BajaNomad - high output alternator suggestions

high output alternator suggestions

Dave - 6-14-2006 at 12:19 PM

I want to charge my trailer's 600ah battery bank using my vehicle engine (98 explorer v6). I figure I need 150 amps minimum (at idle).

Belt size/pulley change? Starter battery drain/ dual vehicle batteries needed?

Doable? Suggestions?

Bajalero - 6-14-2006 at 12:45 PM

Dave ; Call Broadway Auto Electric, Lemon Grove. Ask for Rick (Zitren) , he's the owner and has always had the answers or knows some one who does

Plus never any BS

619 461-4555

lero

High output

Sharksbaja - 6-14-2006 at 01:31 PM

Here are some choiceshttp://www.alternatorparts.com/Extreme%20Duty%20Dual%20Recti...

TMW - 6-14-2006 at 01:59 PM

What is the time frame. You looking for a high speed charge. If your using your car alternator the current flow is limited by how low the battery is (and what the alternator puts out) since it would be a basic constant voltage charger. Your idle speed is probabaly in the 600-800 rpm range and to get max current you'll need to raise the idle speed or change the pulley on the alternator.

bajalou - 6-14-2006 at 02:05 PM

You can get a Isolator at any auto parts store to seperate the current going to the starting battery and the other battery bank. That would allow you to keep the battery bank connected to the alternator (fia isolator) all the time so whenever the motor is running it will be charging the batteries. Isolator keeps the use of the 600w bank from drawing down the starting battery.

Bruce R Leech - 6-14-2006 at 02:18 PM

Quote:

Originally posted by TW
What is the time frame. You looking for a high speed charge. If your using your car alternator the current flow is limited by how low the battery is (and what the alternator puts out) since it would be a basic constant voltage charger. Your idle speed is probabaly in the 600-800 rpm range and to get max current you'll need to raise the idle speed or change the pulley on the alternator.

if you change the pulley to get full charge at idle it will explode on the highway :lol:

Bruce R Leech - 6-14-2006 at 02:35 PM

if you put a switch on the field wire of the voltage regulator and connect it to a 12 volt sorce. when you turn the switch on it will force the alternator to put out full charge. turn it of and it goes back to normal operation. then if you put a throttle cable on it so you can bump the idle up to about 1600 you will get a good charge.

go to any good auto electric and they can make an alternator do what ever you need.

if you are thinking of running anything like 150 amps to your trailer make sure you have a hefty cable run all the way to handle the job and a breaker.

True Bruce but...

Sharksbaja - 6-14-2006 at 02:43 PM

it's more than that:
"When building a custom car from the ground up however, a deeper understanding of the power curve of an alternator is required. Usually a custom pulley or so-called ?power pulley? set is used with a performance alternator. A mismatched pulley ratio and alternator will spell trouble, especially at idle speeds where alternator performance is critical. To avoid this, it is important to understand the alternator?s capability at slow speeds.

An alternator?s output is dependent on speed, but this can be deceiving because this output is not linear. Instead, it follows a curve. Each alternator has a unique curve, and at idle small changes in the alternator?s speed can make a big difference in its output capacity.

Because of the preceding, pulley ratios are very important, especially when using high amperage alternators. The pulley that are supplied with the alternator are matched to the winding and power curve. It is important that any dress up pulley sets do not deviate from this ratio. Typically, a street driven car should have a pulley ratio of at least 3:1. If the vehicle has an automatic transmission with a low idle and the vehicle spends a lot of time cruising, then a higher pulley ratio - perhaps 3.5:1 - should be used. Alternators can take high speeds up to 20,000 RPMs for short periods, so overdriving the unit is not a problem.

The output of high amp alternators can drop off substantially under 2400 rotor RPMs. Therefore, Powermaster does not recommend power pulleys with high amp alternators."

Field Output

MrBillM - 6-14-2006 at 03:25 PM

Over the years, I have built numerous DC Power Gensets using 3.0 - 5.5 HP Briggs and Stratton-type gas engines and Delco Auto Alternators. The method of field regulation that I use is a variation of Bruce's suggestion. I run the 12vdc field through a 1/4 ohm rheostat . This is important on my installations so that the charge capability of the alternator doesn't stall out the engine. Simply using a switch on an Automobile should work fine since there is no such stall concern.

Dave - 6-14-2006 at 03:51 PM

Quote:

Let me rephrase:

As the trailer is stationary, charging will be done at idle speed. Simply put, I wish to use my vehicle's engine instead of purchasing an additional, overpriced :biggrin:

generator. The pulley question was in referrence to belt size not diameter and regulation will solve the charging process. I know how to baby batteries.

