Author Topic: 5 hp B&S generator  (Read 4919 times)

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(unknown)

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5 hp B&S generator
« on: June 26, 2009, 10:34:25 PM »



Hello RE friends


I have a small 12v system set up with 45 watt HF solar panels and 2 garbogens. These feed 2- 125AH Maxx 29 Wall Mart batteries.


My first attempt at generating power started with a poorly suited treadmill motor. I moved on to a unit I purchased from wind blue which was a permanent magnet rotor installed in a auto alternator, a delco 10si. I failed getting this windblue alternator to charge my batteries. Too many rpm needed, and I just could not make any blades that could do it in less than a tropical storm. It went into the barn.


A year or so later, I have a working system controlled by a tristar 45 and dump resistors

from GHURD.

I realized I needed somthing to help out on windless cloudy days.


Out came the not so highly praised windblue unit. I bolted it down to a couple brackets I bent up and powered it with a Briggs & Stratton 5hp engine. Below are my results.


First I tried a windblue stator #520, ment for "high wind" (not Jerry rigged)about 19 ga stator wire


Open volts at max rpm 127vdc

15+a into 15.4v battery. Belt started slipping but was a bit loose when I started so I put on the proper belt and got it tight.


Then I switched out stators to a 35a stock stator


Open volts at max rpm 56vdc

40-50a into 17.2v battery

Heres a video of it charging:

http://s298.photobucket.com/albums/mm249/Southbuck7/?action=view&current=Movie.flv


Yes, battery volts are being pushed too high. Amperage out of this alternator is causing battery volts to jump fast. I was testing with a 85ah car battery at the time.


I then jerry rigged the #520 windblue stator and tested.


Open volts at max rpm 73

40a into (2) 12.8v batteries on cart. This can be regulated down to 15a with engine rpm. Another video:

http://s298.photobucket.com/albums/mm249/Southbuck7/?action=view&current=MVI_0425.flv


Heat on the alternator is helped with stock fan, and Id guess it runs about the same temperatures as it would in a car. It gets quite warm, but I think it will handle it. Time will tell.


I had to detune this alternator due to my small battery bank, with this 19ga stator I can keep my amps into battery within check. My 5hp engine never seems to work hard at charging,  even when I was getting 845 watts out of alternator. Hopefully this will help others in need of a fairly inexpensive, gas generator. Great for those cloudy, windless days.


Now with portable power I can use my inverter anywhere and when Im done I reconnect the batteries to a tristar 45 set in diversion, and let it maintain the batteries for me.


Fused

« Last Edit: June 26, 2009, 10:34:25 PM by (unknown) »

ghurd

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Re: 5 hp B&S generator
« Reply #1 on: June 27, 2009, 06:41:28 AM »
I like it.


I am impressed with the amps it makes at low RPM,


And that it can be started with a battery connected.

G-

« Last Edit: June 27, 2009, 06:41:28 AM by ghurd »
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BigBreaker

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Re: 5 hp B&S generator
« Reply #2 on: July 02, 2009, 07:23:27 AM »
5 HP is 3.7kw so you are really under loading the engine.  Slower RPMs will have lower available HP and slow is good for engine life and noise but you may be burning a lot more gas than you need too.  B&S is a well known brand and 5 HP is a well known sizing.  I'm sure you can find fuel use, RPM and torque charts online.  They may point you in a productive direction.
« Last Edit: July 02, 2009, 07:23:27 AM by BigBreaker »

Fused

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Re: 5 hp B&S generator
« Reply #3 on: July 02, 2009, 09:05:04 AM »
Productive was using what I had available at the time. I already spent money on the windblue PM rotor. After I realized it was not going to work for wind power, it did nothing but use up space. Im sure there is a more perfect setup out there but I was not looking for perfection, just function. As it is, Im able to control 10a into batteries at low rpm, probably not the best fuel efficiency but Im not working my engine hard either. Now I know with a simple stator change I can also crank out 50+ amps when my battery bank grows. It may not work for you, but it suits my needs perfectly.


Thanks for your comment.


And thank you Ghurd for your help on this.


Doug

« Last Edit: July 02, 2009, 09:05:04 AM by Fused »