Generator free camping?? - Page 4 - Fiberglass RV


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Old 02-27-2021, 07:28 PM   #61
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Since they are marketing these to construction workers to power tools all day on a construction site, I would hope that Ford engineers designed them to operate at idle or perhaps step the engine up to "fast idle" when the amperage load goes up.
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Old 02-27-2021, 09:50 PM   #62
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I charged my Oliver batteries with jumper cables at idle. And I charge the HQ19 batteries with the Anderson plug when driving. Both work very well.

A typical, ratio of crank RPM to alternator RPM is between 3 and 4 to 1. At 3-1 with a 750 RPM idle, the alternator would be running at 2,250 RPM. Some trucks also have a high idle feature.

In the early 60s, one of the reasons alternators were adopted was because they put out more power at idle speed, than automotive generators. They proved excellent for police vehicles, ambulances, etc, that spend a lot of time idling and have higher power demands than normal cars. Even if they are not putting out their full power, they are still putting out enough to charge well at idle. They are designed that way.

My new Tremor has twin alternators, totaling 397 amps output. My current Ram, has 240 amps. So it's easy to see that even at partial output, there is plenty. Combine that with the smart regulator they come with and you have a very good charging system.

On my boat, I hacked the regulator and could drive it to full output with the twist of a knob. This was great for charging the twin 8D batteries while out cruising off-shore.

Probably the biggest bottleneck in charging the house batteries from the truck is the conductor size. But as the charge comes up, and the demand drops, the line losses will drop too, so it will reach full charge, with a slightly slower bulk charge.

When we pull out of a camp site, my alternator voltage is reading 14 (no tenths shown, but I assume it is at about 14.1 -14.5). This is with the Anderson plug plugged in and charging the house batteries (4-100AH AGMs). After an hour or so, the voltage drops to an indicated 13, which I assume actually means about 13.2, but I haven't actually measured it. This is the indication that the batteries are at or near full charge.

When I used to occasionally use jumper cables to the Oliver batteries (4 T105 6 volt) I would simply idle the truck for about 30-45 minutes. This was when I did not have solar, and later when I had a suitcase system, but we were in the shade and using a lot of power.

BTW, this plays into the Victron video where they state that lithium batteries will destroy an alternator by "drawing" too much power from it. But what they don't tell you is that they are running the alternator at a full shorted output, at a speed lower than the speed it would be running on an idling engine. In other words, it will never face a demand like that being demonstrated, in the real world. Second, the shown conductors are very large and only about 3' long, so there are no line losses to give a false charge reading. In a real trailer situation, the wires might actually be 20-35' in each direction, or 40 -70' round trip. And third, running that slow, the alternator cannot cool itself with its own fan as well as when running at a normal RPM, and alternators sit on vehicles behind the engine fan, so they normally get partially cooled by the engine fan too. In the video, there is no second fan.

On my boat, I would set the alternator to go to full output with no cutting back as the batteries came up. I had two 8D batteries that could take a lot of amps. I would also run the water maker while the engine was running and it took a lot of amps with its 12 volt motor. There was no radiator, so no cooling fan to help the alternator cool itself. The engine was in the engine room, with engine heat and no breeze, like cars have. I never had any indication that the alternator was over heating or ever had any damage to it. So, I look at those absolute statements about ruining alternators with a skeptical eye.
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Old 02-27-2021, 10:39 PM   #63
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...
My new Tremor has twin alternators, totaling 397 amps output. My current Ram, has 240 amps. So it's easy to see that even at partial output, there is plenty. Combine that with the smart regulator they come with and you have a very good charging system.
...

I think that you'll discover that the two alternators don't sum, they alternate for heat dissipation.
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Old 02-27-2021, 11:25 PM   #64
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I think that you'll discover that the two alternators don't sum, they alternate for heat dissipation.

Well, you may be right, but I don't know of any other vehicles where the alternator has to be switched off to keep it from burning up. Also, if heat was the problem, I don't know why they would be different sizes.