Would I be able to retrofit an alternator with the amp rating/output at idle requirements on my Explorer?

Anyone want to tell me why this is/isn't a good idea? :lol:

Dave - 6-14-2006 at 04:02 PM

Quote:

Originally posted by MrBillM
Over the years, I have built numerous DC Power Gensets using 3.0 - 5.5 HP Briggs and Stratton-type gas engines and Delco Auto Alternators.

You can't get 150 amps out of a 5.5. The idea is not to run it 'all the live long day'. I want 2-2 1/2 hrs run time max to get 90/5% charge.

comitan - 6-14-2006 at 04:07 PM

Dave I don't know anything about alternators, but I think you are starting on the wrong end, you should never take that battery all the way down. To start with put a voltmeter in the system never take it below 12V's if you do you need another battery and I'll leave the charging to others but I certainly wouldn't go overboard on the alternator.

Dave - 6-14-2006 at 04:22 PM

Huh? I would never discharge over 50% capacity.

Bruce R Leech - 6-14-2006 at 04:26 PM

the thing is you will never be able to have an alternator that will put out full charge at idle or nere idle rpms and also perform adequately in normal driving situations. but there are a number of trade offs that you can make to make it work a little better one way or another. but that is all they are is trade offs. what you are trying is not real efficient. the best way will be to get a separate system to charge the batteries on your trailer. I think I would go solar.

Diver - 6-14-2006 at 04:34 PM

Quote:

Originally posted by Dave
Anyone want to tell me why this is/isn't a good idea? :lol:

People will constantly ask you;

Are you guys leaving ?
Going in to town ?
Leaving already ?
When ya coming back ?
Something wrong ?

Besides, it's noisy and makes stinky air. Go solar !
..

bajalou - 6-14-2006 at 04:53 PM

Quote:

Originally posted by Dave
Huh? I would never discharge over 50% capacity.

12V is less than 50% capacity.

following from http://www.windsun.com/Batteries/Battery_FAQ.htm

Voltage on a fully charged battery will read 2.12 to 2.15 volts per cell, or 12.7 volts for a 12 volt battery. At 50% the reading will be 2.03 VPC (Volts Per Cell), and at 0% will be 1.75 VPC or less.

So from that 12.18 V is 50%

Dave - 6-14-2006 at 05:07 PM

Quote:

Originally posted by Bruce R Leech
the thing is you will never be able to have an alternator that will put out full charge at idle or nere idle rpms and also perform adequately in normal driving situations.

Wouldn't an alternator controller work?

Maybe not 150 amps at idle but going with a larger output and playing with the idle a bit? Wouldn't that get me there?

Quote:

Originally posted by Bruce R Leechthe best way will be to get a separate system to charge the batteries on your trailer.

Agreed. I'll probably build a beefier genset like Bill suggests but that's further down the line.

Quote:

Originally posted by Bruce R Leech
I think I would go solar.

I wouldn't even want to think about the costs involved with dependably replacing 200ah with solar. Or, replacing the contents of a 7.5 freezer if the sun don't shine. Can I get a loan?

Look: I've already got the car and I would have to buy the storage anyways. This seems to me to be the easiest, quickest and cheapest solution. K.I.S.S.

comitan - 6-14-2006 at 05:15 PM

Lou

I just put down a random 12v shouln't have, when we on solar RV'ing I never let it get below 12.4 so I guess I was doing good for a dummy.

Dave I'm not an expert but I don't think you have enough battery for the load.

[Edited on 6-15-2006 by comitan]

Dave - 6-14-2006 at 05:23 PM

Quote:

Originally posted by comitan
Dave I'm not an expert but I don't think you have enough battery for the load.

[Edited on 6-15-2006 by comitan]

600ah storage is ample for a 180-220 daily load.

comitan - 6-14-2006 at 05:25 PM

Yes if its a true deep cycle battery like 6 -105 ah 6volt batteries.

Bob and Susan - 6-14-2006 at 05:29 PM

table

Bob and Susan - 6-14-2006 at 05:54 PM

comitan...6 105 ah 6 volt batteries is only...

3 105 ah 12 volt batteries

Charge State ?

MrBillM - 6-14-2006 at 05:55 PM

Most of the charts I've seen over the years for Lead-Antimony Batteries have read:

12.7 = 100% 12.5 = 75% 12.2 = 50% 12.0 = 25% (Resting Voltage)

When testing batteries of unknown or questionable condition, it is important to monitor the battery under a load. I've seen many batteries that will appear to be at full charge and the voltage drops rapidly under any kind of a load.

