zion dual alternator system question

[gerrym51]

in their other models the dual alternator system employs one serpentine belt for the entire system. the y give you a spare serpentine belt since it is not standard size.

when i was looking at my zion package i saw the serpentine,belt.

It was so small there was no way it could do an entire engine let alone with an extra pulley to an extra alternator.

so i thought i either had the wrong belt or the zion was using a separate pulley system with a separate belt. i have heard of dual alternators both ways so that is not an issue but i have a question.

does anyone know if the extra belt alternator system is better or worse or no difference-i am not knowledgeable about this subject

[booster]

IMO, having a separate belt system would be a fairly significant benefit. When the manufacturers design the systems, they size everything big enough to handle the loads, but not with a lot of window. Even putting in a bigger alternator without an extra one, can be too much load for some of the belt systems. If you got a separate belt system, I would consider it a good thing. Just make sure they give you the specs on the belt, and any other expendable parts like idler pulleys, so you can easily get parts if needed.

[gerrym51]

Originally Posted by booster

IMO, having a separate belt system would be a fairly significant benefit. When the manufacturers design the systems, they size everything big enough to handle the loads, but not with a lot of window. Even putting in a bigger alternator without an extra one, can be too much load for some of the belt systems. If you got a separate belt system, I would consider it a good thing. Just make sure they give you the specs on the belt, and any other expendable parts like idler pulleys, so you can easily get parts if needed.

booster-i got an extra belt and the belt number-however in all honesty i would not try to replace either belt myself

and it is confirmed as a separate belt system

[bobojay]

Originally Posted by booster

IMO, having a separate belt system would be a fairly significant benefit. When the manufacturers design the systems, they size everything big enough to handle the loads, but not with a lot of window. Even putting in a bigger alternator without an extra one, can be too much load for some of the belt systems. If you got a separate belt system, I would consider it a good thing. Just make sure they give you the specs on the belt, and any other expendable parts like idler pulleys, so you can easily get parts if needed.

What booster says. Need all part nos.

[wincrasher]

Gerrry,

Can you post some pics of this extra alternator setup?

[gerrym51]

Originally Posted by wincrasher

Gerrry,

Can you post some pics of this extra alternator setup?

i don't take actual physical possesion until the end of next week. I'm also not really mechanically inclined. however i will attempt to get when we get or orientation thursday. the man giving it is very roadtrek knowledgeable and i will attempt to get him to show me

[wincrasher]

Thanks.

I'm interested to see if this is just a commercially available kit, or they've engineered some custom bits similar to ARV.

[gerrym51]

mark posted this


viewtopic.php?f=9&t=3494#p25232

[gerrym51]

Could a 280 amp alternator if the separate pulley for it is large enough give out 280 amps at idle. Just wondering?

[Davydd]

Probably not. The most output I have seen is about 240 at highway speeds. Also, heat diminishes output. Normal seems to be around 200. I don't know how a Promaster is set up but a Sprinter idles normally at about 800 rpms and the Autogen high idle is around 1100-1200 rpms. High idle produces about 150 amps. ARV has ducted air blowing on the alternator for cooling.

As I mentioned before, one hour of driving will restore a day's use of the battery. I probably have a higher use than you will have with an always on wifi booster and cell booster system, two Pioneer receiver units and a boat load of amplifiers. I also just keep the inverter turned on all the time when occupying the B. The inverter on standby is probably eating from 70-100 amps per day. Now that the sun is higher I am getting much more solar contribution and raising my battery reserve during the day despite the inverter on and the compressor 12v refrigerator always at ready to run.

[gerrym51]

Davydd-everything i asked has nothing to do with anything you posted. you have said this spiel at least 20 times-more if you add in other forums-

please

[booster]

How about we give a try at answering the actual question?

Theoretically, you could get full output out of the alternator at idle with the right pully ratios. Unfortunately, those ratios would be spinning the alternator way fast at high engine speeds, possibly causing immediate alternator failure, or at least really shortening life.

There would also be some other possible issues to contend with, would the engine computer get weirded out by the high load at idle, would the alternator get adequate cooling (could cause failure and will cause lower output), would the engine stay cool enough, how noisy, etc.

Possible, yes. Good idea, probably not.

[gerrym51]

Originally Posted by booster

How about we give a try at answering the actual question?

Theoretically, you could get full output out of the alternator at idle with the right pully ratios. Unfortunately, those ratios would be spinning the alternator way fast at high engine speeds, possibly causing immediate alternator failure, or at least really shortening life.

There would also be some other possible issues to contend with, would the engine computer get weirded out by the high load at idle, would the alternator get adequate cooling (could cause failure and will cause lower output), would the engine stay cool enough, how noisy, etc.

Possible, yes. Good idea, probably not.

roadtrek says the zions second alternator gives 280 amps at idle. i specifically asked them at idle. I of course don't believe it/ however since the system is proprietary i can't discount it might be true. Unlike the other roadtrek models the zion gets it's own special alternator/pulley/and belt.

i also have read about bigger alternators than 280. again since i don't have all the info i was just wondering



on the other hand i have been conversing with a woman on facebook who bought a zion 3 weeks ago and was out for their first 3 day trip. she was so happy how t he battery system worked. the salesman said it had the engine generator and 8 batteries. so i guess the system works well with it's extra big alternator and single Northstar sms 400 battery we've discussed in past

[booster]

I would also be suspect of the idle output claim. I looked at some of the DC Power units for Chevy, which are some the highest output at idle and hot around. The best at idle (2400rpm at the alternator) was about 240 amps from a 320 amp unit that cost upwards of $900. It didn't hit full output until 6000rpm alternator. For a vehicle that idles at 700rpm, you would need an 8.6 times pulley ratio, which is huge (most are 3-3.5 ratio) to get to full output. It also means that at 3000 rpm engine speed, it would be turning the alternator at nearly 26,000 rpm, over 50,000 at redline. The normal ratio of 3.5 would turning at 10,500 at 3000 engine speed, and only 21,000rpm at 6000 rpm engine redline.

I just don't think the 280 at idle is reality, but more another of Roadtrek's "misprints" that are really more of fortunate errors that never get corrected.

[gerrym51]

Originally Posted by booster

I would also be suspect of the idle output claim. I looked at some of the DC Power units for Chevy, which are some the highest output at idle and hot around. The best at idle (2400rpm at the alternator) was about 240 amps from a 320 amp unit that cost upwards of $900. It didn't hit full output until 6000rpm alternator. For a vehicle that idles at 700rpm, you would need an 8.6 times pulley ratio, which is huge (most are 3-3.5 ratio) to get to full output. It also means that at 3000 rpm engine speed, it would be turning the alternator at nearly 26,000 rpm, over 50,000 at redline. The normal ratio of 3.5 would turning at 10,500 at 3000 engine speed, and only 21,000rpm at 6000 rpm engine redline.

I just don't think the 280 at idle is reality, but more another of Roadtrek's "misprints" that are really more of fortunate errors that never get corrected.

i know one thing. Roadtrek is tired of my questions-getting down in the weeds. knowing one way or another will not change anything-on the zion the extra alternator is exclusivley the house bank- a bank of one

[booster]

Originally Posted by gerrym51

i know one thing. Roadtrek is tired of my questions-getting down in the weeds. knowing one way or another will not change anything-on the zion the extra alternator is exclusivley the house bank- a bank of one

This old Facebook page references the Nations 270 amp unit on the Zion

https://www.facebook.com/permalink.p...d=147260728552

[gerrym51]

Booster-the 270 amp alternator is a replacement for the promasters original. i have no idea what alternator is used in the dual alternator system