Ford Transit USA Forum banner

Additional alternator for house batteries?

60K views 135 replies 24 participants last post by  HNLHugh 
#1 ·
I did a quick search, but couldn't find anything on this, but will Ford be allowing for dual alternators on the Transit? The reason is that the second alternator could feed a set of house batteries, which would feed a decent inverter. If this is possible, it would be nice for running electrical appliances like a microwave in an upfitted van.
 
#2 ·
Mercedes offers the mounting brackets for a second alternator for the Sprinter as an option, but I think they are the only ones. RAM doesn't offer a second alternator option for the ProMaster either as far as I know.

Having a stand-alone electrical system for the "house" is something I would also pursue if practical. One advantage is that voltage would not be limited to 12 Volts. Of course that too has pros and cons.
 
#3 ·
It looks like American Power (americanpowerinc.com) has a 360 ampere secondary alternator with a bracket, just for the Transit. This allows me to keep the chassis electrical system separate from the house electrical system, which is quite important to me, as Chance mentions above.

If this is true, then I can feed a house battery bank from that. Add an Onan generator, a generator controller, and a Magnum Energy hybrid inverter (which makes up for low voltage by supplementing from the batteries), and any electrical item past the inverter will have a clean 120VAC supply, regardless if the power is coming from the engine, the Onan, shore power, or solar.
 
#4 ·
Chance & mlts22,
Bear with me, not an automotive electrical person.

With 2 alternators, will the engines be able to run both without causing trouble somewhere else? Would you have to connect the 2 or install another alternator belt?

Semper Fi
 
#8 · (Edited)
You do not need two alternators to run a microwave in a conversion.

Attached is my electrical diagram for the Transit. It is very similar to what I had in the sold 08 Sprinter. The Sprinter house electrical was completely separate from the Sprinter vehicle electrical. The house 12 volt system was not even grounded to the chassis. If I wanted I could have removed the house 12 volt system and without changing any wiring it would have worked in the driveway.

What I did in the Sprinter was not the normal RV setup that used the vehicle 12 volt alternator to charge the house battery. There are numerous things wrong with the "normal" RV setup:

1. You do not charge the house battery with a quality 3 stage (bulk/absorb/float) charger.
2. The alternator charge profile is not matched to your house battery.
3. You are charging two different size batteries at the same time.
4. You may be charging two different types of batteries at the same time (Flooded and AGM).
5. You would be charging two different age batteries.
6. You probably would be charging two different brand batteries with different charging requirements.
7. You could overload the alternator.

The solution that worked well for me was to have two inverters. A "vehicle" inverter that was powered by the Sprinter and a "house" inverter that was powered by the house battery. The vehicle inverter was a 600 watt pure sine inverter to provide 120 volt power while driving. That 120 volt power was "shore" power. I also had a real shore power cord. A 3 position battery selector switch (Blue Sea # 9009) could select the vehicle 120 volt power or real shore power or off. The 120 volt power then went to a Magnum MMS1012 1000 watt inverter/charger/transfer switch. The Magnum has a programmable charger where you tell the charger the battery size and type. It then provides the correct charge profile for that particular battery.

The rest of the electrical system included a 255 amp-hr Lifeline AGM 8D battery, the Magnum RC-50 controller and the Magnum BMK battery monitor. I would set the remote to read SOC (state of charge) to keep me informed about the charge level in the battery. The solar system was additional. Solar panel was a 205 watt panel and the solar controller was a Morningstar Sunsaver 15 amp controller. Solar controller was also a smart charger that has bulk/absorb/float matched to the battery type. I went for a year without using either shore power or "shore" power from the second inverter. I did cheat by turning on the vehicle inverter while driving so that my largest load (4 amp DC refrigerator) ran on 120 volt power instead of the house 12 volt power.

The 1000 watt house inverter would run a cheap ($50) K-Mart 600 watt Proctor-Silex microwave. Microwave is ideal because it has old fashioned mechanical dials without a clock or pushbuttons. When not running it would not use any power. Besides I soon learned not to have the Magnum inverter on unless I needed 120 volt power. It used 7% of my battery capacity just being on overnight without any load. They use a lot of power just being on. The microwave used about 1% ot the battery capacity for every two minutes of use.

Transit system will have a few upgrades. Vehicle inverter size will be increased from 600 watts to 1000 watts. I will use the vehicle inverter while driving to charge the house battery or heat shower water electrically or power a 750 watt electric baseboard heater in rear of van. The larger inverter will allow me to charge at the full 50 amps allowed by Magnum, reduce the 5 gallon water heating time from 45 minutes to 30 minutes and I can add the baseboard heater. The solar panel will go from the 205 watt panel to a 300 watt panel. Same physical size. About $75 more that the going $1/watt cost of solar panels. Should be worth the extra cost on grey days.

