Hawk 250 Battery Upgrade

Well, I finally broke down and bought a cheap Chinese Enduro bike. It’s sold in the US as a Hawk 250, and I’ll be posting lots of updates about it and the things I’m doing to it. The first thing you should know is that you can get one unassembled for $1,299, and no more than $1,499 assembled from a dealer. So this is an extremely cheap, and yet street legal (at least in Texas) bike. But as you can imagine, at this price there are probably a few things you want to do to make it a bit more liveable. This is one.

The Hawk 250 comes with a generic, unnamed 12v battery of questionable origin (Size 5.5″w x 2.5″d x 4″h. It’s a standard cheap motorcycle battery that requires routine maintenance such as adding water to the cells. Well, in Texas where it routinely gets up to 110+ degrees I don’t want to rely on being somewhere and having the battery die. So I opted to replace it with pretty much the most high tech battery you can get. A lithium iron phosphate battery, which is a fraction of the size, a fraction of the weight, and yet puts out as much power or more and last for years without any service.

In fact, I actually tried two different size batteries, and both work, but read on and I’ll explain the differences.

Ultra Compact Battery Tender BTL09A120C

I initially chose to use the Battery Tender BTL09A120C Lithium Iron Phosphate Battery which runs $69 at Amazon, and opted for the extra $27 Battery Tender 022-0198LI Green Lithium Junior Battery Charger.

Here are the specs of this battery:

Voltage: 12V
Lithium Cranking Amps: 120
Lead-Acid Replacement Range: 7-9(Ah)
Case Dimensions: 4.21” (107mm) length x 2.2” (56mm) width x 3.35” (85mm) height
Operating Temp: 40 - 140° (F)
Weight: 1.2 lbs
Warranty: 3 Years - Limited*
Max Charge Rate: 10A
Agency Approvals: CE, UN 38.3

• 18 month Shelf Life
• Up to 80% lighter than Lead Acid Equivalent
• 5X the Life of a Lead Acid Battery
• Quad Terminal Configuration for ease of installation
• 2000+ Cycles at 80% Depth of Discharge
• Can be mounted in any direction
• Lithium Batteries do not sulphate

(Skip to the end for the slightly more expensive, but better fitting model if you don’t need the instructions.)

Removing the Old Battery

Step one is to remove the side fairings / panels on both sides of the bike. Each has a single screw to remove, and then they just snap off.

Next, the seat has two 8mm mounting bolts holding it to the frame. Remove one from each side and slide the seat upwards. Now in theory, you don’t HAVE to remove the seat, but it’s so easy to do and it’s going to give you more light and room to work. It also offers the opportunity to inspect wires and bolts to make sure things are secure and tight, so go ahead and do it.

Each of the battery terminals is connected with a 10mm bolt. So use a wrench to loosen it up and then you can pretty much just remove it by hand. Once you’re done, you’ll see a rubber strap securely hooked around the battery and you can remove it and simply slip out the old battery.

Securing the New Battery

The first thing you’ll notice is that this new battery is MUCH smaller than the outgoing unit (yet still more powerful). And although it comes with a bunch of foam spacers that allow it to adapt to a battery box, the Hawk 250 doesn’t have a box, it just has a loose frame the battery slots into.

As a result, I took two long, heavy-duty zip ties, and fed one through a slot in the plastic behind the battery, and wrapped it down under the metal rails and back over the battery. This was extremely secure and probably all that was needed. But just to be certain it wouldn’t slide sideways, I took a second zip tie and secured it around the side.

Keep a couple of things in mind:

1. This is not a good long term strategy. That area is going to be getting hot, and relying on plastic to secure the battery with lots of bumps and things isn’t long term thinking. It would be better to find a metal strap at a hardware store, or fabricate something to take up the extra space so you can rely on the factory strap.
2. If you’re going to rely on zip ties, make sure they are the thick, heavy duty ones. And make them snug, but not super tight. Allow for some expansion and contraction with extreme temperature differentials – and check them periodically to see if they need to be changed! Maybe even carry some extras under the seat.

Attaching the Trickle Charger

The Battery Tender is designed to continuously charge and condition the battery when you aren’t riding. So you can plug it in and forget it. But instead of having to remove the seat to clamp the battery every time, it comes with a quick disconnect wire that to attach and leave hanging somewhere that you can get to it.

I would recommend that you run the bolt through the motorcycle positive and negative terminals, then through the quick disconnect wire terminals when screwing it in. And I fed the cable up over the frame where the seat is, and left it hanging over.

Ultimately, I took a zip tie and folded it up until the plug would just reach outside the side fairings when they were reattached and secured it at that length.

You want to be able to reach under and pull it out to charge, but still be able to tuck it away when you’re riding.

You may argue that this bike has a kick starter, so why worry about charging the battery? Well, because I’m lazy, and saving $26 isn’t worth the possibility of having to jump up and down on the bike trying to get it started.

Battery Tender BTL14A240C Direct Size Replacement

Now, having gone through all of that, if you want to save yourself a lot of hassle (well, not that much really) you could purchase the slightly larger Battery Tender BTL14A240C battery for $20 more, and its a perfect fit without needing to use zip ties or any other method of securing the battery.

The dimensions are 5.27 inch (134 mm) length x 2.55 inch (65 mm) width x 3.62 inch (92 mm) height, which is close enough that the factory rubber strap will hold it in place.

Additionally, it’ll give you double the cold cranking amps (240) which will help the bike start all that much easier. In fact, I couldn’t believe how fast the bike fired up after putting this new battery in and it’s definitely what I recommend.

Here are the specs for the larger BTL14A240C battery:
Voltage: 12V
Lithium Cranking Amps: 240
Lead-Acid Replacement Range: 10-14(Ah)
Case Dimensions: 5.27" (134mm) length x 2.55” (65mm) width x 3.62” (92mm) height
Operating Temp: 40 - 140°(F)
Weight: 1.76 lbs
Warranty: 3 Years - Limited*
Max Charge Rate: 10A

• 18 month Shelf Life
• Up to 80% lighter than Lead Acid Equivalent
• 5X the Life of a Lead Acid Battery
• Quad Terminal Configuration for ease of installation
• 2000+ Cycles at 80% Depth of Discharge
• Can be mounted in any direction
• Lithium Batteries do not sulphate

Summary

All in, ths is about a 15 minute job if you have the materials you need to get it done. And you’ll be rewarded with a battery that should pretty much serve your needs for several years. Hopefully the cheap motorcycle will last as long as the battery!