slightly downgrades there life is the side affect.

I'd rather buy a high output and keep the stock as a backup. Using the amperage calculator on the site I linked, I'm likely up around 170-180 with everything running so a 240 amp alt should work for my needs and allow some room to add on a winch down the line.

 

[mrpurplepenguin]

I've searched around a little bit, but really haven't found anyone who's actually done this. With the dual batteries and a fridge running full time, it's almost looking like my alternator can't keep up the charge on both batteries. I think this was actually the cause of all the problems I was having in my other thread and the main battery just wasn't charging good enough to start consistently.

I have the Expedition Portal cheap isolator setup. 80 amp isolator, connected to a switch that I can flip to either connect the batteries or leave them isolated. I recently installed a dual voltage panel so that I could monitor the batteries and I was surprised to say the least.

When the batteries are isolated, I get a 13.6 - 14.0 charge to the main battery depending on load.

When the batteries are connected, I get 13.4 - 13.6 on the main battery, and 13.0 - 13.2 on the second battery.

If the fridge is running, I get 12.6-12.8 on the second battery, and 13.2 - 13.4 on the main battery.

This leads me to believe that the stock alternator can't keep up with the charging needs of the dual battery system. I'd hate to see what happens when I switch 4 LED pods (2 white, 2 amber) along with the CB over to the secondary battery.

From searching around I found this link:

Toyota 4Runner High Output Alternators

Which has a 240 amp and a 320 amp alternator. I'm thinking a 240 would handle my needs, but not sure if I'd need to upgrade the belts, the wiring, and the isolator system. Either way I'm pretty sure if I keep trying to push the stock alternator, I'm going to kill it because it's working too hard to keep up with the loads I'm putting on it. Has anyone actually upgraded?

A couple of questions:

Are you measuring battery voltages with your dual voltage panel? Have you verified both readouts agree with each other when connected to the same voltage?

Is your secondary battery 'healthy'? Has it been completely depleted before?

A second battery won't add any (perceptible) additional load to your alternator when it's charged, only if you've discharged it and need to bring it back online. I don't know what fridge you're running, but ARB claims theirs draw < 3A of current; not much added load at all.

I'm not sure I'd trust the amperage calculator on that site; their estimations seem a bit high (30A load for A/C??? 25A for halogen headlights and 20A for foglights?????), which would encourage customers to buy more capacity than they need.

The voltages you're reporting don't seem like they'd be an issue on their own; the more load you have, the more the voltage sags. Are you having reliability problems? The only strange thing I see is that adding the 2nd battery with no load on it shouldn't drag the voltage down if that batt is healthy.

 

[Drunner97]

A couple of questions:

Are you measuring battery voltages with your dual voltage panel? Have you verified both readouts agree with each other when connected to the same voltage?

Is your secondary battery 'healthy'? Has it been completely depleted before?

A second battery won't add any (perceptible) additional load to your alternator when it's charged, only if you've discharged it and need to bring it back online. I don't know what fridge you're running, but ARB claims theirs draw < 3A of current; not much added load at all.

I'm not sure I'd trust the amperage calculator on that site; their estimations seem a bit high (30A load for A/C??? 25A for halogen headlights and 20A for foglights?????), which would encourage customers to buy more capacity than they need.

The voltages you're reporting don't seem like they'd be an issue on their own; the more load you have, the more the voltage sags. Are you having reliability problems? The only strange thing I see is that adding the 2nd battery with no load on it shouldn't drag the voltage down if that batt is healthy.

I have a Whynter 45qt. Battery is 3 months old, it's a deep cycle marine battery. I don't necessarily trust their amp calculator either, but I'm sure it's somewhat close.

I've verified the main battery voltage panel directly at the battery using a meter. You can literally watch it drop when I connect the batteries together, and you can watch it go back up when I isolate them again. Keeping the fridge at 32-35 on an 80 degree day cycles it pretty constantly and if we're stopping and going while on the trail it's not getting a long enough charge at 13.1vs to keep the battery healthy.

Could still be that my stock alt is dying since I'm seeing 13.4 at idle (batteries isolated), but if I'm going to replace it, I might as well upgrade at the same time.