This design worked very well for my application. I did buy the HD alternator and the dual AGM batteries in my Transit. I also bought remote start that will allow me to heat up van in morning without getting out of the sleeping bag. I let the van interior get cold at night and I stay warm with a 12 volt heating pad under the zero degree sleeping bag. I also wear a balaclava to keep my head warm. No heater and very little refrigerator run time makes for a quiet nights sleep. Also very stealth.
.
 

Attachments

#10 ·
....cut..... There are numerous things wrong with the "normal" RV setup:

1. You do not charge the house battery with a quality 3 stage (bulk/absorb/float) charger.
2. The alternator charge profile is not matched to your house battery.
3. You are charging two different size batteries at the same time.
4. You may be charging two different types of batteries at the same time (Flooded and AGM).
5. You would be charging two different age batteries.
6. You probably would be charging two different brand batteries with different charging requirements.
7. You could overload the alternator.

....cut......
Orton, all design involves compromise, balancing pros and cons. Since your design keeps coming up I'd like more general information on both sides of the issue in order to compare fully. I don't need details at this time.

You've made great points regarding issues that are wrong with the typical RV system used throughout the RV industry. You've also made a case for what's right with your system. But in fairness, we need to also weigh what's right with typical RV electrical system as well as what is not right with yours.

Can you take a minute or two to also enumerate the standard RV Pros as well as the Orton Cons. Basically I'd like to see both Pros and Cons of both systems.
 
#11 ·
#23 ·
If by normal conversion you mean traditional I agree.

On the other hand newer all-electrical RV vans like Roadtrek and others now have require a lot of juice to power heater or AC. One claimed about 5 KW alternator and 800 Amp-hour (at 12-Volts) of lithium batteries. And since lithium batteries can be charged very fast, a large alternator can be put to great use on a regular basis.

To me it seems there is little middle ground. Some vans will use little power and can work fine off factory alternator, or they will be all electric and need lots of power. Shore power and generators are cheap, but some owners want silence while off the grid. And if they want electric heat or AC that changes everything.
 
#24 · (Edited)
I'm beginning to thing about using a dual sense VSR to handle the isolation, such as JayCorp Technologies - Dual Battery Kit with Smart Isolator Relay

I'd like to find something a bit heftier than 140A, but that will probably be adequate.

It has the advantage of allowing one to charge either battery system from whichever charge source (house...solar or shore, or vehicle) is actually supplying the energy. It also should be real simple to wire the interface between the two battery arrays. Since both house and vehicle will be AGM, charge protocols should be similar.

Any immediate downsides come to mind?

Stan
 
#26 ·
One thing I was wondering about is whether or not idling the engine in a camping setting would be loud enough to be considered a nuisance. I just got back from a trip renting a Roadtrek for about a week, and it seemed to me that the engine at idle was not too noisy. With an alternator of high enough capacity it might only be necessary to idle for an hour or so at the most.


Related to that, I have not seen any options for increasing the size of the fuel tank on these vans. Is it possible? If that were possible, then there would be sufficient fuel to top off batteries if there were not enough solar and the Onan generator and even propane could be eliminated.
 
#28 ·
Van gasoline engines near idle can be as quiet as many generators, but I'd personally worry about exhaust fumes when first starting a cold engine. If near campers outside or in tents that could bother them.

Regarding fuel tank size, it's important to note that Onan generators burn gasoline from vehicle fuel tank so for comparison we have to evaluate the difference in fuel rate between Onan engine and van engine at fast idle.
 
#29 ·
Thanks for bringing that up. The Onan I used briefly was propane, but would the fume issue disappear when using the gasoline Onan as compared to idling the engine? Also, it would seem that the offset of the 2K for the Onan and maintenance on it would pay for quite a bit of inefficiency, if that were an issue.
 
#30 ·
There is little doubt I would never use an extra $2k in fuel by idling versus running a small 2800 watt generator. Depending on use the van engine may burn less. If you can idle engine for an hour to charge batteries and then keep it off the rest of the day versus having to run a generator for hours a day because there is less battery storage, then generator may use more gas. Also the generator weight has to be hauled around 100 % of time, so it reduces MPGs even when not camping.

Regarding generator exhaust fumes, it can be an issue. My sister and brother-in-law have a 5th wheel trailer with an exhaust extender that discharges around 13-ft high. It also reduces generator noise a little.
 
