Big Inverter + Batteries and the Air Conditioner

[pvoth1111]

You just cant add an alternator that produces twice plus the amps with out running new wires.... big wires be careful 250 amps is big wire.....expensive wire.

[Oz]

A topic on dual alternators:

http://www.classicwinnebagos.com/forum/index.php/topic,1213.msg54884.html#msg54884

[eXodus]

yeah is not cheap and not easy to handle.



got the chart from:
http://www.crutchfield.com/S-YMWXwsO1H2V/learn/learningcenter/car/cable_gauge_chart.html


If I would not change the batteries location (under the door steps)  the I would have to get a Gauge 2 cable:

it is expensive but not extrem $60 for 12 foot (can cut it to the right length) :
http://www.amazon.com/2-AWG12-12-Foot-Professional-Inverter-2000-2500/dp/B000J1AQS6/ref=sr_1_13?ie=UTF8&qid=1408223454&sr=8-13&keywords=awg+2+wire

So far I would have to pay $300 for an alternator 60$ and probably at least two Trojans ($200) to start off.

[DaveVA78Chieftain]

Curious - If you replace existing alternator with a larger one, how do you plan on integrating the rest of GM P30 electrical system into you modified design.  Would hate for someone else to follow your lead but get in trouble because things were not addressed.  I take it you have the GM wiring diagrams for your 1993/4 P30 chassis.

Later model P30's have a CS-130 alternator where earlier P30 models use a 10-SI model alternator.  Different hookups.  Anyone considering this please do your research prior to changing anything.

Another issue is belt sizes.  Larger width or dual belts are required for larger amperage (pulley changes required).  If you do not already have a serpentine belt system, you may have to convert to one (not cheap at all) in order to stand up to the additional torque applied by higher amp alternators.

Dave

[TerryH]

And bear in mind that if you don't have a serpentine belt system, 454's are notorious for belt issues/problems/failures.
A lot of info here regarding this.

[circleD]

Be careful getting a bigger alternator. I went through some issues so check the clocking, how many wires it needs 1,2, or 3, the pulley matches the belt and the room for it. I also learned you can get a custom built alternator cheaper than an off the shelf but I wanted to be able to pull into any store and get on. Good luck and power it up 

[eXodus]

Lucky I have serpentine belt for the the alternator, the ac and water pump has a normal belt.  So if the new alternator is not much bigger this should be fine. But I will research the exact measurements for mine and the new one.

Dave at what are you thinking when you think About the wiring ? I think about getting a much bigger ground from the engine to the chassis and running a cable from the negative of the alternator directly to the batterie.

Both alternators should have the same charging endpoint. Suggestions what else to address ?

Cd that's a good idea I will check with the local alternator shops.

[DaveVA78Chieftain]

Granted mid 90's could be different however, on at least 92 and earlier P30 chassis, alternator output goes through a central junction block (system interface), not directly to the battery.  This is purposely done in order to maintain the correct voltage across the system.  Hard lesson learned by all automotive Mfg's way back in the 60's.  Once battery is charged, the concern is to maintain the system voltage around 14.1VDC. 

Dave

[eXodus]

This good to know ! Thanks Dave.

I looked at the wiring and seems you are right again.. The alternator cable is much smaller then the battery cable. When I read the wiring diagram correct there should be a central connection box be somewhere. From this connection point the thick cable continuous to the starter. The Cable which is running from my battery to the not-yet-found-point is probably a 2 AWG. Hopefully I am lucky again and this connection point is somewhere near the alternator, so I can safe on cables

I found it for ground - it's right behind the batteries compartment here all big black cables are getting together. This would be my point to get the second ground to the alternator.

A big plus cable directly to the battery would probably mess up something. This could work with a second alternator which would only charge the house battery.  The alternator is designed to charge to the main connection point - with a direct connection it could maybe overcharge the battery but this is only a guess. Will go hunting for the main point.  Is the Generator started from the house or the chassis battery ?

[DaveVA78Chieftain]

Hopefully I am lucky again and this connection point is somewhere near the alternator, so I can safe on cables

1992 Wiring diagram: walk around to front of RV, open engine access hood, radiator suport bulkhead in front of driver.

Is the Generator started from the house or the chassis battery?

Per 1994 Winnebago Itasca Sunrise F29RQ wiring diagram, house battery

Dave

[eXodus]

sometimes I change my mind and came up with probably a brilliant Idea.


