Alternator that produces AC power?

[justinm001]

Thank you so much, I'm still learning all about how this side of electricity works. My biggest concern is reliability, then performance then price. Weight and size doesn't really play much of a factor and we use this primarily for day trips so having tons of alternator power really helps keep the battery charged.

Problem i'm running into is there isn't many 24 to 48v converters and I haven't found any that do high power and will be at a voltage that'll charge the batteries. Looks like I'll have to get 6 Victron Orion-TR 24/48 8.5a/400w converters and run them all in parallel to give me 2400w then 3 Orion 24/12 70a/840w converters to give me 2500w. This should be just enough to power 2000w AC unit on either/both system minus any losses and maybe cover my 100-150w idle load on the 12V side. I ordered one of each so will try it out hopefully using a couple spare batteries i have to make 24v. 9 converters will take up quite a bit of space and i'll likely need to add fans and some metal mounting to act as a heatsink if I'm planning to run all at full power. I guess one of the benefits is redundancy as well as ability to use switches to control how many are turned on and when... Thinking a couple switches on the dash, one a 3 position 12/48/both and other 3 position off/half/full. This would give me a ton of control in how I want to use that power compared to performance and fuel consumption.

Another option would be to swap the alternators and use the large 270a one for my chassis system and then swap the old chassis with a pair of 24V alternators, wire them together and use the wakespeed i have to regulate them both. I'm just worried about it not being clean enough power for lithium when using 2 alternators in series with a high load like twin 200a 24v alternators pumping 10kw into a 48v system. Maybe this will be the next phase of my build when I want to take the genset out.

 

[mikefitz]

Connect the alternators as follows :

24 volt Alternator1 (12v battery + 12v battery) + 24 volts Alternator2 (12v battery + 12v battery) = 48 volts

Most alternators have the alternator frame connected to alternator negative, you idea would need alternators with fully isolated outputs.
Even then I cannot see equal charging of the two 24 volt batteries.

 

[justinm001]

Most alternators have the alternator frame connected to alternator negative, you idea would need alternators with fully isolated outputs.
Even then I cannot see equal charging of the two 24 volt batteries.

most industrial and higher end alternators have isolated grounds that have a frame ground wire connected.

The batteries wouldn't need to be equally charged. When the alt is running the voltage should be at like 28V regardless of the battery charge rate, just more alt power is charging the lower SoC battery more than the higher one... until they charge up. These batteries are just for buffer so would always stay charged

 

[Vigo]

This should be just enough to power 2000w AC unit on either/both system minus any losses and maybe cover my 100-150w idle load on the 12V side.

I love the idea of dc-dc converters for the 'simplicity' of the system but in practice, if you are talking big watt numbers like 2000w to run an AC, it usually ends up being cheaper and less TOTAL components to simply power an inverter with the main battery voltage, then use AC-powered battery chargers or power supplies to change that back to the other voltages you need.

For example, a $400 EG4 chargeverter could do either 3000 or 5000w from your 24v into your 48v bank.. it just goes through your 24v Inverter first (which itself would have to be able to supply 3000 or 5000w to begin with). If you already had enough capacity on your 24v inverter that is probably cheaper and less pieces to wire in than multiple DC-DC step up converters. You can also get something like 2x these ~$80 1200w 60v power supplies in parallel to get your 2kw number if you didn't need the extra wattage or adjustable current limit of the Chargeverter.

On the 12v side the options are VERY cheap. Basically any 12v battery charger or power supply would be able to keep up with a 150w draw for very little money, say ~$30 or possibly even less. You can get a 360w 12v power supply for $22, like this.

These ideas do rely on you having spare 24v inverter capacity to do these tasks.

 

[justinm001]

I love the idea of dc-dc converters for the 'simplicity' of the system but in practice, if you are talking big watt numbers like 2000w to run an AC, it usually ends up being cheaper and less TOTAL components to simply power an inverter with the main battery voltage, then use AC-powered battery chargers or power supplies to change that back to the other voltages you need.

For example, a $400 EG4 chargeverter could do either 3000 or 5000w from your 24v into your 48v bank.. it just goes through your 24v Inverter first (which itself would have to be able to supply 3000 or 5000w to begin with). If you already had enough capacity on your 24v inverter that is probably cheaper and less pieces to wire in than multiple DC-DC step up converters. You can also get something like 2x these ~$80 1200w 60v power supplies in parallel to get your 2kw number if you didn't need the extra wattage or adjustable current limit of the Chargeverter.

The problem is I have a 5kw 12V inverter and main dc load then 48v 10kw split phase inverters. I don't have any 24v components currently other than my chassis and this massive alternator. I really don't want a 4th inverter and separate system

 

[Vigo]

48V 5000w Quattro connected to 2x100ah 48V SOG rack feeding 12V Quattro

Can you clarify how the 48v quattro is feeding the 12v quattro? Do you mean that the AC output of the 48v is hooked to the AC input of the 12v?

