How to Install Dual Batteries on an Ebike
If you have an ebike and have been wanting more range or speed, you might be wondering how to install dual batteries on your ebike. There are a couple of ways this can be done and some are more viable than others.
When connecting dual ebikes in series, you have to connect the positive of the first battery to the negative of the second battery. After that, connect the remaining free positive and negative connections to the ebike speed controller. All ebike batteries should have a BMS, and problems can arise when running 2 ebike batteries in series. This is because the MOSFETs in the BMS are not going to be rated for the full battery voltage of both packs. Under normal operation, this is not a problem as the voltage across the MOSFETs on both battery packs is close to zero. When one battery dies, however, its MOSFETs will switch into a high resistance state. When this happens, those MOSFETs will experience the voltage of the still working battery and the voltage of the dead cells in the dead battery. In most cases, this will overvolt the MOSFETs in the BMS of the dead battery.
When connecting dual ebike batteries in parallel, you have to connect the positive from the first battery to the positive of the second battery. After that, you can connect the speed controller to either battery. It’s important for the batteries to be at the same voltage before connecting them. If they are not, then a large amount of current will flow from the higher voltage battery to the lower voltage battery. Even if the batteries are at the same voltage when you connect them and everything seems to work fine, its not good to put two batteries of different capacities in parallel. This causes the batteries to be in an imbalanced state of discharge and makes it so the larger battery is always charging the smaller battery at an unpredictable rate. This puts extra strain on everything and reduces the life of the batteries. People usually don’t notice because there is still a net gain in capacity from adding the second battery, but it’s really reducing the overall life of the system.
In this article, we will go over how to install dual batteries on an ebike. We will also explain the pros and cons for each setup, and when to not do each one.
Installing Dual Batteries In Series
So, a lot of people are wanting to know if it’s possible to wire 2 36V ebike batteries in series to make a 72V battery. Wiring up two batteries to make a 72V setup is technically possible, but it is not recommended. The main concern is the Battery Management System (BMS) and what voltage its components are rated for. A BMS controls access to the battery via n-Channel MOSFETs, which are rated for a particular voltage that is some amount higher than the voltage they are used for. For example, the MOSFETs in a 36V BMS are generally rated for 45 volts.
The problem arises when one of the batteries in the series fails, causing the MOSFETs in the dead battery to be exposed to a voltage that exceeds their rating. This can lead to damage to the BMS in the dead battery and, in rare cases, even a fire. To avoid these issues, it’s important to take great care to ensure that neither battery dies.
Using a BMS is necessary as it provides a safety measure for lithium batteries, so bypassing one or both BMS to get around this problem is not a viable solution. However, if you take the necessary precautions and ensure that neither battery dies, it is possible to wire up two batteries to make a 72V setup.
It is possible to tie discharge gate control pins on each BMS together with a wire, but this is an advanced procedure that requires modifying both BMS. Another thing to consider is the voltage differential between two gate pins associated with 2 BMSs in series. There will more than likely be a dangerous difference between the two, so in addition to all the other work, isolation circuitry would have to be employed.
Consider The Rest Of The System
Watts equals volts times amps. If you have an ebike controller that is limited to 30 amps and you have a 48V battery, then how many watts is that?
36 Volts x 30 Amps = 1080 Watts
So, what happens if you double your system voltage by putting two 36V batteries in series?
72 Volts x 30 Amps = 2160 Watts
So, if the controller supports it, then you will get twice the power out of the controller. But only if you want twice the power. The thing about running a higher voltage on an ebike is that you can choose how much of that power to use. So, if you combine two batteries and adjust your power level to half of what it was before, you will have the same 1080 Watt limit at a higher running voltage.
But remember, Watts is Volts times Amps, which means that Amps is Watts divided by Volts. So let’s do the math to find out how many amps would be required to run a 72V load at 1080 Watts.
1080 Watts ÷ 72 Volts = 15 Amps
This means that you can get all the power you were used to while putting your batteries under half the stress as was required before. This will result in a much longer overall battery lifespan and will provide an excellent buffer against voltage sag.