The two alternators are 240 amps and 157 amps. While running the factory winch, and other loads at the same time, it would not be too hard to exceed the output of the higher amp alternator. Especially if the truck was idling. This would mean they both needed to charge at the same time, and I suspect they do. But I can't prove it yet, as the truck has not arrived.
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Old 02-28-2021, 10:09 AM   #65
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Well, you may be right, but I don't know of any other vehicles where the alternator has to be switched off to keep it from burning up. Also, if heat was the problem, I don't know why they would be different sizes.

The two alternators are 240 amps and 157 amps. While running the factory winch, and other loads at the same time, it would not be too hard to exceed the output of the higher amp alternator. Especially if the truck was idling. This would mean they both needed to charge at the same time, and I suspect they do. But I can't prove it yet, as the truck has not arrived.

When the winch draws more power than the generator(s) supply then you are merely discharging your battery or batteries. It has always worked that way.


I don't have an authoritative source for my statement that the (good lord, the language) alternators alternate. I follow the message board https://www.ford-trucks.com/forums/forum279/ which like all message boards has irregular quality. Folks there who I find credible have explained how the alternators function.
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Old 02-28-2021, 01:08 PM   #66
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When the winch draws more power than the generator(s) supply then you are merely discharging your battery or batteries. It has always worked that way.
That is the point exactly. How much battery power does one want to use to run high amp loads, over time? Instead of the alternators doing the work.

Winches, for instance, can draw over 450 amps, and there are other loads in the truck at the same time. In order to be best prepared, it's a good idea to have the alternator carrying as much of the current load as is practical. And winches run better on 14 volts than on 12. And since alternators don't put out full rated current until at a fairly high RPM, and since their output is reduced with temperature, it's easy to see that a 240 amp alternator would only match about 1/2 the load in some cases of heavy use. The batteries are certainly capable, but they are not deep cycle batteries. And a heavy draw on batteries, means much less overall power is available.

I'll be curious to see what the logic actually is on alternator interaction.
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Old 02-28-2021, 02:00 PM   #67
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That is the point exactly. How much battery power does one want to use to run high amp loads, over time? Instead of the alternators doing the work.

Winches, for instance, can draw over 450 amps, and there are other loads in the truck at the same time. In order to be best prepared, it's a good idea to have the alternator carrying as much of the current load as is practical. And winches run better on 14 volts than on 12. And since alternators don't put out full rated current until at a fairly high RPM, and since their output is reduced with temperature, it's easy to see that a 240 amp alternator would only match about 1/2 the load in some cases of heavy use. The batteries are certainly capable, but they are not deep cycle batteries. And a heavy draw on batteries, means much less overall power is available.

I'll be curious to see what the logic actually is on alternator interaction.

Take a look at https://madocumentupload.marketingas...42336&v5=False which will get you the "SEIC / PTO APPLICATION INFORMATION" document. SEIC is "Stationary Elevated Idle Control".


Also go to www.fleet.ford.com/truckbbas and follow your nose to Superduty and you'll find a lot of information on subjects that you didn't know you were interested in.
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Old 02-28-2021, 02:23 PM   #68
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...
I don't have an authoritative source for my statement that the (good lord, the language) alternators alternate. I follow the message board https://www.ford-trucks.com/forums/forum279/ which like all message boards has irregular quality. Folks there who I find credible have explained how the alternators function.
if you have a smaller and larger alternator in parallel, both wired with the same gauge wiring, and both outputting the same voltage, the total current load will be split between them. if half the current exceeds the output capacity of the smaller alternator, its output voltage will drop and it will contribute less current to the total, so more of the load will transfer over to the larger alternator, also running that smaller alternator at its max output could overheat and burn out its regulator.
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Old 02-28-2021, 02:48 PM   #69
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if you have a smaller and larger alternator in parallel, both wired with the same gauge wiring, and both outputting the same voltage, the total current load will be split between them. if half the current exceeds the output capacity of the smaller alternator, its output voltage will drop and it will contribute less current to the total, so more of the load will transfer over to the larger alternator, also running that smaller alternator at its max output could overheat and burn out its regulator.

