This morning I went out with a few guys in the local EV club to a salvage yard. One of the members knows the owner and got the call that he had just gotten in a few forklifts. So, we headed off to pull parts. We got a lot of stuff, but this nice voltmeter will be going on the mower. Its also has an hourmeter on it. I just need to get in contact with Curtis to get the pinout for the gage. Apparently it is capable metering 24, 36 or 48 volts which is very nice if I decide to bump up to 48V.

http://ecorenovator.org/pictures/ecorider059.JPG

Lucky dog. That'll be perfect for the mower. Are you still/also planning a meter on each battery? Or at least a single LED?

Yeah, the individual monitors are 'very close' according to Tom (the guy who is designing them). They'll likely replace this gauge. However, since I am using new batteries, balancing issues shouldn't really be a problem.

The Curtis website may have the info you need to wire it up. I found a manual for mine there.

I tried. The gauge must be an old model and they don't have the manual online.

Shouldn't be! But you won't know for sure unless you monitor them individually. Strongly recommended.

I agree, and I definitely will be getting individual gauges.

In other news, Curtis already got back to my email that I sent this morning. So, I have the pinout for the gauge. Very impressive customer service.

I started working on the battery racks last night. I'm planning on putting one up front (requires modification to the grill/top cover) and two right behind the seat. I'll get pics when I get some good progress.

Battery rack work continues. Here are a few pictures of the progress.

Here is the rack that will hold the two rear batteries. I cut the pieces but haven't done any welding yet as I am clean out of gas for the welder. It is made out of .75x.125 angle iron.

http://ecorenovator.org/pictures/ecorider060.JPG



Here are the support braces. They are bolted to the frame up front with two bolts on each side. They are 1.5x.125 angle iron.

http://ecorenovator.org/pictures/ecorider061.JPG



Put the fenders back on to test fit.
http://ecorenovator.org/pictures/ecorider062.JPG



Throw a battery on it. Everything looks like it lines up very well.
http://ecorenovator.org/pictures/ecorider063.JPG



Here is a lower profile shot. I will be adding braces going to the far extents of the rack to steady it.
http://ecorenovator.org/pictures/ecorider064.JPG

Wow! Now I get an idea of the size of those batteries. They're huge!

Your mower must be smaller than the Electrak.

On Friday I was able to get a new tank of gas for the welder, so the rack work continued today.

I started out the day welding up the rectangular rack for the two rear batteries.
http://ecorenovator.org/pictures/ecorider065.JPG



I forgot to mention this in my last post, but I notched out the angle iron in the very front so it is easier to get a wrench in to install and remove the main support members.
http://ecorenovator.org/pictures/ecorider066.JPG




After centering and clamping the rack on the back, I made some brackets to bolt the rack to the main supports.
http://ecorenovator.org/pictures/ecorider067.JPG



They were welded one on each side of the main supports.
http://ecorenovator.org/pictures/ecorider068.JPG



And, then I popped a few holes to bolt them up together.
http://ecorenovator.org/pictures/ecorider069.JPG



At this point, I wanted to see how it was all going to hold. It snugged up all the bolts and it actually seemed okay just with this. However, I didn't feel right hanging that much weight that far back off of the larger angle iron. I also didn't like the batteries hanging that far to each side of the main support. Mowing around the yard creates a lot of vibration and shock loading, so this thing has to be solid.
http://ecorenovator.org/pictures/ecorider070.JPG



So, I made this bracket to brace the sides and help hold up the back.
http://ecorenovator.org/pictures/ecorider071.JPG



Since there was no room to have a bolt head inside the battery rack, I ended up shaving down the head of a bolt and welding it into the rack to create a stud.
http://ecorenovator.org/pictures/ecorider072.JPG



And, here is how it looks once it is all bolted up. The added brace really solidifies things. I will be adding another one to the other side.
http://ecorenovator.org/pictures/ecorider073.JPG

Very nice work. In other news, I just found out I can literally flip my Father's gas tractor backwards over itself without really trying. Good thing the hitch it back there, else I'd have landed on my head at 6.8 MPH.

