Here is a new thread to document my testing and proof of concept.
I tried my Xantrex PROWattSW 2000 inverter, and while a great inverter, it just can't handle high surge loads, so no go.
So after a lot of research I ordered this AIMS Pure Sine 4000 watt unit from Amazon and installed it today:
AIMS Pure Sine 4000 Watt Inverter (http://www.amazon.com/Power-PICOGLF40W12V120V-4000W-Inverter-Charger/dp/B00JBND8VK/ref=sr_1_fkmr0_1?ie=UTF8&qid=1441502893&sr=8-1-fkmr0&keywords=aims+4000+watt+pure+sine+wave+inverter)
This inverter/charger has 7 battery type charge settings, has a 100 amp charger and you can adjust the charge rate from 0% to 100%. I liked the customization available.
It has a rating of 4000 watts continuous and 12000 watts peak. This is not a lightweight inverter, it weighs 72 pounds.
Since it does not have built in branch breakers, I installed a 2 circuit branch breaker box, with 2 - 20 amp breakers, one for the front roof air, one for the new duplex outlet I installed in the kitchen. I fed the inverter with a 30 amp breaker in the coach main panel. This required running a new 10 gauge supply wire to the inverter from the main breaker box, and 2 - 12 gauge wires from the inverter sub-box back to the coach main breaker box, one for the front roof air, one for the new duplex kitchen outlet.
After wiring was complete, I fired it up and everything functioned as it should.
Now the big test, could this inverter start and run the roof air. Yes, it started and ran no problem. The running amps was approx 170. I did some testing with my son holding the engine RPM at approx 1700 to simulate cruising speed and the with the headlights on the alternator was supplying approx 200 amps.
I'll post additional info after I do some actual road testing
Yes, good catch, fixed it - 12 gauge wires - for 20 amp circuits.
The 200 amps were measured on the alternator wire to the isolator while the engine was held at 1700 RPM.
Nice work Peter. Looking forward to how this works out. Please keep us informed.
see ya
ken
Great write up on this project. Did you upgrade the alternator too?
Wow! :D Peter I know a lot of folks would love to use one AC and no generator when driving down the road; however, seems like a lot of draw from the batteries when you stop for breaks and meals. Great idea and you appear to be very knowledgeable. Will be really interested on your follow up as to how all this works. DAN
5 or 6 years ago Foretravel offered this as an option on a new coach.
Dont remember if it was just the Phenix.
200 Amps requires 3/0 copper wire. Does the alternator have that size of wire. You can get by with smaller but with a continuous load it will get warm.
turbojack:
Yes, first I wanted to see if I could find an inverter with enough surge capacity to overcome the locked rotor amps of the A/C compressor.
My plans now are to beef up the 12V charging system with a 40SI alternator, larger isolator, and as you mentioned, heavier cabling to the isolator and to the batteries.
I have a 2800W outback inverter, and was planning on running the front AC off it once I upgrade to an atwood air command. I can easily run the dometic penguin off my honda eu2000i while parked, so I'm sure the outback will manage. bigger brushless alternator in my future! glad to see it worked for you, pretty much how I expected it would.
With that kind of current, it make make sense to ditch the isolator install a manual switch or some type of solid connection like a solenoid (combiner). The diode isolators sucks up power as current passes through it, and you are using lots of juice now.
Yes, the isolator gets pretty hot - wasted power. I am also considering wiring the alternator directly to the house batteries as this is where the large current is required, and use a smart combiner to connect to the chassis battery. Here is one my son used in his Lincoln to add a 2nd battery for the sub-woofer amp. It has worked well now for almost a year.
Cole Hersee 48530 Smart Battery Isolator 200A (http://www.amazon.com/Cole-Hersee-48530-Battery-Isolator/dp/B00LMGPHW2/ref=sr_1_1?ie=UTF8&qid=1441548542&sr=8-1&keywords=cole+hersee+battery+isolator&pebp=1441548543716&perid=1AN88N3ERBB8RCAQ50B0)
I installed a yandina in place of the isolator. Combiner 160 Sheet (http://www.yandina.com/c160Info.htm)
If you direct wire to house batteries, I'd have wire in a switch or make up a mechanical jumper just in case the combiners fail. You can just wiring it together manually in 1 minute if needed.
How about a second alternator where the stock AC compressor is now? Might keep alternator temps down and a failure would not be disabling. Wire directly to house batteries? An alternator running close to capacity will have a shorter life. Inverter should have 10-20x AC startup load for long life.
