Category: News

Introduction: Batteries Everywhere, Risks Everywhere

Lithium ion batteries are in basically everything we use — phones, power tools, e-bikes, you name it. And yeah, they’re convenient. But if you’re careless, they can swell, overheat, or even catch fire. I’ve had a few batteries puff up after I left them charging too long… needless to say, it freaked me out. That’s why lithium ion battery safety isn’t just a buzzword — it’s something worth paying attention to.

Stuff You Might Not Think About

A lot of people think “just don’t overcharge” and call it a day, but there’s more:

• Thermal Runaway: Basically, when a battery gets too hot internally and goes haywire. I had a spare battery get unusually hot while sitting on my desk in the sun — it never went up in flames, but lesson learned.
• Physical Damage: Dropping a battery, poking it, or even squeezing it too hard can mess up its insides. I once dropped a pack in the garage and thought “meh, it’s fine,” but it had minor swelling — tossed it immediately.
• Charging Habits: Using random chargers or leaving batteries plugged in overnight is tempting. I’ve done it, and honestly, it adds up. Small mistakes can shorten battery life or worse.
• Environmental Factors: Heat, humidity, salty air — all of these accelerate battery aging. I live near the coast, and my batteries definitely suffer more than friends inland.

My Practical Safety Tips

Here’s what I actually do (and you can too):

1. Stick to decent chargers
   Don’t use random USB adapters you find in drawers. Even if they “fit,” it’s better to be safe.
2. Keep an eye while charging
   Overnight charging is convenient but I usually just charge when I’m around. A battery getting a bit too warm is a sign to unplug immediately.
3. Store them right
   Cool, dry, ventilated spots are best. Cars in summer? Not great. Learned that the hard way.
4. Check regularly
   Look for swelling, leaks, or weird smells. Any odd signs? Retire that battery.
5. Dispose properly
   Tossing them in regular trash is a bad idea. Find a recycling spot, or you’ll regret it when stuff leaks.

Handling Battery Mishaps

Even if you’re careful, accidents happen. Here’s my low-stress approach:

• Keep a metal box or fireproof container for old/damaged batteries.
• Never throw water on a burning battery — a fire extinguisher rated for electrical fires works better.
• Isolate the battery from flammable things if it starts heating up unexpectedly.

Wrap-Up

Lithium ion batteries aren’t evil, but careless handling can turn them into a hazard fast. Making safety a habit — checking batteries, using decent chargers, storing them smartly — saves money, time, and stress. Honestly, once I got into a routine, it became second nature, and I’ve avoided mishaps ever since.

If you’ve been flying FPV for a while, you’ll know it’s often not the motors holding you back—it’s the battery. The FPV drone battery isn’t just a power pack, it’s the heart of how your quad flies: punch, flight time, responsiveness. When I first started, I messed up plenty—either the pack didn’t fit, or it sagged so hard the drone just dropped. Only after burning through a few packs did I start to get it right.

Common Battery Types

The usual suspects are LiPo, LiHV, and sometimes Li-Ion. LiPo is the bread and butter, reliable and everywhere. LiHV can push a bit higher voltage per cell (up to 4.35V), which feels snappier, but the packs don’t usually last as long. Li-Ion is more about endurance—don’t expect crazy punch, but they’ll keep you in the air longer.

• For racing, I stick with mid-capacity, high C-rated LiPos.
• For long-range cruising, I carry Li-Ion packs.

The Voltage and “S” Debate

4S or 6S? It’s kind of like arguing over coffee with or without sugar—comes down to habit. 4S is cheaper, more universal, 6S gives harder punch but demands electronics that can keep up. My rookie mistake was buying a 6S pack while my ESC wasn’t rated for it… fried instantly. Lesson learned: check your setup first, then pick the battery—not the other way around.

Balancing Capacity and Weight

Big capacity means longer airtime, but also a heavier bird. And in freestyle, that heaviness kills flow. For me, 1300mAh is plenty. Bigger than that, tricks start feeling sluggish.

• Quick tip: don’t just look at the number, hold the pack in your hand. Imagine it strapped on your drone—you’ll instantly know if it’s too much.

C-Rating and Voltage Sag

The C-rating on the label? Take it with a grain of salt. Packs advertised at 150C often behave like 70C. The real test is when you punch throttle—the sag tells the truth. I’ve learned to rely on other pilots’ feedback or test packs myself instead of chasing numbers.

