Hi, I have been wanting to start this project for a while now but just recently got a hold of an electric wheelchair for a good enough price and was wondering if you could give me some guidance on whether or not this model would work for the wheel motors. It is a Shoprider Streamer Sport powered scooter from an auction and I'm picking it up tomorrow, however, the hand controller joystick remote is disconnected and the listing said that it may need replaced but from the looks of your guide it appears only the motors are used? My question is if you know whether this scooters motors will suffice and if I can also use the existing wheelchair battery/batteries or if I will definitely need to order different ones?
Also, I'm sure you have seen the instructions someone else has online for a similar remote mower that is red, in which the existing wheelchair motors AND wheels are used, the motors appear to be directly driving the wheels rather than being mounted higher up and utilizing a chain that runs down to the wheels. This seems easier, or at least simpler, to build at first glance to me but is it not feasible or ideal?
Do you think it is possible to do this without having to weld or should I just break down and buy a cheap welder finally?
I already have a 4.5hp Murray push mower I'm hoping will work. I also have a radio controlled 3.5 channel helicopter I don't use and was wondering if that remote could possibly work for this project? It looks like yours is 6 channel, is that the minimum channels needed or will a 4 channel or even the 3.5 channel radio transmitter work as well?
I was planning to order a sabertooth 2x25 controller board (unless you recommend a different one) but do you have a detailed shopping list of the other components, primarily the electronic ones since I have limited experience with this, that I can download or something? I have read your guide on makeprojects.com but am still a bit unclear on the other boards needed, or at least the best ones to buy, since you mention a few different options and since that article is at least 4 yrs old I wondered if it was updated or if better options have come out since then. I tried to go to the ridiculouslygoodlooking.com links I found scattered around the Web pointing to specific component lists but none of the links seem to work now.
I really appreciate all the info you have been kind enough to post for instructions and your willingness to take the time to help people with this, that is very kind of you.
Thanks,
Nick
Ok, so I have removed the motors from the electric wheelchair and tested them to verify that they work. Unfortunately, the charger does not work.
I also got a welder to use in order to make the frame.
I purchased your book, new, so I will use that as a guide.
Will any of the small lawn and garden batteries work or do I need marine or auto batteries for this project? The lawn and garden batteries are much cheaper and take up a lot less space but I'm not sure whether or not they are technically deep cycle batteries.
Hi Nick,
you will need to get some batteries labeled as 'marine deep cycle'. They are sold anywhere that car batteries are sold, but I found that Walmart has the cheapest price around where I live, usually around $65 each. You can get any size that you want, but generally, the larger ones will provide more run time between charging.
Using standard car batteries or lawn batteries is not a good idea, as they are not supposed to be drained of their charge.. only meant for starting the vehicle/riding-mower, then they get recharged via the alternator. They will fail after a year or so if you continually drain/recharge them. I have been using the same deep-cycle marine batteries for 4 years now and still running strong, so they should last you a while.
I do still recommend the Sabertooth for ease of use and reliability, the 2x25 works great.. I opted for the 2x60 for about $50 more and it is even better, but either will work.
As far as a radio goes... the Sabertooth is most easily used in the R/C mode which reads the standard R/C signal (servo signal) from the reciever (rx) and automatically converts the signals into forward/reverse. Using a setup from your helicopter could work, but does not likely send the same signal that the Sabertooth requires... you would probably need to use an Arduino to read the helicopter recevier and convert that into a servo signal (that is my guess). Also I have no idea what the range would be (probably not great) and this is all assuming that it is a radio transmitter.. if it is an Infrared model, you can forget using it outside. If you want to post a pic of your transmitter/receiver or the model number of your helicopter, I could probably tell you better.
You can buy the 6-channel setup that I use for about $40 from here hobbypartz.com or you can use a pistol-grip style for about the same price. Either will work, the pistol grip is easier to setup, but the standard 6-channel is more versatile.
As far as welding goes, you can build it with just bolts, but welding some joins can help strengthen the frame and keep bolts from vibrating loose. I used very little welding on my current Lawnbot, but went ahead and welded the bolts that are permanently fixed to keep them from coming undone over time.
I am happy to help answer questions, so feel free to ask!
cheers,
JD
Ok great, thanks. I'll probably just order that same RC controller then to avoid complications (this is going to take me long enough as it is, lol). I guess I will need to order that 6 channel receiver on that page as well, or does it come with one?
As far as a charger goes, do you just use an automotive type charger? It would be nice to have a charger built in so that I can just use a power cord to plug it into the wall to charge.
I will probably get a couple of Interstate brand deep cycle marine batteries but how many AH will I need on the batteries to be able to hold a charge for at least a couple hours while mowing? Would some of the cheaper interstate ones with 18 or 19 AH be sufficient or would I need more?
