# Dc motor for cart



## Wessie (May 29, 2013)

Hi all you clever people.
I've been searching for you for a long time. I am a very enthusiastic fisherman. the problem i have is that I have to walk a lot of kilometers up and down the beach. I want to build a cart that can carry my gear for my. I want to use a battery operated motor (as no motorized vehicles are allowed on the beaches). I hardly ever have more than 25-30kg's with me. I want it to be belt driven. I can build houses and do a lot of things with my hands, but dont know anything about mechanics... Where, what, how?


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## Duncan (Dec 8, 2008)

Hi Wessie

Do you want to ride the "cart" - or walk alongside?

If you want to ride I suggest you have a look for a small lawn tractor or quad bike with a blown engine


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## puddleglum (Oct 22, 2008)

If you are wanting a light weight pull behind unit, what about building a 2 wheeled unit with a tiller handle using old bmx bike parts? You could get an e-bike wheel or drive motor for one side and mount a thumb throttle and brake to the handle.


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## Wessie (May 29, 2013)

Hi guys. Thanx for the replies. I thought of using a Yamaha 5hp sideshaft motor and actually do have one, but those damn things are so noisy and bulky and I will loose a lot of space. If all else fails I will go that route. I will be satisfied to just walk infront to steer. I have uploaded a picture of what I currently have to work from. The front wheel will be changed to a single wheel as those dont have a big turning circle. I got a quote from a company that specializes in wheelchair motors, but that and a very nice transaxle will set me back $180 and that is crazy? I'm not spending that kind of money the gear is not that heavy


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## alvin (Jul 26, 2008)

I once used a treadmill motor ($ free) on a bicycle. I mounted the motor over the rear wheel with the flywheel of the motor pressed tightly to the tire. Three 12 volt AGM batteries and an on - off switch. It would not take off from dead stop but would propel the bicycle once it was rolling and power it up hills.

Maybe something like that would work. Less voltage would slow it down some,but a real controller might be better.

Alvin


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## puddleglum (Oct 22, 2008)

Another option might be a 2 wheeled electric scooter, if you can find one used for cheap. It would have most everything you would need for parts. Chain drive might not be good in sand though.


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## Wessie (May 29, 2013)

Hi there!!!!
Its been a while. Cannot bigin to tell you how many hours I've spent on researcing this kart.

Finally settled on two walkbehind golfcart motors. I'm using one for each rear wheel. Not taking any chances of the motors draining the batteries while I still have 5 kilometers to go. Its not gonna be fun pulling that thing through the thick sand. Had a nasty one 2 weeks ago. The kart is still in the pull stadium(I suppose you first have to pull before you ride). Anyway with about a kilometer to go the front wheel went flat. The weight on the kart caused the frontwheel to push into the sand. I completely lost my sense of humour.

Anyway, back to the drawing board. I need to look at batteries for these to motor and then I am thinking of adding a solar panel to charge the batteries while I'm on the beach.

Was thinking of deepcycle, but at R2500 thats a no go. I would need two or what? 
The other option was a normall lead acid battery. 62ah not bad but it weighs 15kg's.

So what now????


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## electro wrks (Mar 5, 2012)

Here's a motorized hand truck I made in 2008, as posted on another thread. The big lawn tractor tires worked well on loose ground. You still needed to keep the load balanced and this was a factor limiting the assist power. But, the low power electric motor, through a recycled mobility scooter trans-axle, eliminated most of the pushing and pulling effort. For more range, there was plenty of room to stack more batteries :


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## Wessie (May 29, 2013)

Hi Electro.
I cant see the truck. File opens but its black. 
I hear what you are saying anout stacking batteries for range, but here-in lies the problem. I need to keep the weight down of batteries so that I can add fishing gear etc.


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## Wessie (May 29, 2013)

Hi Electro.
Saw your handtruck. Crazy!!!
What size is that battery and how long could you keep going on the sand.

I wonder if this forum is closed or do I just have you guys stumped?


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## PStechPaul (May 1, 2012)

You can use my EV Calculator to determine approximately what you will need. I figure that the cart and the gear should be no more than about 25 kg and top speed will be 3.2 km/hr (2 MPH). And I'll use a rather steep 20% slope and I'll make the rolling resistance ten times what I have as default.