Care and Maintenance Tips

Take care of your packs, and they’ll take care of you. My habits now:

• Charging: always balance charge, avoid fast-charging unless necessary.
• Storage: around 3.8V per cell if you’re not flying soon.
• Temperature: let the pack cool before recharging, especially after summer flights.
• Retire early: swollen or leaking packs go straight to disposal—don’t risk a mid-air fire.

Conclusion

Finding the right FPV drone battery is a lot like finding a good pair of shoes. Specs are useful, but the real match comes from how you fly and test. Don’t get blinded by marketing numbers. Fly more, try different setups, and you’ll eventually land on the perfect combo that just feels right.

If you’ve ever tinkered with RVs, small boats, or solar setups, you’ve probably run into 12 volt LiFePO₄ batteries. Unlike the old-school lead-acid type, these lithium cells hold their voltage really well and last a lot longer. From personal experience, having a stable 12.8V output means fewer surprises—your lights don’t dim halfway through a trip, and small electronics keep running reliably.

Voltage and Charge Behavior in Practice

Here’s the thing about these batteries: their voltage hardly drops until they’re almost empty. In my setups, I usually see:

• Full charge: ~14.4–14.6V
• Floating: ~13.5V
• Nominal: ~12.8V
• Minimum: ~10V

You can push below 10V, but that tends to shorten battery life, so I try to avoid it. It’s better to size your battery a bit bigger than you think you need—trust me, it saves headaches later.

Capacity, Cycle Life, and BMS

These batteries come in many sizes, from small 50Ah units to 300Ah or more. What really stands out is the lifespan—most survive thousands of deep cycles. Another key feature is the Battery Management System (BMS). From my own testing, a good BMS is worth its weight: it stops overcharging, over-discharging, and protects against heat. I’ve seen cheaper systems fail in hot environments, so choose wisely.

Tips From the Field

• Charging: Use a compatible charger. I often go slow and steady—it’s easier on the cells.
• Temperature: Avoid charging when it’s freezing; the BMS may prevent it anyway, but a little warmth helps.
• Series & Parallel: If you wire multiple batteries, try to match capacity and age.
• Storage: If not using it for months, store at around 50–60% charge to keep it happy.

Where They Shine

From my experience, these batteries are versatile:

• RVs and campers: No sudden voltage drops, longer trips are easier.
• Boats: Great for small trolling motors.
• Off-grid systems: Cabins, sheds, tiny homes—you name it.
• Backup power: Perfect for emergencies or intermittent power.

Even though the initial price can be higher than lead-acid, the convenience and longevity usually make up for it.

Alt Text: Off-grid cabin powered by a 12 volt LiFePO₄ battery and solar panels

Conclusion

Switching to a 12 volt LiFePO₄ battery is often worth it. They’re reliable, stable, and surprisingly long-lasting. My advice: plan for a slightly bigger capacity, respect the BMS limits, and you’ll enjoy consistent power for years.

Getting to Know the 36V 18650 Pack

If you’ve ever messed with e-bikes or scooters, you’ve probably seen a 36V 18650 battery pack. Basically, it’s a bunch of cylindrical lithium cells (those AA-looking things but a bit thicker) wired together to hit around 36 volts.

Sounds simple, right? Ten cells in series (10S) give you the nominal 36V. Fully charged, you’re around 42V. Too low, and you might damage the cells — usually don’t go below 30V.

Here’s a pro tip from experience: one time I ran a 10S2P pack on a mid-drive motor, and it just couldn’t handle hills. Lesson: don’t skimp on the parallel count if you actually want decent range.

Common Setups and Capacities

• Small packs: 36V 7–8Ah — good for light scooters or small e-rides.
• Medium packs: 10–15Ah — typical commuter e-bike setups.
• Big packs: 20–30Ah+ — for heavy loads, long rides, or DIY energy storage.

Quick math: if each 18650 cell is 3000mAh and you do 10S3P, you get roughly 9Ah. Not exact, but close enough for planning.

Things You Should Watch Out For

BMS (Battery Management System)
No exceptions here. Without one, your cells get unbalanced fast, and the weakest one drags the rest down. Get one with overcharge, over-discharge, and short-circuit protection. Seriously, don’t skip this.

Heat
High current makes heat. A tightly packed 10S4P with no airflow can age fast. Give your pack a bit of breathing room. I learned this the hard way.

Space & Shape
Not every frame has room for a brick. Sometimes flat 10S2P layouts work better for slim scooters or compact projects.

