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IRDEW

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I have a new fifth wheel and I am going to add some parts for boonedocking. I would like input on sizing and configuration.

First I would like to add a Onan 2500w LP generator, I like the electric start and no security issues.

The generators main purpose would be to charge the batterys or power one a/c unit. The batterys would be charged thru a Magnum MS 2000 inverter. The inverter would supply Cpap machine, computers and device chargers.

The batterys would be two L-16 AGM 6V to replace the two small wet cell batterys from the factory.

And 200-300W of solar in the near future. So my question are:

 

Should I install the larger 5500w generator just to charge batterys?

It has an oil filter and pump and the smaller one does not

 

The inverter is oversized a little, just right?

 

Any battery sizing comments?

 

All of this will mount in the front generator compartment and we will be fulltiming soon.

It's a lot of parts to order sight unseen and I want to get it right. And you guys are pretty darn smart.

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There are experts on this board so I will just give my preliminary thoughts and let them correct me and fill in the blanks.

 

I understand why you want the electric start with the Onan but be aware that Onans use quite a bit of LP and are not as quiet as the Honda EU 2000 and other small gasoline inverter generators.

 

The 2500 probably would run the AC, double check with others, but may have problems especially when it kicks on as they take on a surge upfront.

While the AC is running your batteries may not get much charge. If you have microwave, coffeemaker, crock pot. The Onan will not run them at the same time as the AC. I don't know your anticipated usage of the AC but if you would be a high user that would give me some concern. On the other hand your battery bank is relatively small so it should not take the generator long to get them charges

 

If you will be camping in warm climates and using the AC a lot I would tend toward a larger generator. The option I finally settled on is to buy twoHonda EU 2000 generators. This allows me to use just one when AC is not a concern but they can be connected and operated essentially as one unit giving you 4000 watts when necessary. You lose the electric start but gain more flexibility, fuel efficiency and quiet running. They do however increase the risk of theft in comparison to the Onan..

 

Your inverter may be somewhat oversized but its a good unit and I think that is a reasonable choice.

 

It would be helpful to know the rated Amp Hour capacity of your new batteries (nice upgrade to AGM). I suspect they are about 220 amp hours. You need too remember that you can only use half that capacity. You should add a battery monitoring system to your system so you can watch this. Drawing down your batteries too far will shorten their life or kill them. I do not know the draw of a cpap machine and that would go a long way in answering whether the battery bank sizing is sufficient. A 4 battery system probably makes more sense. You can always add them later but adding new batteries to old batteries shortens the life of the new batteries to match that of the old. Because of this people on this board usually will advise sizing up on the battery system.

 

One last thing is that putting the batteries( even AGMs) together with the inverter in the front compartment will give some folks here concerns. You may need to consider a seperate vented battery box. AGMs still gas off and this can cause an explosion from a spark on the inverter, dave

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Propane is nice if you don't use it much but it is often inconvenient and expensive to get propane and you'll use more gallons of it than gas. Gas generators do have more maintenance but for most folks they are the best choice.

 

The electric start is nice but depending on your situation you might like the lower noise levels and reduced fuel usage of one of the inverter/generators like the Honda.

 

Add up your expected loads to pick a generator size, if you can turn the air conditioner off for 10 minutes to microwave something and that meets your needs then use the lower usage number in your calculations.

 

With the big inverter you could run it to power your smaller AC devices and the microwave and use the generator to power your air conditioner and a good smart multi-stage converter. That gives your devices better quality power and reduces the maximum power draw since it is buffered by the batteries. Size the converter so that you have enough power to run it and the air conditioner at the same time but don't go too large and exceed the maximum recommended charge rate of your battery bank. The inverter's charger can't be used while it is also making AC power so the converter/charger is needed for this.

 

AGMs are nice and when charging from a generator and high power charger their ability to accept a charge faster than flooded batteries can save fuel and generator run time.

 

When you get ready to add solar you can usually do the bulk charging with your generator and the acceptance charge using your panels if you are making enough more power from them than you are using. That is a huge help with flooded batteries, a bit less but still nice for AGMs.

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Mumbly, those are good questions and there a fine group of experienced gents here to supply answers and opinions so I may as well toss my hat in the ring.

 

1) I have a new fifth wheel and I am going to add some parts for boonedocking. I would like input on sizing and configuration. First I would like to add a Onan 2500w LP generator, I like the electric start and no security issues. The generators main purpose would be to charge the batterys or power one a/c unit.

