Golf Cart/ Portable Power Plant

[Dualfuel]

 For the last few years I have been using a 36v golfcart around here. This season, I am upping the ante with this rig...I am going to up its voltage to 48v, and mount solar panels on the roof. Its going to get an inverter, charge controller, and a storage box.
Last few years we have cut our fire wood with electric chainsaws...but this year is different, the wood is still piled out in the field...I think it would be more efficient to move the power plant out to the wood pile, so as to use the electric saws. Of course, there will be an ancillary increase in efficiency, involving moving ME away from the kitchen.

So the discussion I would like to have here is about 48volt equipment. I would like to find an  inexpensive 48v MSW inverter in the 5000 watt range.
I would also be interested in some 48v MPPT charge controllers...

[mike90045]

Rogue solar makes a decent mid range, full feature MPPT controller. (MPT-3048)
http://www.roguepowertech.com/
The MidnightSolar Kid is also a good one too.

Rogue, Morningstar, Midnight, Xantrex(Conext/Schneider-Electric), Steca, Blue Sky and Outback, all make reliable models of varied capacity and input voltages.  Morningstar has no meters on theirs, it's an extra $100 for the meter instead of a blank panel.  I have one (mppt60 & meter) .

Beware of re-badged, un-certified imports that merely have a label saying MPPT.

for electric motors, pure sine reduces power draw by at least 10% over mod sine, unless the motors are the brushed universal AC/DC motors.   On pure sine, motors also run cooler.    I like shopping at http://www.solar-electric.com/, they have a decent selection of inverters.  5KW is not going to be cheap.  I run off a full feature 48V Xantrex (Schneider Electric) XW-6048  6KW 

Can you use 2 inverters, one for each saw ?  Or does your saw really need 5KW ?

[Dualfuel]

Thx Mike for the links,
I have three saws...and I might as well review them here...I have the Husqvarna 316e which is the cadillac of electric saws...$300 with a 2 yr warranty..and you end up using it! The switches quit working on these saws. The good news is they are rebuildable and easy to change. $26 a pop, for switches.
The saw I use the most is a Remington 16" Versa saw...I think its 1650watts. Its $80.00 at Menards and for an additional $8, Menards gives you a 1 yr free replacement warranty. We cut 8 full cords last season with a Versa, before stripping the gears and taking it back to Menards and getting a replacement with no questions asked...
Finally, when all else fails I have an ancient Poulan electric that is painfully slow, 14" bar, cracked handle, but still works after 15 years. I paid $40 at Walmart for it, then. I don't recommend either the Poulan or the Husqvarna.
All saws are brush motors. All saws have worked on both MSW and PSW inverters, or real AC from generators.

It is entirely possible that the Versa will run on less then 5000watts...I run it on a Magnum 2812, and a "Kaching" Ebay 5K MSW inverter. It does equally well on both.

The constraints I am working around are: The Melex golf cart is originally 36volt, but the solenoids operate at 12v, and the motor control is entirely mechanical, so bumping it up to 48v is the only way to match the solar equipment to cart voltage....meaning, I got laughed at, when I tried to buy 36volt inverters, charge controllers, and panels.
The other constraint is more mechanical...namely that I am going to leave the cart out at the wood pile exposed to the elements, so I need robust components. I also need to be really good about the enclosure for the inverter.
I cannot imagine building a roof on the cart that could hold more then 4 Kyrocera 135w panels so, I am looking at a charge controller in the, less then 30amp range. Still you never know...if I built the roof like a kitchen table with fold up sides I might be able to double that wattage...although I have found that with a battery bank the size of the golf cart's 8, six volt T-105s, I can cut all day in full sun with 280watts worth of panels. Please read "cut all day" as several minutes of cutting and hours of lift and tote, putting the wood on the buck, and loading it in the trailers.
The caveat here is that I am going to test the melex on 48v pulling the wood trailer...I am looking for a little more "snoose" going up hills with the trailer. If it does do what I think it will, then I will begin welding the roof in earnest.
DF

[bschwartz]

Could your "kitchen table" folding panels be used in the fold down position as walls of sorts when not in use to protect the electronics from the elements?

[Dualfuel]

Dear Brett,
Most definitely, and, during the spring, they will catch that last sun until 1030pm. I have always had that problem of getting the panels cranked around to the north during the last few weeks of spring and the first early weeks of summer.