I thimk (sic) that that is true if the field current is managed in the fashion that we are used to. With these non-symmetrical alternators I suspect that there is some sleight-of-hand managing the field current to switch them.


I haven't read about this stuff in years and hope I'm not leading anyone down rabbit holes.
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Old 02-28-2021, 03:10 PM   #70
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If you want to run the alternators in parallel you need an active voltage control loop, which adjusts the field currents together and a differential field current control loop for load sharing. In a former life I designed this stuff for multiple paralleled standby diesel generators, but in our systems, which were AC we controlled the throttles for frequency and real power sharing and field current for voltage and reactive power sharing. It was fun stuff.
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Old 02-28-2021, 03:41 PM   #71
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If you want to run the alternators in parallel you need an active voltage control loop, which adjusts the field currents together and a differential field current control loop for load sharing. In a former life I designed this stuff for multiple paralleled standby diesel generators, but in our systems, which were AC we controlled the throttles for frequency and real power sharing and field current for voltage and reactive power sharing. It was fun stuff.
Back in 1999 when the W2K panic was going on , I installed 3 large parallel 13,800 VAC generators for Target Corporate headquarters . Spent many a night with a couple of engineers making sure the generators would transfer properly ,were up and supplying power in the designated time frame , the frequencies would sync and they shared the load . Target had a battery backup system but it could only carry the load for a short period of time
Spent all day Dec 31, 1999 and half the day on Jan 1, 2000 on standby in case the power grid went down —Nothing Happened thank God
Carl you have my respect , it’s one thing to install something but it’s takes a smart person to design it
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Old 02-28-2021, 05:20 PM   #72
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Y2K! Brings back some memories. We sold integrated UPS/standby generator systems to major data centers and large high risk manufacturers. Our whole service department was on the road doing exactly what you were doing, and fortunately it was uneventful. When we wrote our monitoring system program and engine generator operator interface programs in the 80s and 90s (written in C) we used 2 digit dates. You know what we had to do! Then we had to upgrade all our customers. The PLC programming didn't have any date functions which was a blessing because upgrading would mean scheduling reduced risk periods in all the data centers. It was certainly an interesting career.
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Old 02-28-2021, 05:33 PM   #73
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I started writing code in the mid '60s. Our "big" "engineering" machine (IBM 1620) was all decked out with two (count'em two) massive 1 megabyte disk drives with interchangeable media. Who could afford four digits for the year when two digits would do?
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Old 02-28-2021, 05:35 PM   #74
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Why would someone want three phase 208 power to run their house in an emergency? Just curious. I could certainly see 240 volt single phase tied properly into the house box with a transfer switch. And a main breaker rated for the output of the generator to limit the use as needed. Otherwise people will be running the electric water heater, electric stove, several hair dryers and arc welding in the garage, at the same time, or at least trying to.
Well now the 208 three phase is close to what the Prius generates to run the car.
As it happens the 208 3 phase is made up of three 120 volt phases. The problem is that most houses require 240 volt "two phase".
But the basic power is there.
IF you accidently had a 208 three phase air conditioner etc. then you are set.
Many 240 volt electrical appliances will run on 208 vac.
For that matter you could generate 240 just as easily, but then you would have to create a neutral to give 120- 130 volt for the single phase loads.
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Old 02-28-2021, 05:53 PM   #75
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I started writing code in the mid '60s. Our "big" "engineering" machine (IBM 1620) was all decked out with two (count'em two) massive 1 megabyte disk drives with interchangeable media. Who could afford four digits for the year when two digits would do?

Alan,

Sounds like COBOL and Fortran kind of stuff. I do understand the date thing with memory being so valuable. I remember our first IBM PC. We had a whopping 256k of RAM and a whopping 10 megabyte hard disk. It used to take 45 minutes to compile and assemble our monitoring system program. Today it would probably take a few seconds! Amazing how far we have come.
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Old 02-28-2021, 06:05 PM   #76
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I started writing code in the mid '60s. Our "big" "engineering" machine (IBM 1620) was all decked out with two (count'em two) massive 1 megabyte disk drives with interchangeable media. Who could afford four digits for the year when two digits would do?