#34 · (Edited)
There are lots higher amperage VSRs out there. I believe that I have seen a 400 amp version somewhere. Here's a link to a 200 amp model: Dual Sensing Smart Start SBI 12V 200A (SBI212D) - REDARC . Of course there is a tradeoff between amperage and cost.

Question: Is the use of the VSR primarily to charge a second set of batteries without needing a second alternator? Also, if one were to go the route of a second alternator, would that be a more flexible choice if one wants to upgrade the system later with a larger secondary battery bank?
 
#35 · (Edited)
I think a VSR gives more flexible charging options (car->house, house solar->car, shore->car) than you can get with either an extra alternator, or with a diode isolator. I think it will also be far simpler to install both mechanically and electrically. It will be cheaper by far than an alternator set-up.

I plan to use the alternator just to recharge batteries, not as a direct PTO source for other stuff. For my purposes, I think an extra alternator would be real overkill. I think the Transit's 220A stock unit should be adequate to recharge both banks at a reasonable rate.

BTW, I got pointed to a 200A VSR with a built in bypass capability. 1315-200 Battery Separator - Smart Charge Priority Systems. I expect that I can use one of the upfitter switches to engage it if necessary to get enough starter oomph.
It is available for a bit over $100 here: http://www.allbatterysalesandservice.com/browse.cfm/4,5736.html
 
#49 ·
Hi Orton,
I haven't made my way through your build reports yet.

So, sorry if this is something you've already answered:
Does your inverter system allow for house charger circuitry (solar or shore) to also charge the car battery?

Stan
 
#73 ·
The main reason I'm looking at a secondary alternator is not just to charge the house batteries, but to power a Magnum Energy hybrid inverter while on the road. This way, I can run the roof A/C, use the microwave, and other items without needing to fire up a generator, but when parked and off-grid, I can use an onboard Onan, since it makes more sense to run a generator for hours and hours for A/C than to put the wear and tear on a vehicle's engine and drivetrain. The battery bank I'm looking at is fairly modest, but the ability to run appliances with just the engine on is useful.

If this can't be done, running the Onan while on the road is doable, but might as well use the chassis engine as a backup if needed.
 
#75 · (Edited)
The main reason I'm looking at a secondary alternator is not just to charge the house batteries, but to power a Magnum Energy hybrid inverter while on the road. This way, I can run the roof A/C, use the microwave, and other items without needing to fire up a generator, but when parked and off-grid, I can use an onboard Onan, since it makes more sense to run a generator for hours and hours for A/C than to put the wear and tear on a vehicle's engine and drivetrain. The battery bank I'm looking at is fairly modest, but the ability to run appliances with just the engine on is useful.

If this can't be done, running the Onan while on the road is doable, but might as well use the chassis engine as a backup if needed.
Ah, I see. If you expect to be to be drawing >2000W continuously while driving, then a second alternator begins to make sense.:nerd:

But does that work out to be more efficient AC generation than just running the Onan while you're driving?

I'm wondering because the Onan may not have the 12V I^2R losses or inverter inefficiencies, and, of course, is far simpler to implement.

Stan
 
#77 ·
I expect an Onan engine is less efficient than the van's engine, and may end up burning more fuel overall. Onan lists fuel rate at 50% load which would be close for a 2800 watt generator powering a small roof-mounted AC.

From a fuel-economy standpoint, I think having a rear AC driven by van engine is probably most efficient. It's likely more efficient when van engine turns AC compressor, versus turning alternator that runs inverter that runs electric motor that turns AC compressor. Just a guess though.
 
#88 ·
I do boondock and also city camp. I avoid RV parks like the plague. The Sprinter van was stealth as the Transit van will be. For my use I have an electrical system that does not require any intervention on my part. I do set my Magnum remote to read SOC and glance at it to keep track of the house battery status. I have learned not to turn on the house 1000 watt inverter unless I need 120 volt power. Inverter will use 6% of the battery capacity overnight just running without a lead. Larger inverters would simply use more battery capacity so it is not a good idea to buy a larger inverter than what is necessary. I have learned that I can run a 600 watt microwave but it uses 1% of my 255 amp-hr. battery for every two minutes of operation. I do not heat the van at night. I have learned to use a 12 volt heating pad to stay warm without any noise.
I am still learning and will make changes to the Transit build based on what I have learned. The electrical system has become something I do not have to think about. It simply does its thing. Kind of neat that a solar panel with the right charger removes electrical issues. I do have a crude shower that is not like one at home but you are clean after using it. I can shower inside van on a city street. I do feel very free knowing I can drive almost anywhere and stop for the night.