[Lloyd]

How about re-thinking.

Leave the GC as is and use it for the tractor. Then you are free to build yourself a purpose built trailer/ Power Station. It can then be, the bat bank, solar support,  and inverter house.  You could go as far as building it to IP-68 folded up or out. You might even armor it, depending on the neighborhood, and how often you visit the woodpile.

Use your tractor/GC to tow it to the wood-pile, and leave it.

Lloyd

Thx Mike for the links,
I have three saws...and I might as well review them here...I have the Husqvarna 316e which is the cadillac of electric saws...$300 with a 2 yr warranty..and you end up using it! The switches quit working on these saws. The good news is they are rebuildable and easy to change. $26 a pop, for switches.
The saw I use the most is a Remington 16" Versa saw...I think its 1650watts. Its $80.00 at Menards and for an additional $8, Menards gives you a 1 yr free replacement warranty. We cut 8 full cords last season with a Versa, before stripping the gears and taking it back to Menards and getting a replacement with no questions asked...
Finally, when all else fails I have an ancient Poulan electric that is painfully slow, 14" bar, cracked handle, but still works after 15 years. I paid $40 at Walmart for it, then. I don't recommend either the Poulan or the Husqvarna.
All saws are brush motors. All saws have worked on both MSW and PSW inverters, or real AC from generators.

It is entirely possible that the Versa will run on less then 5000watts...I run it on a Magnum 2812, and a "Kaching" Ebay 5K MSW inverter. It does equally well on both.

The constraints I am working around are: The Melex golf cart is originally 36volt, but the solenoids operate at 12v, and the motor control is entirely mechanical, so bumping it up to 48v is the only way to match the solar equipment to cart voltage....meaning, I got laughed at, when I tried to buy 36volt inverters, charge controllers, and panels.
The other constraint is more mechanical...namely that I am going to leave the cart out at the wood pile exposed to the elements, so I need robust components. I also need to be really good about the enclosure for the inverter.
I cannot imagine building a roof on the cart that could hold more then 4 Kyrocera 135w panels so, I am looking at a charge controller in the, less then 30amp range. Still you never know...if I built the roof like a kitchen table with fold up sides I might be able to double that wattage...although I have found that with a battery bank the size of the golf cart's 8, six volt T-105s, I can cut all day in full sun with 280watts worth of panels. Please read "cut all day" as several minutes of cutting and hours of lift and tote, putting the wood on the buck, and loading it in the trailers.
The caveat here is that I am going to test the melex on 48v pulling the wood trailer...I am looking for a little more "snoose" going up hills with the trailer. If it does do what I think it will, then I will begin welding the roof in earnest.
DF

[LowGear]

I'm working, OK playing with a 36 volt Cushman golf car (notice no "t").  One of the manuals I have pulled off the Net recommends bumping it up to 48 volts.  Everything should work better says it.  So I'm faced with replacing the 36 to 12 volt thing with a 48 to 12 volt thing.  I wish I had popped the extra $11 for the 24-60 to 12 volt thing now that I'm faced with going to the 48 volt common denominator world.  Those of you that know me realize I'll run what I got until it smokes and then replace it with the correct thing.  And yes I've attended the lectures about how much power there is in three or four 12 volt lead acid batteries. 

Curiosity questions.  If it's a mobile battery station then why is it being left out?  Where are you that the June and July solar angles make that much difference?  (You're cutting fire wood so I assume you're North of the tropics.)  Wouldn't two 250-270 watt panels be a lot better than four 135 units?  Wouldn't it be better to leave these saws running between cuts as much as possible to reduce current flow and extend switch life?

Casey

PS.