Alan,

Sounds like COBOL and Fortran kind of stuff. I do understand the date thing with memory being so valuable. I remember our first IBM PC. We had a whopping 256k of RAM and a whopping 10 megabyte hard disk. It used to take 45 minutes to compile and assemble our monitoring system program. Today it would probably take a few seconds! Amazing how far we have come.
That was Fortran II and assembler stuff. The toroid ferrites in the memory were woven together by grandmothers. And the memory was 8K characters. Here my memory gets hazy. The 1620 was a variable word-length machine and we usually ran it as 32 bit words, 4 characters per word. Not bytes.
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Old 03-01-2021, 08:31 PM   #77
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I found an interesting post regarding DC-to-DC chargers.

https://hooshmand.net/dc-dc-charger-vs-vsr-isolator/

Some of the author's statements include:
  • An automotive voltage regulator may not be designed to put a full charge into the tow vehicle battery. He states that they may only charge the tow vehicle to 80% or so in order to extend the tow vehicle battery's life.
  • There are issues with having dissimilar batteries (tow vehicle and trailer) in parallel; one will generally come up short. (That's something we've often noted when people ask about putting two 12 volt batteries in their trailer.)
  • The distance between the batteries and the line losses in the conductors matter a great deal. A less-than-robust connection like my proposed "pee-wee" jumper cables could leave the trailer battery receiving no charge if the tow vehicle battery has been topped up and the vehicle's voltage regulator quits charging.
I don't know if or when I will ever go the DC to DC charger route. But, this lends some weight to the idea of using a 12V to 120V inverter at the tow vehicle to power the trailer's battery charger.

Now, the Escape trailer's WFCO battery charger may not be the best, but remember I am looking at this whole proposition from the perspective of infrequent, partial charging to supplement the solar panel.

I also figure that any inefficiencies inherent in the inverter are dwarfed by the inefficiencies of running the tow vehicle's engine to charge a trailer battery.

Now I need to do some experimenting. My clamp-on current meter is not suited to measuring DC current. I may just try observing the gain in battery charge over time, or I might buy a cheap $20 hall-effect meter if I want to try and monitor the charging current.

https://amazon.com/dp/B01DDQM6Z4/?co...v_ov_lig_dp_it

What do you think?
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Old 03-02-2021, 07:06 AM   #78
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The first two issues stated are not a concern if you just want to put a 20-30% charge in the trailer battery. Regarding the third issue, you should use large cables.

The ammeter you found looks perfect for your science experiment. I have a Fluke 325 which cost around $230, but I use it all the time. I also have a Victron BMV700 which also measures the battery current. You really need a device like the BMV700 if you have lithium batteries because the voltage does not vary much, making it difficult to estimate charge level. The BMV700 measures power in and out and computes state of charge based on what is taken from a fully charged battery. Over time it will drift as the battery ages but you can compensate for it.
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Old 03-02-2021, 12:20 PM   #79
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You really need a device like the BMV700 if you have lithium batteries because the voltage does not vary much, making it difficult to estimate charge level. The BMV700 measures power in and out and computes state of charge based on what is taken from a fully charged battery. Over time it will drift as the battery ages but you can compensate for it.
That had not even occurred to me as I've never considered the practical issues with setting up lithium batteries. As you say, the flat voltage discharge curve would make it challenging to measure the state of charge by measuring voltage, while I am able to use a $13 volt-meter/USB charger for our lead-acid batteries.

While I enjoy reading about advances in technology, I often tend to spoil the fun by asking myself pointed questions about costs and benefits. On the other hand, the growth of RV sales and the increasingly limited availability of campsites may lead me to take a closer look at improving our boondocking capability over time. So, I appreciate these discussions.
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