 

[riceandpho]

i think you might have a wiring problem, if the fridge is on and truck is running, the voltage should be the same 13.4-13.8, i myself run dual batteries and a mechman 240amp alternator. i only see my voltage dipped 12 on old batteries, but with the new batteries i have, i maintain a 12.6 on full tilt at idle, when i give it the 2000 rpm rev, the voltage comes back up to the normal 14v.
have you did a big 3 upgrade? try that to stablize the voltage. it might give you an extra volt.

 

[Drunner97]

i think you might have a wiring problem, if the fridge is on and truck is running, the voltage should be the same 13.4-13.8, i myself run dual batteries and a mechman 240amp alternator. i only see my voltage dipped 12 on old batteries, but with the new batteries i have, i maintain a 12.6 on full tilt at idle, when i give it the 2000 rpm rev, the voltage comes back up to the normal 14v.
have you did a big 3 upgrade? try that to stablize the voltage. it might give you an extra volt.

Except you just hit the nail on the head. You're running a 240 amp alt with your dual batteries and you're seeing consistent voltage whereas the stock 130 isn't doing it. Which isolator are you using? I haven't done the big 3 upgrade but I've been reading more and more on it today. I went ahead and ordered the 240 amp alt from the link in the OP, so I'll start there along with an upgrade to a 200 amp isolator (currently on an 85) as well as upgrading to 1/0 cable from the 4 gauge I used initially.

 

[snowboardwcu]

is this at idle or 2k rpm?

When the batteries are isolated, I get a 13.6 - 14.0 charge to the main battery depending on load.

I agree that you may have some wiring issues. time to compartmentalize:
1. what is the voltage of each battery not connected to anything?
2. what voltage does the alternator output (idle and at 2k rpm) disconnected the batteries (just supplying the vehicle alone)

we've covered that your voltage sags as you increase load. this is good. we need to determine why you aren't ever getting higher than 14v. if it were me I would work on that and not include the fridge in the equation until you figure that out.

is your alternator clean, free of debris and crust? (does that matter?).
can you top off both batteries with a charger and see if you get better voltages?

 

[Drunner97]

is this at idle or 2k rpm?


I agree that you may have some wiring issues. time to compartmentalize:
1. what is the voltage of each battery not connected to anything?
2. what voltage does the alternator output (idle and at 2k rpm) disconnected the batteries (just supplying the vehicle alone)

we've covered that your voltage sags as you increase load. this is good. we need to determine why you aren't ever getting higher than 14v. if it were me I would work on that and not include the fridge in the equation until you figure that out.

is your alternator clean, free of debris and crust? (does that matter?).
can you top off both batteries with a charger and see if you get better voltages?

There's another thread somewhere where I was having charging issues that details out the voltages.

So far as I can remember though:

1. Fully charged both batteries show 12.6 non running. Second battery is low right now because I had the fridge running a couple days and I'm not driving enough for it to charge fully right now but it's up to 12.5 with no drain.

2. At idle completely just on the system (with everything removed) I'm at like 13.4, at 2k I'm at 13.6-13.8

3. Alt is probably dirty or dying. Most of my issues started after a deep mucky water crossing after a long weekend of running the fridge, air conditioning, and being at idle or slow speeds off road. I'm fairly convinced that's half the problem although I did swap in a new alt at one point in my troubleshooting process but I never checked charging with the new one because I started having idle issues which seems to be fixed .

 

[snowboardwcu]

i think i remember this other thread. I'm in the middle of designing my dual battery system; pretty sure I came across it while looking into proper voltages and charging info for AGM's.

13.8v seems low. IIRC the alt should put out like 14.3v-14.7v above 2k?

Most of my issues started after a deep mucky water crossing after a long weekend of running the fridge, air conditioning, and being at idle or slow speeds off road.

personally I would put on my money on this being most if not all of the problem. good change the alt and probably even the wiring got gunked up with water/mud, or even possibly shorted out. can an alt partially short out? like one set of coils in it? trying to think why its only providing 13.8

it sounds like you're out on the trails now, when you get a chance you should try spraying down the motor compartment, clean out the alt and try your best at the wiring too.

really curious to see what this ends up being....

 

[Drunner97]

i think i remember this other thread. I'm in the middle of designing my dual battery system; pretty sure I came across it while looking into proper voltages and charging info for AGM's.