I have no need to own a power station with so much power available that I could sell it. All I want is a system that provides all the power that I use. This is not rocket science.
 
#84 · (Edited)
Hi Orton,
I agree that one must design for what they expect to need.
However, chuckling at smaller conversions with larger power systems may be premature before you understand the reasons for sizing those systems.

For example, I WILL have about 500W solar, a 2KW inverter charger, 30A shore service, ~ 400AH AGM house battery bank, and 220A charging capability. Not too much smaller than your chuckle. But let's look at why that will be what I build:


  1. 220A charging. Not much choice about this if I want the (dual) AGM car batteries. Not an other option from Ford. And I want those AGMs so the charge profile will be similar to my house batteries.
  2. 500W solar. I live in the PNW. Much of my camping will be boon-docking in deep forest under rainy, snowy, or at least heavily clouded skies. Do I expect to need 500W all the time? No. Will I need this in the summer if I'm on the east side of the state? No. What I do want is enough panel to scavenge whatever ambient light is available, in the poorest conditions I reasonably expect.
  3. 2KW inverter. Do I regularly expect to need 2KW? No. What I do want to do is run a microwave a few times a day for a few minutes, run a toaster, and brew some coffee. But I don't want to be current starved when I turn on the microwave, etc.
  4. 400AH battery bank. Do I expect to regularly draw this down? No. I want to have power regularly available for the microwave, etc. even though my charging ability will be limited (see #2 above). I want to keep that happening as long as possible without needing to run the engine or moving to someplace sunny. That means a bigger battery reserve than what I'd need if I was camping at a Southern California desert or beach.
  5. 30A shore power. Why? Not because I plan to stay at campgrounds. Instead, I want this because I will have the van plugged in at home, so the Magnum can properly maintain the AGMs. Why 30A? Because that's a very common and cheap socket at RV supplies.

I don't think these are extreme, or even slightly unusual requirements. Will there be far more power available than I'd need if I was forced to go further south? Of course.

However, I'm pretty sure these power requirements would hold under circumstances like I describe, even if I had a short wheelbase Transit, PM or Sprinter. Smaller conversion size is largely irrelevant.

I suspect geography has a bigger role to play for most folks' designs than a desire for overkill power in small campers.

Finally, I have a couple of questions. Can you point me to data indicating how much battery life is likely shortened by using a stock Ford inverter (with a possibly "incorrect charge profile" vs. something like the Magnum?

If the issue is maximum charge held, not battery life, unless an alternate charging system's additional cost is amortized in a reasonable time frame, compared to cost of increasing battery size, that's actually an argument for running a somewhat larger battery set. I'd call "reasonable time frame" the expected battery life. Is there any data on this?

Without this data, how can one be expected to make an informed trade-off decision?
 
#89 ·
Boondocking along Gulf Coast in summer is a lot different in that it requires air conditioning at night in order to sleep because of the typical high temperatures combined with high humidity. It can be miserable otherwise.

To run AC one has to run van engine (done that a few times in present van for a couple of hours), run a generator (did it a few times with previous RV), have shore power (we stay at campsites mostly out of this necessity), or run efficient AC off large battery bank and inverter (my future goal).

Of these options only high-capacity batteries and inverter is "stealth". And as estimated previously, it would take approximately 400 Amp-hours of energy to run AC most of night.

Obviously this is approximately 20 times more energy than many campers can get away with if all they have to run at night is small fan. The "need" for air conditioning at night in some parts of the country is a game changer unless one expects to have shore power.

It may seem ridiculous to install 800 Amp-hours of battery capacity like Roadtrek and others are offering as options, but if you are spending well over $100k on a luxury Class B what's another few thousand to replace a generator with silent batteries?

Their costs are high because they use a very high capacity engine-driven alternator, lithium batteries, solar, and large inverter that can handle the starting current of a roof-mounted AC. Going all electric is no doubt expensive. My goal is to try to go all electric on a budget without having to depend on a generator or idling the van to sleep at night when AC is needed. To keep costs down I will not use solar and will apply those funds towards additional batteries which are needed more for my use. Very different needs for very different conditions.
:)
 
#90 ·
... Of these options only high-capacity batteries and inverter is "stealth". And as estimated previously, it would take approximately 400 Amp-hours of energy to run AC most of night. ...


Have you estimated usage for electric heat when it is cold? I still trying to retain the calculations. Would you take a 1500 W heater divided by 110V to get amps and multiply by the number of hours? (eg 10) I come up with roughly 1/3 of the AC usage.
 