Charging habits
You don’t always have to charge to 42V. Charging to 80–90% can extend lifespan a lot. I do this now, and my packs last longer than before.

Where They’re Used

• E-bikes & scooters — the classic use, 250–500W motors run fine on decent packs.
• Portable power — for camping, lights, or DIY power banks.
• Small tools — lightweight equipment, vacuum bots, or custom setups.

Pros and Cons

Pros:

• Good energy density, compact for what it offers.
• Flexible design: tweak for range, power, or balance.
• Mature tech — cells and BMS are easy to get.

Cons:

• Needs careful handling — bad things happen if mismanaged.
• Heat can sneak up fast.
• Heavy if you go over 20Ah.

Wrapping It Up

The 18650 battery pack 36V is pretty much a sweet spot for DIYers and e-mobility enthusiasts. Strong enough for most mid-range motors, but not a monster to handle. Build it smart: don’t cheap out on BMS, pick your cell count wisely, and plan the pack shape before welding — redoing it later is a pain.

What’s 18650 E-bike Battery Pack?

If you ride e-bikes, or are thinking about a DIY upgrade, you’ve probably run into the term 18650 ebike battery pack. So, what’s that exactly? An 18650 cell is basically a small cylinder, about 18mm wide and 65mm long, with a voltage around 3.6–3.7V and capacity usually between 2900mAh and 3600mAh.

Why are these cells so popular in e-bikes? They pack a lot of energy for their size, they’re pretty stable, and honestly, a little bump or scratch usually won’t ruin them. Still, don’t go throwing them around—treat them with respect and they’ll serve you well.

Battery Pack Design and How to Choose One

One 18650 cell alone won’t do much—you need a bunch connected in series and parallel to make a real pack. Some common setups you’ll see:

• 10s3p: 10 cells in series, 3 in parallel. Works for 36V systems.
• 13s4p: 13 in series, 4 in parallel. Usually for 48V systems.
• 13s5p: Higher power setups.

A few practical points when choosing a pack:

• Capacity: Want to ride farther? Bigger is better.
• Discharge Rate: Powerful motors need cells that can actually handle the load.
• Quality: You don’t need to know brands, but better cells generally last longer and are safer.

DIY Battery Packs: Quick Reality Check

If you like tinkering, making your own 18650 pack can be rewarding—you control the capacity, voltage, and discharge limits. But there are some catches:

• Pros: Total control, you can customize it exactly how you like.
• Cons: One slip-up and you could short the pack or mess up the balance between cells. That’s dangerous.

Honestly, if you’re not 100% confident with battery tech, a pre-built pack is way safer. DIY is fun, but safety has to come first.

Some Common Pack Configurations

• 36V 8Ah pack: Perfect for low-power motors, cheaper, comes with basic BMS protection.
• 48V 11.6Ah pack: Higher capacity, good for long rides or stronger motors, includes BMS protection.

A quick tip: bigger isn’t always better. More capacity means more weight and bulk, and that can make your bike feel clunky. Pick something that fits your riding style and needs.

Safety and Maintenance Tips

Even solid 18650 cells need some love:

• Check them regularly: Watch out for swelling, leaks, or weird smells.
• Avoid overcharging or overdischarging: Using the right charger really helps battery life.
• Storage matters: Keep the pack cool, dry, and away from heat.

A personal habit: after each ride, I check the voltage and give the connectors a quick wipe. It’s small, but it actually helps the pack last longer.

Wrap-Up

The 18650 ebike battery pack might seem straightforward, but there’s more to it than meets the eye. Choosing the right design, capacity, and keeping it well-maintained makes a big difference. DIY can be rewarding if you know what you’re doing, but pre-built packs are convenient, safe, and reliable. Pick a pack that balances power, weight, and range, and you’ll enjoy smooth, hassle-free rides.

Introduction

I’ve been riding e-bikes for a few years now. I started with a 36V system, tried other voltages later, and eventually came back to realize: 36V ebike battery can actually be pretty handy in certain situations. It has its pros, but also some limits. Below I’ve combined what I gathered from several articles with my own riding experience. Hopefully this helps if you’re choosing or using a 36V battery.

What is 36V Ebike Battery? Voltage, Capacity, and Energy Basics

A typical 36V battery, when fully charged, usually measures about 42V with a multimeter, and it cuts off around 30V when the BMS steps in.

The formula is simple:
36V × Ah (amp hours) = Wh (watt hours).

Wh is basically the number that tells you how far you can realistically ride. For example, a 36V 10Ah battery equals roughly 360Wh.

