Is there such a thing as an "all purpose" smart charge controller?

[ssullivan]

Here's the scenario:

My business is about to sell. I am moving onto land for a few years (10?). I am designing a "land boat" which will basically be an RV from the ground up.

Since I'm starting with nothing, I have the luxury of designing a perfect electrical system.

I'm wondering if anyone has ever seen an "all purpose", smart battery charge controller. I want to take power from solar panels, the engine alternator or a DC genset, then put a switch between the sources and my battery bank. The switch would allow me to select any of the above "input" sources of power, then run the power through some type of "smart charge controller" to provide the optimum charge cycle to the single battery bank.


I don't want a different charge controller for solar, then for a DC genset, then for the engine alternator, etc...

Is there a simple way to take many different power inputs and tie them together to one battery bank?

[Pblais]

I don't want a different charge controller for solar, then for a DC genset, then for the engine alternator, etc...

I would just start with leaving the engine alternator alone and let it do what they do without trying to make it do any more. It isn't built well to do charging while parked. You can run the generator while driving no problem though.

I worked at a company that had high tech vans with lots of electronics gear. Our first ones used the biggest alternator we could find with a lead acid battery bank to fill in plus we ran the AC all day when it was hot (the gear). We ran off the alternator and battery bank for 8 hours then recharged the bank at night plugged in. In the end it really didn't work well and we added a motor generator with a pure sine wave inverter and ditched the battery bank totally. I would run the generator whil motoring for large loads and then perhaps use the alternator for light loads.

Some stuff should be just like the boat as far as battery banks and DC generators. You may find a propane fridge to be a better deal as they don't serve so well on boats but are used a lot in RV's. That would make the fridge, stove and heat all propane powered. That just leaves the roof mounted AC unit and of course isn't going to happen without a generator or an AC outlet.

The solar panels are a tough one. So you really want to park in the sun instead of the shade? I'ld anchor my boat in the shade all the time but it's just almost impossible to do that and not run aground. You really don't want to park the RV in the sun to run solar panels. The AC needed isn't going to offset the solar power gained. In any event a solar regualor may not be needed if you manually turn it on when actually using power. Maybe you could rig up 250 watts but parking in the sun has it's real disadvantages.

As far as multiple inputs, my boat has a rotary switch that can enble a gen set or a shore power line. I would think that is really what you want. I would say you probably do want to use some 12 volt lighting, pressure water, and maybe a few other gizmos and a battery bank could handle that easy. Perhaps an inverter for standard small home appliances too. The size of the RV will dictate how many tons of batteries you can haul, but I would think not much.

[Strygaldwir]

Outback solar has notions of creating a multi source charge controller. I don't recall them having such an animal as of yet. But it is worth a try. They do make outstanding alternate energy products and are one of the leaders in the field.

Keith

[ssullivan]

Keith: Is this the charge controller you were talking about?

http://store.altenergystore.com/Char...NTROLLER/p861/

Paul: Couple questions, and a better description of my intended power usage is probably in order. I will be operating this system *exactly* like someone who lives at anchor. 80% of the time (or 90%?) I will be away from any "shore power." I plan to have a self-contained unit, the same as any good bluewater cruising vessel (or anchoring vessel). I will be completely independent from any camp grounds or any utilities, and will fill up water periodically, just like a cruising sailor. Hence, the term "land boat" my wife and I have been using.

Also, the "land boat" will have 100% cold flourescent lights, marine style refrigeration, etc... etc... Everything will run off 12V, except that we will have an inverter permanently wired to all of the outlets in the vehicle for incidentals such as laptops and cell phones and an electric razor. Total energy consumption for the place is 287AH per day. I plan to have no battery charger, since I'm building my own DC generator. (May start selling these for a living too)

Couple questions:

1) So are you suggesting that I not use the primary (engine mounted) alternator as a source of power when I happen to be motoring? I know the ouput is meager, but wouldn't it be a good way to top things off if I'm driving somewhere anyway?

2) I'm a sucker for renewable resources and the Little Cod woodstove. I also can't stand looking for propane. It's hard to find and expensive. So, I plan to run the refer off 12V, and have a wood stove, as I do now. I'm going to try and find a used alcohol stove/oven for cooking. I find it much more simple to wander into any hardware store and pick up a few gallons of alcohol than to find a propane filling station. I guess this one isn't a question. More of a statement. I'm just trying to be clear on the overall system layout. We are going for as much independence as possible here, since we will be "gunkholing" permanently.

3) Very good point about solar. It will be hot. Very hot. We do not plan to have any air conditioning, and will go where the climate is acceptable. However, always having to park in the sun might be an issue... so will finding a spot that is in the sun. What does that leave? Wind maybe? It's a tough call, but we want to build something that can be self-sustaining, like what we have now (which does indeed run off diesel and a genset), but I was hoping to get away from fossil fuels all together.