Lookin' good.

The back rack is all finished up. The side supports really stiffened up the whole thing.


Second brace is all finished up and bolted on.
http://ecorenovator.org/pictures/ecorider074.JPG



It holds the batteries very solid now.
http://ecorenovator.org/pictures/ecorider075.JPG




I made sure to design it so I retained usage of the trailor hitches. It isn't real clear, but both are still very accessible.
http://ecorenovator.org/pictures/ecorider076.JPG




And, here is how it looks with the fenders and seat back on. Not too bad, and easy access for checking the water level since they are flooded batteries.
http://ecorenovator.org/pictures/ecorider077.JPG

By the way, does anyone have any tips for cleaning up angle iron for painting? I have a small sand blasting booth (table top) that I can use for the side supports, but the other pieces are too long to fit in it. Right angle die grinder and some abrasive pads?

I always buy anything that I think is a good deal when it's a good deal for me, if I have the cash on hand.

Reason being, even if I don't have whatever it goes to, someone does, and they'll need it eventually, or I can use/modify it to work on something I do have. I've yet to lose anything by doing this, but you get really good at it over the years I've been doing it, to the extent that I can usually sell things for far more than I pay for them, making it worthwhile to hold onto them for awhile.

It does tend to piss off neighbors, though... they don't like the "junk" laying around. Good thing I don't really care, and they don't live *right* next door.

Greenies. The green scotch brites or steel wool and an angle grinder. If you can sew, sew some steel wool onto a buffing pad so it's "fluffy" and that will let you get into the corners better.

More rack making finally. This time it was a rack up front for one battery right in front of the motor.


So, I started out again making a rectangular box to seat the battery on.
http://ecorenovator.org/pictures/ecorider078.JPG



I wasn't too keen on welding to the mower frame, so I made some pieces so I could bolt it together. This just makes it easier for upgrades/changes later if I decide to do anything.
http://ecorenovator.org/pictures/ecorider079.JPG



I welded raiser legs on the box and positioned and leveled it over the mounting brackets.
http://ecorenovator.org/pictures/ecorider080.JPG



Here is the after welding shot.
http://ecorenovator.org/pictures/ecorider081.JPG



At this point, the battery rack was strong enough to hold the battery up.
http://ecorenovator.org/pictures/ecorider082.JPG



But, as usual I went ahead and put an extra support on the front to really solidify things.
http://ecorenovator.org/pictures/ecorider083.JPG




Now, the battery racks are mostly done. I still need to think of how I'm going to tie the batteries down. The cover to get at watering the batteries runs the full length of the battery, so its going to make things a bit more difficult there. Other than that, I just need to wire it all up, mount a few things (contactor, voltmeter, etc.) and I'll be up and running!

Glad to see another update. Is there one last grass-cutting left to do this season? It's going to snow soon, you know. ;)

Yeah, I was hoping to have it wired and cutting this weekend yet. However, I didn't have time. I'm going to try and rush to get it done early this week and then just take advantage of the first chance to cut. However, it is supposed to snow Wednesday!

Just got back from my first test drive. I had nothing hooked up except the contactor. Not that having the ammeter would help as it is pitch black out atm. I would have been able to see the voltmeter though. :)

This past weekend I took the time to piece the mower together enough to actually do some work. I was able to get the lawn mowed with two charges, but I still have some hangups with it.

The pulleys are still sized wrong. 1st gear is way too slow to mow, and 2nd is very fast. I spent most of my time mowing in 1st gear. However, the majority of the power to mow goes into keeping the blades spinning, so I'm loosing tons of power by not being able to mow faster. Resizing the pulleys will allow me to slow the mower down in 2nd gear to a reasonable speed and also slow down the blades so they aren't sucking soooo much power.

The drive belt is slipping. I did try mowing in 2nd gear for a while. It worked okay despite flying around the yard. However, when I hit a bit of an incline, the mower would really slow down. So, I need a smaller belt or I need to adjust the clutch. Moving around this time, the mower was pulling 50A vs the 25A it had been using previously in my testing.