13.8v seems low. IIRC the alt should put out like 14.3v-14.7v above 2k?



personally I would put on my money on this being most if not all of the problem. good change the alt and probably even the wiring got gunked up with water/mud, or even possibly shorted out. can an alt partially short out? like one set of coils in it? trying to think why its only providing 13.8

it sounds like you're out on the trails now, when you get a chance you should try spraying down the motor compartment, clean out the alt and try your best at the wiring too.

really curious to see what this ends up being....

Won't be back on the trail until the end of the month which is why I'm trying to get things situated. New alt should be here tomorrow and I'll be installing this weekend. If I can source some 1/0 from home depot I'll rewire the isolator with the 200amp one and fuses that should be here tomorrow too. The dual batteries are wired with 4 gauge currently.

I've cleaned just about every ground and connector I can find, although I may clean the engine bay before I swap just so I don't risk getting any gunk in the new alt. When I ran to the store earlier main battery only was running 13.6 at idle and 13.8 at load, battery is at 12.7 not running.

 

[riceandpho]

i had a stock alternator before and it would dip as low as 12.2 at idle on full tilt with 2 group 31 batteries, i upgraded since my alternator failed on me, heard the whinning sound and it finally decide not to put out a charge. well the stock alternator lasted 8 years, also since u said you run the second battery almost down, itll show that low voltage during charge, its not really good to make the alternator work that hard, good to invest in a smart charger. incase you leave everything on dead. have a good charger and charge both batteries up. i dont think the voltage or alternator issue, also do a big three when you decide to purchase a high output alternator. mine does about 147 at 800 rpm idle and 246 at 1800 rpm. just make sure you get a quality alternator. also on my setup i dont use an isolator, since i dont plan to have my stereo on for long periods of time. i usually have a remote switch inline with the sub amp and just cut that one off, and have both my front and rear amps on.

 

[Drunner97]

Welp, just because everything likes to keep me guessing when I think I had it figured out, something throws another curve ball. 14.2 on startup this morning, held 14.0 down the street to my son's school. Flipped the switch leaving the school, held 13.8 and 13.4 (main/house) once I hit the freeway on the way to work, it held 13.6/13.4. Still not the 14+ I should be seeing on both batteries, but once more this is making me lean towards the Alt going out because it's not staying consistent. Can't wait to see what the 240a alt does to the equation this weekend.

[MENTION=5149]riceandpho[/MENTION] I'm assuming you upgraded the 140a alt fuse when you upgraded to the 240a alt?

 

[Drunner97]

Swapped in the 240a Alternator on stock wiring tonight.

The good:

13.8v at idle on the main battery isolated. Still not quite the 14+ I should see, especially with a HO alt, but it's an improvement above the 13.4-13.6 I was seeing previously.

The Bad:

Still seeing a major drop once I connect the batteries. 13.4-13.6 on the main and 13.1 - 13.4 on the house at idle.

Something is obviously still not right with my dual battery setup. Currently I have an 85a isolator with 80a fuses between the cables on 4g wire. Granted I know that I'm under fused, but that's the directions I got from the Expedition Portal cheap dual battery setup.

I should be receiving a shipment of 1/0 cable and connectors (25 feet each of red/black) which should be enough to do the big 3 upgrade as well as swap in a 200a isolator w/ 200a fuses.

I'm hoping to see a drastic improvement once I upgrade the Big 3 and the isolator setup based on everything I've been reading. If I don't, then I seriously have something majorly wrong with my entire electrical system. I don't know if it really makes a difference, but my current 4g 80a setup isn't soldered, just crimped in the ring connectors. When I redo everything with 1/0 I plan on using solder in hopes that I'm just not transferring the current/voltage well enough via crimp alone. I'll also be hooking up both batteries to a charger to get them fully charged before testing anything further, especially since my house battery has been unable to fully charge the last two weeks.

 

[riceandpho]

Welp, just because everything likes to keep me guessing when I think I had it figured out, something throws another curve ball. 14.2 on startup this morning, held 14.0 down the street to my son's school. Flipped the switch leaving the school, held 13.8 and 13.4 (main/house) once I hit the freeway on the way to work, it held 13.6/13.4. Still not the 14+ I should be seeing on both batteries, but once more this is making me lean towards the Alt going out because it's not staying consistent. Can't wait to see what the 240a alt does to the equation this weekend.