Why transforming everything to 110V, when you can get nearly every electric gadget in 12V direct ? I came up with the Idea. Why spent a lot of money on a inefficient inverter ($300 or much more) ?
- Table + Smartphones - USB - charger - got a lot of them for the 12V plug - no additional cost
- TV- I am not watching TV only movies - so I would use my Laptop or TFT screen. - no additional cost
- Computer ATX 12V powersupply - already have one from my old CarPC - no additional cost
- Laptops - a 12V to 19V Laptop charger is between $12 and $20
- 2 way Fridge - convert to 3 way fridge, no Idea yet, but the 12V heating element is around $50. When I read the wiring right - I could probably rewire the 110V entrance to be used as 12V heating (It's only a relay) - so would be a serious 12V conversion. Or get a used 3 way.
- install 12V plugs throughout the coach, one double socket is $6 - some cables and addition fuses maybe $50
- Everything else in my coach runs pretty much directly 12V or propane.
a 12V conversion could be done for cheap
I've got still to deal with my AC problem but I'am working on a 12V solution. http://www.classicwinnebagos.com/forum/index.php/topic,10133.0.html Here the time is working for us - DC compressor are really new now, but in 2 years they are normal and every shop starts using them. They a variable and more efficient then 110V motors.
Future small electronics are all coming in 5V or 12V or 19V.
So would be a inverter a step in the false direction ? Try to keep old legacy devices alive ?

[eXodus]

So I got the Coach A/C repaired.  Was expensive, but hey it is Florida. You can not live without it.

Yesterday I started my Inverter Setup. Just got two of Costco 6V 220AH batteries for $85 a piece.  Now I've got two 12V (on old 105 AH Deep Cycle and a 800A Cranking Coach battery) and two new 6Vs.

Don't know how to get them together yet but I figure something out.
On the way is a Whistler Pro-2000W Inverter

It's not pure sine, looks like a good modified sine. Most reviews are very good. I got I for whopping $120 in a Sale of Amazon.
I want to run my fridge, the Fan in the A/C unit, vacuum and maybe sometimes the A/C and my Microwave of it.

My electronics are not in danger, I will still follow the route of getting new electronics directly to DC/DC. Just got a Car-Charger for Dell Notebook.

As soon as I get this setup running I will post some Pics. $300 for a possibility to run everything of batteries (probably only a short amount of time) is not too bad.
Now I'm looking into how to get Solar on the roof, to get back some power into the batteries.

[pvoth1111]

Does that inverter have a Duty cycle rating....2000 peak perhaps for a very short time.

[sasktrini]

Looked it up... maximum surge capacity of 4000W.  But it may not be enough to run air or microwave... it may though.

[eXodus]

Will simple try it. Amazon has the best service and if it's not working I just send it back in the first 90 days.
No questions asked.
My A/C is a 13500 BTU model which is stated with 1200w running.  The Microwave is 1500w, we use it very very sparely. Every other week to reheat a meal. If this thing is not working I don't care.

I'm on a paleo diet so everything we eat is fresh.

Today I installed the two golfcart batteries in the tray under the steps and discovered that the PO had hooked up the house battery to the coach and the other way. So the last two month I was starting the engine of the deep cycle battery, which worked surprisingly well.  I had to remove the 105Ah 12 deep cycle, not enough space...  Just stored it

Hopefully now everything is in the right place. I'm a little confused even without the charger running I had always the same voltage at both batteries ? only 0,02 volts apart ? Where is this isolator between the batteries ? could this thing be dead ?

The main thing I need the inverter for is my new/used Household fridge. It is a GE which needs about 200-300w running and the energy star rating states something about 1 kwh a day.
I don't bother anymore to fix the Norcold, too expensive.

[Froggy1936]

Make sure you check the running volts @ the fridge/ AC They may start and run at only 90/95 volts But that voltage will cause serious motor damage to the sealed units ! I would not operate at less than 105 Volts constant ! Frank

[DaveVA78Chieftain]

Where is this isolator between the batteries ?

Under front hood, PDF page 2. http://www.winnebagoind.com/diagram/1994/111515.pdf

Root page: http://www.winnebagoind.com/diagram/1994/94_f29rq_wiring.htm
Dave

[eXodus]

Thanks guys for the hints !!
Thx Dave, will look into the isolator during the weekend.

So far so good. The Inverter arrived looks goods and like quality.