[Edited on 6-15-2006 by MrBillM]

Bob and Susan - 6-14-2006 at 05:59 PM

12v times 150 amps = 1800 watts

a generator that produces 2500 watts all the time would only cost less than $300

Most generators come with 12v bulk charger capability...

Noise...run the charger while you're in town :lol:

Bruce R Leech - 6-14-2006 at 06:00 PM

sorry Dave I was just trying to help.

comitan - 6-14-2006 at 06:44 PM

:yes:

Inverter solution?

Sharksbaja - 6-14-2006 at 07:09 PM

Using my 2500w inverter to power a 2-10 amp 110ac 12vdc battcharger I can keep my back-up 12v batt(batt) constantly charged when running or not. It also charges a completely dead batt pretty fast. Of course there are tradeoffs.

You would still have to get a bigger alt but at low engine speed you should have all the dc you could use. Low RPMs plus you can have ample AC to use for recharging or topping off his trailer set-up and the ability to draw off the vehicles batt reserves when necessary.
Here is the site I used set up my AC system: http://www.whistlergroup.com/faq-inverters-answers.asp

Bruce R Leech - 6-14-2006 at 07:47 PM

Quote:

Originally posted by Sharksbaja
Using my 2500w inverter to power a 2-10 amp 110ac 12vdc battcharger I can keep my back-up 12v batt(batt) constantly charged when running or not. It also charges a completely dead batt pretty fast. Of course there are tradeoffs.

[/url]

Corky I don't understand using battery's and inverter to charge the Batterers. Have you invented perpetual motion :?:

Sharksbaja - 6-14-2006 at 11:15 PM

No, it's inverted perpetual motion :lol:

Actually Bruce my inverter keeps my spares and moto batts charged via a cheap B&

charger. My thinking was, Dave said he neede more low RPM output. With an inverter you can literally drain what is in your vehicles batt if you need the DC while a at low RPM if need be. It's much easier to run an AC cord from your inverter back to your trailer with a charger than huge DC cables. I assume that the trailer batts will be isolated.

jimgrms - 6-15-2006 at 06:41 AM

Dave you would be better of just getting a port generator the price will be close and think of the fuel youl will save

