Inexpensive alternator Regulator Modification

[Roadtripp]

Whoa, thanks for the information overload lol ? , the https://marinehowto.com/category/alternators/  link is loaded with clearly written and illustrated information. I read through changing from internal to external alternator regulator. And I also read through the ACR (automatic charging relay)or automatic voltage sensing relay section https://marin https://marinehowto.com/automatic-charging-relays/ ehowto.com/automatic-charging-relays/
  I have a much better idea of why the charging systems do what they do and why the stock system doesn’t perform for deep cycle applications. For anyone building a engine driven DC charger instead of a generator this is valuable information on how to setup the alternator, regulator, fuses, and power distribution. 
 A second alternator is an interesting option. But on vans there’s the heat and space consideration. But there’s another way to have a second alternator and set it up any way you like:
  Let’s take a look at the simplest example. I read one guy (solarhomestead.com) successfully charges his house battery with a unregulated Motorcraft alternator driven by a 10 hp Diesel engine with a manual throttle. The old Ford truck alternators are $100 and 100 amps. I forget how big his battery bank was but it’s waybigger thana van house b

[Roadtripp]

To continue the previous comment: the solarhomested guy says the battery voltage doesn’t matter when running at what I think is called full field voltage. He adjusts the rpm. I forget exactly what rpm but it could be slowed down to finish the charge. Or just finish it with solar. This is important to top up and balance the battery bank every few days. Let’s face it, it’s not a boat, it’s just a van or RV. No one is going to drown if the batteries won’t start the engine. With this setup the big engine in the van doesn’t need to be run. And the system can be built however you like it. 
 There is another interesting possibility for the engine driven DC charger: if the full field alternator output is run into a mppt charge controller in parallel with solar panels wired at high voltage then the panels act as a zener diode and clamp the voltage. They work seamlessly and efficiently together. A big programmable mppt charge controller like 80-100 amps would be nice. Still no alternator regulator involved. 
 I don’t know what happened to the solarhomestead guy. His blog just stopped after he said he was sick. I hope he is ok.

[Gr8ful]

On the ambo if you set the parking brake the rpms double. I have a battery isolater. I found this if it can offer anything http://www.amsterdamhouseboats.nl/voltage_regulator.htm

[sternwake]

My 50/120 alternator at hot idle speed (~525 engine rpm) can make right around that 50 amp figure, but going to 900 rpm it can make about 85 amps and does not achieve that 120 amp mark until ~2400 rpm, which I rarely hit.  These amp curves to rpm will vary with all alternators.
Fully fielding the alternator is basically asking it to make everything it can, at that rpm.


So spinning fast, a fully fielded alternator can easily push a battery up well past 15.0v, which is generally abusive to the battery.  Pushing the voltage much above 15 does not recharge it all that much faster than 14.8v, but the battery will surely be fizzing up a storm and getting hotter quickly.


So if this guy is running a direct engine to alternator DC charger, and not bothering with a traditional voltage regulator which controls the field current to the alternator, he must be using the rpm of the motor to prevent overvolting the battery when it is above ~75% charged or he risks voltage going too high, possibly damaging some items still connected to it.

Perhaps he only uses it upto 80% charged or so, and there is no point in running the generator/engine when one's solar panels output can maintain absorption voltage by themselves


But do not believe that no voltage regulation is required.  Every solar controller, every ' smart' charging sources, some manual charging sources, are all using their maximum amperage output( bulk) until a set voltage is achieved( absorption), at which point less amperage is needed to maintain that voltage and amps will taper closer and closer to zero as the battery approaches full charge at which point it can revert to a lower float voltage designed to prevent discharge and minimal overcharge while still powering ay DC loads.


Premature revertion to float voltage is a deeply cycled lead acid battery's murderer.  The better charging sources allow one to choose how long to hold absorption voltage, but the person in charge has to decide how long this is to be, and this will always be different at different temperatures, and the depth of the battery state of charge when charging began, and the health of the batery itself, so good enough or some happy medium, or willful ignorance can take over.


Getting a lead acid  battrey to 98% charged is good, but only half as good as a true 100% charge, and this becomes more and more true the deeper the depth of discharge was, and or the number of cycles accumulated since the last true full charge occurred.


Whatever method is employed so that the batteries reach absorption voltage eary enough in the day that the solar can take over and hold them there until amperage declines to a prescribed low point, the happier the batter, the longer it will live and the better it will perform during that more reliable lifespan.


High recharging amperage applied  from the battery's most depleted state of charge early in the morning, can do in a half hour what might take the solar panels alone several hours to achieve. Lots of 'too much amperage' nannies out there.  Do not fear high amp recharging as long as the voltage is limited to 14.8v or less.  high amperage limited to 14.8v is less  abusive than allowing the battery to start the next discharge cycle undercharged.