I think i need a better big-picture view of what you power with these two inverters to give my best response, but i'll attempt a suggestion even in my half-blind state anyway:

Since you have such a large 12v inverter, I'd suggest using your 24v alt/starter-batt system to feed the 12v system (since 24 down to 12 is cheaper than 24 up to 48) and using the 12v inverter to power an AC charger/power supply for the 48v battery system if you ultimately want to get power from your 24v alt into your 48v system. Im assuming the only reason you would ever need to transfer 2000w is for the purposes of running the air conditioner, so if that's the case you could simply wire an AC circuit from your 12v inverter to the air conditioner and mount a cheap manual transfer switch to switch that air conditioners power feed between the 12v and 48v systems as needed. If you don't need 2000w of alternator power into the 48v system for any other reason you could get by with a much smaller/cheaper 48v charger/power supply to feed from the 12v inverter into the 48v battery bank. Cheapest I know of is roughly 6 cents per watt of 48v power supply. Aka if you only wanted 600w of transfer from your 12v inverter to your 48v battery bank, a power supply to do that would be ~$35 at rock bottom of the chinesium options.

I looked up what a "100a vanner" is and it sounds like you already have a 100a 24-12v non-isolated step down converter right there, but it's not clear to me whether that is ever hooked to your 12v lifepo4 bank or not. If that's an option there's ~1kw of power from your 24v alt into your 12v quattro right there. If not, I would suggest adding some (2 or 3) of these 70a 24-12v Victron DC-DC converters from your 24v system to your 12v lifepo4 bank. I suggest those only because you'd be getting Victron quality/support at a relatively small upcharge vs buying the same capacity of chinese DC-DC from a brand like UXCELL or some other clone entity.

Hope i haven't misunderstood to the point of this entire post being useless, but i feel like i might have.. lol

 

[justinm001]

Can you clarify how the 48v quattro is feeding the 12v quattro? Do you mean that the AC output of the 48v is hooked to the AC input of the 12v?

I think i need a better big-picture view of what you power with these two inverters to give my best response, but i'll attempt a suggestion even in my half-blind state anyway:

Since you have such a large 12v inverter, I'd suggest using your 24v alt/starter-batt system to feed the 12v system (since 24 down to 12 is cheaper than 24 up to 48) and using the 12v inverter to power an AC charger/power supply for the 48v battery system if you ultimately want to get power from your 24v alt into your 48v system. Im assuming the only reason you would ever need to transfer 2000w is for the purposes of running the air conditioner, so if that's the case you could simply wire an AC circuit from your 12v inverter to the air conditioner and mount a cheap manual transfer switch to switch that air conditioners power feed between the 12v and 48v systems as needed. If you don't need 2000w of alternator power into the 48v system for any other reason you could get by with a much smaller/cheaper 48v charger/power supply to feed from the 12v inverter into the 48v battery bank. Cheapest I know of is roughly 6 cents per watt of 48v power supply. Aka if you only wanted 600w of transfer from your 12v inverter to your 48v battery bank, a power supply to do that would be ~$35 at rock bottom of the chinesium options.

I looked up what a "100a vanner" is and it sounds like you already have a 100a 24-12v non-isolated step down converter right there, but it's not clear to me whether that is ever hooked to your 12v lifepo4 bank or not. If that's an option there's ~1kw of power from your 24v alt into your 12v quattro right there. If not, I would suggest adding some (2 or 3) of these 70a 24-12v Victron DC-DC converters from your 24v system to your 12v lifepo4 bank. I suggest those only because you'd be getting Victron quality/support at a relatively small upcharge vs buying the same capacity of chinese DC-DC from a brand like UXCELL or some other clone entity.

Hope i haven't misunderstood to the point of this entire post being useless, but i feel like i might have.. lol

So I have 50a shore and 100a genny going into a pair of Victron Quattro 48v 5000w inverters as a split phase setup. This then feeds into most loads including in2 of my 12v 5000w Quattro which powers the rest of the loads (1 ac and some outlets). I have 6 ac units in my coach and a ton of electronics. My 12v system handles all the house DC loads.

I have a genny 12v battery which is separate not attached to anything.

The big engine runs off 24V power using 4 12v batteries in a series/parallel. This uses the 100a vanner for the chassis 12v and equalizes everything. None of this is connected to my LFP systems and it has its own 70a 24v alternator.

I ordered a 24/12 70a and a 24/48 8.5a which I'll try to wire into the 24v chassis battery using just that 70a alt. If these both work good I'll try to link my 24v 270a alternator into the chassis batteries so I have even more charging capacity. I should be able to put 6 of those 48v and 3 of the 12v all together to get a ton more power.

We use the coach mainly for day/weekend trips. Each battery system has 10kwh batteries so if I can get 2kw on each from the alt I then can charge 20% an hour, and/or use AC units.