In practice, 36V batteries are often used for daily commuting or leisure riding. They’re not built for extreme speed or crazy torque, but on flat roads and mild hills, they get the job done. Higher voltage packs can give you stronger acceleration and climbing power, but not everyone needs that.

Pros and Cons + My Hands-On Impressions

Pros

1. Affordable & widely compatible
   36V systems are super common, with plenty of controllers and motors designed around them. This makes it easier to match components and you don’t have to worry much about overvoltage frying the controller.
2. Lower heat & safer stress levels
   Since it’s not a high-voltage system, heat build-up is usually less of an issue during city rides with stop-and-go traffic. I’ve noticed this in hot weather commuting — my 36V setup didn’t make the controller burning hot to the touch like some higher voltage builds.
3. Good balance between weight & size
   For the same Wh capacity, 36V batteries tend to be reasonably compact and not too heavy. This matters a lot if you need to carry your bike upstairs, like I do.

Cons / Things to Watch Out For

1. Limited climbing and acceleration
   On steep hills or when carrying extra load, a 36V battery feels a bit sluggish. One time I went full throttle on a steep incline and the bike just crawled instead of surging forward.
2. Range varies a lot depending on assist level
   If you’re constantly riding on max assist or full throttle, your Wh will vanish quickly. The “theoretical range” on paper rarely matches the real ride.
3. BMS cut-off quirks
   If the BMS lets the voltage drop too low, it can damage the cells. But if it’s too conservative, it might shut you down early. I’ve had a ride where the display still showed a bit of battery left, but the BMS just cut power — not fun.
4. Charger compatibility matters
   The wrong charger or poor charging environment can reduce efficiency and shorten battery life. Fast charging also means more heat, so let the pack cool down before and after.

Range Estimates & Real-World Example

Here’s a quick table for typical capacities, along with my own riding results.

Battery Type	Voltage (V)	Capacity (Ah)	Energy (Wh)	Estimated Range (flat road, light assist, ~70–80kg rider)
36V 8Ah	36V	8Ah	~288Wh	~25–35 km
36V 10Ah	36V	10Ah	~360Wh	~35–50 km
36V 12Ah	36V	12Ah	~432Wh	~45–60 km
36V 15Ah	36V	15Ah	~540Wh	~55–75 km

My ride example:
With a 36V 10Ah battery, riding in the city with light slopes and medium assist (not full throttle), I usually got around 40 km per charge. But on a day where I carried a passenger, rode multiple hills, and stayed on high assist, it dropped to about 28 km — a big difference.

36V vs 48V Ebike Battery Comparison

Feature	36V Ebike Battery	48V Ebike Battery
Typical Voltage (full charge)	~42V	~54.6V
Common Capacity Options	8Ah – 15Ah	10Ah – 20Ah
Power Output	Moderate (good for commuting, flat terrain)	Higher torque & speed (better for hills & heavy loads)
Range	25–40 miles (depending on capacity and riding style)	35–60 miles (with larger capacity)
Top Speed Potential	Usually capped around 20 mph (32 km/h)	Can reach 25–30 mph (40–48 km/h) depending on motor
Weight	Lighter, easier to handle	Heavier, adds bike weight
Cost	More affordable	Higher price point
Best For	Daily city commuting, light riders, budget setups	Riders who want speed, power, longer trips, or hilly terrain

Buying & Maintenance Tips

Some lessons I’ve learned, plus advice often hidden in articles:

1. Match your controller and motor
   Check the controller’s voltage range and the motor’s safe limits. Don’t risk overheating or damaging them.
2. Go a bit higher than your daily need
   If your commute is 40 km, a 10Ah might be borderline. A little extra capacity goes a long way.
3. Wiring & connectors matter
   Loose, cheap, or non-waterproof connectors are weak points. Pay attention here, especially with budget batteries.
4. Charging habits
   • Don’t always drain it near empty. Even if your display shows a little left, better recharge earlier.
   • Let the pack “rest” after a ride before plugging in, especially if it’s warm.
   • For storage, keep it around 30–60% charge and avoid high heat.
5. Check voltages occasionally
   A multimeter can show if total voltage or cell balance is healthy. Look out for swelling, heat, or unstable output.

Conclusion

If your rides are mostly commuting, urban, or light terrain with average loads, a 36V ebike battery is a solid and reliable choice. It’s affordable, widely supported, and easy to maintain.