All in all, I'm actually going to build out an entire "boat" on land in this thing. The marine systems are far FAR superior to anything they have for RVs. Only other issue: Why did I pick winter to do another huge refit again? Dain Bramage.

[Vasco]

Sean,

Have you got to the head design phase yet? If you're going to avoid camp grounds you're going to need something that doesn't require pump-outs.

[ssullivan]

Yup. I have a very simple design: RV head to holding tank located directly below it on the undercarriage. The tank will have a drain pipe for draining into other types of containers to cart it off, or use one of the more standard RV dumping stations.

I don't want to get too far out into RV-type talk, since I want to be sure and stick to items that are useful to the cruising community. I thought the power discussion would be.

[hellosailor]

Sean-
"1) So are you suggesting that I not use the primary (engine mounted) alternator as a source of power when I happen to be motoring?" I'd suggest reading over Balmar's web site about what and how car alternators are meant to work. The charging system on a car (or truck) typically is designed to run for long periods without damaging the battery. It is not designed for deep discharge. That means it quickly reduces charge after a start, often never really puts back more than a90% charge unless it ir running for hours, AND the alternator is not designed to handle high heat loads for long periods.

You need to look for an alternator design that can sustain high loads, which probably means contacting the alternator makers to get specs for "continuous" rated output. Probably will need an extra set of fan blades and cooling fins or over-rated diodes as well, so they can withstand lots of charging heat. And you'll also need an outboard regulator, like Balmar and others make. Essentially you "should" and will WANT, to replace the stock charging system completely. Keep the old alternator as a spare, install a proper deep cycle heavy duty system for your primary task.

[ssullivan]

Hellosailor: I agree completely. The shells I'm looking at converting into a "land boat" come with 150-200 AMP alternators already installed. I also will be buying a Balmar alternator and linking it to a Yanmar 10hp air-cooled diesel engine to run as my DC genset. Given the various inputs (which might include solar or wind or nuclear reactor?), I wanted to buy a single device to run any of these DC sources through that would then regulate and/or control the charging of the battery bank.

I'm trying to have a single device that will accept DC charging currents of varying size (100 AMP, 200 AMP, or just a trickle from solar), then convert whatever power its getting into the proper current and voltage for 3 phase "smart" charging.

I am going to have to pray to the gods (aka Rick from seattle) for this one...

[hellosailor]

Sean-
"The shells I'm looking at converting into a "land boat" come with 150-200 AMP alternators already installed." bear in mind, if that's for typical service that's not continuous duty rating.

"I also will be buying a Balmar alternator and linking it to a Yanmar 10hp air-cooled diesel " 10hp is about 7500 watts, at 14.4 volts that's about 520 amps of capacity ignoring losses and such. You might not need that much hp. And, air cooled engines are always less efficient than water-cooled engines. Simpler, but inefficient. How big a battery bank are you planning to hook up to this thing?

"I wanted to buy a single device to run any of these DC sources through that would then regulate and/or control the charging of the battery bank. "
I'm not familiar with what can manage many inputs into one output that way, in theory it should be simple but we all know about theories.<G>

It might be simpler--and more robust for being redundant--to set up your system so that flipping a switch one way let the engine charge everything, and flipping it the other way let the genset charge everything. That way each has a separate regulator and all, isolated, redundant, simple.

[ssullivan]

Thank you, Hellosailor for the comments. They are appreciated very much.... please read down for responses inline with yours:

Originally Posted by hellosailor

Sean-
"The shells I'm looking at converting into a "land boat" come with 150-200 AMP alternators already installed." bear in mind, if that's for typical service that's not continuous duty rating.

-Absolutely. I am just planning on using the engine alternator to give some extra charge to my batteries and keep them topped off if I happen to be driving. It is not a primary system, but might work in a pinch as a backup system just to keep the fridge going.

"I also will be buying a Balmar alternator and linking it to a Yanmar 10hp air-cooled diesel " 10hp is about 7500 watts, at 14.4 volts that's about 520 amps of capacity ignoring losses and such. You might not need that much hp. And, air cooled engines are always less efficient than water-cooled engines. Simpler, but inefficient. How big a battery bank are you planning to hook up to this thing?

-The engineers at Balmar told me I needed 1hp for every 25 amps their alternators could deliver. I plan on buying a 200 amp alternator from them, which requries 8hp. Yanmars come in 6 and 10hp. I have to get the 10, unfortunately. It's the one on most air cooled diesel gensets. I had no idea that the air cooled engine was very inefficient. I use maybe 5 gallons of diesel a week (less probably) to keep the boat I have now running. Do they make small water-cooled engines of this tiny horsepower rating for under $2000? I'm planning to hook up either 4 or 6 Trojan T-105's. So, somewhere in the vicinity of 450AH to 675AH. Probably 450. I was planning on hooking the Yanmar up to the Balmar for a few reasons: 1) I can replace either one individually when they break, 2) DC gensets are a ripoff, 3) I thought it would be efficient to produce DC for the batts directly rather than produce AC, go through chargers, and convert to DC for charging.

