zero

An added comment. Winnebago having that relay instead of a rectifier makes the difference between " no charge at 30 amps" to "some charge at 30 amps." I have not found Ohm's Law to lie yet. If that setup shown (by Derek) used a rectifier instead of that relay shown and has 15 feet of wire - at 30 amps - 14 volts at the alternator, drops to 12.3 volts (approx) by the time it tries to get to the "house" battery. 12.3 volts cannot charge a battery that requires at least 12.7 volts to be fully charged. By using that relay, at 30 amps - voltage drops to 12.9 volts. Still dismal, but at least high enough to charge. A lot of loss to heat and poor circuit design. Just because Winnebago did it, does not mean it is optimal. Not sure what the point of all this issue. The post - as I recall - was about a blown 30 amp fuse hooked to an alternator capable of sending 60 amps. How is that confusing? How anyone can claim that the alternator is not capable of sending more then 30 amps down a 10 gauge wire is beyond me. Very easy to prove.

I have no idea what the actual circuit length is in the Winnebago diagram. I DO see that it uses a relay and not a rectifier-based isolator. So that is more voltage going to the 10 gauge charge wire because there is no voltage drop across the rectifiers. Also, Winnebago has slow-blow, self-resetting circuit breakers in the line and not fuses. 30 amp as I recall. So when the "house" battery calls for more then 30 amps of charge - the system says "no" after a second or two. I'd rather have full charge capability in my system. I also have two "house" batteries in back, not one;

Back in the early 70s when pickup truck was not as common as today - Hertz Ford pickups had 300 sixes. I rented them often and they were assume. 2WD, standard cab and lots of power (on a relative scale). Seemed to have much more snot that Chevys HD 292 straight-six. If you want to compare a 6000 lb. Ford pickup with a 6000 lb. Toyota RV, I think that Ford needs to have a 4.1 to 1 rear-axle ratio and that is unlikely. Mine has a 3.33 axle-ratio. I have no idea why the 4.3 GM does so well in some RVs. I drove a 1995 AWD Astrovan for years with a Vortec 4.3 and absolute best highway mileage was 18 MPG. Granted, that was at 65 MPH. I also just sold a 1995 Dodge 3/4 ton van with a 3.9 V6. That was only 2WD and absolute best mileage was 18 MPG (kind of disappointing). Many Winnebago Lesharos and Phasars have been converted to Buick 3.8s or Dodge 3.8s. Reports are they get 15 MPG on the highway as opposed to the 14 MPG they originally got with 2.2 liter gas engines. They weigh around 6000 lbs. and have roofs as high as many Winnebagos. Single 14" tires in back though. I love the Dodge/Chrysler 3.8 V6. My 1998 Dodge AWD Grand Caravan has 300,000 miles and runs like new. Does not burn a drop of oil and never had any major repairs. Gets 21-22 MPG with a full load and feels like it has all the power my Chevy Astrovan AWD did with the 4.3. It might just be because it is more aerodynamic.

One other thing I didn't see mentioned. Automatic trans needs 7-9 horsepower to run (that's loss). I suspect there are more 2.4s around with manual trans then 3 liter V6s. Another factor when comparing.

Just an added comment. #10 cannot even carry 30 amps for a 20 foot run. If 14.2 volts on the alternator end, and around 13.8 once it leaves the isolator - voltage by the time it travelled 20 feet would be 12.6 volts and that is less then a charged 12 volt battery. I.e. no charge possible.

I don't know what vehicle you or I are talking about. Thus why I gave a length. Some of these Toyota RVs have the cranking battery and the "house" battery both under the hood and the charge wire is sometimes only 2 feet long. If we are talking about a rig with the "house" battery in the rear - it is a whole different situation. I have two "house" batteries in the rear of my Minicruiser. Actual length of the charge wire is 16 1/2 feet and I have #2 copper with an 80 amp circuit-breaker.

Torque is twisting force. I.e. it the rotational twisting power of the engine's flywheel to send power to the drive-wheels. Torque is what keeps you going at a certain speed without fighting the gas pedal. Horsepower is a number made from torque and math. I can't speak from your experience, but I also don't get it. I still own a 1995 Ford F150 with the 300 cubic-inch straight six. I also used to have the older 240 cubic inch version in my 1966 F100. I also had a 1995 Toyota pickup for a long time with a 2.4 engine. I suspect when it comes to hill-climbing, the 1995 F150 4WD I have right now would beat that 2WD Toyota I had. A typical 80s-90s Ford F150 with 2WD weighs around 4500 lbs. and has 265 pound-feet of max torque at a low 2000 RPM. A typical 80s-90s Toyota 2WD truck weighs around 2800 lbs. and has 140 pound-feet of max torque at 3600 RPM. So the Ford has 16.9 lbs. of truck per 1 pound-foot of torque. The Toyota has 20 lbs. of truck per 1 pound-foot of torque. I think you are kind of comparing "apples to oranges." I Toyota truck with a Ford 300 six would go like h*ll.

