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The Different Types of E-Bike Batteries

A Look at Lithium-Ion, Lithium-Iron-Phosphate and Solid-State E-Bike Batteries

Without the invention of lithium-ion batteries, e-bikes might not have taken off. Lithium-ion batteries offer a level of energy density and capacity per pound that older battery types, like nickel-metal-hydride (NiMH) or nickel-cadmium (NiCd). In addition to greater capacity and energy density, Li-ion batteries don’t develop a memory if not fully charged (as can happen with NiCd), or just suddenly shut off when low on power (as NiMH batteries do), but they aren’t perfect.

There are two newer battery technologies on the horizon and one of them is beginning to be featured in some e-bikes. One type is lithium-iron-phosphate (LiFePO4), which we will take a look at after we examine solid state batteries, because solid-state batteries share more in common with lithium-ion batteries.

The Electric Bike Report team is thrilled at what’s to come from new battery tech, but there’s some interesting things already happening now with different types of e-bike batteries. Let’s explore them all, shall we?

What is a solid-state battery?

Stromer ST7 prototype with ceramic solid state ebike battery

A solid-state battery is, in fact, a lithium-ion battery, but by another name. Why have a different name? Its construction and materials used are slightly different. Both batteries feature an electrolyte solution. Okay, but what are electrolytes?

Electrolytes are minerals (generally in the form of salts), that can carry an electrical charge. Electrolytes help move the electrical charge that causes a muscle to contract in people. Think Gatorade.

In a lithium-ion battery, that electrolyte solution is a liquid and it helps conduct ions in both the anode (the + or positive end of the battery) and the cathode (- or negative end of the battery). The anode and cathode are separated by a barrier between the two ends of the battery. The issue with this technology is that should that barrier between the anode and cathode be ruptured, a chemical reaction can begin that can result in thermal runaway, the process that results in lithium-ion batteries catching fire. Also, the main ingredient (by volume) in the liquid electrolyte is ethylene carbonate, which is flammable and produces toxic gasses when burned.

By contrast, a solid-state battery uses a solid electrolyte throughout the battery. This form of electrolyte is more stable and won’t swell due to temperature change or experience thermal runaway like a traditional lithium-ion battery.

Aside from the safety benefits that come a solid-state battery, there are additional selling points to this technology. The first, biggest is that a solid-state battery offers increased capacity because it doesn’t need a thick membrane separating the anode and cathode of the battery. So, more charge, same physical space.

How much more energy capacity can a solid-state battery offer over lithium-ion? It’s hard to say, unfortunately. That’s because of a wide range of battery capacities. The technical term for this capacity is called “specific energy,” and it is expressed as watt/hours per kilogram (Wh/Kg). On the low end, a lithium-ion battery may offer only 75Wh/Kg, though most range between 150 and 200Wh/Kg. At the high end, the current iPhone 14 contains a lithium-ion battery with a 250Wh/Kg energy density.

By comparison, solid-state batteries are being produced that offer 350-400Wh/Kg. Depending on the battery in question, that’s at least double the specific energy, but potentially as much as four times as much energy. .

What that means is that an e-bike with a battery that currently weighs 8 lbs. could conceivably see it replaced by a battery that weighs half as much, but offers twice the capacity.

The second big advantage is that solid-state batteries enjoy a longer life cycle, meaning they can be charged and discharged more times.

More is good, but that’s not terribly specific, so let’s quantify that some. The average lithium-ion battery can be charged around 2000 times. Some handle closer to 3000 cycles. By comparison, a solid-state battery may offer as many as 10,000 cycles before needing to be replaced.

Solid-state batteries will also benefit from far shorter charging times, with some batteries being able to reach 80 percent charge in 10 minutes and 100 percent in 15.

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Retrospec Chatham Rev+ ST Review

A comfortable, speedy, and affordable cruiser with classic yet contemporary design!

Don’t be fooled by the retro design of the Retrospec Chatham Rev+ ST; this cruiser-style e-bike might resemble an old-timer, but it packs some serious punch! We tested the bike’s real-world performance in addition to just admiring its great looks. Read all about it in this Retrospec Chatham Rev+ review!

The bike’s appearance is really its defining feature, and we think Retrospec nailed the design by balancing form and function. The Chatham Rev+ uses a curved and angled top tube to keep the frame from flexing, while the larger, more contemporary down tube seamlessly hosts its fully integrated battery. It’s an artful design that perfectly fuses new and old!

We were pleasantly surprised by the bike’s pricing; the Chatham Rev+ has an uncommonly high-quality ride feel backed up by unexpectedly good performance for an e-bike starting around $1,300. The bike feels well-made, but also thoroughly thought out, with a number of small but impactful details included – like the chain guard and tires – to elevate its ride quality.

The 26”x3” Compass fat tires add comfort to the ride by absorbing vibrations from the road, but they’re not the only comfort element we appreciated. The bike’s upright riding position is relaxed and enjoyable, and its wide, thickly padded seat is accommodating. These elements, along with the curved handlebars, are defining features of cruiser-style bikes – and why their riders love them so much!

To get the full scoop on the bike’s specs, components, and real-world performance, see our full Retrospec Chatham Rev+ review below.

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Saris Door County 2 Hitch Rack Review, 2024

This Motorized Bike Rack Takes Care of the Heavy Lifting When Transporting E-Bikes

Sairs Door County 2 E-Bike Hitch Rack

Saris’ Door County 2 is a hitch-mounted rack that uses an electric motor to simplify raising and lowering your electric bike when loading and unloading from the rack. The main benefit is it eliminates you having to manually lift and lower your e-bike, making transporting much easier for you. Most riders will appreciate this because electric bikes tend to be heavier than traditional bikes (and we certainly don’t want to do heavy lifting after a ride!).

We got to check out the Saris Door County 2 to see how well it lifts and transports e-bikes. It can transport two e-bikes, up to 60 lbs. per bike. We used several bikes for testing, including a commuter, cruiser and adventure bike. All of our bikes have 26” tires that are no wider than the rack’s 3” limit. Installing the rack was as easy as any other rack, just slide in the 2” hitch into your vehicle’s insert tube, and secure it with the locking pin.

*Editor’s Note: Updated 12/13/2023 with a fresh review of the Saris Door County 2

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