H/O alt question

[ssh 924]

I have a 1997 jeep wrangler, the stock alt makes about 90amps and idles at 14v without amps connected.

If I put a h/o alt 200amp, at idle what would my voltage be without amps connected? I'm assuming its going to vary from one vehicle to another, but stock alt 90amps = 14v idle, so 200amps = 14.5v? 15v?

Is there any way for me to estimate the voltage at idle?

[Impious 1,476]

The voltage likely won't be significantly higher at idle than you currently have. The purpose of a high output alternator isn't to increase voltage at idle, but to limit voltage drop when under heavy load (and typically at non-idle RPM's) by having higher current output capabilities.

[abmoore 8]

Your voltage also depends on your batteries. A 12 V battery is normally regulated at 14.6V when fully charged on a stock electrical. A 16V battery requires a 16V alternator and will charge up to 19V. So a new aftermarket battery has a chance that it will rest higher than 12.4-12.6, and a chance that it will charge greater than 14.6V, like you sometimes may see when a voltage meter reads 14.8V. Also depends on the battery, AGM batteries shouldn't be used above 14.6V because it damages the cells. All of these numbers are plus minus some percentage but generally around here.

[ssh 924]

Okay, well this is going to be in my daily driver around town, so 99% of the time when im listening to music it won't be at idle but actually driving in higher rpms

So I could go with a h/o alt and get a 14v battery and charge it at 15v-16v and then when im driving around town the alt will make sufficient power and the battery will have more power than a regular 12v. Correct?

I'm planning on getting the sae-1200d, I see its rated up to 15v, so would the h/o alt make too much? or would I have to get a regulator?

I would rather have an h/o alt and a good battery than multiple batteries.

Edited April 21, 2010 by stefanhinote

[abmoore 8]

There are 12V batteries and 16V batteries that are most commonly used. To upgrade to 16V, you need a different alt, regulator, and a few extras since your electrical system is designed to work at 14.4V, not 19V. So no, just by adding a HO alt, you cannot run 16V.

There would be no point in getting that extra .5 V anyway, it would be less than 100 watt difference, which you will never be close to hearing. A better box would make a bigger difference. And for that amp, a secondary battery would be enough, or a larger starting batt. A HO alt could help some but it might not be worth the money for you, but I could be wrong.

Edited April 21, 2010 by NCSU ECE

[ssh 924]

When you said there is a chance the battery could charge greater than 14.6v, were you referring to 12v batteries? If so I could use a h/o alt and just a 12v battery, right?

Thanks NCSU ECE

[abmoore 8]

When you said there is a chance the battery could charge greater than 14.6v, were you referring to 12v batteries? If so I could use a h/o alt and just a 12v battery, right?

Thanks NCSU ECE

I meant more of a luck of the draw due to the tolerance of the voltage in the batteries. And sometimes when sitting for a while on a cool day I see mine sitting at 14.7, that's all I meant. Some people on here use the XS Power regulator, hopefully one of them chimes in about that, I myself am interested in it since you can set your voltage to 15.2 or something like that.

[ssh 924]

When you said there is a chance the battery could charge greater than 14.6v, were you referring to 12v batteries? If so I could use a h/o alt and just a 12v battery, right?

Thanks NCSU ECE

I meant more of a luck of the draw due to the tolerance of the voltage in the batteries. And sometimes when sitting for a while on a cool day I see mine sitting at 14.7, that's all I meant. Some people on here use the XS Power regulator, hopefully one of them chimes in about that, I myself am interested in it since you can set your voltage to 15.2 or something like that.

Okay, well I'm thinking about getting an h/o alt soon

If I can afford to get two batteries I will, but for now i'll probably have to make due with one. This is what im looking at: Mean Green MG1334 - Mean Green Alternator for 91-98 Jeep® Wrangler YJ; Cherokee XJ & TJ with 4 or 6 Cylinder - Quadratec

[gonzala 1]

Hey, fellow jeep owner here. I just put a 200 amp alt into my cherokee, while I did need to grind the mounting brackets a bit it went in without to much yelling and cursing. Bought it off ebay though which sounded a little sketch I'll admit but I haven't had any problems with it and my amp doesn't go into protection mode anymore. Mean Green alts are just crazy expensive.