"I wanted to buy a single device to run any of these DC sources through that would then regulate and/or control the charging of the battery bank. "
I'm not familiar with what can manage many inputs into one output that way, in theory it should be simple but we all know about theories.<G>

-ha ha ha! True. It seems like it would be simple enough, right?

It might be simpler--and more robust for being redundant--to set up your system so that flipping a switch one way let the engine charge everything, and flipping it the other way let the genset charge everything. That way each has a separate regulator and all, isolated, redundant, simple.

-I suppose it would be more redundant to have multiple regulators. I had wanted to avoid that after seeing the cost of a solar regulator, then a Balmar charge controller, etc... but alas, you may be right here. There might be no product that can handle inputs from various DC sources and charge a battery bank using a "smart charging" cycle.

[Lodesman]

Sean,

Not suggesting a purchase of one of these - they're way over-priced, but there're a lot of good ideas and nuggets of wisdom that you might find useful on this site: http://www.earthroamer.com/main_truck/vehicles.html

Good luck,

Kevin

[hellosailor]

Sean-
"-The engineers at Balmar told me I needed 1hp for every 25 amps their alternators could deliver. "
Well, One hp is about 750 watts (not quite) is about 50A at 14.4v so I guess they are figuring in a 50% loss of efficiency overall. Conservative engineers, but they do have a good rep.
You might ask Yanmar about the load and load factors, depending on how conservative their 6/10hp ratings are, the 6hp might do well because it would be running under a "fuller" load. I can't see that there really is a 50% loss, I think Balmar just wants to make sure you don't say they stalled out your engine.

"Do they make small water-cooled engines of this tiny horsepower rating for under $2000? " No idea, I'm not familiar with that market.

"2) DC gensets are a ripoff, 3) I thought it would be efficient to produce DC for the batts directly rather than produce AC, go through"

I would think that producing DC with a modern PWM alternator is the most efficient way to produce DC, yes. With gensets producing AC there is usually some time and energy spent on trying to get everything spinning in a way that produces 50Hz or 60Hz cycles to keep the AC gizmos happy, and the DC takes a back seat to that. Going DC only means a simpler set, as long as DC is all you need.

"-ha ha ha! True. It seems like it would be simple enough, right?"
Does "Yeahbut" sounds familiar?<G> Generator regulators regulate by load shedding. Alternator regulators ideally use PWM to control the amount of power actually produced, instead of dumping it. So if you want one gizmo to do both, you really need two gizmos, plus interfacing and controls. At that point, you've now got two ways the one critical controller can fail, too.

"-I suppose it would be more redundant to have multiple regulators. I had wanted to avoid that after seeing the cost of " Some of the costs can be avoided, or minimized, by designing the whole system as a system.
For instance, if your battery bank is typical for rechargable cells (wet, dry, AGM, whatever) it can take a float charge equal to 10% of the nominal charge rating "forever" without cooking or being damaged. And if it is wet cells, that literally becomes forever since all you'd need is to check the electrolyte and top it up once in a while anyway.
Now, you can only stuff charge INTO those batteries at 1/4 or 1/5th the nominal rating anyway. So...let's say you have a 1000AH battery bank, for round numbers. You'll damage (cook) it by charging at over 200AH, and you can charge it "forever" on 100AH. If your solar array puts out 100AH maximum, and doesn't exceed the max charging voltage for the battery (remember to figure in your diode block, or don't use one if you set up a relay to disconnect them, etc.), then you need no regulator. If your solar array puts out 200AH...yeah, you need either a regulator, or a timer, or a human with a memory. And a lock-out switch that allows the genset (with the smart regulator) OR the solar array, but not both at once since they'd go past the 200AH maximum charge rate anyhow.

Sometimes, a little common sense and human supervision can replace a lot of wee nasty silicon creatures, waiting for you to turn your back on them and get caught in the open.<G>

[ssullivan]

Hey Kevin,

Thanks! This is very close to the exact thing I'm building. Obviously the guy who designed this spent some time on boats. Too many similarities.

I did glean one very useful idea from his site already: I had no idea there were such things as diesel catalyst ovens! I feel like I can't live without one now. Only trick is to find them in the USA. They seem to be available under the Wallas brand in the UK, but a quick internet search turned up nothing. Just like the guy on this website, I'm as anti-propane (for myself, not to push on others) as they get.