#91 ·
What makes conversions interesting is the number of different ways people use the conversions. Building a conversion to run air conditioning is a completely different design challenge than just needing to run a refrigerator, charge computers, occasionally use a microwave and use some LED lighting.

What I have been suggesting for an electrical system is totally inappropriate for someone that needs to run air conditioning overnight.

One comment that may be useful: I have been considering making some curtains with Thinsulate drapery lining to wall off the sleeping area in my van. Instead of trying to heat the whole van, just heat a much smaller area where you sleep. Curtains could be easily hung each night from my 80/20 overhead cabinets. Maybe there is a way to do something similar with air conditioning to reduce the power requirements. Cooling the sleeping half of the van instead of all the van and cab area could reduce the electrical load to less than half from trying to cool the whole van.
 
#102 · (Edited)
I did not read every post in this thread but I will tell you
about something I just used-

A friend of mine had left her car parked in her garage
for a month- Toyota -
the dome light had been left on car would not start
and the battery voltage was .03 volts-
not even one volt -I figured the battery was toast -

A friend of hers purchased one of those tiny battery
jump starter gizmo battery things for $50
at walmart -
was about the size of 3 packs of cigarettes -

All of these jumpstart battery gizmos that I have ever
seen were Total pieces of sh*t and I figured No Way
was this tiny battery pack going to start this car -
Just wasted $50 -

I followed the directions and hooked this jump
start battery hooked to the cars battery for 5 minutes-
Amazingly the car spun over and fired right up -
WOW --

The jump battery looked like it was made from
5 or 6- 18650 batteries -
the kit included some adapters to charge cell phones
and other stuff -

I know that these vans have larger harder to
start engines but after seeing how easily
and quickly this jump battery kit
worked I have changed my mind on having one
of these as an emergency option -

Bigger engine = leave it connected for longer
before trying to start -

I am not 100% sure that this link is to the
jump kit I used but it looks close and cost the same --
http://www.walmart.com/ip/11000mAh-Car-Battery-Emergency-Jump-Starter-USB-Power-Bank-Charger-w-LED-Light/46103853

Also when reading the options list for the Transit
one option was a Alternator Bracket for around $900 -
like most of the other options listed for the Transit-
there was zero details -
so I have no clue exactly what it is -
 
#103 ·
It seems that both Roadtrek and Advanced RV Class B camper vans are eliminating Onan generators in favor of an auxiliary engine alternator with a Balmer voltage regulator designed to handle the correct charge profiles for AGM, Lithium, etc. A larger capacity inverter is used to power the Air Conditioner, Microwave, etc. and various combinations of AGM and Lithium batteries are used. The auxiliary alternator they use is available for the Transit as linked in the post above and here. Has anyone used this aux alternator?

http://www.nationsstarteralternator.com/Dual-Alternator-Kit-for-Ford-Transit-Van-p/a2-0072-280xp.htm
 
#106 ·
I will use a very quiet 12 volt heating pad. If I was going to buy a fuel heater I would probably buy the propane fueled under the floor Propex. Propane burns cleans compared to diesel so heater should be more reliable.

I did spend a night parked next to a Sprinter with an Espar cycling on/off through the night. Do not think I could sleep well with that noise.

Gasoline is a more dangerous than diesel.
 
#108 ·
The choice of gas or diesel Espar pretty much depends on what your van is. No way would I install a fuel tank for the other fuel when I have 25 gallons sitting there already.
I haven't gotten around to installing my Espar yet- but one thing I am including is a marine rated fuel selector valve- this will allow me to run it off the onboard diesel then when cleaning is needed switch the fuel valve to a hose pigtail stuck in a temporary jug of kerosene.
I read where the kerosene cleaning method works fine and is much easier than disassembly. We'll see. Comments from anyone that has done it?
 
#109 · (Edited)
I haven't gotten around to installing my Espar yet- but one thing I am including is a marine rated fuel selector valve- this will allow me to run it off the onboard diesel then when cleaning is needed switch the fuel valve to a hose pigtail stuck in a temporary jug of kerosene.
I read where the kerosene cleaning method works fine and is much easier than disassembly. We'll see. Comments from anyone that has done it?
I too have read that a regular dose of kerosene works wonders with keeping the diesel models clean. The dealer that I visited yesterday had a kerosene tank plumbed to his workbench and was running the D2 on kerosene to clean it out. He showed me the jet assembly of another that he was working on. He indicated that the diesel versions that he installs on service trucks need an annual disassembly for cleaning, but those might be heavily used and abused Espars. And businesses might be opting for annual maintenance rather than waiting for them to clog up.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top