But if you regularly climb steep hills, carry heavy loads, or crave high speed and strong acceleration, you might want to look at higher voltage systems — or at least beef up your 36V setup with higher capacity cells and robust components.

Introduction

I’ve been riding e-bikes for years, starting with 36V systems, then 48V, and now seeing more setups supporting 52V batteries. A 52V ebike battery is tempting: slightly higher voltage means potentially more speed, better hill climbing, and longer range. But “higher voltage” also comes with risks and compatibility concerns. I’ve summarized key points from top articles and added my own practical experience, so you can see if 52V is worth upgrading to.

What Is 52V Ebike Battery?

Voltage directly affects motor output, hill-climbing power, acceleration, and efficiency under load, wind resistance, or slopes.

• A 52V battery can output higher voltage than 48V (~58–59V when fully charged).
• Higher voltage at the same current gives more power (P = V × I), so hills feel easier.
• Be careful: your controller and motor must support the higher voltage, otherwise overheating or damage may occur.

Articles often compare 24V / 36V / 48V / 52V, showing that 52V has an advantage in speed and load handling.

Advantages and Potential Drawbacks (Experience + Sources)

Advantages

1. Better Hill Climbing & Acceleration
   Installing a 52V battery on a system previously running 48V shows noticeably faster throttle response and smoother uphill rides.
2. Possible Range Increase
   If you ride gently (moderate assist, steady speed, minimal hills), 52V batteries can slightly extend range compared to old 48V batteries.
3. System Efficiency
   Some controllers work more efficiently at higher voltage—less current needed for the same power, reducing heat in wires during long rides or climbs.

Drawbacks / Cautions

1. Compatibility
   • Ensure your controller and motor can handle the full charge voltage (~58–60V).
   • Check battery dimensions and mounting space—52V packs can be bigger and heavier.

1. Heat & Battery Life
   High voltage + high current (climbs, full throttle, heavy load) increases heat. Poor heat dissipation can shorten battery life.
2. BMS Protection
   A good 52V battery should have reliable overvoltage, overcurrent, and temperature protection. Some faults occur when BMS enters protective “sleep mode.”
3. Charger & Charging Time
   Use the correct voltage/current charger. Incompatible chargers may undercharge or trigger protection early.

52V Battery Capacity Comparison

Battery Type	Nominal Voltage (V)	Capacity (Ah)	Energy (Wh)	Approx. Dimensions (mm)	Weight (kg)	Typical Use
52V 10Ah	52V	10Ah	~520Wh	365×90×110	~3.5	Light commuting, short urban trips
52V 15Ah	52V	15Ah	~780Wh	390×110×110	~4.5	Commute + suburban rides, 40–60km range
52V 20Ah	52V	20Ah	~1040Wh	420×120×120	~5.5	Long-distance, cargo delivery, hills
52V 25Ah	52V	25Ah	~1300Wh	450×130×130	~6.5	High range, mountainous/long climbs
52V 30Ah	52V	30Ah	~1560Wh	480×140×140	~7.5	Heavy-duty riding, long trips

Selection Tips:

• 10Ah/15Ah: Light, city-focused, limited range.
• 20Ah: Balanced; I’ve personally ridden 50–70 km in mixed terrain without issues.
• 25Ah/30Ah: Heavy, needs careful mounting; good for long trips or heavy loads.

Upgrade / Selection Advice + Practical Tips

1. Check controller & motor support
   Ensure your system can handle 52V full-charge voltage (~58–60V).
2. Choose the right capacity
   Higher Ah = longer range. Avoid batteries with insufficient capacity, or you’ll charge constantly.
3. Secure wiring & connections
   Loose connectors can cause sudden power cuts on climbs. Use thick wires, sealed connectors.
4. Charging habits
   • Avoid fully discharging before charging.
   • Do not charge/store in extreme hot/cold conditions.
   • Store at ~30–60% charge if not riding for long periods.
5. Monitor battery health
   Occasionally check voltage per cell or balance, watch for swelling or abnormal heat.

My Minor Issues / Lessons Learned

• Full-power riding on a new 52V battery consumed more than expected; range gain wasn’t dramatic at first.
• Using a 52V battery with an older 48V controller caused overheating; throttle power dropped to protect components. Adding airflow helps.
• Long idle storage led to minor self-discharge; battery showed full but effective mileage decreased.

Summary

52V ebike batteries are great if you want extra hill power, faster throttle response, or occasional long rides/heavy loads. But for flat-city commuting or limited budget, stick with existing voltage unless your system supports it safely.