Bruce R Leech - 6-15-2006 at 07:01 AM

Dave check this site

http://www.sterling-power.com/htm/ar12vd.htm

Bruce R Leech - 6-15-2006 at 07:04 AM

Split Charge Diodes

All boats have at least two battery banks - some have three. These tend to be the engine start battery, the domestic battery bank (please note that if you join three or four batteries together in your domestic battery bank it is still one battery), and the bow thruster battery. Having introduced 2-3 battery banks onto your boat, the problem then is how do you charge them from one alternator source?
There are four various options employed by boat builders. Below are the options with a short explanation giving both the positive and negative aspects.
1) Rotary switch. This system tends to be very dated, and is not very common on boats. It is recognisable as a large circular switch with four marked positions on the switch. It is marked off, 1, 2 and both. The good side of this system is it is easy to install. The bad side is that it needs constant human intervention to ensure it works. Failure to operate it correctly will result in all batteries being discharged or not being charged correctly, and possible damage to the alternator. They also tend to suffer failure if large prolonged current is passed through them. The spring in the switch can over-heat and loses its tension; this leads to a exponential break down of the switch and is manifested in heat. When these switches fail they tend to melt the plastic case (if you are lucky). Simply check the temperature of the switch every so often by touching the back of the switch - it should be cold.
2) Split charge relay. This system is both dated and extremely dangerous, and more than likely will make your boat fall short on CE requirements, especially if a inverter is used or a bow thruster. The good side is, that it is easy to fit and requires no alterations to the standard engine system, but merely connects the domestic battery bank to the engine battery via a relay, which is energised when the engine starts.
The bad side (and the very dangerous side) is that a relay is prone to vibration faults and over loading. Say for example you have a 70 amp relay on your system and a 55 amp alternator, and you fit a 1500 watt inverter which can draw150 amps and one morning the domestic battery is flat. So you start the engine to charge the domestic batteries, the 70 amp split charger relay will come on line to enable the alternator to charger the domestic battery bank. Then you load your inverter to 150 amps, the 150 amps will not be drawn from the domestic battery because it is flat but be drawn from the engine battery (which is full). That means you will draw 150 amps up the split charge cable and through the 70 amp relay. If you are lucky you will destroy the relay, if you are not so lucky then you will set fire to the cross over cables, hence the dangerous aspect. The system must be suitable for the purpose for which it is installed this is clearly not. Be warned about split charger systems using relays.
3) Split charge diodes: By using a set of diodes on a heat sink, one can ensure no back feed through the diode, thus ensuring that high currents from other battery banks do not flow up the charge lines and cause a fire. This is the most common method by far employed round the world and is the standard in the USA, for 3 reasons: safety, safety and safety.. However, all is far from perfect. The big down side with a split diode system is the voltage drop across the diode (in the order of 0.8-1.2 volts), which dramatically reduces the charge rate of the alternator on average by about 70%. However, do not forget the safety feature.
4) 0 volt-splitting systems: These are electronic devices using a control circuit and driving mosfets. The end result is a very low voltage drop across the splitting system (in the order off 0.04 volts but no reverse current flow is permitted due to the operation of the mosfets. A good analogy is the safety of the split charge diode with the performance of a split relay. However, at a much higher financial cost, this system is ideal where a vehicle or engine is being used and the alternator cannot be altered for warranty or other reasons. However on standard marine engines where a advanced regulator can be used much better to employ the lower cost diode with a advanced regulator, (see performance below).
Conclusion:
Test 1: From fig1 we can see the voltage drop across different splitting systems. This directly relates to the ability to charge the batteries, the larger the voltage drop across the device, the less effective the batteries charge.
Test 2 shows the clear advantage of using advanced regulators in conjunction with a conventional split charge diode. The advanced regulator automatically compensates for the voltage drop across the diode, plus the high charger 4-step program increases the charge rate even further. The above tests were on a 300 amp hour battery bank, but can easily be extrapolated to 400 amp plus.
The ideal system is clearly a standard low cost split charge diode (for safety and cost) and an advanced regulator on the alternator to compensate for the diode faults and charge at the constant current charging curves. This not only charges 2-3 times faster (on a good installation, but much higher on a bad one) but puts about 100% more useful power into the batteries.
For a twin alternator system, the ideal system is: on the largest alternator, fit direct to the domestic battery bank and attach an Advanced Regulator to that alternator. On the smallest alternator split this with a split charge diode between the engine battery and the domestic (and any other battery bank) and add another advanced regulator to it. This gives maximum charge rate to the domestic batteries.

Bruce R Leech - 6-15-2006 at 07:06 AM

chart

Bruce R Leech - 6-15-2006 at 07:07 AM

chart 2

Bruce R Leech - 6-15-2006 at 07:07 AM

photo

HOW TO SIZE AND USE YOUR BATTERY BANK

Bruce R Leech - 6-15-2006 at 07:21 AM

Here is another good site that might help you

http://www.glacierbay.com/1batcrg.asp

Bruce R Leech - 6-15-2006 at 07:27 AM

Dave there is a good book that I bought many years ago that has been invaluable to me over the years. it has a wealth of info for a small book. I lived on 12 volts for a long time and I have tried everything.

Living on 12 Volts with Ample Power

http://www.amplepower.com/products/living/index.html

Confusion says:

Sharksbaja - 6-15-2006 at 03:08 PM

What???? You didn't like my ac to dc to ac to dc scheme? Seems silly donut.

Ok, so I'm not a rocket scientist or electrician but I' m trying to sort this out;

40 amp charger 40 amp charger requires 5.91 continuous ac amps .
For 100 amp dc starting mode it draws 11.29 ac amps.

Using this formula:
P = V * I

P is power in Watts
V is voltage in Volts
I is current in Amps

Watts = Volts times Amps

12v X 40a = 480 watts

12v X 100a = 1200 watts
-----
Given the 2500 watt inverter puts out a constant 20.8 amps it seems I would have a surplus of watts at this rate.

So it seems I have stumbled onto perpetual energy. :lol:

Get more out than you put in??

NOT!

Now I'm confused :?:

Bruce R Leech - 6-15-2006 at 03:16 PM

the thing is that the manufacture lies about the 100 amp output so it makes it seem to good to be true and it is :spingrin:

Too Good to be True

MrBillM - 6-15-2006 at 03:27 PM

If you purchase one of those High-Output Alternators, simply take it to one of the numerous Auto Parts Stores or Garages that have a test bench and pay them to test the maximum output. Knowing for certain is worth the few bucks spent. The only challenge at some of those auto parts stores will be finding someone who knows what they're doing.