| Battery and Charger |
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Before you start building your engine decide what size battery you are going to use. If you are starting
your build early in the season don’t buy your battery yet. Instead take the measurements of it and make a
wooden or cardboard mockup to use while designing the engine. This will do two things for you, keep you from
having to move a heavy battery around during the design phase and it will ensure you have a fresh battery
right before your season starts. The picture on the right shows the battery mockup for my first train.
There is plenty of research you can do on the internet about batteries so
I am only going to give you the basics for the train.
It needs to be a 12 volt Deep Cycle battery. These are used on boats and RV’s to run trolling motors and
electrical devices. You are most interested in the Amp/Hour rating of the battery. The higher the number
the longer your train will run! Get the biggest Amp/Hour rating you can afford and fit inside your engine
housing. Getting a Sealed type battery would be best but not necessary. I have used both sealed and non-sealed
over the years and prefer to save the money and go with the standard non-sealed type. Over the past 10 years,
I have had to replace my battery every other season so keep that in mind for ongoing cost.
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The first train I built used two batteries instead of one. The picture to the right shows the batteries being charged
(Two 12v 33 AH batteries). This engine running on two power wheels motors can run for approximately 5 hours on a single
charge with these two batteries. I was not sure how long the train would run with
one battery so I built the engine to hold two thinking I could add the second one if needed. It turns out I
needed the second battery not only for additional power but I also needed more weight over the drive wheels for
traction. The battery serves two purposes:
1. Provides power for the motors and accessories.
2. Provides weight so the drive wheels can get better traction on the tracks. This is also why you will want to
put your battery inside the engine and not your trailing cars.
Running two batteries requires a few additional steps. You need to connect the batteries in parallel and you need
the ability to disconnect them from the wiring harness so they can be charged independently. You may also need to
buy an additional battery charger so they can both be recharging at the same time. Additional fuses and another battery
cut off switch will be needed. In short, if you can avoid using two batteries I would, as it just adds complexity to the system.
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My second train was designed around a much larger battery. This was chosen for its larger Amp/Hour capacity
to keep the wheelchair motor spinning while pulling more cars. This engine can run for approximately 5 hours
on a single charge using this battery.
Interstate Marine/RV Deep Cycle
Type = 29DC
Amp/Hour Rating = 125
Reserve Capacity Minutes = 210
Weight = 61 lbs
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Don’t forget to design a hold down clamp for your battery. You don’t want it to move around and damage your engine.
You never want these things to happen, but my engines have been dropped (once), derailed (once), and flipped
end over end (once). Each time they survived with only a few scrapes but my batteries never budged.
The hold down pictured to the right is made from a piece of angle iron that is attached to the train base so it
keeps the battery from sliding around. The angle iron has small tabs that wrap around the
lower corners of the battery to keep it in place. You can see a small piece of the tab on the lower right back
corner of the battery. A link of chain is welded to the angle iron and provides a loop for the long hold down bolt
to attach to. A scrap piece of oak wood is used to go across the top of the battery.
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| Battery Charger Information |
There are lots of 12 volt battery chargers out there and almost all of them will work to recharge your battery
but there are a few things you can look for that will make it easier on you and your battery. The first tip is
to buy an “Automatic” charger. This type will automatically adjust the current and length of charge according to
the battery's charge level and then shut off when the battery is full. A “Manual” charger on the other
hand may overcharge your battery and requires you to turn it off. The next tip is to find one that has a
deep cycle setting or a slow charge rate such as 2 Amps. You will want to use a low amp charge for deep cycle batteries.
If you choose to add a “charging port” to your engine as suggested on the electrical page you will need to modify
the leads coming out of your battery charger. I cut off the clamps that came with the charger and wired the leads
into the round trailer connector I used for the charging port. This makes charging the battery each night a breeze.
I just insert the trailer connector into the receptacle and turn on the charger. The picture to the right shows the
charger plugged into the back of the engine.
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