The temperature was pretty low. On Friday, I think it was roughly 40 degrees when I was mowing. This really kills the power output of batteries. I believe most electric cars loose about half their range in the winter.

The batteries have not been used yet. On Saturday, my second time using the mower, I was able to go quite a bit farther on one charge. I think this was a combination of exercising the batteries the day before and also warmer weather (55 degrees).

So, totaling this all up, the mower was consistently pulling 110A the entire time I was mowing. Unfortunately, I didn't think of timing it to see how long the battery actually lasted. In summer and with the pulleys sized correctly, I think it will be pulling ~70A.

But, that is the last time I'll be mowing for this year. Time to put the snow blower on!

I had the mower out for the first time this year. Mowed half the yard (on two charges). The batteries lasted a LOT longer on the 2nd charge, so they definitely need to be woken up (they don't last as long after sitting for long periods and need to be 'exercised'). Mowed great, still need the pulley's resized though for more run time and reasonable speeds. I also noticed my drive belt is slipping so I'll need to adjust that as well. In addition to that, I need to get some permanent wiring in there. I'm still using alligator clips to power the contactor and on/off switch as well as the voltmeter.

I gotta say, I love the mower. After basically wheeling the mower out of the garage, and giving the batteries a quick top off charge I was mowing without any problems. After mowing I got out my gas powered weed wacker... just pull after pull and even after it was running it wasn't running good. What a pain. I'll be replacing that soon with a Ryobi 18V lithium ion trimmer that HomeDepot is selling. I'll write up a review once I've used it a bit.

The ecorider lives!!!

How many minutes run time would you say you got per charge?

And how did you decide when to quit and recharge?

Dang, I knew I forgot something haha. I didn't time how long I could run.

To decide when to stop, I just have a voltmeter monitoring total pack voltage. When I hit 33V, I stop. This is a bit low, but thats what I'm currently using.

Run time would be good nerdly info to know.

So you still have half the lawn left to do? Going to mow some more tonight?

Re: Trimmer

Ryobi usually makes some pretty good tools. They're a sister (brother?) company to Black and Decker, as well as Ryan, and a couple smaller companies.

I had some tools from the Ryobi +ONE kit, they were a dream to work with on sites where power was a commodity (no waiting for a hookup, etc.), but the batteries didn't seem to stand up to the length of use I needed from them. As such, I employed 2 chargers and 2 spare batteries.

The lithium kits have longer run time, and more power-per-minute discharge capacity when necessary. They're supposed to be a better battery for the tools than the +ONE kit's batteries, because they can stand up to longer discharge cycles (continuous duty) and use.

I look forward to your review!

Yeah, I still have my field left to mow. I'll do it sometime this week. I'll get the runtime then.

I mowed my field last night. Got it all done in one charge. It seems I have roughly 25 minutes of use until my pack voltage gets down to 33V. Not too shabby. I'm hoping that the pulley changes will increase that to about 30 minutes.

One other thing I noticed while cutting this weekend was that my motor is running hot. Not real happy about that, but its not crazy hot, so I should be able to deal with it with some sort of fan. I'm currently thinking about putting a radial fan on the tail shaft and make some ducting that goes over the motor.

I've been emailing back and forth with some of the local EV guys. They all say I should resize my pulleys before worrying about cooling the motor down. I figured thats what they would say. I think I am going to look into borrowing a controller so I can dial in a speed that works good so I can go with the smallest pulleys possible. This in turn should bring my amperage draw down to the lowest possible as well and give me longer run times.

Mowed the grass this weekend. Boy was it thick. I could tell because my ammeter was reading higher than normal and my voltage was sagging lower than normal under load. Still, the mower did a great job going through it all, no problems at all.

After cutting I did take some time to go over the mower. I greased up the fittings and removed the drive belt. I'll be picking up another correctly sized one tonight so it doesn't slip anymore. I also figured out why I don't have any brakes and will get that fixed with a trip to the hardware store as well.