Another option could be the 160 amp alt from a 05 grand cherokee, you would just need to locate one with the right plug for the voltage regulator that matches your jeep or try to attach the wires is some fashion to the alt.

[ssh 924]

Hey, fellow jeep owner here. I just put a 200 amp alt into my cherokee, while I did need to grind the mounting brackets a bit it went in without to much yelling and cursing. Bought it off ebay though which sounded a little sketch I'll admit but I haven't had any problems with it and my amp doesn't go into protection mode anymore. Mean Green alts are just crazy expensive.

Another option could be the 160 amp alt from a 05 grand cherokee, you would just need to locate one with the right plug for the voltage regulator that matches your jeep or try to attach the wires is some fashion to the alt.

Thanks Gonzala, I'll look into the stock alt on the newer cherokees and see what other alts are out there.

[j-roadtatts 1,129]

a HO alt won't charge at any different voltage than a factory one, reason being, the voltage reg built into the alt controlls volts. The purpose of the HO is to maintain the same voltage with or without a LARGE AMP draw. The two alternaters will do the same job until you demand more AMPS than the factory on can produce, THEN this is where the HO will keep a constant 14.4, and the factory one will NOT be able to keep a constant voltage.

I personally would recommend a HO alt over a second battery for a daily driver.

What to expect from an HO alt, WHEN you crank the volume up, the amps "maintain" authority, and will not start to fade.

I personally like DC Power Alternators, and feel YOU get what you pay for.

[ssh 924]

a HO alt won't charge at any different voltage than a factory one, reason being, the voltage reg built into the alt controlls volts. The purpose of the HO is to maintain the same voltage with or without a LARGE AMP draw. The two alternaters will do the same job until you demand more AMPS than the factory on can produce, THEN this is where the HO will keep a constant 14.4, and the factory one will NOT be able to keep a constant voltage.

I personally would recommend a HO alt over a second battery for a daily driver.

What to expect from an HO alt, WHEN you crank the volume up, the amps "maintain" authority, and will not start to fade.

I personally like DC Power Alternators, and feel YOU get what you pay for.

Thanks, I understand it now

So If the h/o alt is large enough then I won't have voltage drop (or much less) compared to stock. Sounds perfect. DC power doesn't make one for a wrangler, but I read in some jeep forums and everyone likes the mean green one. thanks for the help

Edited April 21, 2010 by stefanhinote

[abmoore 8]

First of all, that is not necessarily true. I recommend the opposite. For the amount of current you are pulling, a decent agm battery under the hood and a small secondary in the back should be fine. An alternator cannot discharge current instantaneously, although it does make a difference in larger set ups where the alternator is straining to charge the system. It is also not good for the life of a battery to be discharged everytime a large note hits. So the combo of the two is obviously the best, but with only one hundred some odd amps, the battery route will be cheaper and sufficient. If you do look at alts, there are other proven brands like powermaster, ohio generators and iraggi.

[j-roadtatts 1,129]

First of all, that is not necessarily true. I recommend the opposite. For the amount of current you are pulling, a decent agm battery under the hood and a small secondary in the back should be fine. An alternator cannot discharge current instantaneously, although it does make a difference in larger set ups where the alternator is straining to charge the system. It is also not good for the life of a battery to be discharged everytime a large note hits. So the combo of the two is obviously the best, but with only one hundred some odd amps, the battery route will be cheaper and sufficient. If you do look at alts, there are other proven brands like powermaster, ohio generators and iraggi.

An HO alternator supplys the current continuously NOT instantaneously. SO NOTHING is straining, not the battery, not the amplifier, not the HO alternator.

A larger or dual battery is only helpful for a short instataneously burst and then is useless until charged again. THIS IS the "claim to fame" of the AGM gel batterys is they recover quick. What is going to make them recover quick????? one of two things either you will turn down the volume until your factory alternator recharges them OR YOU INSTALL a HO alternator and DON'T have to turn the volume down to recover, you just keep enjoying your music.

