Front A/C while driving using SOLAR + ALTERNATOR

[followingsea]

Originally Posted by NealC

Going into solar you think only about boondocking but there are other advantages as we're learning.

Interesting discussion! My BIL who does not own an RV but loves my 30 year old TT hass been reading up on soft starts and tells me I need one.

So I watch the video. Then I check price.

I learned I do not have to spend $600 for both AC.

Why? Because my generator is properly sized.

My technology is power generation. Most of your electric power is made with steam turbines because one steam turbine generator can supply a city of a million people.

If you are a city of one home then an internal combustion engine is what you need to turn your generator. ICE/generator scale nicely up to 10 MW. You can store a lot of energy in fuel tanks.

There are other less practical ways to make electricity. Solar for example. It is not very practical because it requires a large surface area and it is not reliable. Since MH have battery storage already now it is just a matter of system capacity.

For those who hate science stop reading. The amount of power used by an AC does not change with soft start does not change.

So the disadvantage of solar is that it add weight and drag to the MH increasing power demand on the ICE.

[C.Martin]

Originally Posted by 10 fan

I finished my project Tuesday (half the solar) and ran the air off the batteries on the way to Camp Newmar. It worked perfect. I ran out of time so haven't installed the new BIM yet. As expected the alt. never charged the house batteries. It was nice to be able to run the air all night and not listen to the generator.

Wow...that is some system you've built...

[jcussen]

Originally Posted by NealC

Congrats on your setup. It is nice to make use of solar and/or great batteries and be able to run an AC off of it. Going into solar you think only about boondocking but there are other advantages as we're learning.

Yes, sometimes I park my coach out in field with no electricity available. Solar keeps both battery banks charged and runs my two ceiling vent fans [thermostatic]. And supplies power to HWH compressor to keep coach level.
But most important, keeps the memory on my sat receiver.

[joes2901]

Newmar was a pioneer in some technologies like slides, comfort drive, 3" well insulated walls, etc. Now it is time for Newmar to spec a variable speed DC powered air conditioner from a high quality builder. It will be more efficient because the energy lost by inverting 12 volt DC (or from a 24 or 48 volt battery bank) to 120 volt AC will be avoided. A DC powered variable speed compressor and high efficiency heat exchanger and variable fan in the rear cap would send compressed refrigerant to a cooling coil with a variable flow TVX valve with a variable speed DC fan. Then variable dampers to provide proper air flow to satisfy the cooling need of up to 3 zones.

Nearly 2 years ago I upgraded my home 5 ton AC to a Trane XV20i 5 ton system with 4 zones (I contracted for 20 Seer, 115 outside and 75 inside and 16 adults). The old system could pop the 60 amp breakers on occasion; the Trane converts AC to DC current and uses 40 amp breakers with no problem.

My Aug 2016 electric bill with the old AC running 24/7 was $803. Since the new AC the highest monthly bill was $321, avg about $280 for 24/7 in the hottest months. Last Sept it was 116 degrees outside and the AC maintained 75 in all 4 zones. The compressor ran at 81% from noon till 7PM and dropped to 67% till 10PM and 41% through the 90 degree night. It was also cycling off and on; the fan ran 24/7 at a variable air flow.

My home entertainment room with sunshine on 3 sides in the summer, computers, and plasma TV used to be the hotest room and it stays 75 now and only 31% compressor speed due to the zoning.

The point of the above is that this kind of efficiency is overdue on Newmar RVs which now can be running up to 3 ACs drawing up to 51 amps trying to maintain 75 degrees inside when it is hot and sunny outside. The windshield area would be cool because variable dampers provided the required chilled air there. Battery banks and solar could maintain coolness when the voltage drops below 108 volts in the RV park or while cooling when not connected to shore power. If less AC energy was required the battery bank and solar could keep a RV cool when boondocking (my preferred way of using a RV).

[C.Martin]

Originally Posted by followingsea

Interesting discussion! My BIL who does not own an RV but loves my 30 year old TT hass been reading up on soft starts and tells me I need one.

So I watch the video. Then I check price.

I learned I do not have to spend $600 for both AC.

Why? Because my generator is properly sized.

My technology is power generation. Most of your electric power is made with steam turbines because one steam turbine generator can supply a city of a million people.

If you are a city of one home then an internal combustion engine is what you need to turn your generator. ICE/generator scale nicely up to 10 MW. You can store a lot of energy in fuel tanks.

There are other less practical ways to make electricity. Solar for example. It is not very practical because it requires a large surface area and it is not reliable. Since MH have battery storage already now it is just a matter of system capacity.

For those who hate science stop reading. The amount of power used by an AC does not change with soft start does not change.

So the disadvantage of solar is that it add weight and drag to the MH increasing power demand on the ICE.