Might try an old AC for RVs but using butane/propane instead for an experiment. Has been done on a lot of cars. Should drop the current requirement way down, especially for startup.
A to Z propane/butane conversion at Possum Living: Possum Living: Propane Refrigerant for Automotive Air Conditioning (http://www.possumliving.com/2012/08/propane-refrigerant-for-automotive-air.html)
May not be legal in all states.
Pierce
I dunno, it almost seems like less effort to install/repair the over the road chassis a/c. Ours works *very* well and will cool us up front until about 87-90F outside. It is a very clever option though. You could also install a later model a/c unit that pulls less amps.
I don't mean to be a smartass.....but all this labor and expenditure to save 1/2 gal of diesel an hr while your motorhome is getting 7mpg? I need a beer.
Ah, you can't help it Twig :D For us, it isn't about saving the half gallon an hour of Diesel, but being able to run the A/C for short periods off of the inverter. Say while stopping for lunch... or while plugged into a buddies 15amp circuit while driveway camping and the starting current pops his breaker. Having the soft start set up and an inverter circuit that can be switched to supply one A/C would be helpful. Still, we already have the 3000 watt inverter and the large battery bank (4 8D's), so a soft start set up would be a minimal extra expense and helpful in other ways. Just my thoughts...
Don
I like prfleming's thinking, why run and put hours on your generator, when you can use a fraction of the power of your main engine to run your ac. I doubt that the ac would decrease the mpg that much, and if you had solar to augment the alternator, maybe no decrease. Even at $2.00 a gallon, your gen will cost you a 6 pack or two, a day to run.
Jim
The new coaches are set up for it so I am sure ours can too. I think there is enough room on my coach to put a bigger alternator. The issue would be lining up the belts and increasingt He wire and a new isolator. I do not think it would be a hard upgrade and I have been thinking of doing it too.
Something like this might support the energy consumption
http://delcoremy.com/Documents/Brochures/Delco-Remy-55SI-Brochure-5-12.aspx
Fixing the Dash A/C, which I think the original reason for this idea, is probably cheaper and more effective.
On my coach the dash ac will cool driver and co-pilot only. If you are carrying anyone behind the front area in hot weather, you pretty well must have overhead ac.
Jim
Too bad it only comes in pad mount (though I am sure that could be worked around), and especially too bad it is $2173! (lists for over $3K). Still, 430 Amps... wow!
8600529 by DELCO REMY - ALTERNATOR 55SI 12V (http://www.finditparts.com/products/2318511/delco-remy-8600529)
Way more than necessary, but I like overkill! I will keep my eye open for a super ebay deal on a 250 to 320 amp or thereabouts. If I can get it cheap enough... I will start with the soft start set up and figure out the need vs our puny 160 amp Leece Neville.
Don
I just run my generator- keeps all 3 airs and the entire coach comfortable.
Don this one would give you 320 amps and is available in 3 mounting styles
http://delcoremy.com/Alternator-Models/40SI-High-Output-Brushless-Heavy-Duty-Alternator.aspx
Ernie, I do the same thing and am almost at 5000 hours on my generator. I think for the odd times that you do not need all three but just one unit, a engine driven way of running it would be very nice.
I think it would probably be more cost effective to do what the Prevost currently does which is to tie several smaller alternators together. There is one on the engine and a long belt that sends power to a bundle of 3 more of them off to the side. It all looked very elaborate. I imagined the headache of it all wearing out as it aged. I would probably add a pair of 160 amp alternators to my existing setup.
Update:
With the installation of the AIMS 4000 watt inverter complete, I'm upgrading the rest of the 12V charging system to handle 250 amps continuous current flow. I'm ordering this 3 battery isolator, and will tie 2 legs together to have a 100 amp current capacity for the chassis battery, and a combined 200 amps current capacity for the house batteries. I know a lot of folks have suggested battery combiners, but I feel a diode based isolator will be more reliable.
Sure Power 300 Amp 3 Battery Isolator (http://www.ase-supply.com/Sure_Power_3003_Battery_Isolator_p/sp-3003.htm)
I mean as long as it is rated high enough - my isolator has been alive for 16 years now ;)
When i was getting ready for Residential Fridge project i had also looked in to this to find out what would it take to also run a overhead AC with battery power. At the time I had installed a residential refrigerator i also had to purchase and install a new inverter along with upgraded batteries. So I wanted to hit two birds with one stone. We live in TX and we love air conditioning.