Originally Posted by Lodesman

Sean,

Not suggesting a purchase of one of these - they're way over-priced, but there're a lot of good ideas and nuggets of wisdom that you might find useful on this site: http://www.earthroamer.com/main_truck/vehicles.html

Good luck,

Kevin

[Rick]

Balmar's numbers regarding output current versus input driving hp is reasonably accurate for what are called "large frame automotive air-cooled alternators". The normal run-of-the-mill small frame automotive alternators are not as efficient. The large frame units are only about 1 inch larger in diameter yet LOOK a lot larger.

Balmar makes no alternators. They specify from the usual alternator manufacturers that the aluminum cases be powder coated. Powder coating reduces the cooling factor and, therefore, is inferior for a continuous steady-state power output than a "stock" alternator. Imagine painting in the coarse aluminum castings (purposefully done this way for cooling) on an air cooled motorcycle engine and you get the idea. This powder coating is another reason for needing an alternator temperature sensor that their regulator may have to prevent overheating (yes, it is not a bad idea anyway as long as no sacrifice is made to overall reliability). If you like their regulators buy one yet buy a non-coated aluminium high output large frame alternator from someone else and hook it up to their regulator.

Pray that you have no neighbors when you run that air-cooled generator. You will have no friends when you do. If you park near water the sound may travel relatively unattenuated for literally over a mile.

The only true dc generator that I can recall is a Hall-effect generator. These were (are?) used by the railroad to generate huge low voltage currents to weld together rails and were very good. Don't know why no one makes lower current models yet that may happen with the growing switch-mode power semiconductor industry which will facilitate efficient conversion to various other voltages. Otherwise other rotating devices are all basically internally ac generators with either mechanical commutators or discrete diode rectification to get the dc, as you know.

System designs have existed since the 80's which would do what you desire whereas a "black box" would accept inputs from various charge sources and loads, both ac and dc. The last decade has actually seen some prototype designs built yet financing and individual personalities have conspired against us seeing any practically produced product. I actually had one part of that system designed which was a "universal" regulator that could operate either as a shunt or series or peak-power-point tracing 200 Watt device. Again, company politics torpedoed the development. Because high frequency switch-mode power electronics has rapidly progressed it is possible to create bi-directional power transfer devices that operate with good to excellent efficiency and cover milli-Watts to Megawatts. It only takes a perceived sufficient profit before these products will appear.

Keep in mind that the RV market is more than 10 times larger than the total marine boating market (including all small boats). The RV market is much smaller than the trucking market and the trucking market is much smaller than the automotive market and lags the automotive technological development by about 10 years. With this economic view you can understand just why the marine market products just do not have the economy of scale for incentive for manufacturers.

People like yourself are miniscule in numbers within the RV market. The rest want turn-key system solutions where they walk in, buy a class A, B, C or whatever and drive it away. So, the technological developments are mostly driven by contributions from Onan (Cummins) and others with regard to electrical systems. Such products you will not likely buy not already provided as an OEM on a coach, for example.

Even back in the 90's I saw a few do-it-yourselfers put coaches together with huge pv and battery systems to drive air conditioners. Very expensive and not reliable at least at that time yet they did work for awhile. You will probably drool over the new Onan coach systems in that regard coming out (no, I didn't say that they had a pv only source).

Another comment about alternators: Large frame 12V and 24V alternators will deliver 2.5 to 2.9 kW and are limited by pole saturation, especially in the 12V applications. If one eliminated the diodes and delivered the alternator 3-phase ac output to a 36 to "12" V transformer THEN used active rectifiers one could get about 4kW from the same alternator. This allows the stator windings to develop higher voltages without the magnetic reaction caused by higher field currents when operating at the former "12V" conditions. Why haven't we seen such products? Money, profit, and numbers of potential customers.

Good luck on reinventing the RV wheel.

[hellosailor]

Rick, I think I'm the one that brought up Balmar. Good point that they don't "make" alternators, but then again I suppose a lot of companies job out for the specs and have them built to spec the same way. Heck, Hitachi and NipponDenso didn't "make" their own alternators, they sent out baskets of parts to home piece-workers to be assembled at night, like the garment trade in the late 1800's here.

Balmar's powder coat is there to resist corrossion in the salt air, probably not right for Sean's RV unless he spends a lot of time on the Alaska Highway.<G> But I mention them because, in theory, they spec diode frames and diodes designed to run at high output for sustained periods--unlike a stock automotive model, which can't take sustained loads. There are other places, RV and specialty shops that sell "iceburg" and "supercooled" kits with oversized fins and diodes, but I wouldn't know any of their reputations well enough to recommend them. (Would you perhaps?)

So if Rick wants "lots in, one brain, all power out" black box regulation...forget the theory, does anyone MAKE and SELL such a critter?