 

[justinm001]

I also have this thingy that I have no idea what it does. If I switch it to alt2 it lights both the red alt lights up. I asked the Prevost forums and no responses, didn't see anything in the manual but to be honest didn't look much as it's literally a paper box full of notebooks and never been able to find anything in there

 

[Red_Fir]

Soo if you had an AC " alternator" running "near" your desired voltage you could use a Sola Isolating Transformer to clean up the sine wave and voltage, also a clever individual could use a freq drive to transform and tune up the voltage and sine ( a freq driv converts ac into a "pool" of dc and then using a computer signal it cycles a reversing relay in adequate time to provide proper sine, and the voltage is also controlled in amplitude), but ... both are tremendously wasteful Sola's get so hot you can literally cook on them, and freq drives while elegant are power hungry in their own right.
There are a couple of alternators that put out 200 amps (2400 watts! the equivalent of a regular twenty amp outlet on your house.) and they advertise you can weld with them, but ... its a minuscule duty cycle -weld for a minute and let it cool for five.
Generally the rule is never load any circuit more than 80% so thats 1600 watts ... and an extended run even at the reduced capacity will let the smoke out!
Finally every alternator (and most generators) start producing AC, and its rectified with diodes or in the case of generators via clever arrangements of the pick up brushes, a very few use SCR's, the diodes can be removed and then the amplitude of the AC voltages are controlled entirely by field strength (the regulator), and rotational speed.
You can spend months sorting this solution out, and it will still be an attention demanding kludge and for just a few dollars Harbor Freight will sell you a generator that will be quieter, more dependable, and all you need to do is provide a well ventilated compartment for it to sit, you can find generators fueled by everything from woodsmoke (producer gas) to waste motor oil, and if your not feeling adventurous remotely started, dual fuel, automatic transfer controlled, that once installed will run out of your main fuel tank and require an oil change every 3 months ... and nothing else.

 

[justinm001]

Thank you! I think the best option if I was dead set on this is to get a small 24v lead acid battery then a 24v inverter. Hook this up to 1 or 2 massive alternators (50dn+ is 450a) and have the inverter turn on when then engine is running.

I'm planning on going with a bunch of DC to DC converters and hooked up my large 24v alternator to my small 24v alternator which is hooked up to my chassis batteries.

I tested this with a 24 to 12v Orion 70a and somethings wrong. Somehow my basement bay door lights were all on but were 12v and not the 24v and when I turned the key they were 24v. I suspect someone rewired these or did something as there's 2 switches in the coach to turn them on/off and neither have ever done anything. They only turn on with the key and have contact sensors on every door so only are on if door opened. I plan on replacing these all with led strips but the 24v has been the problem. Also I'd like them to be on all the time or at least use a switch.

Also the 24 to 12v Orion wasn't charging so maybe faulty. Need to diagnose more

 

[jberger]

Most Prevost chassis are wired with both 24v and 12v outputs from the same house bank. I think you probably need to validate the wiring and loads for each then work out the architecture based on those details. When you buy a used coach, you inherit whatever was done before and it gets expensive when the previous owner made changes that weren't recorded anywhere.

A couple of hours at a Prevost service center would probably get that stuff mapped out for you and ensure you aren't burning up anything with the incorrect voltage. Once you get it mapped out, label and document the heck out of it so there is no roadside repeat performance.

 

[justinm001]

Most Prevost chassis are wired with both 24v and 12v outputs from the same house bank. I think you probably need to validate the wiring and loads for each then work out the architecture based on those details. When you buy a used coach, you inherit whatever was done before and it gets expensive when the previous owner made changes that weren't recorded anywhere.

A couple of hours at a Prevost service center would probably get that stuff mapped out for you and ensure you aren't burning up anything with the incorrect voltage. Once you get it mapped out, label and document the heck out of it so there is no roadside repeat performance.

The problem is that Prevost makes the chassis then the customizer company makes the rest. Typically they don't touch eachothers stuff but in this case it seems they did. On top of this the coach had its 12v house system upgraded at somepoint to a firefly system, so I have a couple of panels with wires yanked out and even some labeled with ? Or labeled as sconces and I don't have any sconces. Also during all this alternator stuff I fried the firefly panel so rewired the lights temporarily.

I'm just starting on renovating the interior so will trace and find all wiring then properly label and configure to fit my needs.

With this specific issue I connected a cable from the chassis alt + to the coach alt + which has a 2/0 cable going all the way to the front bumper where my 12v is. The coach alt is turned off with nothing connected to field. I connected this to the 24/12 Orion with a ground and 12v to my house system that's all upgraded. Somehow the lights were dim so I checked the voltage at the fuse and they were 12v with key off and 24v with key on. I disconnected the Orion cables and all back to normal. This was with engine off.

I'm assuming that 2/0 cable is directly wired 40ft but need to check. I'm a bit stumped on if there is something on that cable how is the Orion passing 12v on the 24v input.