For us i ended up determined that running the dash AC with occasional need to run a overhead AC with a generator is more than good enough. There are times such as when i was traveling from TX to OR last August I was running the dash AC with a small fan running on the floor from bedroom facing front. Fan was running from the inverter as well as the fridge ... while under way.
I plan on upgrading our overhead AC units to less noisy one ... I did not look in to it yet but perhaps the new ones also draw less amp .... perhaps then it maybe worth while looking in to this again to see if it will be cost effective to operate one via "DC" power.
For now i chose to have FT convert the Dash AC to new a134 refrigerant. That turned out great. It works better than ever now.
12V charging system update:
The Sure Power 300 amp isolator arrived today. It is a beast - it weighs 16 lbs, and has 1/2 inch studs. I took a picture next to a beer bottle for comparison. Also, note in the detail photo: MADE IN USA.
Now that I have it I will temporarily mount it and measure length of new 3/0 cables from the alternator positive to isolator, from isolator directly to each battery bank and from alternator negative to battery negative. I will be ordering custom made cables from Bay Marine Supply:
Bay Marine Supply - Custom Cables (http://baymarinesupply.com/store/electrical/wiring/custom-battery-cables.html)
I'll post more pictures as the 12V charging system upgrade progresses.
Blue Moon.. b^.^d
So why not put on an engine driven generator? If the point is to run one AC while driving without running the generator than about $1100 gets you a 3500 watt 120 v engine driven generator with a constant voltage regulator.
http://www.fabcopower.com/generat/bgen.htm
I appreciate the direction and effort (and $) Peter is putting into this. When he is done he is going to have a very powerful 12 v system while underway. When he stops what ever batteries he has (and I bet they will be fully charged) without any other power source are still the limiting factor. More batteries, more solar. What he learns and discovers will be valuable to all of us power nerds.
I came to realize that the older coaches and even some newer ones, have basically enough 12V capacity to keep the coach running with the headlights on, and maybe charge the house batteries when needed, for a short time, until fully charged. But, as soon as you put a continuous demand on the 12V system, like running a fridge, or a roof air, you reach limits pretty quickly.
Fast forward to 2015, we have available a new class of "super" inverters that are ultra efficient, and have a 300% surge capacity. We have high current isolators, and high current alternators, and new battery technology.
As I said in the beginning, for me this is a "proof of concept", using some of the new technology available today. Plus, I have always wanted to "modify" what ever I have to make it better... ^.^d It used to drive my Mom crazy...
Thanks, Peter,
A fellow "fixer". I am very interested to see what improvements and enhancements are available.
So what is the prevailing choice for a bigger alternator? I have a 250 amp capacity Sterling Zero Voltage Drop three battery bank smart isolator. I think I have enough demand that batteries never get fully charged while driving. I think I can increase the output voltage on the incumbent alternator but it seems I need a bit more. I believe I can get the 160 amp alternator rebuilt to about 200 amps for about 1/4 the cost of a Delco Remy 40si J180 Mount 12v 240 amp 8600339. How do you know what mount you need?
I have a feeling this thread is going to break some records...ha ha, it just keeps on goin'...
If you originally had a Leese-Neville, which is a favorite of Foretravel, this is the J-180 Long Hinge (3 point mount). The alternator of choice for replacement/upgrade I think is the Delco 40si at 300 or 320 amps. There is a 300 amp 40si on ebay that I am watching, but I haven't made an offer yet.
In 2012 Delco released the 55si for the fire truck market, which can output 430 amps, but this only comes in pad mount, and is designed to use a serpentine belt with an active tensioner. This won't work well with a double V-groove pulley like most of us with older coaches have.
I'm curious to what the bill is thus far? looks to be about $1500 and still need an alternator?
Another idea is to install a larger A/C compressor, or install another one and have more A/C capacity.
I think you could spend $245 for a soft starter and run it off the standard 2500W Inverter and stock alternator. Will get around to doing that in the next few months and see how it works.
If you're looking at upgrading the alternator, have you also considered hydraulic generators or PTO driven generators?
HYDRAULIC GENERATORS 3KW - 12KW | HYDRAULIC GENERATORS FOR UTILITY TRUCKS,... (http://www.fabcopower.com/generat/hgen.htm)
If I was really interested in this type of science project, I'd take the 3phase of an exisiting alternator (before the rectifier) and figure out how to run it through the inverting box on say a Honda eu3000i generator. Higher voltage and more efficient..no wiring issues.