Installing Dual Batteries In Parallel
It is possible to wire two ebike batteries in parallel to increase capacity and it is much safer and much more tolerant to error than wiring them in series, as it eliminates the risk of overvoltage damage to the BMS.
When wiring two ebike batteries in parallel, it is important to ensure that the batteries are of the same type, and capacity and that they are rated for the same voltage. This is because if one battery is larger than the other, it will more than likely have lower internal resistance and will provide more than its fair share of the load current.
This will lead to an imbalance in the system that will be quickly and unpredictably corrected by a rush of current from the larger battery to the smaller one on every discharge. This can damage both batteries and if the wiring between the two can’t support the higher currents, it could start a fire.
When doing this, you have to make sure that the positive and negative terminals of each battery must be connected to the same terminals on the other battery. Before connecting the two packs together both packs need to be at the same voltage, within.1v of each ideally. If this is not done correctly, it will cause a short circuit, which can cause burns and/or ruin one or both batteries.
Consider The Rest Of The System
When adding two batteries in parallel, whether they are properly matched or not, the rest of the system doesn’t know any different. It will see the same running voltage and power will be applied as normal. It is worth mentioning, however, that because there is another battery there to share the load, each battery will bear less of the load than it otherwise would have had it been the only battery in operation.
This helps to extend the life of the batteries and works against the face that if the batteries are mismatched, overall life is reduced. This situation ends up creating somewhat of a balance that produces an overall net-positive effect when adding batteries in parallel, even if they are mismatched. This is why many people swear by this method and say that it works perfectly.
Simple Way To Install Dual Batteries On An Ebike
The best way to use multiple batteries on an ebike is to put them in parallel. This is only truly viable if you have two matched batteries, though. If the batteries are not matched, the best thing you can do is use a switch to toggle between them. The problem is that switches that can handle that amount of current are often expensive and bulky. So, the simple solution is a manual one.
When your first battery dies, simply unplug it and plug the other battery in. All you have to do to make this possible is to run the wiring in the right places on your bike and put the connections in the most ideal spots for you to switch them.
Swapping over a cable into another port is a quick, painless procedure and it is the easiest, most effective, and safest way to install dual batteries on your ebike. The only downside is the fact that it is not automatic and requires the bike to stop for a moment. This is a more than worthy tradeoff, considering its low cost and simplicity.
There are also battery discharge combiner modules, but it is important to keep in mind that they often have relatively low current limits. For example, the first listing for the linked battery combiner specifically says to not use it with a non-geared motor. This is because without gears, starting from 0 uses quite a bit of power. Whereas the second one does not have that noted since it can handle higher amperage.
[[ aff type=aff ~ link=https://amzn.to/3FsO8kx ~ title=`Dual Battery Pack Balancer` ~ image=https://admin.cellsaviors.com/storage/dual-battery-balancer.jpg ~ description=`Perfect for applications using 40A or less this will easily allow you to parallel two batteries. ` ~ height=small ~ buttonText=`Check Price` ]]
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Consider The Rest Of The System
This is the least invasive way to add dual batteries to an ebike in terms of system characteristics. This is because the batteries are not connected at the same time, so all the precocious and disclaimers above go out the window. In fact, because the batteries are totally isolated and never used together, you can even confidently mismatch different voltages, capacities, and even cell chemistries.
You could have an LFP pack for short runs as they have an extended cycle life and you could have an NMC pack for long range as they have the highest energy density. You could have a large, 48V pack for long runs and you could have a small, 72V back for short races on a track or other closed circuit. The possibilities are endless because the batteries are never connected at the same time. As long as your controller supports the voltage of whatever battery you plan on connecting to it, it will be fine.
Installing dual batteries on your ebike can be a great way to increase its range and speed. However, the method of connecting the batteries is crucial to ensure safe and reliable operation. Connecting the batteries in series involves connecting the positive of the first battery to the negative of the second battery, and then connecting the remaining connections to the speed controller. However, problems can arise if the batteries are not matched and one battery dies, which can overvolt the BMS in the dead battery.