 

Since you have a fifth wheel, unlike a motorhome with on board gas tank, I can see why an LPG Genset is desirable to avoid carrying 5 gallon gas tanks in back of the truck. But I hope you have bigger then a 30# LP Tank???? If not you may need to carry an extra 30# Cylinder or a couple 20# in the pickup. I have seen a ton of fifth wheels many use a bigger Gas powered Honda or Yamaha in the truck in the 3000 to 3500 range and have a couple 5 gallon gas tanks. That or a pair of the smaller Hondas capable of coupling together when more power is needed. Gas is easier to buy then LPG which cuts in favor of a gas genset. The idea of needing two smaller Hondas doesnt sound as good to me as a single 3000 or 3500 Honda or Yamaha etc., I think Id go with a single larger gas unit and haul a couple 5 gallon gas cans then 2 small gensets or an LPG genny ITS YOUR CALL a smaller genset LPG or Gas will still run the roof AC

 

PS take a look at some of the Hyundai (never could spell that lol) small portable genset reviews on You Tube running an AC

 

All the 2500 Gensets Ive seen and used will indeed power one roof AC, but if the compressor is running you may not be able to run a microwave and hair dryer or a high current bigger battery charger at the same time, while a 3000 or 3500 will.

 

 

2) The batterys would be charged thru a Magnum MS 2000 inverter. The inverter would supply Cpap machine, computers and device chargers.
The batterys would be two L-16 AGM 6V to replace the two small wet cell batterys from the factory.
And 200-300W of solar in the near future. So my question are:

Should I install the larger 5500w generator just to charge batterys? It has an oil filter and pump and the smaller one does not

 

See above, a 3000 or 3500 should run one AC and a Smart Charger, 5000 may be more then needed but sure, it will work.

The inverter is oversized a little, just right?

 

Not a problem, I have a 2000 PSW as a 1000 may be marginal

Any battery sizing comments? I

 

I have 460 Amp Hours with four lead acid golf cart batteries, 400 watts of Solar, that suits me plenty but it depends on your energy needs

All of this will mount in the front generator compartment and we will be fulltiming soon.
It's a lot of parts to order sight unseen and I want to get it right. And you guys are pretty darn smart.

 

NOTE See our recent threads, having batteries in the same enclosure as Chargers or Inverters may be a problem. Be sure the batteries are well vented with enough CFM for cooling purposes and venting the gasses. HOWEVER AGM isn't so bad a problem as lead acid, but you still need cooling and venting

 

Again, its your call, if it were me with a fifth wheel Id use a Honda or Yamaha 3000 to 3500 watt GAS POWERED genset,,,,,,,,,at least 400 Amp Hours of battery energy storage,,,,,,,,,,,Minimum 200 to 400 watts of rooftop solar, you can get by with lesser if they are adjustable to the sun,,,,,,,,,,,,,,,,,a Smart 3/4 stage charger at least 60 amps and more preferably. You see people with 50 or 100 watts of solar and a 1000 genset and a couple golf cart batteries all the way up to 500 to 1000 solar watts and a 5000 to 6500 genset and 6 or 8 or even 10 batteries SO GO WITH WHAT SUITS YOUR NEEDS, no right or wrong here.

 

John T

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MumblePeg We don't know your experience level so if you don't undertand the terminology let us know. It is compllicated enough without having to learn a whole new vocabulary. For instance if you don't know the difference between a converter and inverter=== back us up. One of the benefits of us giving multiple answers is that you not only get a variety of opinion but we each tend to say things in a slightly different way and if one of us doesn't ring a bell for you the next one might, Additionally reading Jack Mayers web site on solar electrical is always time well spent. Dave http://www.jackdanmayer.com/

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I get where your coming from with one larger gas genset John the only other factor I would add is that since it will be a portable outside of the fifth wheel, upper body strength, backs etc become an issue. A honda 3500 might be much tougher to handle than two 2000

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I thought long and hard on the Honda generator, I know they are quiet and very reliable but, I have spent too much time pulling lawn mower and outboard motor cords. So the smallest Honda with elect start is a 3000W. I also didn't think it was a good idea for a gas generator in the belly of the rv. The comparison of Dealing with gas or propane is sort of a wash. There are propane conversion kits for the Honda I haven't studied them. I have two 10 gallon propane tanks thought they would last pretty good just using them for hot water, cooking and charging batterys with a small gen set.

The battery capacity is 390ah each @ 6volts. So these two 390AH 6v batterys in series have 390ah capacity of which 50% max is usable correct? 195 ah seems like a lot

.

FLA of the Cpap with heater is 1.7 A

The inverter could be mounted in the old battery compartment but the only place for the batterys is with the generator. The generator compartment is well vented but I could box the batterys and vent them.

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Sounds good. I would just double check the lp consumption per hour on the Onan web site. If you don't plan on a need for propane for heating that makes a difference. I just remember being shocked (no pun intented) when I looked at the gallons or lbs per hour used by Onan. How is your heating and refrigeration powered? If those things are not used, I would again double check Onan propane consumption, but that might be a viable plan. I carry 60 lbs of propane and Onan still did not make sense to me when I considered heating etc,. Many use them , however. What is your brand of battery? That is as very high rating. You are also correct that almost all of us with gasoline generators move them outside the rv compartment to run. As far as them being hard to start.. You must not have a honda lawnmower. One pull.

