1st stage of power for OTG

[ncgyver]

Ok I decided to build a 12v gas powered charger using a B&S 5 hp , a 12si and a pair of Trojan 6v's or 12v's to start and adding on.  From reading all of your posts I've come to the conclusion that eventually a Hybrid system is going to cover most of my applications. So I would rather invest in agrowing Battery bank / Inverter and grow the system with Some solar , eventually ending up a 3kw diesel Gen set.
a couple of questions:
Is oversizing my inverter so I can grow into it OK ?

My understanding is 6v's will be slower to discharge and faster to recharge

AT this point should I hook up my 80 w sharp panel to a separate Battery or send it all to the available bank?
Sorry for the newb ?'s , but I'm just a DIY guy trying to get up to speed.
Thx

[Tom Reed]

A log of questions here.

It is ok to oversize the inverter, however larger inverters usually have larger idle currents. Also as the draw increases on a battery bank the output voltage will drop even on fully charged batteries. When the draw is decreased voltage will recover. On a small battery bank with a large inverter you may be able to draw enough power to trigger the inverters low voltage cutout at high loads. Running your charger during high loads will help.

No difference in charging with the 6v's. A battery bank will have given amp hour capacity. With deep cycle batts you will be able to safely draw 80% of that capacity with out damaging the batts. It will take the given amp hours drawn + around 15% to recharge the bank.

Hook the panel to a charge controller and hook the controller to the battery bank. Don't want to boil all the water out of your new batts.

[mike90045]

80 w is a pretty small panel, but it will keep the batteries topped off to prevent self-discharge from killing them.

[ncgyver]

I had the panel from my RV. I'm going to add on to my solar array as we go along. WE just put the foundation in and I need some power on site. BUt I want the components to be part of the total system.  When we used to be OTG in the RV all I kept saying is "I wish I had more Battries" . So I'm trying to build up my battery bank and ways of keeping them charged/. I'm really liking the idea of a Motor driven DC charger for now. I already have the motor sitting around.
Looking at some trojans or Sun Extender's next

[ncgyver]

Ok I ordered a Leece -Neville 110-555jho for my DC gen/ charger. I've read on posts about having to rectify the output going to the Batteries ? And also would like clarification about the charging process, monitoring it and how to make it work with my  solar panel. Can somebody draw me a simple schematic   ( components , wiring, fuses) This is my 1st attempt at building something like this.
Thx

[Lloyd]

Ok I ordered a Leece -Neville 110-555jho for my DC gen/ charger. I've read on posts about having to rectify the output going to the Batteries ? And also would like clarification about the charging process, monitoring it and how to make it work with my  solar panel. Can somebody draw me a simple schematic   ( components , wiring, fuses) This is my 1st attempt at building something like this.
Thx

Hi NC,

To get the most out of your system you need to make sure the alt is set up for external regulation, and is not one the self excite/on board regulator types....if it is, it's easy to convert to external reg. with a couple of parts from Leece.

How far from the bats is it to the alternator round trip?, you'll need a couple of bus bars, 1 for ground, and 1 for positive.

The solar panel should have it's own charge controller, that you will hook up to the pos/neg bus bars.

I really think you should look for and buy a book by title "Living on 12 volts" it's a little paperback sold in most marine stores, but any good book store will have it, or be able to order it...think Amazon. http://www.amazon.com/Living-Twelve-Volts-Ample-Power/dp/0945415028/ref=tmm_pap_title_0?ie=UTF8&qid=1311218358&sr=8-1 It'll be the $9.38 you ever spent.

By the way, you won't have to worry about a rectifier...it's on-board the alternator already

Lloyd

[Lloyd]

Somee links for your continued enjoyment.

The mother of links http://www.google.com/search?q=living+on+12+volts

http://www.marxrv.com/12volt/12volt.htm

http://www.henry-davis.com/GMC/Living.PDF

http://www.motherearthnews.com/Renewable-Energy/1984-11-01/Low-Voltage-Living.aspx

[ncgyver]

Thx Lloyd ! I'm all over that info...

[mobile_bob]

the two ample power books
wiring for 12 volts, and
living with 12 volts
are excellent primers for anyone getting started with DC systems

they can be found on ebay or amazon from time to time for less than 10 bucks each
both should be in one library in my opinion

bob g

[ncgyver]

I received my 110-555 JHO  Alternator today,so I'm ready to build this thing! ANyone recommend pulley size / belt configuration ? ALt will be driven by a  8 hp B&S ...

[luv2weld]

What speed do you want to run the engine??
If there is already a pulley on the engine, what size is it (diameter)??

The formula for figuring the size of the pulley for the alternator or generator is:

D2 = D1 x N1 divided by N2

D1 - Diameter of pulley on engine

D2 - Diameter of pulley on generator

N1 - RPM of engine

N2 - RPM of generator

Ralph

[SteveU.]

Hey ncgyver
Commonly available pulleys are going to be a deciding factor otherwise your costs are going to skyrocket. Most common "V" belt pulleys for these truck alternators will be a duel belt 2.75-3.5" OD. This style alternator want to be spun at a minimum of ~4000 RPM to be in its lower fat output range and to have enough fan air flow cooling. So if you were willing to listen to that B & S screaming along at 3600 RPM you would need a ~3.9" engine driving pulley. You will find this size in a taper lock difficult to find, and have to be belt wear retentioned frequently.
So three ways to do this:
1) MaxPower. Go with a ~5" double groove taper lock engine pulley by the 3.5" alternator pulley. Engine speed of 3600 RPM would spin the Alt at ~5124. No Problem - this alt is good for 8000 RPM continuously.
2) Practical-Pragmatic. Same set up but slow the engine speed to 3000 RPM and avoid the screaming-meemy nervous breakdown - Yours! You will get better engine life, belt life and ALt life  this way and it should still produce the 6 hp you will need for hot Alt output of ~120 amps (1500 watts of electrical and 1500 watts of heat) at ~4286 RPM.
3) Idealism. Single belt 10.5" engine pulley at 3000 engine RPM driving an Alt 8" single groove pulley at 4000 RPM. Look at lawn mower decks and you will see with bigger pulleys with more surface contact and belt wrap they prove able to do this.

Yes you are going to want an external field control regulator so you can manually keep the Alt turned off until the engine is up to speed and has full lubrication going. Other wise with a discharged battery bank the engine will load stall out at starting up. PITA on a hand cranker.

Regards
Washington State Steve Unruh

OOPS!. I just reread and your B&S is only 5 HP?? 8 hp and I was thinking of an answer on another forum. Go with the 3600 RPM MaxPower set up. Only expect to get 90-100 amps. Still 1100-1200 watts. Then just run longer. Batteries will only accept power in so fast anyhow without damage. Most 12 volt electric forklift chargers are limited to 75 amps max. Once you tire of this engine you can up size, slow down and then get full Alt output to recharge the batteries AND inverter power supply.

[ncgyver]

My B&S is 8 hp. I had a 5 vert shaft but found a brand new 8hp / horizontal shaft for $60. I think I like option number 3.
Where can I get a "external field control regulator"?

[SteveU.]

Ah! I see. I connected your name with an 8 hp B&S in your GM 10-12 SI PM alternator topic.
There Mobile Bob recommended a Sterling brand 3 stage external voltage regulator for this Prestolite/LN Alt. On other "Automotive alternator" topic threads there are 2-3 other brands recommended.

I really like those 12 volt links you put up here Mr. Lloyd. Thanks. I will be passing these on.

Regards
SteveU.

[ncgyver]

What about the internal voltage regulator om the Alt.?