On the other hand, connecting the batteries in parallel involves connecting the positive of the first battery to the positive of the second battery, and then connecting the speed controller to either battery. It’s important for the batteries to be at the same voltage before connecting them, and to avoid putting two batteries of different capacities in parallel as it can cause an imbalanced state of discharge and reduce the life of the system.
We hope this article contained everything you wanted to know about how to install dual batteries on your ebike, thanks for reading!
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There is a common misconception that silicone wire can handle higher current than PVC wire, this is not true. Silicone wire is better than PVC wire in other ways. In this article, we will break down the benefits of silicone wire and go over the misconceptions between the two wire jacket types.
Common Port and Seprate Port BMSs have a few differences one of those being the main connections into and out of the BMS. We will break down the purpose of the P and C connections that you commonly find on a separate port BMS.
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In almost all cases building your own battery pack is a great way to save some money. On top of that you will be learning new skills and some of these skills are becoming more and more in demand. As we to move towards battery-based solutions to a power storage needs, today is the day to learn how to build!
Himiway Launches 3 New Models Including Their First Ever Dual Battery Ebike
Until now, Himiway has focused solely on fat tire ebikes, a category that has served them well. In their latest ebike drop in late 2021, four new fat tire ebikes were released. Now the company is switching things up. Two of these new ebikes will appeal to those who love the Himiway ebikes but want something a bit more nimble and lightweight.
But don’t worry fat tire fanatics, Himiway released their longest-range ebike yet, and yes, it’s a fat tire bike. For 2023, we have three new additions, the Himiway Pony, Rambler and finally, the Rhino. Let’s dig into the lineup and be sure to keep an eye out for our Himiway reviews of these models on YouTube.
Himiway Pony: Lightweight and Affordable
The Himiway Pony diverges from anything Himiway is known for. In fact, it’s not even an ebike because it lacks pedals altogether. It’s affordable, at just 499 for the 5Ah model and 599 for the 10Ah variation. Unsurprisingly, the Pony uses a 36-volt system compared to the 48-volt systems most often found on ebikes. Himiway is touting a range of up 20 miles on the larger battery though I imagine most riders will get around half that.
The Pony is one of those last mile, or last-few-mile mobility solutions. It’s got a 300-watt motor with Kenda 20 x 2.4″ tires. The short wheelbase and small frame mean this ebike is easy to transport.
Hauling it up a set of stairs or bringing it inside shouldn’t be too much of a hassle since it only weighs 33 lbs (35 lbs for the larger battery version). It’s just 50.4″ long, with the handlebars reaching 41.7″ high, though they are telescoping both for adjustability and portability. The Himiway Cruiser above gives scale to just how tiny the Pony is.
The motor is engaged with a right hand twist grip throttle and it will get you going up to 16 mph. Stopping power is provided by the single rear mechanical disc brake. Offered in 5 different colors, the Pony starts shipping in April 2023.
Our review of the Himiway Pony
So who’s this for? Some may laugh at this ebike, but trust me there is a market. It reminds me of the Jetson Bolt ebike, which is also compact, though with a pretty different design due to the small wheels. I’ve seen a surprising amount of Jetson ebikes during my travels. People commuting or simply those just looking for a super affordable ebike that is capable of short trips.
Himiway Rambler: Commuter/City Ebike
New to the Himiway lineup is the Rambler, a fully outfitted commuter or city ebike. This is the model that I imagine most people were waiting for. Fat tire ebikes can be heavy, and not everyone feels comfortable riding them. The Rambler is also more nimble with its 27.5 x 2.4″ tires, and even better, it’s a step-thru frame design for increased accessibility.
What’s interesting is the Rambler starts at 1,299 with a hub motor and mechanical disc brakes. Want hydraulic disc brakes? Just 200 more. And for those that want a mid-drive ebike, the price is 2,199. So Himiway is letting customers choose between three different options without having to go with a different model/frame.
