Battery Pack for Makita UC4000

[Kilted]

Yup, you read that right. I just ran the first test of a battery pack for my Makita UC4000 electric chainsaw.

Well OK here is the description:
* Prosine 2000 watt inverter/charger http://www.xantrex.com/web/id/41/p/1/pt/7/product.asp Thats 2000w continuous, 4500w peak power. The unit also has a 3-stage 100amp charger built in.

* 2 x 6v-220amp batteries Concorde SunXtender AGM deep cycle, (broken link removed) PVX-2240

* Battery box

* 250amp DC breaker/switch

* 4/0 cable for connections.

* Small furniture dolly so I can move it around the garage.

This was put together to allow transporablility setup for easy disassembly so I can take it with me to the neighbor to cut up locally downed tree's.

Questions:
WHY? Why not? So I could go out and buy two gas powered chainsaws for the same price.

'Cause I wanted to. Also, my SUV is electric Toyota Rav4EV, I have electric lawn mower, I have electric chainsaw, AND I have 5.2kw of solar panels on my house, it's an electric thing.

So how well did it work. It will not be until this weekend that I will have a chance to give it a full test.

First impression - runs BETTER off of inverter than regular plug. No slowing down motor seems very strong. Also lower noise, no gas, no fumes, no vibration, etc.

The inverter has a display of power usage. I was seeing 12v @ 200+amps, and 120 volts @ 20amps. That chainsaw is putting out 3+hp! No wonder it cuts so well, the only real question now is how long the battery lasts.

Last year when I was out using OP power I had problem with popping breakers on 15amp circuits. Using this rig I can charge from a low power circuit and run from the battery. The charger can be turned off/on from the remote control panel.

By the way DO NOT even dream of running this thing from any regular car starting battery you MUST have the high power deep cycle ones.

I had also considered using a Honda EU2000i generator from what little I've seen I donot think that generator could have handled the load, it's continuous load is 1600w and 2000w peak. That chainsaw seems to run about 2000w+ / 750w or about 3+hp.

I'll add to this on the weekend when I have more data. I can also do pictures later.

-- Brandy

PS, I got the inverter refurbished, would not even dream of doing this at list price. Battery box cost more than the inverter/charger.

 

[Kilted]

Update,

Today I had a chance to cut up the tree the Arborist dropped off.

Over all it's about 1/8 cord of wood. About the amount I could get
in a single load in my Rav4EV. I started with a fresh charge on the
battery pack, it took me about 1.5 hr to cutup and move the pieces to
the back yard out of the way. I also scooped some of the sawdust into
the recycler about 3 times. This created a duty cycle of about 30%-
on, 70%-off giving the battery time to rest.

I checked the status panel during a cut of a large log with 250+ amps
from the battery and 22+ amps @ 118v AC. The chainsaw at no load was
8amps @ 118v AC. Name plate rating on the chainsaw is 12.9amps. I
honestly do not see where 12.9amps rated loaded comes from, certainly
not while I'm operating it. This really explains why I have trouble
with 15 amp circuits popping breakers. The inverter comes with a 15amp
AC breaker, I guess it has a high surge limit.

The battery pack finished at about 15%-20% down. Excellent
performance for my needs. From my experence last year the Rav4EV
load limit is ~1/8 cord. So I should be able to cut a load without
problems. Unloading and resting takes 1+hr, during which the battery
would be on charge.

The built in smart 3-stage charger is 100amps the highest charge rate
I've seen ~70 amps, bulk charge this morning after I finished took
~1hr. This would have the battery at about 95% charged.

I am also setting up so I can take advantage of a friendly neighbor
who would allow me to borrow some electrons. I could then charge
during those breaks when I'm loading, moving sawdust, setting up for
the next cuts.

I am taking pictures, but the construction is not finished yet.

Over all I am very please with the results.

-- Brandy

 

[par38lamp]

I really enjoyed your post. I briefly considered the electric Makita and an inverter, but never really knew what the saw would draw. Now I know, and what I figured was too low.

I would of powered it from a running vehicle, but 200A @ 12VDC is a lot to ask of any vehicle charging system. Perhaps it would be like a winch (similar duty cycle).

Post the pics, please!

 

[Kilted]

Pictures! Overviews
OK here are the pictures:
First, is an overview of the completed battery box, inverter and just visible the furniture dolly it sits on.