[MENTION=5149]riceandpho[/MENTION] I'm assuming you upgraded the 140a alt fuse when you upgraded to the 240a alt?

i left the fuse in fuse box alone, just ran another fused positive lead during my big 3 upgrade. those 13.4-13.6 seems normal on a 80-90% charged battery. my stock alternator stayed at 13.3 on my scanguage with 2 group 31 batteries and 3 amps on.
http://www.toyota-4runner.org/group-buys/216396-northstar-battery-group-buy-2-0-a-8.html#post2392142
is where i cleaned it up a little bit.

 

[riceandpho]

Swapped in the 240a Alternator on stock wiring tonight.

The good:

13.8v at idle on the main battery isolated. Still not quite the 14+ I should see, especially with a HO alt, but it's an improvement above the 13.4-13.6 I was seeing previously.

The Bad:

Still seeing a major drop once I connect the batteries. 13.4-13.6 on the main and 13.1 - 13.4 on the house at idle.

Something is obviously still not right with my dual battery setup. Currently I have an 85a isolator with 80a fuses between the cables on 4g wire. Granted I know that I'm under fused, but that's the directions I got from the Expedition Portal cheap dual battery setup.

I should be receiving a shipment of 1/0 cable and connectors (25 feet each of red/black) which should be enough to do the big 3 upgrade as well as swap in a 200a isolator w/ 200a fuses.

I'm hoping to see a drastic improvement once I upgrade the Big 3 and the isolator setup based on everything I've been reading. If I don't, then I seriously have something majorly wrong with my entire electrical system. I don't know if it really makes a difference, but my current 4g 80a setup isn't soldered, just crimped in the ring connectors. When I redo everything with 1/0 I plan on using solder in hopes that I'm just not transferring the current/voltage well enough via crimp alone. I'll also be hooking up both batteries to a charger to get them fully charged before testing anything further, especially since my house battery has been unable to fully charge the last two weeks.

upping the big 3 with 1 gauge should help, but you wont see much benefit with 1 gauge to 2nd battery if you dont draw lots of power, even tho running 1 gauge through out the whole truck, you can prepare yourself with later power draws. you dont need to solder, a good crimped ring connector will do fine, i use a hydraulic crimpper and it works just fine, cleaner than my old fold and hammer technique .

 

[Drunner97]

Finished the upgrade today. 1/0 on the big 3 and 1/0 for the dual battery along with a 200a isolator and fuses. Noting above that the system seems to like 13.4-13.6 that's just about exactly what I'm at across both batteries now. I'm holding steady at 13.6-13.8 at idle fully charged on both batteries. With my lights on, a/C full blast, and fridge running I'm maintaining 13.6 at idle whereas before my house battery would be about .5 less.

What's interesting with all the research I've done, is that some people have achieved 14+ with the big 3. There's a 3rd gen video on YouTube that the guy got up to 14.3 after the upgrade. Either way, I'm happy maintaining at 13.6 at idle, especially with the fridge running, because I shouldn't drain either battery on the trail now if we're slowly going through things.

 

[riceandpho]

Finished the upgrade today. 1/0 on the big 3 and 1/0 for the dual battery along with a 200a isolator and fuses. Noting above that the system seems to like 13.4-13.6 that's just about exactly what I'm at across both batteries now. I'm holding steady at 13.6-13.8 at idle fully charged on both batteries. With my lights on, a/C full blast, and fridge running I'm maintaining 13.6 at idle whereas before my house battery would be about .5 less.

What's interesting with all the research I've done, is that some people have achieved 14+ with the big 3. There's a 3rd gen video on YouTube that the guy got up to 14.3 after the upgrade. Either way, I'm happy maintaining at 13.6 at idle, especially with the fridge running, because I shouldn't drain either battery on the trail now if we're slowly going through things.

the voltage is fine. unless you have fresh agm batteries you might see a increase. fresh fully charge batteries will give different reading.
<iframe width="1280" height="720" src="https://www.youtube.com/embed/VBu8jpgrNyg?rel=0" frameborder="0" allowfullscreen></iframe>
see my old battery reading? 13.3 is fine.