I’m looking to put together a kit for a custom cart. I called and was referred to this forum to get help from tech support advisor to build the kit. I would prefer to do this over the phone though.
The process of us putting together a custom kit requires us to make several technical calculations and also to create the kit's photograph and order page which takes a considerable amount of time so it is not something that we could do over the phone. However, we could put together a custom kit through this forum, or through a support ticket if you prefer.
To begin the process of creating a custom kit we need to ask a few questions about the design goals for the project:
All of those design goals can easily be met with our parts and a custom kit, however, a 24 Volt system would not be powerful enough for a 500-pound load under deep sand and steep hill conditions so a 48 Volt system would be needed instead.
With the parts that we carry and can get, we do not have access to any drivetrain parts that would offer a neutral clutch or neutral gear, so with our parts the beach cart could either have forward and reverse with no neutral or freewheel, or it could have forward-only and a freewheel so it can be pushed forward without any resistance from the motor.
If the beach cart will not have mechanical brakes and it will be used to go down hills or inclines then the gear motor will provide a significant amount of braking power if the cart does not have a freewheel, if the cart has a freewheel then it will coast downhill without any resistance from the motor.
A motor mounting plate on a hinge that a bolt on one end can be removed from to allow the motor to pivot towards the axle for easy chain removal may be an easy way to add an emergency neutral gear to the cart in case the batteries die.
I ran a top speed and gear ratio calculation for walking speed using our 48 Volt 1000 Watt gear motor and 16.5" wheels and here is the result.
The top speed in this calculation will be realized on hard level ground, and when the beach cart is going through deep sand or up steep hills the top speed will be a little lower.
A 70 tooth sprocket for #41/#420 chain has an 11-inch diameter and such a large sprocket is needed to obtain a walking speed gear ratio due to the large wheel diameter.
At 3 MPH 4 miles will take 1 hour and 20 minutes to travel and 8 miles will take 2 hours and 40 minutes to travel, so the battery pack needed for a 4-mile range will be half the size needed for an 8-mile range. What I can do is calculate the battery pack size for a 4-mile range and 8-mile range and then if a 6-mile range is chosen we can split the difference. Here are the calculations.
Here is a preliminary parts list for the kit:
The parts above with question marks after them are choices that would need to made for the kit.
If you prefer a 24 Volt system and could accept a 250-pound weight capacity for deep sand and steep hills then we could put together a 24 Volt 450 Watt kit for around half the price as the 48 Volt 1000 Watt kit.
Please let us know your thoughts on all of this and we can take it from there.
Our 24 Volt 750 Watt motor does not have gear reduction so it would not work for a beach cart due to its high output shaft speed.
Our 36 Volt 1000 Watt wheel motor is geared for a 15 MPH top speed with a 12-inch wheel so its gear ratio is too high for a beach cart.
A gear motor needs to be used to obtain the right gear ratio for a beach cart. We do not carry a 24 Volt 1000 Watt gear motor and the largest 24 Volt gear motor that we carry is 650 Watts. A 24 Volt 650 Watt gear motor with a couple of 22Ah or 35Ah batteries will be able to propel 750 pounds and have a 4-8 mile range on hard ground with some sand and some hills, however, deep sand and hills consume much more power than hard ground does so the battery pack size would need to be doubled to obtain a 4-8 mile range under continuous deep sand or hilly conditions.
With a 500 pound load in dry sand, a 650 Watt motor may work as long as the wheels do not dig too deeply into the sand. Different beaches have different types of sand so if the sand allows the wheels to sink deeply into it then the cart will consume a lot of power and if the wheels do not sink very far into the sand then the power requirement will be much lower.
When we design our beach cart kits we design them for the most demanding conditions such as superfine deep sand so if the conditions at the beach where the cart will be used at are not so demanding then a kit with a smaller motor and battery pack may work fine.
One design requirement of electric beach carts is that they need to have two wheel drive, otherwise, if only a single wheel is powered it will dig into the sand and the cart will not move. You will need to source the axle, axle bearings, bearing hangers, and axle to Wheeleez adapters from another store because we do not carry those parts. For the axle to Wheeleez adapters, we recommend contacting electricbeachwagons.com because they are the only ones we know of who produces them. They can inform you regarding what size axle works with their adapters, and then you can let us know what axle size you will be using so we can include a sprocket or freewheel adapter with the kit that fits that size axle.
If you do not want the beach cart to have a freewheel then to speed up the kit making process we could make a kit without an axle adapter, and you could order an axle adapter from the same store that you purchase the axle from and have the axle sprocket custom made to fit that adapter. This way there would be no hold ups in us designing the kit and we could design one and have an item number so it is ready to order right away.
Please let us know your thoughts and we can take it from there.
We have both freewheel adapter and sprocket adapters for 3/4" axles.
I agree that under those conditions and with a top speed gear ratio that is around 3 MPH the 24 Volt 650 Watt gear motor will work well. Two 12V 35Ah batteries will create a large battery pack that will provide a long range and for a longer range, we also carry 50Ah, 75Ah, and 100Ah batteries that could be included with the kit.
The freewheel adapter slides onto the axle and has a keyway so a keystock can be installed between it and the axle to keep the adapter from spinning on the axle, and it has two set screws to hold it in place on the axle. It is used along with a freewheel and sprocket in a configuration as shown below.
The freewheel allows the cart to be pushed forward without any resistance from the motor, however, it does not allow for the motor to run the cart in reverse because if the motor spins backward then the freewheel will spin freely on the axle and not transmit the motor's power to it. So with the parts that we have available, there is the option of having a freewheel with forward only, or having no freewheel with forward and reverse.
I can start working on the custom kit and have it ready very soon. Before I can start on the kit I would just need to know if you want the kit to have a freewheel and forward only, or no freewheel and forward and reverse, along with what size batteries to include with the kit.
Please let me know if you have any questions.
Here is the pricing, dimensions, and weights for those two batteries. There is a 10% discount on kits so the kit's battery price will be 10% lower than shown below.
Please let me know if you have any questions.
Considering my planned usage do you think 35ah will be sufficient??