Ever seen an inverter built into the dashboard OEM of a car? I just drive older rigs, but this is news to me. No fan either! Built into the dashboard of my 2004 Toyota Matrix/Pontiac Vibe I just got.

I made a long trip yesterday to southern Michigan to get the Pontiac Vibe AWD I've been searching for. It is actually a Toyota Matrix. These things tend to go high around here. Finally found this one at a repair-job-gone-wrong at a body-shop. Quarter-panel was fixed around the gas-filler and paint does not match perfect. Makes no difference to me. I rushed down to get it with an agreed-upon price of $2100. I got there and some goon was begging the shop owner to sell it to him for $2500. Nice that the shop-owner was a man of his word, and stuck to the price we had agree on. He had promised me that he'd hold at that price once I left home and heading down to his place with my trailer. NEAT little car. Runs real nice for a 1.8 liter engine. Odd though. It has a very high compression (like muscle-cars from the late 60s). Variable valve time, and all kinds of modern tweaks. Also no d*man timing belt! Odd though. I compared it to a Toyota 18RE engine from 1974 (2 liter fuel-injected) to this one. Not much difference. 1974 engine makes 115 max horse @ 5600 RPM, and this 2004 engine makes 120 max horse @ 5600 RPM. One thing I find odd. This car has a 115 volt AC outlet built into the dashboard. I've never seen a car with one of these OEM before. But maybe I am behind the times. One funny thing. As I understand it - this VIBE is 100% Toyota except for the badges and the radio. Matrix uses a Toyota-sourced radio, whereas the Vibe uses a GM sourced radio. So wouldn't you know it? NO display working on the radio and I come to find out it is a problem with many of these radios used in GMs (even in Corvettes). I found a place that "rebuilds" them for $150. Ends up the problem is three little incandescent light bulbs that burn out prematurely. They are soldered in to the circuit board. I've got to ask. Who the heck in this day and age would put incandescent light bulbs and solder them into a radio other then Government Motors? The Corvette radio repair place offered to sell me three new light-bulbs for $30 shipped to my house, if I want to repair myself. I searched around and found a place on Ebay that is shipping me a 10-pack for $5, free shipping.

Made a type. Obviously, the 3 liter @ 2500 RPM makes 6 pound-feet more torque. At 3000 RPM, the 2.4 beats the 3 in torque.

Here is a dyno comparison of the 2.4 to the 3 liter when running at 2500 RPM which I think is a pretty normal engine speed for general driving. 2.4 makes more torque at lower RPMs. 2.4 four- makes 54 horsepower and 102 pound-feet of torque @ 2500 RPM. 3 liter V6 - makes 66 horsepower and 108 pound-feet of torque @ 2500 RPM (less then the 22RE). 2.4 four- makes 65 horsepower and 115 pound-feet of torque @ 3000 RPM. 3 liter V6 - makes 82 horsepower and 112 pound-feet of torque @ 3000 RPM (less then the 22RE). 2.4 four- makes 72 horsepower and 115 pound-feet of torque @ 3200 RPM. 3 liter V6 - makes 90 horsepower and 118 pound-feet of torque @ 3200 RPM

I think what counts is actual road-tests and not max power stats from running on Dynos. That being said, dyno tests show this: 1988 - 22RE made 114 max HP @ 4800 RPM, and 140 lbs. max TQ @ 3600 RPM. 1988 3VZ made 145 max HP @ 4800 RPM and 180 lbs. max TQ @ 3400 RPM. That HP means little to me. That extra 40 lbs. of torque at a slightly lower RPM likely makes a nice difference though. What I do NOT know is how they compare in "normal" driving when the engine is only running around 2400-2600 RPM. I suspect, or hope, not many here drive their RVs around at over 4000 RPM.