Hooked it up to the two batteries, and it has an AC/DC Voltage Meter included and shows how much watt the devices are drawing. So far so nice.  120V AC
I did a couple of tests,
- Vacuum 900w - check
- Microwave 1600w - check (didn't expect that)

- A/C fan including other stuff around 400w - check


A/C compressor - it goes into protected BUT, since I just plugged in the Shore power cord every other thing in the coach (converter, charger, etc) is also running. Have to run some wires to try the A/C alone. Or maybe my two batteries are insufficient and I have to get more.  DC-Voltage was dropping significant to 11.5v while running the Microwave.  According to the manual the Inverter shuts off under 10.5v/


This afternoon I did try the fridge and installed it. Was a nice job in 95 degrees in Florida, the roof Air is blowing Ice-cold but it's still hot in the Coach.
The GE 11.8 Cubic feet fridge, has the perfect width, 23.5 inches is about 6 inch taller. and 2 inches deeper.
So I had to remove the drawer underneath and modify the platform.
[smg id=6799]


The fridge is drawing about 300w during startup and settles down to 120w. So my 2000w inverter is way to big :p doesn't even spins the fan up.
[smg id=6800]

[eXodus]

after using it a weekend it goes back to Amazon.


It powers the fridge perfectly. But ! I think this unit has a problem with the fan regulation. After a couple of hours running without any noise it starts spinning the fan, but a soon the fan starts it stops. So it only spins up shortly. After this 20seconds of some electronic noise, then the fan starts again and stops.
This repeats forever.


So I think this inverter has a problem.
Some lessons learned, in 90 degrees the compressor of the fridge runs really long. I have to get the cabinet better insulated against heat from the wall and the roof. I can get probably 2-3 inches insulation around every side of the fridge. This should help to cool this.


I need a better charger for my Golf Cart batteries. The Converter/Charger only supplies about 3-9A of charge.
It's Florida so I probably go for a Solarpowered Charger.

[sasktrini]

the fan should have a thermostatic switch, and only kick in if it gets hot (case and coolinig fins would be hot to the touch).  If you are only running it at 400W, you probably aren't risking thermal shutdown, hence no fans.

Consider that in the location on the wall by the door, you have great airflow, unlike an enclosed cabinet.  So cycling the fans is normal.

I dare you to try running the microwave or AC off of your inverter.  You won't know until you push it to capacity.

[pvoth1111]

are sure your batteries weren't being consumed too quickly....there is no free lunch.

[eXodus]

i know fan cycling, it's like every laptop and other electronic device has, it gets hot it starts blowing, that's normal

But this inverter doesn't starts blowing, the fans only turn on shortly 1-2 seconds and then go out. So there is something wrong.

I did run the refrigerator over the whole 4 day weekend off the inverter. The fridge has running 120w. I could get it over a whole day without dropping under 12.3v
Then I had to run the generator to recharge.

[eXodus]

so tried 4 differnt inverters now, 3 of them had the same stupid not working fan regulation then the first one. the other one simple didnt started the fridge, even it was a 500/1000w.  now I ve got a 1000/2400w, modifined sine which is running my fridge just fine,

without ever turning on the fan, finally. they all didnt get warm at all. since iam only drawing about 100-120w for a couple of minutes per hour they shouldnt.

yesterday till today i just let it running abOut 36 hours in a row, with everything else in the coach on batteries. (waterpump standby, lpg dtection) today my volt meter showed 12,2v at about 70 degree which gives me about 50-60% of charge left.

i have only wired my two golf cart batteries, so about 220ah. So far so good, since we are not planing to stay more then 3 days in a row at one place i can be maybe go without the genset.
the alternator should charge the batteries in 2-3.hours.

the inverter is now soley for the fridge, i will get all equipment for my gadgets in 12v.

[sasktrini]

Sounds like a good fit!  Thanks for the updates!  I'm deep in construction in winter, and not yet using my inverter for more than power tools occasionally.

[eXodus]

today I did install an Outlet which is wired from the Inverter inside my Generator bay.

This allows me to unplug my Generator and to plug into the Inverter, basically powering the whole RV of my small red inverter.  Basically an Idiot proof transfer switch. I'm also adding a switch do deactivate my Battery Charger.

I had been thinking about an auto transfer switch, but since I'm running my fridge of the inverter I don't want there any switches in between, because the fridge is vital