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Another consideration of putting the generator in the back of the truck is the bed height of the newer trucks. Nothing is accessible over the sides without a ladder. And a bolted down generator you can't reach with the tail gate down

Has anyone put a small gas fuel cell in the generator compartment?

John I may have to look at more batterys and the 2000w inverter contains a 100a smart charger. With the generator in the truck it does leave more room for batterys. It's a lot to ponder, so many options.

I'm gonna work on the LP consumption later that was the reasoning behind the smaller 2500w genset.

Anybody store their portable generator in the generator compartment then remove it and chain it to the landing gear for use?

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Mumbleypeg I came across this eairleir but did not see any rates for the 2500. When I was looking I looked at the 5000 and these rates scared me off but I have other appliances and heating dependent on propane.

1/2 load is.60 gph and full load is.95 gph

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I store Hondas in front compartment and then take out and chain when in use. I see it very often. Honda does sell a metal reinforcement bracket for the handle so people cannot easily saw through the handle. The more portable,-----the easier to steal..so many tradeoffs.

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Hey Mumbley,

 

I found one of those You Tube reviews for the 2000 W Hyundai Inverter Generators you might take a look at. There are several such reviews (both good and bad I'm sure) on You Tube. Likewise, I'm sure there are reviews (good and bad) for Honda or Yamaha or others.

 

https://www.youtube.com/watch?v=LV-_7ym8jjA

 

NOTE, I'm NOT saying they are bad, I'm NOT saying they are good, I'm ONLY the messenger, so like or hate them or the Honda or Yamaha or any brand. They may be great, they may be a piece of crap. Take up any arguments with Hyundai or the You Tube reviewers, I haven't tested them.

 

PS Heres a Yamaha review

 

https://www.youtube.com/watch?v=1WWLykLDrBU

 

PS Heres a Honda review

 

https://www.youtube.com/watch?v=nT9G9Ie3nEM

 

John T

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I know. I started in the exact same position as you and really wanted propane becuase I already carried it and I wouldnt have to worry about gas cans. I still don't like the gas can part but refilling propane is expensive and not an especially joyful experience in and of itself. Do you drive a gas vehiccle you could at least siphon out when needed and carry an empty can. I drive diesel so that was not a solution.Two sites I used to give me an idea of pricing on gas generators are: http://www.electricgeneratorsdirect.com/ and http://www.electricgeneratordepot.com/?gclid=CjwKEAjwp_uqBRClvrrXmsbPog4SJACK4gIP34S_jsVsn_VCcXp6Pac4L3-DOZ1Ycly8YiAbxDzW4RoC1v7w_wcB.

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If you have a newer C-Pap machine you can probably get a 12V plug in for it. They generally take 120V AC and convert it down to 10V DC IIRC.

I just got one for my C-Pap and used it last week, it worked flawlessly with the humidifier running all night.This will save you running the inverter all night.

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Double - Mumbley - I posted that about CPAP and it became vaporware.

 

My CPAP - I got a 12 v cord for it and added a 12 volt outlet by the bed. The machine and humidifier use 3.5 amps - 42 watts. We'll assume 8 hours of sleep. So that is 42*8/12 = 28 ah (amp hours) of battery per night.

 

Inverter uses 18 watt standby (turned on).

Inverter ha a 85% eff (sitting there at idle or 40 watts)

PS for the CPAP at about 60 % (measured on mine - bunch of power factor in there)

 

What this boils down to:

42 watts @ 60% (CPAP PS) == 66.66 watts / 0.85% (inverter) = 78.4 watts + 18 watt standby = 96 watts X 8 hours / 12 volts = 64 ah. That is about the max you want to do on a battery. Most batteries are in the 110 ah range and 50% is 55 ah.

 

You can put your own numbers in here, but these are the ones that I measured on my machine. UP and DOWN is just one big loser (battery power that is). Even on shore power, I still run off the batteries. If you've ever had a power outage at night, you'll know why!! (Space alien sitting on my face sucking all my breathe away)

 

We have 660 ah of battery capacity, solar, Honda gen, and another 400 ah on the truck with a diesel gen.

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John all of those generators seem high quality and capable. Just boils down to price and personal preference.

Dave my truck is diesel so no help there and some of these new gas cans you need a drill and hole saw to get the fuel out

And I took a closer look at my CPAP and it has two power sources 12V .5A for. The machine and 120V. 1.7A for the heater. And like Bill mine is gonna run at night.

Bill those small loads do add up, a larger battery bank may be in order for my project.

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I'd think you could add a gas tank under your fiver at some spot so you could carry your generator fuel there. Topping up the vehicle in town and then transferring to the trailer tank would sure be less hassle than carrying cans. You might even look into adding a transfer pump so you don't have to siphon and pour to make the transfer.

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