I agree that the 3 liter, generally speaking, is not as well designed nor as durable as a 20R or 22R or 22RE. The 3 liter has a timing belt to deal with, a poorly engineering valve-train, and a history of head-gasket problems from them moving too much. I don't want an engine that needs lubricated head-gaskets because of excessive movement. 3 liter Toyota and 2.5 liter Subarus are known for that problem. That all said - the Toyota four-cylinder engines certainly were durable when compared to other engines of the time. But now? Plenty of other makes of small engines just as good or better. Some are lower-tech also. I find it kind of frustrating that a 4.3 liter GM V6 often gets better fuel-mileage then a Toyota four-banger pulling the same weight and pushing against the same wind resistance. Yet, the 4.3 is pretty much based on a engine that came out in 1955.

Here are some more road tests. Note how the heavier Chevy with the biggest engine beats them all in speed and fuel mileage. Pop-up roof I suspect helps a lot. Good old fashioned pushrod engine too. 1979 19’ Odyssey on Toyota. 2.2 engine and four speed manual . Weight 4770 lbs. 7' 6"high. 0-60 MPH = 32 seconds. 40-60 MPH = 19 seconds. 1978 Trotwood, Toyota . 2.2 engine and four speed manual, 3470 lbs, 0-30 MPH – 5.5 seconds, 0-60 MPH – 21 seconds, 40-60 MPH – 12 seconds. 1978 Galavan 400 on Datsun chassis. 2.2 engine, 4 speed manual trans. Weight – 3730 lbs. 0-30 MPH – 5.7 seconds, 0-60 MPH – 20.5 seconds, 40-60 MPH – 11.5 seconds. 1978 Galavan 400 ,Toyota chassis. 2.2 engine and four speed manual 16’ long, weight– 4000 lbs. 6' 8" high. 0-30 MPH – 5.7 seconds, 0-60 MPH – 20.5 seconds, 40-60 MPH – 11.5 seconds 1977 Dolphin RV on Toyota chassis. 16’4” long. 4 speed manual trans. 2.2 engine and four speed manual. 4000 lbs. 8’4” high 0-60 MPH = 37 seconds, 40-60 MPH = 19 seconds 1979 Sand Pak, Toyota chassis. 2.2 engine and four speed manual. 9' high. 4500 lbs. 0-60 MPH=32 seconds, 40-60 MPH=18 seconds 1990 Provan Tiger, 4.3 V6, auto trans. Pop-up roof. 6' 10" high. Weight = 5400 lbs. Aver. fuel-mileage @ 60 MPH - 15.8 MPG 0-60 MPH=15.1 seconds, 40-60 MPH=8.6 seconds

Not the ones with pop-up roofs like the Chinooks.

Nonsense. I watch 60 amps on my amp-gauge every time I start my tractor and it is only wired with 10 gauge copper. Technically, 10 gauge is rated at a max of 55 amps and is supposed to be fused at 30 amps for safety. Note my tractor draws no more amps when I start it then a Toyota pickup. If I begin with a full charged battery, then crank the engine for 5 seconds - that lowers battery voltage enough to created a 60 amp surge of charge as soon as it starts. Usually only for a few seconds and then it tapers right down. Do that with a Toyota RV with two batteries calling for charge and you expect a lower amp demand? I don't get it. Not unless you are "tricking" the alternator's voltage sensing circuit somehow. I will note that if someone has a rectifier-based isolator that simply cannot pass 60 amps safely (or even 40 amps) - it's a different story. Some just blow out and go dead. Been plenty of people on this forum with dead isolators. Note that a 10 gauge copper wire, 2 feet long, with 60 amps @ 14 volts - only has a voltage drop of 1.7% which is pretty low.

Just a side-note. I've got a Denso alternator on my farm-tractor that came off a Toyota truck. I have a amp-gauge hooked into it instead of a voltmeter with a 60-0-60 amp scale. Every time I start the engine that meter gets pinned all the way to 60 amps and it feels like the needle is going to bend. Only happens for a few seconds and only if I've got the engine revved up. The belt also tends to slip a little unless I lower the RPMs until the battery catches up. Same sort of thing to some extent has to happen with our Toyota RVs. More good reason to have a relay for an isolator instead of a box of rectifiers.

Many old cars had remote mixture and remote timing adjustment (20s-30s). From the tests I've read - fuel injection that is computer controlled keeps the air-fuel ratio correct when altitude changes, but does not offset the loss of power. All engines, regardless if carbed or electronically injected - lose 3% power for ever 1000 feet of altitude unless they are supercharged. With a mechanical or exhaust-driven supercharger, the loss is only 1%. It is the reason why many early turbochargers were sold as "altitude compensators." I saw a recent test on a new 306 horsepower 3.5 liter Toyota car that made 306 HP at sea-level. It dropped 245 HP at 6700 feet, and dropped to 215 HP at 9900 feet. That engine has variable valve timing, electronic direct injection, a very high 10.5 to 1 compression ratio, etc. and still had all that power loss.