[abmoore 8]

First of all, that is not necessarily true. I recommend the opposite. For the amount of current you are pulling, a decent agm battery under the hood and a small secondary in the back should be fine. An alternator cannot discharge current instantaneously, although it does make a difference in larger set ups where the alternator is straining to charge the system. It is also not good for the life of a battery to be discharged everytime a large note hits. So the combo of the two is obviously the best, but with only one hundred some odd amps, the battery route will be cheaper and sufficient. If you do look at alts, there are other proven brands like powermaster, ohio generators and iraggi.

An HO alternator supplys the current continuously NOT instantaneously. SO NOTHING is straining, not the battery, not the amplifier, not the HO alternator.

A larger or dual battery is only helpful for a short instataneously burst and then is useless until charged again. THIS IS the "claim to fame" of the AGM gel batterys is they recover quick. What is going to make them recover quick????? one of two things either you will turn down the volume until your factory alternator recharges them OR YOU INSTALL a HO alternator and DON'T have to turn the volume down to recover, you just keep enjoying your music.

Reread my post, I said it doesn't supply current instantaneously. Most alternators DO NOT continuously supply max current. With more reserve power, those short burst don't affect the voltage as much. And most likely his alt will not be putting out full power, unless he is reving his engine... Batteries also don't recharge immediately, it's a logarithmic recharge. And what about long drives when the alt heats up? Then it really is not putting out full current. Like I said the combo is the only sure way of maintaining voltage constantly, I was trying to save him money because with that little amount of current draw, he will be fine with batts. Even cheap ones like Dekas. With less than 200 amps of current, ESPECIALLY with music, there is no need to spend $5-600. I have seen many cars be fine with just larger batteries pulling that same amount of current. And he WOULD be discharging the stock battery every time a large note hits.... The alternator can't immediately charge that. Maybe we can agree on a battcap or something like that. Recharges quickly and discharges fast, it's not like he is competing.

[j-roadtatts 1,129]

To answer the OPs question, No a HO alternator will not charge at any different voltage than your factory one unless its regulated to do so.

[j-roadtatts 1,129]

a HO alt won't charge at any different voltage than a factory one, reason being, the voltage reg built into the alt controlls volts. The purpose of the HO is to maintain the same voltage with or without a LARGE AMP draw. The two alternaters will do the same job until you demand more AMPS than the factory on can produce, THEN this is where the HO will keep a constant 14.4, and the factory one will NOT be able to keep a constant voltage.

I personally would recommend a HO alt over a second battery for a daily driver.

What to expect from an HO alt, WHEN you crank the volume up, the amps "maintain" authority, and will not start to fade.

I personally like DC Power Alternators, and feel YOU get what you pay for.

I am not recommending that the OP spend 5-600 bucks on an HO, BUT do think anyone contemplating adding a second battery should also concider a HO alternator as a better solution for a Daily Driver.

[abmoore 8]

a HO alt won't charge at any different voltage than a factory one, reason being, the voltage reg built into the alt controlls volts. The purpose of the HO is to maintain the same voltage with or without a LARGE AMP draw. The two alternaters will do the same job until you demand more AMPS than the factory on can produce, THEN this is where the HO will keep a constant 14.4, and the factory one will NOT be able to keep a constant voltage.

I personally would recommend a HO alt over a second battery for a daily driver.

What to expect from an HO alt, WHEN you crank the volume up, the amps "maintain" authority, and will not start to fade.

I personally like DC Power Alternators, and feel YOU get what you pay for.

I am not recommending that the OP spend 5-600 bucks on an HO, BUT do think anyone contemplating adding a second battery should also concider a HO alternator as a better solution for a Daily Driver.

Agreed. ::

Edited April 21, 2010 by NCSU ECE

[j-roadtatts 1,129]

Good to see ppl agreeing,lol. Anyways I voted everybody up +1 for helping in this topic. (execpt myself).

[abmoore 8]

Good to see ppl agreeing,lol. Anyways I voted everybody up +1 for helping in this topic. (execpt myself).

Back at you ::

[ssh 924]

Yeah thanks for all the help you guys.

[abmoore 8]

No problem, keep us updated on the decisions you make or if you need anymore help with that.