  If one has all the time in the world to recharge, like when plugged in then 10 to 13 amps per 100Ah of capacity will be less abusive, but when that next discharge cycle is 6 hours away, let those high amp charging sources do their thing until the solar alone can take over and maintain a safe absorption voltage for the battery temperature.
High amp charging can quickly heat a battery, especially an older one, so lesser absorption voltages are required.  Battery temp sensors are wise, even if it is just a K type thermocouple taped to the battery case that one can read with their multimeter and manually lower voltage accordingly.

The trick is to be able to force this high amp potential charging source, to seek mid 14 volt ranges and hold them.  When new my battery would accept 2/3 more amperage at 14.7 vs 13.7v.  now towards the end of its life it axcepts merely 2x as much as 14.7 vs 13.7v.  All this talk of alternator voltage regulation is all about forcing it to seek and hold 14.7v until the deeply discharged deep cycle house battery is ull, or charging it as rapidly as safely possible when driving.


Also at the end of a battery's life, the time it takes amperage at absorption voltage to taper to 0.5% of capacity( agm, 1 to 3% for flooded) ) takes much much longer than when it was younger and healthier and had less resistance.  The sooner in the day my battery reaches 14.7v, the better the chances are that  it reaches full charge before the next discharge cycle begins that late afternoon or early evening.  Achieving a true full charge daily can yield impressive service life from lead acid batteries.  Anything less than that is detrimental to some degree, but ideal recharging can be taken to ridiculous extremes, costing more time and money than simply accepting shorter battery life and accepting battery replacement more often.


But people should at least  know what Ideal battery recharging would be, and then decide how much effort time and money they wish to expend towards maximum ideal battery longevity. Good enough for one person might be woefully inadequate for the next.

[Roadtripp]

On the ambo if you set the parking brake the rpms double. I have a battery isolater. I found this if it can offer anything http://www.amsterdamhouseboats.nl/voltage_regulator.htm

Thanks for the diy regulator link. It includes some very practical information and looks to be an effective circuit. Next I am going to order a inexpensive but large dedicated voltmeter so I can watch how my stock system operates. 
  You could run a tool shop from your Ambu with it idling. Did it come with instrumentation to see voltage or current? 
 I’ve seen the Vanner inverters that are used in commercial work vehicles. I imagine the house wiring in your Ambu is extensive. 
 My 96 Chevy short bus looks to have the stock 1 ton van charging system. I’ve not had time to look closely at it but everything looks stock. But I’ll be adding solar and a DC CHARGER run by a small engine. So I really appreciate the link for the diy regulator

[Roadtripp]

My 50/120 alternator at hot idle speed (~525 engine rpm) can make right around that 50 amp figure, but going to 900 rpm it can make about 85 amps and does not achieve that 120 amp mark until ~2400 rpm, which I rarely hit.  These amp curves to rpm will vary with all alternators.
Fully fielding the alternator is basically asking it to make everything it can, at that rpm.


So spinning fast, a fully fielded alternator can easily push a battery up well past 15.0v, which is generally abusive to the battery.  Pushing the voltage much above 15 does not recharge it all that much faster than 14.8v, but the battery will surely be fizzing up a storm and getting hotter quickly.


So if this guy is running a direct engine to alternator DC charger, and not bothering with a traditional voltage regulator which controls the field current to the alternator, he must be using the rpm of the motor to prevent overvolting the battery when it is above ~75% charged or he risks voltage going too high, possibly damaging some items still connected to it.

Perhaps he only uses it upto 80% charged or so, and there is no point in running the generator/engine when one's solar panels output can maintain absorption voltage by themselves


But do not believe that no voltage regulation is required.  Every solar controller, every ' smart' charging sources, some manual charging sources, are all using their maximum amperage output( bulk) until a set voltage is achieved( absorption), at which point less amperage is needed to maintain that voltage and amps will taper closer and closer to zero as the battery approaches full charge at which point it can revert to a lower float voltage designed to prevent discharge and minimal overcharge while still powering ay DC loads.


Premature revertion to float voltage is a deeply cycled lead acid battery's murderer.  The better charging sources allow one to choose how long to hold absorption voltage, but the person in charge has to decide how long this is to be, and this will always be different at different temperatures, and the depth of the battery state of charge when charging began, and the health of the batery itself, so good enough or some happy medium, or willful ignorance can take over.


Getting a lead acid  battrey to 98% charged is good, but only half as good as a true 100% charge, and this becomes more and more true the deeper the depth of discharge was, and or the number of cycles accumulated since the last true full charge occurred.