Second, shows the DC. power input and a RF reciever that can turn the AC input power on / off remotely. The AC switch is in the gray power box to the right. This AC switch is a 120v AC 20amp BSR X10 remote control switch. Since I intend to use this system a AC power load shifter, I needed to be able to remote control when the battery is recharging.

Third, shows both the AC power switch, top gray box, and DC breaker bottom. The DC breaker is in a custom made bracket mounted to the battery box. Note the SS-rubber cable clamps, these are needed to take the strain off of the breaker. Note also the size of the power cable it's 4/0 welding cable.

End of the overviews.

-- Brandy

 

[Kilted]

Pictures: Battery Box

First, top view of the open battery box. Not much to see here. The yellow thing hiding under the cross over cable is the temperture sensor. Note the ropes tied around the batteries. Each battery weighs 67lbs, it was a pain just getting them out of the shipping box. I needed some way of lifting them in/out of the battery box. Check out the terminals, they are not lead, there is no exposed lead on these batteries the terminals are phosphorus bronze. Over kill? Nope just high quaility batteries.

Second, inside the battery box showing the strain relief washers. All fasteners are stainless steel and I used all nylon lock nuts. This way things can be a triffle loose and not fall off.

Third, pictures of the batteries. Here you can get a better view of the lifting ropes.

-- Brandy

 

[Kilted]

Pictures: Results

First, my growing woodpile in my backyard. Hard to say how big it is something less that 1/4 cord, and growing. The local arborist has been dropping off wood when ever he finds something good. What makes him real happy I will take the wood in what ever size he bucks to. I have a chainsaw and splitter. Most of this pile is from my own back yard as I'm having some over grown trees cut back. I was cutting up the bucked sections on Friday while the arborist was here and he tried the chainsaw, I was running it off of the inverter. His comment the saw seemed to be pretty powerful it had a lot of power in reserve, it did not seem to be straining for the cuts he made. Battery capacity I have not run the batteries down yet, but my guess is one charge should do 2-4 times the woodpile pictured. Friday afternoon while I was cutting up that wood my solar was feeding back to the grid at Peak Rate. On Peak Rate is NOT when you want to be using power hungery tools, dishwashers, electric clothes dryers, etc.

Second, my Avalon Perfect Fit in action burning last summers Ash which I have about half left. I live in Silicon Valley, CA so my winters are pretty mild, I do not attempt to do any 24/7 burns. First off no one is at home during the day and it just is not cold enough. When I arrive home from work about 6PM I will light the fire, second load goes in about 8-9pm, that's it for the evening. IF it is going to be a cold night 30F's I will load again about 10-11PM. The house is insulated and all windows are dual-pane and/or low-e glass pack. I usually run the furnance in the morning, it warms the house and dry's the towels in the bathrooms. So I use about 1/2 cord of wood a season. That's why I can get away with all electrics and depend on the suburban forrest for wood. So between new windows, house insulation, new woodstove and global warming I have reduced my wood usage. I use to use a full cord of wood a season.

Third, battery pack and inverter in the back of my Rav4EV. By taking out the right rear seat and moving the passenger seat forward, the rear foot well is large enough to hold the inverter and battery pack. This leaves the whole cargo space empty virtually assuring that I can overload the vehicle with firewood. I guess I'll have to watch the tires and springs.

-- Brandy

 

[Kilted]

I really enjoyed your post. I briefly considered the electric Makita and an inverter, but never really knew what the saw would draw. Now I know, and what I figured was too low.

I would of powered it from a running vehicle, but 200A @ 12VDC is a lot to ask of any vehicle charging system. Perhaps it would be like a winch (similar duty cycle).

Post the pics, please!

Well the way you handle that is to have a battery to buffer the load. I orginally started out looking at using the vehicle's charging system. My 'traction pack' holds 28kwh and I wanted to see if I could draw from it. That got down to some serious power engineering and well outside my expertise. Next was how to tap into the charger circuit I could not easily figure out how to keep from burning it up. That lead me to the current configuration. Stand alone, transportable, enough capacity to handle one load, actually it looks like there is enough power stored in the battery that I would be exhausted before it. The Prosine inverter/charge is a really top end unit, excellent inverter and a high power 3 stage charger. As such it can fill in during power outages etc.

You could also have a connection to your vehicles chargeing system to charge the "house battery" while you are driving you may need a larger alternator. Go to the Xantrex website and download the manual. This inverter was designed for RV/marine use, the manual shows you how to connect it up.

-- Brandy