Recommended approach:

1. Confirm system voltage tolerance.
2. Use batteries with appropriate capacity & BMS protection.
3. Start gently—don’t immediately ride at full throttle.
4. Regularly check voltage, cell balance, and heat.

Riding electric bike with custom ebike battery at 36 volts is common, especially for commuters, city riders, and those who want a balance between cost, weight, and performance. From what I’ve read and from builds I’ve helped with, here’s a deeper dive into what 36V means, what to expect, and how to do it better (warts and all).

1. What “36V” really means

“36V” is the nominal voltage of the pack — in practice, fully charged it might be around 42V, and when discharged it should drop to something like 30V before the battery management system (BMS) cuts off to avoid damage.

That means, although you see “36V”, the usable range of voltage is wider. Controllers need to be compatible with this range, or you’ll get voltage sag, poor performance, or even risk damage.

2. How capacity & voltage combine to affect range

One formula that keeps showing up is:

Wh = Volts × Amp-Hours (Ah)

So 36V × 13Ah battery has ~468 Wh.

What that translates into, for real riding, depends heavily on a lot of variables:

• Rider weight
• Terrain (hills vs flat)
• How much you pedal vs relying on throttle or assist
• Speed, wind resistance, tire pressure

From experiences people share: a 36V pack with around 10-14 Ah often gives 30-60 km (≈ 20-40 miles) in mixed riding conditions.

If you bump up capacity (say 15-20 Ah), the range goes up, but so does weight, cost, and size. At some point you’re carrying more battery than you need. My own test ride with 11Ah on a 36V saw promising numbers until I hit hills or harsh wind — then performance dropped more than I expected.

3. Advantages & trade-offs of 36V vs higher voltages

Using a 36V battery (versus, say, 48V) has pros and cons. Here’s what I gathered + what I found from building or helping others build:

Advantage	Trade-off / What to watch out for
Lower cost: 36V components are usually cheaper, wires/controllers don’t need as much overhead.	Less top-end speed / torque, especially under heavy load or steep hills. You’ll notice difference vs a higher voltage pack.
Less stress on parts: less heat in wires/connectors at given power if voltage is lower. Better durability in long use.	Voltage sag: as battery depletes, voltage drops, performance drops. Also, for higher power draws you need more current, which can mean thicker wires or more losses.
Sufficient for many commuting / casual riding needs: with mid-capacity (10-15Ah) 36V is often “good enough.”	Weight vs range tradeoff: to get long range at 36V you need higher Ah, which adds size / bulk. For many people that means custom ebike battery design must consider space and weight.
Simpler charger / system-compatibility: many kits/controllers are designed around 36V.	Less “future-proof” margin: if you want steeper hills, heavier loads, or more speed later, 36V may limit you. Upgrading voltage means replacing more than just battery sometimes.

4. How to choose or build a good 36V custom ebike battery

Since custom ebike battery is the core, here are concrete steps + my own lessons:

a) Decide your target usage

• How far you ride daily (commute, errands, weekend ride)
• Terrain: flat vs hills, stop & go vs steady speed
• Weight you carry (bike + rider + load)
• Weather: heat, cold — batteries suffer both ends

Knowing these helps pick Ah, battery shape, cooling, mounting, etc.

b) Capacity & cell selection

• Choose Ah that matches your range goal, but don’t overshoot too much (you’ll carry extra weight)
• Cell chemistry matters: some offer energy density, others offer better stability / longer life. My builds with higher energy-density cells gave more miles but heated up more; had to add cooling or good ventilation.
• BMS: must support the current your motor draws and offer safety features (over-discharge, overcharge, cell balancing). Better to over-rate BMS rather than under. I once used a BMS that was just barely rated; under hard load it got hot and dropped output. Changing to a beefier BMS made it more stable.

c) Construction & packaging

• Layout: series (to reach voltage) × parallel (to get current + capacity) cell arrangement must match space. If your frame has limited space, shape the pack to fit (slim, flat, external rack etc.).
• Wiring & connections: use thick wires, good connectors; minimize resistance and potential weak spots. Spot welding or well-done nickel strip connections is preferred. Keep things clean, well insulated.
• Enclosure: good casing that protects from water, vibration, and has some airflow or heat paths. Even if not perfect, sealing critical joints helps. My first custom battery pack got damp inside — performance dropped until I fixed the seal.

d) Charging, care & safety

• Use correct charger that matches voltage and chemistry. Don’t overcharge. For a “36V” pack, charger should match its full charge voltage.
• Storage: if not using for a while, store at partial charge (around 40-60%), in a cool, dry place.
• Regular checks: look for swelling, loose wires, heat spots. Clean contacts. Keep battery case clean.
• Real-world testing: don’t trust only spec-sheet. Do a full charge/discharge test in conditions similar to your usual riding. Measure real range & temperature behavior.