I drove a 1981 diesel Chevy Chevette with a 1.8 liter for years (just got rid of it last year). Also a 1991 VW Jetta 1.6 liter diesel. Neither had turbos. I still have my 1985 Isuzu 2.2 diesel mini-truck with 4WD also with no turbo. Your Mercedes is a rocket-ship compared to some of the diesels I've had. But when comparing one turbo-diesel to another, it is amazing how different then can be. My 1992 5.9 liter turbo-intercooled Cummins has much more power then my 1994 7.3 liter turbo diesel Ford and the 5.9 gets better fuel mileage too. Even odder - the Dodge has 3.50 axle whereas the Ford has 4.10 axles - yet the Dodge pulls much better with a load.

Nobody in their right mind is going to install an isolator rated for less then the alternator max output. So at least with OEM, any older Toyota RV is going to have an isolator rated for at least 50 amps and a newer one at least 60 amps. Now adays I doubt you can find a new one rated for less then 70 amps. Also note that although 10 gauge wire is usually protected with a 30 amp fuse, it is approved to carry up to 55 amps for short periods of time. 12 gauge is approved for 41 amps, again for short periods of time in short runs. Thus why it is much better to have a slow-blow circuit-breaker or a slow-blow 30 amp fuse and not an "instant blow" fuse. It is the same reasoning used in standard household wiring. A 20 amp circuit breaker is engineered to allow up to near 50 amps for short periods of time and not trip.

I love the Chinook and it is fun to drive and has plenty of power (as compared to the Minicruiser). It can also get 22 MPG. But . . having a bathroom with us with the Minicruiser is a huge asset. I kind of like the power steering too. Using the Chinook makes us feel like a bunch of hippies "roughing it" in our VW van, on the way to Woodstock. Using the Minicruiser makes us feel like we have a small, comfortable home with us. We are planning on driving out to the southwest next year from Michigan and I still haven't decided which one we are going to drive. In the mean time (this winter) I'm thinking of finding a way to build a small bathroom in the Chinook. We'll see. If I could find a way to get 18 MPG with the Minicruiser and do 65 MPH with it - it would be my #1 choice. I don't think that is possible however, unless I stick a turbo-diesel into it.

Here is a comparison of the 3 liter V6, 21 foot Winnebago - compared to a 17 foot Dolphin with a 2.2 liter four-cylinder Dolphin 2.2 liter straigh 4 - 0-60 MPH in 37 seconds. 40-60 MPH in 19 seconds. Fuel economy average - 15.1 MPG Winnebago 3 liter V6 - 0-60 MPH in 23.3 seconds. 40-60 MPH in 13.1 seconds. Fuel economy average - 12.7 MPG

Trailer Life magazine did a road-test on a new 1990 Winnebago 21 footer with the 3 liter V6. Fuel mileage for a near 4000 mile trip no faster then 60 MPH came up with 12.7 MPG average. Had the highest tankful with 15 MPG and the lowest tankful at 10.6 MPG. The driver said when climbing a 6% grade - it could just maintain 50 MPH at a 4000 foot altitude. On flat ground - 0-60 MPH in 23.3 seconds. 40-60 MPH in 13.1 seconds. The driver also noted that at 55-60 MPH on a flat-highway it seemed to cruise well. But at 65 MPH he said the pedal was pushed near to the floor all the time.

A coach battery that is 50% discharged could easily ask for, and get over 30 amps of charge from a 60 amp alternator. I've seen it happen many times. It is one good reason that when first starting RV with a worn-down "house" battery - start the engine and let it idle for awhile before revving it up and driving. That 60 amp alternator only puts out around 20 amps when the engine is at low speed and it only takes a few minutes for the high-surge demand of the battery to get lower. It kind of baffles me why anyone finds this concept "unlikely." That is what an alternator/regulator does. It senses low voltage and attempts to correct it by upping the amperage. A 60 amp alternator is called just that because it can send 60 amps to your battery if it is low.

Not possible in my case. I never park/camp for more then one night at a time and then drive with lots of charge going on. Once home, my Toyota RV is plugged into a 10 amp dual-output battery maintainer. So even if the inverter was left on - it would not matter. Never going to happen though. It has a pretty bright light that comes on when "on." Hard not to notice.