Whatever method is employed so that the batteries reach absorption voltage eary enough in the day that the solar can take over and hold them there until amperage declines to a prescribed low point, the happier the batter, the longer it will live and the better it will perform during that more reliable lifespan.


High recharging amperage applied  from the battery's most depleted state of charge early in the morning, can do in a half hour what might take the solar panels alone several hours to achieve. Lots of 'too much amperage' nannies out there.  Do not fear high amp recharging as long as the voltage is limited to 14.8v or less.  high amperage limited to 14.8v is less  abusive than allowing the battery to start the next discharge cycle undercharged.

  If one has all the time in the world to recharge, like when plugged in then 10 to 13 amps per 100Ah of capacity will be less abusive, but when that next discharge cycle is 6 hours away, let those high amp charging sources do their thing until the solar alone can take over and maintain a safe absorption voltage for the battery temperature.
High amp charging can quickly heat a battery, especially an older one, so lesser absorption voltages are required.  Battery temp sensors are wise, even if it is just a K type thermocouple taped to the battery case that one can read with their multimeter and manually lower voltage accordingly.

The trick is to be able to force this high amp potential charging source, to seek mid 14 volt ranges and hold them.  When new my battery would accept 2/3 more amperage at 14.7 vs 13.7v.  now towards the end of its life it axcepts merely 2x as much as 14.7 vs 13.7v.  All this talk of alternator voltage regulation is all about forcing it to seek and hold 14.7v until the deeply discharged deep cycle house battery is ull, or charging it as rapidly as safely possible when driving.


Also at the end of a battery's life, the time it takes amperage at absorption voltage to taper to 0.5% of capacity( agm, 1 to 3% for flooded) ) takes much much longer than when it was younger and healthier and had less resistance.  The sooner in the day my battery reaches 14.7v, the better the chances are that  it reaches full charge before the next discharge cycle begins that late afternoon or early evening.  Achieving a true full charge daily can yield impressive service life from lead acid batteries.  Anything less than that is detrimental to some degree, but ideal recharging can be taken to ridiculous extremes, costing more time and money than simply accepting shorter battery life and accepting battery replacement more often.


But people should at least  know what Ideal battery recharging would be, and then decide how much effort time and money they wish to expend towards maximum ideal battery longevity. Good enough for one person might be woefully inadequate for the next.

 Thanks for describing how the lead acid battery should in a perfect world be charged and cared for. Not abused. I’m still confused when I have loads on and charging if it’s really 100% or not. My voltmeter is not calibrated can throw metering off. And I have a amp hour counting meter but it doesn’t work. One set of batteries I have no idea how old they are. The other batteries were fairly new so I’m going to get the amp hour meter working and keep track. 
 I just learned from a friend who has gotten Pelton wheel micro hydro alternator systems to 70% efficient how he does it. He is using the same old Motorcraft alternator the solarhomestead guy uses with a small engine. But the hydro alternator has had permanent magnets installed. I was wondering how much solar he uses to clamp the voltage of the alternator so I asked him today. With hydro he says to use about 1:2 or half the solar to the full wattage of the alternator (it’s ok to go with more solar wattage to alternator wattage than this ratio but not less). Connect both solar and alternator to the input of a mppt charge controller designed for high voltage input, typically 150-250 VDC max. Then set the desired charging voltage and amp limits. 
  That’s for a hydro driven alternator which has a lot of slippage of the water on the Pelton wheel. For a engine driven full field alternator he says to use a 1:1 ratio because the alternator will be putting out full output. There’s no slippage unless a belt is slipping terribly. So a 60 amp alternator should have about 600-700 watts or more of solar. However this would go over the amperage limit of a 80 amp mppt charge controller on a 12 volt system. My inverter is 24 volt so mine would be a higher voltage system. In this example a 80 amp charge controller would work with a 24 volt system. The 80 amp mppt charge controller would probably work ok on a 12 volt system but any power over 80 amps would be clipped and wasted as heat. It might work ok as the solar and the alternator may not produce full power most of the time anyway. And as you mentioned there’s no point in going over 15 volts. It becomes counterproductive. The throttle controlling alternator rpm could be fine tuned to find a sweet spot on the acceptance rate of the batteries and the power curves of the solar and alternator. He says placing a rectifier in the field circuit of the alternator is easy and gives more adjustability.
From my understanding this DC charger method is much more efficient than using a AC generator. A AC generator is terriblly ineficient if powering a non power factor correceted charger. I met someone who had wore out their Honda generator and ruined their batteries trying to charge that way.
You’re system is great in that you don’t seem to need a lot of this stuff. Yours is adjustable, has meters, and 85 amps at 900 RPM is great. If I like the Chevy I got recently I’d consider improving the stock charging system. My issue is I’m so dang tall I have not fit in any of the vehicles I’ve had so I get tired of them and sell them.