Great, more ideas are coming in... ^.^d
Does someone with more hydraulics knowledge than I have know if the on-board hydraulic pump for the power steering has the capacity to run one of these - 8 GPM @ 1500 psi? My gut feeling is maybe not...
Update:
Well, the guy on eBay and I came to an agreement...the Delco 40si 300 amp alternator arrived today!
I swapped out the Delco 28si I was using, the install was easy. I am still using the stock 2 gauge cabling until I do the upgrade to 3/0 cabling. I roughed out the amount of 3/0 cable I'll need today to completely re-wire my alternator-isolator-battery-ground wiring and with a little extra I'll need to order 75 feet. After consulting with Don & Tys (AKA acousticart) I am going to order the FTZ crimper from Bay Marine Supply and make my own 3/0 cables.
It was getting dark, but I confirmed the alternator was working, and did some preliminary load testing at idle, and it produced approx 176 amps at 600 RPM with an inverter load. I will take the coach out tomorrow and road test it.
Note: On my coach the alternator ground wire is red.
For everyone that is asking, my 2nd offer of $600 won the 40si alternator. ^.^d
Peter,
Did your 28si use the same wiring as your L-N original FT alternator?
Did you have to make any changes to that to go to the 40si (brushless, right?)?
What is the gauge of that red ground wire in your new alternator picture?
(BTW, my plan is to use mostly black 4/0, but use red heat shrink on the ends of positive wires.)
Thanks,
Trent
The Delco 24si, 28si and 40si alternators need ignition excite when connected behind an isolator. This is why un-informed truck repair shops add jumpers to isolators when installing new Delco alternators - to get the 12v excite that Delco alternators require, not realizing that there are better ways to do this.
This can be accomplished in 2 ways - an ignition wire with a diode connected to the alternator B+ (as was stock on my '91), or install an isolator with an ignition exciter post to provide the excite (diode is internal to the isolator connected to the alternator B+).
So, on my '91, the ignition excite-diode wire is connected to the alternator B+ and provides the voltage the 40si needs to start charging.
The diode (in the exciter, or externally connected to the ignition wire) prevents "back flow" when the alternator starts charging. Without the diode, this back flow would exceed the current capacity of the small gauge ignition excite wire.
The gauge of the red ground wire is 2 gauge. All my stock alternator and isolator wiring is 2 gauge, I will be upgrading this to 3/0 gauge. I also plan to buy all black wire, and use red heat shrink on the positive wires.
To clarify some questions:
The Delco alternators have 3 small terminals in addition to the B+ post:
"S" - Remote Sense
"R" - Relay
"I" - Indicator Lamp
The sense wire from the isolator start battery post connects to the "S" terminal. The other 2 terminals should not be used.
The "R" terminal is not the remote sense terminal. The "I" terminal is not the ignition excite terminal. The ignition excite needs to be provided with an ignition wire with a diode connected directly to the alternator B+, or by using an isolator with an ignition excite post (diode is internal to the isolator connected to the alternator B+ post).
The L-N alternators set up for DUVAC have an ignition excite terminal, and the ignition wire is directly connected to it. So when changing from a L-N alternator to a Delco alternator you need to be aware of the above requirements.
Do you think the alternator will overheat drawing 176 amps at idle? I'd imagine with an a/c you could have a theoretical max draw of 200 amps so it really could sit pulling full load at idle for long periods right?
Piku
The 40si is rated at 190 amps at idle on the spec sheet. But, yes, I think you would not want to draw high currents for long times sitting idling. I plan when running the a/c, to just use common sense and switch to the genny when the coach is not going to move for an extended time.
Here is a pretty good deal for a Delco 40si 275 amp alternator with a L-N J180 mount.
Delco 40si 275 amp alternator (http://www.finditparts.com/products/635855/delco-remy-8600280?srcid=CHL01SCL010-Npla-Dmdt-Gusa-Svbr-Mmuu-K635855&gclid=Cj0KEQjwqNiwBRDnq93MioaqtKQBEiQAb7Ezn_cZrWT9NyGEHJRaqxgHudkhh6GSGYZ7KNQOfaHZfrQaArxe8P8HAQ)
This isolator would match up nicely with the above alternator, and has the exciter post for the ignition wire for Delco type alternators.
If upgrading, I would recommend at least beefing up the wire from the alternator to the isolator, and wire from the alternator to ground.
270 amp isolator with ignition post (http://www.dbelectrical.com/p-7086-new-multi-2-battery-isolator-270-amp-heavy-duty-with-exciter.aspx)