[Dualfuel]

Dear Llyod,
The cart tows the wood trailer....if it runs out of power, I would be able to just leave it. As it is now, I have to charge it at the oil shed with its solar system, and limping back on dead batteries is a PITA, much easier to dismount and wander off in an ADHD moment, and come back to find the cart charged.
Armor..ha ha...they cut ALL the trees down, no need for armor anymore...I sure have had my fair share of stuff smashed by trees though...
Dear Casey,
The cart is either parked outside at the wood pile or at the camp...the cheapskate in me says walk my fat a$$ down the hill to the camp for lunch rather then drive.
I am north of 48 latitude...for June and July the sun at noon is more north then overhead.
That is good to hear about the switch from 36 to 48...I suspected as much, because I put a voltmeter on the cart and watch it at various accelerator settings...and its not uncommon for the batteries to be down to 5v if you floor it..
DF

[Lloyd]

Dear Llyod,
The cart tows the wood trailer....if it runs out of power, I would be able to just leave it. As it is now, I have to charge it at the oil shed with its solar system, and limping back on dead batteries is a PITA, much easier to dismount and wander off in an ADHD moment, and come back to find the cart charged.
Armor..ha ha...they cut ALL the trees down, no need for armor anymore...I sure have had my fair share of stuff smashed by trees though...

DF

That's why I said re-think IT!!!!

Under my plan you have two trailers, and one GC/cart/Tractor.

Now tow the purpose built  Power trailer to the wood pile. Now this trailer is the POWER Center. So it holds your, bats, inverters, and solar panels. So now you have a charging source at the wood pile, for the saws as well as the GC/cart/Tractor. As well as the one at the shop.

The armor is only to stop the would be thieves, from departing you of your duly needed electrical components, that makes the Power Station valuable, at the wood pile.

Note second trailer, is for hauling the wood.

Lloyd

[LowGear]

I am north of 48 latitude...for June and July the sun at noon is more north then overhead.

I need some help here.  I'd do it myself but I don't know how to ask google. 

I thought the sun was only 90 degrees or greater in the two tropic zones?

At what deflection to the sun does a solar panel start declining in measurable power?  Is it linear?

Casey

[Dualfuel]

Dear Casey,
There are two imaginary lines...the tropic of Capricorn and the tropic of Cancer...today, first day of spring, the sun is 90deg to the surface of the earth halfway between the northern tropic, and the equator.
Dear Lloyd,
Ok got it...two trailers. Will have to think and look at my junk pile...The enclosure doesn't have to withstand thieves...but nature is pretty fierce here.

[LowGear]

Duelfuel,

I think you need to check this page out.

http://www.geog.ucsb.edu/~joel/g110_w08/lecture_notes/sun_angle/sun_angle.html

Casey

[SteveU.]

Hi DualFuel
Old thread but I've been off MCG a long time.
Your wood cutting needs will still be the same.
Interesting you critique on the Husky electric. Who'da thought.
Gifted my then 82 year old father-in-law a Stihl MSE 180 back in 2005 for woodshed limb blocks splitting. HARD Use! Blocks ripping to get down through 6" hard dense limb roots. His only problem was tooth breaking on the original set up pico chain. 2nd year swtiched it to standard 3/8" chain and that stopped. Better chips/strands anyway for the chicken litter and woodgas filtering. Powerful electrics start at full power/torque with no give at all. He used this for three years until his death. I used another year until brushes worn. Light show/ozone smell. ~100 hours loaded using. Still have the saw with new brushes.
Nothing broke.
I'd say these are The "Cat" of electric saws. For a "Cat" price and worth it.
The new 36 and 48 volt battery pack saws look too light of cycle duty to me. I said pass, thank you to the saw shop guy. But an option to try and direct power.
Regards
Steve Unruh

[Mad_Labs]

I also have a 36V cart and have been considering a similar project for a while now. I think I am going to go with a power trailer instead of putting it on the cart itself.  My cart has a pick-up type of bed and tailgate and no roof. I like the idea of being able to set the mobile power rig where I need it and then still be able to use the cart. Also it leaves the extra load of batteries detachable and panels and toolbox detachable. I have a couple of areas where the brakes wouldn't handle a full load of firewood and the extra batteries and such. I also plan to be able to easily connect the cart motor to the trailer if you need to.

I may go 12V just because I have an old trace 2512 that is a beast. It is reated for 2500 but will actually do far more. Runs a welder fine. I would like to go 48V on both, as my motor and controller could handle it. But then I'd need a new inverter and charger. So I may be stuck with 12V.

Jonathan

[LowGear]

I still can't take it.  Seattle has a latitude of nearly 48 degrees.  Trust me!  The Sun does not get 90 degrees or more to surface of the surface of Puget sound.

How goes the 48 volt conversion?  I should have mentioned my cart components are of the early style and rely on resistance to modify the voltage to the motor.

Casey