Both motors are rated at 500 watts and come with slightly above-average 15Ah batteries. On the mid-drive Rambler is a Bafang M600 motor with 120 Nm of torque. It’s paired with Bafang’s color LCD screen in the cockpit.
Himiway has also spec’d the bike with a large 500-lumen integrated headlight. Fenders, a rear rack, and integrated brake light are also included. The Rambler will be offered in “Himi Grey”, pearl white and mint green.
Our review of the Himiway Rambler
We always like to see affordable ebikes that still offer good components for the price and that’s what the Rambler offers in its base-level configuration. While there are a few companies offering city-style ebikes in the 1,300 range, it’s nice to have choices. For those that want hydraulic brakes, 200 seems like a reasonable price to pay, but even more, there are few choices for mid-drive ebikes at the low 2000 mark. Plus, the M600 is a tried and true motor from Bafang, and that 120 Nm of torque should power riders up any hill.
Himiway Rhino: Prioritizing Dual Batteries
Himiway couldn’t release ebikes without a fat tire model. Enter the Himiway Rhino and Rhino Pro. The Rhino is offered in two variations, both with dual batteries. The 1000-watt hub motor (90 Nm torque) Rhino model is priced at 2,999, and the 1000-watt (160 Nm torque) mid-drive “Rhino Pro” is priced at 3,999. Both models have throttles and are capable of speeds up to 28 mph while pedaling (20 mph on throttle alone).
Both bikes come with two 48V 15Ah batteries for a total of 30Ah of capacity (1440 watt-hours). One battery is housed internally in the top tube and the other in the downtube. Due to the large battery, the Rhino is no lightweight at 97 lbs, something potential buyers will want to consider.
This isn’t a typical fat tire ebike either, Himiway decided to go with extra wide 26″ x 4.5″ tires for those who plan to venture off the beaten path. The Rhino comes equipped with hydraulic disc brakes, integrated lights, fenders, and a rear rack. Color options are midnight forest and “Himi grey”.
Our review of the Himiway Rhino
The Rhino is geared towards those who really want to extend their adventures. It’s on the pricey side for a fat tire ebike which can be found typically for between 1,500 and 2,000, but the Rhino offers double the battery capacity of the average fat tire ebike. This bike is also powerful, no matter which motor you choose.
Our Take on the Himiway 2023 Launch
This is quite the diverse lineup, and no one can argue that Himiway isn’t exploring other types of ebikes and what people want out of their ebike. We’re most excited about the Rambler, given its value price point. The Pony and Rhino will appeal to more specific use cases. Let us know in the Комментарии и мнения владельцев section below which Himiway model you’d like us to review in depth.
Overview of Dual Battery Solution and Range Extender Battery
Some e-bike riders need a longer range for their e-bike. The mtb user wants to have more fun on the dirt roads or e cargo bikes users need to carry more goods for long rides. What would be the perfect solution for them to have a range boost for their e-bike? Dual battery and range extender?
Discover more about dual battery solutions from LEV battery manufacturer.
What are Dual battery system types？
There are two dual battery setup types: parallel (dual battery) and power bank (range extender). The main difference between them is how they operate as well as how much power each type can produce.
Choose and click to discover more about dual battery products.
Both types were designed to solve a problem, but it came down to personal preference for those who purchased e-bikes equipped with two e-bike batteries or range extender batteries.
The parallel battery type
We have the battery control unit fully integrated with the BMS. It will optimize the use of both batteries and keep them at the same voltage when they are connected. With two batteries in parallel, the output voltage is the same as one battery, but the amp hours are doubled.
This way allows both battery discharge at the same time and has twice the range or power of a single battery. It increases the total capacity directly.
Another way is having only one battery power the e-bike, and automatically switch to the second battery when the first one is out of power. Also, it can be switched manually as well. Each battery in a dual battery system can power the motor independently.
Both ways can give riders more battery capacity and more range for a smooth ride. For dual battery system, it will also improve the acceleration of your e-bike.