Kit,

The Easy Start doesn't save energy...it is strictly a tool to help reduce the Locked Rotor amp draw. This allows people to start up a rooftop air when using an Inverter or Smallish Inverter Generator. If you have 50A shore or an 8k+ generator you prefer to use...the Easy Start isn't going to benefit you at all.

I don't know what angle you speak of when you say solar isn't reliable. I have had zero problems with solar. It has charged my batteries everyday without fail since installation. My Onan, on the other hand, just caused my coach to go to the shop for a week. A poorly assembled screw came loose inside and worked it's way into the governor assembly. Gen would shutdown immediately upon startup. Had to lift coach to drop genset (I don't have a sliding drawer) disassemble, remove screw, replace a broken AC power terminal strip which I imagine got broken when they removed the unit. Cost was going to be over $1300...but they must have felt guilty. They charged me only $630. Yep...on a generator which I had a total of 110.7 hours on. I hope the reliability goes up from here...I do like having the generator. Just wish it had proven itself as reliable as solar.

And my solar kept the batteries charged and fridge running while coach sat in yard waiting to get a maintenance bay.

[palehorse89]

Going to be interesting to see how long the OEM alternator's hold up ........the KA has a large battery bank and a 350 amp alternator to do this..........and yes, the solar is also helping out........
An how it will affect the battery life.

[10 fan]

Originally Posted by C.Martin

Wow...that is some system you've built...

Thanks , I can't wait to get the other 6 panels up.

[followingsea]

Originally Posted by C.Martin

Kit,

.the Easy Start isn't going to benefit you at all.

I have had zero problems with solar. It has charged my batteries everyday without fail since installation.

Charlie thank you for agreeing with me.

How does your solar work at night?

This post is about using air conditioning going down the road with the alternator being the reliable power supply.

One question raised is how that use will affect the reliability of the alternator. There may be issues with the long term reliability of your AC by adding an aftermarket gadget.

The basic problem with gen sets in RV is that they are owned by people not trained in making electricity and they bounce down the road.

I have a 20 year old MH. It is designed to run both AC on the gen set. I could spend $$$$$$ to do it a different way.

But why?

[jcussen]

Originally Posted by followingsea

Charlie thank you for agreeing with me.

How does your solar work at night?

This post is about using air conditioning going down the road with the alternator being the reliable power supply.

One question raised is how that use will affect the reliability of the alternator. There may be issues with the long term reliability of your AC by adding an aftermarket gadget.

The basic problem with gen sets in RV is that they are owned by people not trained in making electricity and they bounce down the road.

I have a 20 year old MH. It is designed to run both AC on the gen set. I could spend $$$$$$ to do it a different way.

But why?

You have made it clear in your many, many posts. that you do not believe in any supplemental type of energy production on a motorhome. It seems you often aim your comments at people that already have solar. In my mind, a waste of time. If you feel so strongly about your position, start a brand new thread and label it. "Why I don't like solar power" and invite comments on your position.

[garyspang]

I had a hard or quick compressor start circuit fail on my retrofit heat-pump that only draws 7.7 amp when cooling. The failure tore the compressor off its mounting pad from the huge sustained stating torque during the failure, and opened up (burned out) the stator in my 30 amp generator.
The quick start circuit consists of an extremely large capacitance auxiliary starting capacitor that is connected in parallel with the existing normal starting capacitor using a physically large positive temperature coefficient (PTC) thermistor. During starting the thermistor has a very low (several ohms only) resistance and connects the auxiliary starting capacitor to supply a very large starter current that causes a quick compressor acceleration to the running speed. The thermistors starter current self heats it into a large resistance (PTC several hundred ohms) and almost eliminates the effect of the auxiliary starting capacitor all the time thereafter while the compressor is running. All this in about one second.
Unfortunately my thermistor shorted internally and held the huge starting inrush current indefinitely. The reaction torque and monstrous sustained current caused the damage. The compressor was remounted. The quick start circuit was replaced and the heat pump was removed and sold. The generator was replaced with a new one.
The soft start computer controlled start circuit, instead of quick start, is the solution I did not know about at that time. This is definitely the way to start any mobile A/C unit.

[C.Martin]

Originally Posted by jcussen

You have made it clear in your many, many posts. that you do not believe in any supplemental type of energy production on a motorhome. It seems you often aim your comments at people that already have solar. In my mind, a waste of time. If you feel so strongly about your position, start a brand new thread and label it. "Why I don't like solar power" and invite comments on your position.

Deep breath...

It’s all good guys. I know, I know,,,Kit likes to rain on the solar parade. But it’s all good. No harm playing devil’s advocate. He may even have saved someone the expense of buying a MicroAir Easy Start that didn’t really need one.