5. What to expect in real rides (my experiments + others)

• On flat or gently rolling terrain, using pedal assist, a 36V 10–12Ah pack often gives 25-45 km with good setup. If you go full throttle or steep hills, that drops a lot.
• If battery is under-spec’d in Ah relative to motor draw, you’ll see voltage sag: slower take-offs, less power on hills.
• Temperature affects a lot: hot weather reduces life or increases sag; cold weather also cuts capacity. On a cooler morning, I lost ~10-15% range compared to midday rides.
• Charging habits matter: letting battery run down completely often, or always charging to 100% every time, can degrade life sooner. Using middle range (say 20-80%) can help longevity.

Conclusion

A 36V custom ebike battery is a solid choice for many riders: commuters, casual users, city dwellers. It offers a good balance of cost, weight, ease of maintenance, and performance—provided you choose your capacity, components, and build style carefully. If you plan for your real usage (terrain, load, assist level), and give attention to safety and enclosure, you’ll likely get a battery that rides well and lasts long.

When it comes to riding an electric bike, the battery is often the one thing that makes or breaks the experience. Store-bought packs are convenient, but they don’t always match your frame, your range needs, or even your style of riding. That’s where custom ebike battery comes in.

Over time, I’ve read a bunch of guides and also built a few packs myself, so here’s a mix of structured info and personal trial-and-error stories.

1. Why bother with custom ebike battery

The main reasons are pretty clear:

• Fit – you can shape the pack to slide neatly inside your frame or rack space, instead of forcing a bulky brick into an awkward spot.
• Flexibility – choose your own voltage and capacity depending on whether you want speed, long range, or just a balance of both.
• Quality control – you pick the cells, BMS, and wiring. Done right, it can outlast cheap factory packs.

The flip side? It can cost more than an entry-level ready-made battery, and you take on the risk of safety, wiring, and repairs.

2. Key parts of a custom ebike battery

Here’s what really matters when you start building or planning:

Part	Why it matters	A quick tip from experience
Cells (18650, 21700, LiFePO4, etc.)	Energy density, discharge rate, safety, and lifespan differ a lot.	I once used cheap cells with low discharge ability—looked fine on paper but sagged badly on climbs. Upgrading to stronger cells fixed it.
Voltage	Controls how fast your motor can run, and must match your controller.	Too high can fry electronics, too low wastes potential. Stick to your motor’s rated range.
Capacity (Ah)	Bigger = longer range, but heavier.	Always add a little margin. Real-world range is usually less than specs.
BMS (Battery Management System)	Protects from over-charge, deep discharge, heat, short circuit.	Don’t cheap out. I used an undersized BMS once—it overheated under heavy load.
Casing	Protection from bumps, water, and heat.	My first build leaked water during rain. Fixed it later with sealing strips.
Wiring / Connections	Must handle current safely.	Thin wires get hot, cause voltage drop. Always overspec a little.

3. Steps to build custom ebike battery

1. Define your needs – Write down your commute distance, hills, and load. Decide on target voltage and range.
   Example: I planned for a 30 km ride with hills, so I went 48V and aimed for ~25–30 km real range.
2. Design the pack (series × parallel) – Voltage = series count, capacity = parallel count. Make sure each cell’s current rating isn’t exceeded.
3. Choose BMS & safety parts – Match voltage, allow extra headroom in current rating. A temp sensor helps a lot.
4. Assembly – Spot welding nickel strips is more reliable than soldering. If soldering, keep heat low to protect cells.
5. Enclosure & thermal management – Think shock resistance, waterproofing, and ventilation. A mix of plastic + aluminum can balance weight and cooling.
6. Testing – Don’t just slap it on the bike. First do controlled charge/discharge cycles, then small road tests. Adjust if it overheats or range feels off.

4. Safety and common mistakes

• Fake or poor-quality cells – Specs look amazing, but they sag fast or die early. Source carefully.
• Poor heat management – A sealed box with no airflow = hot pack and short lifespan.
• Underrated BMS – Looks fine until you sprint uphill and suddenly it cuts out.
• Voltage mismatch – Wrong pack voltage fries controllers or just runs inefficiently.
• Ignoring waterproofing and vibration – Real roads aren’t clean labs. Water and bumps kill bad welds fast.