I ordered the sabertooth dual 25a motor driver and it shipped out today, so hopefully it will arrive soon. So as far as the circuit boards/electronic wiring goes, since I'm using the sabertooth, do I just get one of those perf boards or bread boards to be able to wire up the receiver?
thanks again,
Nick
Hi Nick,
the receiver I linked to does include a receiver, so you don't need to buy anything else there, but you will need 2 servo cables (female ends) like this one:
http://www.aero-mate.com/images/servo%20wire%20M.jpg
If you can find a female to female servo cable that is around 12" long, you can cut it in half and use one side for each channel.
You will basically need to wire up the black wires both to the Sabertooth GND terminal, the red wires both to the Sabertooth +5v terminal, and the orange wires seperately to the Sabertooth S1 and S2 terminals.
As for battery amp/hours, I think the ones I bought have like 60-80 amp/hours and they will last about 6 hours straight or long enough for me to mow my entire yard about 3 times between charges. I dont know if 19 amp/hour would last more than an hour, but I guess it depends on how big and hilly your yard is.
For chargers, I use a standard automotive charger.. since I only mow about every few weeks, I just put the 12v charger on the lowest setting (2 or 6 amps) and let it charge each battery overnight. If I was in a hurry, I might put the charger on 15amp for a couple of hours each.
I have a small charger that came from an old powerchair that will charge at 24v, but I have never tried it on the Lawnbot. It would be handy though.
Cheers,
JD
Ok, I guess I'll have to break down and get the bigger batteries then.
Can you recommend a good, relatively well priced, battery charger? I would like to go ahead and get one that is able to test the battery load etc. so I can use it to test used batteries in case I buy some on CraigsList or something. Would also like the kind that can tell me when the battery is fully charged. I imagine the ones that are adjustable would be the most versatile so I could set it to charge at diff volts/amps and what not but I'm not familiar with the good brands/models. I thought you might be since you have used them in the past.
I pulled the trigger on this Interstate SRM-24 marine battery because I had a $20 off a $100+ purchase at Northern Tool and also had some store credit for there. It has about 80 something AH, link below. You might have to copy and paste this link into your browser or add that last parenthesis manually (can't get the link to post correctly).
http://www.interstatebatteries.com/Content.aspx?dsNav=Ntk~SearchGroup%7Csrm+27b%7C3%7C,Arpp~12,A~Part+Number,N~4294784989-4294749800-4294749799-2147384897-2147384903-2147384905-4294749798,Nr~AND(P_unique_id%3AInterstate+Batteries+SRM-24+SRM-24)
So I still need to pick up one more battery, I'm trying to decide whether to get another Interstate SRM-24 which, after using another $20 off coupon would be $80 before the core charge/tax/fees/etc. or get one at Walmart. Which battery model from Walmart were you talking about when you said you were able to find them from Walmart for the cheapest? Was it this EverStart 24DC?
http://www.walmart.com/ip/EverStart-Group-Size-24DC-Marine-Battery/20531540
I also wanted to ask you if you think it would be a good idea to go with the slightly larger 27 group size battery with more AH or do you think the extra 1.82 inches in length and 5.5 more lbs would be pushing it for the weight distribution when mounted on the mower behind the rear wheels? Because both the SRM-24 and SRM-27 Interstate batteries are the same price at Northern Tool and so either would be $80 after the coupon and both the 24DC and 27DC at Walmart are pretty comparable in price as well. Supposedly, on Walmart.com the Q&A indicate that the 24DC is a dual purpose cranking/deep cycle battery while the 27DC is deep cycle only, so I thought it might be better for the lawnbot because of this but I'm just concerned about the increase in weight and the larger size. These are the two larger, 27 group size batteries I'm considering:
http://www.walmart.com/ip/EverStart-27DC-6-Marine-Battery/16795212
I received my Sabertooth motor controller in the mail yesterday, which I got used on Ebay for $80 so I need to test it, so other than deciding on the final choice of a battery to buy from a local store all I will be waiting on is the radio transmitter/receiver to ship. So, I need to get that ordered but wanted to get your opinion on which to buy: Do you think this model would be better for only about $10 more (shipping is free if your order is over $50 anyway)?
Again, thank you, I really appreciate your help.
Ok, I finally got it complete and working, thanks for the help. I do have two questions for you though:
1 - How do you wire lights to a channel on the remote (FS-CT6B)? I bought an LED floodlight that only has 2 wires (neg/pos) but I'm not sure how to wire it to the receiver so it can be turned on/off with one of my switches on the remote. Can I just wire the pos wire to the power source and the negative to the servo lead somehow, so I can plug it into a channel on my receiver or do I have to by a special control board of some kind to go between the light and the reciever? How did you wire your lights?
2 - One of my wheelchair motors runs a bit slower than the other. Does this mean it is going out? Is there anything I can fix or open up the motor and check that could be replaced to repair it? Such as the gears inside or bearings, etc?
thanks!