Now, I just need to borrow a tach from one of the EV group members so I can correctly size my next set of pulleys.

I'm also contemplating bumping my voltage up to 48V to reduce the amps the motor draws. I'm not sure how much smaller of a pulley I'll be able to go with, so that is the alternative. I don't want to keep running the motor at such high amp loads. Sooner or later the heat will kill it.

Well, disaster struck about a week ago. It was my own fault. I had a battery literally explode on me. I had gotten a new drive belt and hooked up the brake finally, so I took it for a spin around the yard to see how it worked. I also decided to see what 3rd gear would do with the new belt. It took the front wheels off the ground. My face was very much like this: :eek:. Anyways, I took it back to the garage and wanted to test out my new hydrometer which tests the state of charge of the battery, way more accurate than a voltmeter. Anways, I was peeling off one of the covers and there was an explosion. Apparently (and I obviously didn't know this) batteries let off hydrogen gas while in use as well as when charging. I knew about the charging part, but not about the in use part. So, it blew a 2" hole in the side of the battery case, another 1.5" hole in the top of the case along with multiple other cracks and acid all over the place. Thankfully all I got was a little scratch from the cover hitting my arm. A box of baking soda later and the mess was contained. I'll get pics up later of the battery.

Anyway, I ordered another two batteries. While talking with the EV club guys, I decided it would be better to bump the voltage up. This not only will give me more than 30% more run time, but it will also lower the amperage to the motor which had been running warm. So, I'll be killing tow birds with one stone. Now, I REALLY need to get new pulleys. :)

Glad nothing worse than a scratch happened.

I'd never heard of gassing from discharging, myself. And the online references I found to it aren't particularly quality ones either.

How long had it been since you had charged up?

Regardless, we really should be wearing safety goggles at a minimum working around batteries. (I'm guilty of not taking precautions.)

Also: woo for 48v! :)

Heres the pic of the battery. Yeah safety glasses probably wouldn't be a bad idea...

http://ecorenovator.org/pictures/ecorider084.JPG


http://ecorenovator.org/pictures/ecorider085.JPG

That's kinda scary! What do you think triggered it to explode? Was there some source of ignition (static discharge, spark, cigarette)?

My only guess would be static. The covers fit pretty snug, so I guess the rubbing created the static. :confused: All I know is let it sit for a while before taking covers off now! :o

New member here. I just finished reading your thread on the electric mower. I am considering doing the same with my old Toro 8-32. I saw the pic you posted early on of your property. I was wondering how big the area you are mowing is. It looks to be about 2 acres. I was wondering because I am trying to determine how much mower I will need to build to mow my 1/2 acre less buildings.

Thanks.

Welcome to the site toolingjim. Wow, you're right down the road from me. :)

Anyways, the lawn is a little under an acre, but it feels like more than that. Perhaps because its so spread out? My current battery pack is roughly 5.4 kWh. Below is a picture of the current chunks I do the lawn in.

I'm sure that this will change once I get the extra battery on the mower as I'll have 30% more capacity and pulling less amps from the batteries also makes them last longer. I'm hoping to go from a run time of ~25 minutes to ~35 minutes.

http://ecorenovator.org/forum/attach...1&d=1275910035

The batteries are here if I didn't mention that already. However, now I have a problem with charging 4 batteries instead of just 3 batteries. Previous to this, I would usually mow before noon on the weekend. After mowing, I would put a 2A charger on one battery and a 10A charger on another battery. By the end of the night, the 10A charger would be ready to go to the next battery and the 2A charger just stayed on the one battery overnight. This would allow me to get the second charger in by the next day for mowing again.

So, I am looking into chargers that will allow me to do the same thing. The only thing is I have one more battery to charge, so I won't be able to charge overnight now and mow the next day. That means I need more/faster chargers. Right now I have my sights on buying two Soneil 1214S chargers. They are only 7A, but have a slew of nice features. They do run about $70 each, but seeing as how I've already blown the budget for this project with the new batteries, I might as well just get it running real nice now. :) These chargers would allow me to just plug in and forget about the mower until it was charged.