[sternwake]

So you are wanting to run a separate engine to spin an alternator, through a MPPt charge controller, charging a 24v battery bank?

The MPPT solar controller is nice because one can set the absorption voltage and how long to hold it, on most of them.

BUT, do you need this? Do you really need a three stage charger from an alternator?

If the goal is to dump a lot of amps into depleted batteries, 24v of them, then I would spin an externally regulated 24v alternator and have the external voltage regulator set for 28.8 to 29.4v.

There is little point in trying to achieve 100% state of charge running an engine, when solar alone can finish off the last ~3 hours worth. Obviouly there is not always solar for the job, but one can always decide to run the engine until amps taper to a prescribed setpoint or the hydrometer reveals the flooded cells to be fully charged.

So the gas powered alternator is basically used only as long as it takes for the solar to be able to take over. A big bad bulk charger. And the solar has the three stage automatic finishing charge.

No reason to make the alternator three stage through a MPPT controller, run the 24v alternator just long enough until your solar can take over and complete the task.

There's more than one way to skin the cat, but one does not have to make it more complicated than necessary.

3 stage charging is to prevent overcharging. Get the battery to absorption voltage hold it for X amount of time, then stop when teh batteries are full.

a 24v alternator wholse regulator is set to 28.8 to 29.4 is going to quickly recharge batteries to 80% charged. It is basically a one stage charger. The only issue, which is not really an issue since one is running an annoyingly loud generator, it turning it off before overcharging starts. Pretty much impossible to recharge a lead acid battery from 50% to 100% in less than 4.5 hours, so if one is worried about overcharging and will not be there to shut off DC genny, fill it with 4 hours worth of fuel.

Here is a 24 volt power factor corrected adjustable voltage power supply rated for 500 watts.

https://www.mouser.com/ProductDetail/MEA...ShWw%3D%3D

I have the Meanwell rsp-500-15, It can do 600 watts. 40 amps worth of charging all day long, but I rarely need 40 amps for more than 20 minutes.I did modify mine with more ventilation heatsinking and a better potentiometer for voltage adjustment, and with a wattmeter on the output.

If i had a 24v battery bank I would be powering one of these Meawell power supplies from an AC Generator or the grid, as a purpose bult 24v DC generator is good only for charging a 24v battery bank.

[Gr8ful]

On the ambo if you set the parking brake the rpms double. I have a battery isolater. I found this if it can offer anything http://www.amsterdamhouseboats.nl/voltage_regulator.htm

Thanks for the diy regulator link. It includes some very practical information and looks to be an effective circuit. Next I am going to order a inexpensive but large dedicated voltmeter so I can watch how my stock system operates. 
  You could run a tool shop from your Ambu with it idling. Did it come with instrumentation to see voltage or current? 
 I’ve seen the Vanner inverters that are used in commercial work vehicles. I imagine the house wiring in your Ambu is extensive. 
 My 96 Chevy short bus looks to have the stock 1 ton van charging system. I’ve not had time to look closely at it but everything looks stock. But I’ll be adding solar and a DC CHARGER run by a small engine. So I really appreciate the link for the diy regulator

Yes it has a digital unit that changes from voltage, amps being put out, rpms, temp, etc. You can lock it on whichever you want. I've never seen it go over 14.7 & usually under 14.5 amps. Horton seems to have got it right. Yes I have plenty of 12v & 120v outlets. I've done several battery, inverter, Onan genset systems with only 1 solar panel to keep the 6 GC batterys charges when gone & got 12 years out of 2 different installs but never ran the batterys very deep. We'd remote start the genset & make a drip pot of coffee then shut it off so 1/2 hr a day. Also had a switch that let the genset warm up a minute before swithing to the genset & a 65 amp charger. Did have a hi/low switch that started/shut off the genset at adjustable low/high battery voltage but I removed it as Onans didn't have low oil shut shutdown & my buddy ruined several cars running out of oil. I did a system for my boss who used the low oil shutdown to know when to add oil on a different genset. I have a 10 amp Deep Cycle charger & a stanley GBCPRO 
 Fully automatic multi-voltage smart golf cart and vehicle battery charger-6-48V automatic voltage detection-3 stage high efficiency automatic rapid/maintenance charging-Battery voltage tester-Microprocessor controlled-Lightweight portable design-Round & rectangular golf cart connectors included. (Fits most popular golf carts)-O-ring connectors allow for universal and permanent installation.-Battery clamps for 6-24V applications-Float mode monitoring