I get about 75 watts (0.1 HP), and 24 Wh/km (39 Wh/mile). So you could use a very small DC motor and a 12V 12Ah SLA which should easily give you 2 miles all uphill. For 12" diameter tires the rotational speed will be about 56 RPM. The difficult and potentially expensive part will be achieving the ratio and getting the power to the wheels, but you can probably use parts from a small riding mower or self-propelled push mower, and you can get small gearmotors as well. You may also be able to use most of the parts from a battery operated drill. Here are some parts that might do the job for you:

http://www.herbach.com/Merchant2/me...AR&Product_Code=TM01MTR4476&Category_Code=MTR
http://www.ebay.com/itm/24V-DC-Gear-Motor-/271253412792

Neither of these is exactly right for your application. There are lots of very small motors but really too small, and those that have the power you need are mostly too large and expensive, or AC. So probably using a drill would be best, unless you can find a junk battery powered kid's car or trike.

For the battery, this is a good deal:
http://www.ebay.com/itm/UPG-UB12120...er-Medical-Rechargeable-Battery-/190776244178

This should work for the controller:
http://www.ebay.com/itm/181051717518

I hope this answers your question and gives you some idea of what you will need to build something like this. I think the drill will be your best bet and it already has a spring-loaded speed control trigger that should be used for safety, like a "deadman switch". Something else to consider is the type of gearing and the ability to freewheel when you don't need power assist. And you might also think about the type of motor and drive that will also function as a brake when going downhill (and possibly providing some regeneration).

If you want to save weight, you can consider Lithium batteries, and perhaps motors and controllers from this company:
http://www.hobbyking.com/hobbyking/store/__15521__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack.html


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## Karter2 (Nov 17, 2011)

Batteries are either going to be very expensive (LiFepo) or very heavy (lead).
no avoiding that im afraid. !


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## Wessie (May 29, 2013)

Thanks for the rellies guys.

What if I add a 2.5 petrol lawnmower engin and inverter to charge the batteries as needed.? It will still be easier to hide than say a normal lawnmower engin won't it?


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## Wessie (May 29, 2013)

That should read replies. New phone and not used to touchscreen.


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## PStechPaul (May 1, 2012)

The LiPo battery pack I showed weighs a little over a pound, has 5000 mAh at 14V (70 Wh) and costs $24. That would probably be good for a couple of miles of average use, and you could use an extra one in parallel, or as a spare to swap out. Hobby King and Turnigy also have inexpensive chargers and BMS and meters that could be used with this.

The 12V 12Ah SLA I showed weighs about 9 pounds, costs about $24, and will probably be good for 2-4 miles. I figure the cart will weigh about 10 pounds more with the motor, and it should be able to carry about 30 pounds of gear for a total of 50 lb or 20 kg.

I think the R/C hobby LiPo batteries should be OK for something like this. LiFePO4 would probably cost about 2-3 times as much for 70-100 Wh, but they would last forever. 

This is really a very low power and low energy application. I was surprised myself when I saw how much 75 watts can do. It's really very much in the realm of portable drills, and it might even be possible to buy a complete drill and chuck it onto a driveshaft and not even scavenge the parts. You can get a complete new 12V Lithium drill and charger for $45 including shipping:
http://www.ebay.com/itm/SEARS-CRAFT...OWERED-CORDLESS-DRILL-BRAND-NEW-/151091070254

Here is a thread about a cordless drill-powered walk behind tractor/cultivator that is a similar project, except it needs a lot more power:
http://www.mytractorforum.com/showthread.php?t=237102&highlight=drill+power

[edit] Just saw your question about a charger. You can get a 30W 12V solar charger for about $63:
http://www.ebay.com/itm/30W-30-Watt...attery-Charger-Off-Grid-RV-Boat-/271167309560

And you can get a hand crank 30W generator for about $50:
http://www.ebay.com/itm/Hand-Crank-...-Emergency-Bugout-FREE-SHIPPING-/300953291173

So with 3-4 hours of sunlight or cranking you could get one or two miles worth of energy to get back to the car. You can get chargers that run off the car cigarette lighter too.


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## Wessie (May 29, 2013)

Hi guys. Thank you very much for your input. I spoke to a person from Sinetech and like Karter2 he also reckons I am not gonna get away from the weight not to speak of the cost.
Plan B then. 2.5hp sideshaft gas lawnmower engin and alternator to charge the battery. Do I need 2 battries or will I get away with one battery for the two motors. (I am still waiting for a reply from EMD for the specs on these motors).


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