Final thoughts

A custom ebike battery can give you the freedom to ride farther, climb stronger, and fit your bike perfectly—but only if you take the time to plan and build carefully. Done right, it’s worth every hour you put in. Done sloppy, it’s a safety hazard.

So: measure twice, weld once, and always test before trusting your build on a long ride.

Why 21700 Packs Are Getting So Much Attention

If you’ve been around anything that runs on lithium batteries—whether it’s drones, e-bikes, power tools, or even flashlights—you’ve probably noticed the buzz around 21700 battery packs. The name comes from the size: 21 mm in diameter and 70 mm in length. They’re slightly bigger than the classic 18650 cells, but that extra space means a nice jump in capacity and discharge performance.

From my own experience, the biggest difference is that devices simply last longer without adding bulky weight. You don’t really notice the size increase, but you definitely feel the performance upgrade.

Understanding the 21700 Lithium-ion Cell

At its core, a single 21700 cell usually holds 4000–5000 mAh with a nominal voltage of 3.6–3.7 V. Fully charged, it hits 4.2 V, and cutoff usually happens around 3.0 V.

• Energy density: around 250–300 Wh/kg
• Cycle life: often 300+ full charge cycles before noticeable drop
• Applications: anything from electric vehicles to compact electronics

In practice, I’ve seen these cells hold up better under high current draw compared to 18650. Less heat, less sag, and more usable runtime.

Designing 21700 Battery Pack

A single cell is great, but where it really gets interesting is when you start building packs. Typical setups combine cells in series (S) and parallel (P) to reach the voltage and capacity you want.

For example:

• A 4S1P design gives you about 14.4 V / 6 Ah—perfect for replacing older 18650-based packs.
• A 4S4P setup jumps to 14.8 V / 20 Ah (296 Wh). This is compact but still provides a lot of punch for RC gear or field equipment.

Most packs these days also include a battery management system (BMS)—that’s the little brain inside keeping everything safe from overcharge, over-discharge, or overheating. Honestly, I wouldn’t touch a pack without one.

The 14.8 V 20Ah 21700 Pack in Real Use

This one deserves its own spotlight. I tested a 4S4P 14.8 V 20Ah pack for FPV and it was a game changer.

• It can push up to 60 A continuously, with 100 A peak bursts.
• Handles cold mornings down to −20 °C without complaint, but also runs stable in hot weather.
• Despite being nearly 300 Wh, the weight stays reasonable enough to strap onto a drone or carry for field work.

In real use, you’ll notice fewer voltage dips under heavy throttle and longer flight times. Sure, it’s pricier than a traditional 18650 setup, but the efficiency gain makes it worth it.

Picking the Right 21700 Battery Option

Not all 21700 cells are built the same. Some are optimized for high capacity (great for long runtime), while others are tuned for high discharge rates (better for power-hungry tools or drones).

There’s a fun discussion I came across where hobbyists compared popular options. The consensus?

• High capacity models are nice if you’re after runtime.
• High performance models (like those tested for max output) cost more, but you’ll feel the difference if you’re pushing limits.

Bottom line: don’t just buy the cheapest 21700 you see. Match the cell to your actual use case.

Key Specs at a Glance

Here’s a simplified table to keep things straight:

Parameter	Typical Range for 21700 Cells	Notes from Real Use
Size	21 mm × 70 mm	Slightly bigger than 18650
Nominal Voltage	3.6–3.7 V	Standard lithium-ion chemistry
Full Charge Voltage	4.2 V	Always use proper chargers
Capacity	4000–5000 mAh	Some hit above 5000 mAh
Energy Density	250–300 Wh/kg	Better than most 18650s
Max Discharge Current	30–60 A (cell dependent)	Packs can peak much higher
Cycle Life	300–800+ cycles	With decent care
Common Pack Configs	4S1P, 4S4P	Popular in 14.8 V designs

Final Thoughts

The 21700 battery pack isn’t just another fad—it’s quickly becoming the standard in high-demand applications. Whether you’re building your own 16S2P pack for a custom project, flying FPV, or just want your flashlight to outlast a night hike, these cells deliver a noticeable upgrade.

If you’re stepping into DIY battery building, my tip is: spend time on the BMS and connections. The cells themselves are powerful, but it’s the pack design that determines safety and performance.