I don’t profess to have all the answers yet, or ever...but it’s fun experimenting and learning more and more. Yes...I am a huge proponent for Solar. Honestly, I hope that someday manufacturers will do a total revamp...Solar, climate controlled battery compartments, 24v or even 48v systems...coach and chassis... charge parameters for alternator, solar, Inverter/chargers all in the same page so the BIM plays nice... or we continue to integrate things along the way and find work arounds as we go.

I have never told anyone Solar would save the world, or pay itself off in 5 years...it’s just another power source. Limited by daylight, roof area, battery capacity, etc... I have always felt more comfortable flying two, three, or four Engine jets. Redundant engines, generators, hydraulic systems... I like the same (redundancy) in coach systems. City water or Fresh Water tank and 12v pump...Shore power, generator power, solar power, battery power... Gas grill, UUNI, Blackstone...two methods of connecting propane to all. I hate it when a single failure leaves you stranded or miserable.

So continue to share ideas...whatever they are. If someone wants to avoid solar, they are free to do so... As a matter of fact, I wouldn’t even recommend it unless a person feels that it fulfills a desire or need they have for their particular way of RVing.

Back to running A/C off solar + alternator.

Speaking to the Prestolite tech...the Alternator can produce. It still has a finite lifespan...and making it put out 171Amps for four hours will use that lifespan faster than 11Amps it appears to produce without the A/C running (once chassis battery rebounds after engine start)... Rated for 240A...I have recorded a spike of 250A right after Engine starts...depending on sampling rate, I’m sure the momentary pike is more than that. The alternator has a curve depending on temperature and engine speed...so, I’m thinking that the 171 avg is right about where it should be. I was hoping the alternator was sharing the work equally...but I would have to tweak my solar charge controller settings, or trip the voltage regulator in the alternator to balance this. Not something Inreally want to deal with routinely.

Heading home tomorrow...I’ll try to remember to set the BT Clampmeter up on the chassis - house line...to see how much of the Alternator output is actually making it to the house side.

[jcussen]

Though I would do one more test on running the ac without an standard ac source, and before I ordered a bigger alternator. Current one is 160 amps. Inverter input 160 amps. Solar input to batteries, 40 amps. House battery draw 130 amps. Started engine and went to high idle, merged banks, and retested. Battery draw now 70 amps. So appears alternator is supplying house side 60 amps, plus whatever chassis side is consuming. Alternator is set for 13.6 volts, house batteries were sitting at about 13.4 volts, so possibly house batteries were not at the stage where they would take a bulk charge and the alternator was only supplying enough to maintain float? Over my head for sure.

BTW. I also do enjoy playing the devil's advocate , but before I try to debunk someone else's ideas, I will be sure to have enough concrete facts, to back up my opposing view.

[C.Martin]

Originally Posted by jcussen

Though I would do one more test on running the ac without an standard ac source, and before I ordered a bigger alternator. Inverter input 160 amps. Solar input to batteries, 40 amps. House battery draw 130 amps. Started engine and went to high idle, merged banks, and retested. Battery draw now 70 amps. So appears alternator is supplying house side 60 amps, plus whatever chassis side is consuming. Alternator is set for 13.6 volts, house batteries were sitting at about 13.4 volts, so possibly house batteries were not at the stage where they would take a bulk charge and the alternator was only supplying enough to maintain float? Over my head for sure.

BTW. I also do enjoy playing the devil's advocate , but before I try to debunk someone else's ideas, I will be sure to have enough concrete facts, to back up my opposing view.

Very nice balance. I was hoping for that. On my last drive...the alternator was practically pinned at 170A +/- and my solar controller would see the higher voltage of the Alternator and drop it’s output. Puzzling. I think if I had the voltage regulator on the alternator turned down a bit...or the float voltage in the solar controller tuned up a bit...I might get better load balancing between the two. Occasionally, the voltage would trigger another bulk in the solar controller and the PV would shoot up. I didn’t really see less output though from the alternator. It was still churning out amps...so the batteries would get charged up and float again. I know I’m being too picky. I should be happy the a/c is working, and ai’m getting to my destination still fully charged and ready for a night of boondocking if I want. Hope to check into Harvest Host when I retire...so we can mix stops on longer trips...a blend of rv destinations with hookups...and some Harvest Host/BLM or National Parks wo/hookups as well.

I’ve got Flooded Lead Acid...and can’t imagine long period of C/10 amp draw is great for them. AGM would be better. Lithium even better yet, but I’m not sure how best to get the alternator (regulated to Lead Acid chemistry) to contribute...since the Lithiums voltage is already higher. So, it becomes all battery and solar doing the A/C work.

[10 fan]

Originally Posted by Rvlegaleagle

Does installing a soft start void out the A/C warranty?

I'm at Newmar and got my AC fixed today, The fan went out. They asked me if I added that box (easy start) said yes and explained what it was and that it only affects the compressor not the fan. They replaced the fan motor and control board, no charge. I was a little worried.