Advantages of an e-bike Dual battery
A dual battery system offers several advantages over just one battery system. This is especially important for those who want to ride their electric bikes for long distances.
The dual battery system is a more permanent solution. Once it’s installed, it will be there as long as riders own the specific bike. In other words, riders can FOCUS on the riding experience without worrying about the charge level or when to recharge the battery. With eco mode, riders can have even longer rides.
For example, dual battery systems can provide longer run times, more power, and greater flexibility. The Bosch dual battery system is a great example.
They can also be used to store energy from solar or wind systems, providing a backup power source in the event of an outage. Dual battery systems are the best option for those who want the most from their e-bike.
Disadvantages of a Dual battery system
A dual battery system has a few disadvantages.
First, it can be more expensive than a single battery system, because you need to purchase an extra battery.
Second, it can be more complicated to install and design. And require a spare battery control unit or fully integrated with BMS.
Finally, it can add additional weight to the e-bike, which can affect performance.
However, these disadvantages are outweighed by the many advantages of dual battery systems.
The range extender type
The range extender is a second battery, that is plug-in with the main battery. When the main battery is getting low, the range extender battery can start to charge the main battery. It works as a “power bank”.
The range extender battery usually has a smaller capacity than the main e-bike battery. When the main battery is drained, the range extender battery will start to power charge the main battery. Some systems may require the e-bike to stop when charging the range extender battery.
Advantages of a range extender battery
Riders will not need to modify their e-bike or dual battery system. Just mount it on the down tube or top tube. Even can work in their backpack.
Also, thanks to the smaller capacity and size, it is easier to carry with riders in their backpack. While riders check the view or take a lunch break, it will start charging. After that, they can take the ride again.
It is affordable, easy to use, and a readily available way to increase ride quality.
Disadvantages of a range extender
Just as with any other product on the market, there are a few disadvantages that come with using a range extender battery. Depending on your needs, it may or may not be a major drawback.
The main disadvantage of the range extender battery is that you will have to keep charging two batteries separately, which can quickly become tedious and time-consuming if they’re drained at different times.
Another issue with the range extender is the charging rate. Because it works as a power bank, it usually takes the same amount of time to fully charge your main battery as using the normal charger. If you are doing a lot of climbing with your e-bike, the range extender may not have enough power to keep up.
The last part is if the main battery is dead, the range extender may not power your e-bike directly.
Despite these few disadvantages, the range extender battery is still a great option for those who want to extend the range of their e-bike.
Which Dual or Range extender battery type should riders choose?
There are advantages and disadvantages for both dual/range extender battery types which will depend on your product preference as well as what you plan on designing the electric bike for.
The best thing that can do is to test out different dual/range extender bikes to see how they feel while riding them because it may come down to comfort rather than what looks cool or has more power output.
Also, don’t forget about the price! Even though it might look like dual batteries are the way to go, you may find that a range extender battery might be compatible with your existing product line.
The future of electric bikes
The dual battery system (two parallel batteries or battery range extender) has the potential to take electric bikes into the next generation. This system provides both high power and extended range, which is what you need for an e-bike to become your primary mode of transport. This means that in the future there may be more e-bikes with dual battery systems than those using a single battery.
The dual-battery system is not only more powerful, but it is also easy to maintain and service. This means that there is less chance of a breakdown.
And you will spend less time and money on repairs. So overall, the dual-battery system provides many advantages – making it the better option for your e-bike.
Range extender with Smart BMS. It works as a power bank and can work with many popular systems and recharge your main battery.
It has 180 watt-hours of energy and supports up to a 3A discharge rate as a power bank. A suitable solution for your current product line. It is perfect to place on the bike down tube or water bottle holder. Easy fit in different frame sizes.
Tritek also provides a dual battery setup. With our new BMS battery technology, it can safely switch or parallel. The frame battery’s low-weight design can increase range without too much additional weight.
Dual battery systems are the best option for those who want the most from their e-bike. Compared to a range extender battery, dual batteries offer longer run times, more power, and greater flexibility.
However, depending on your needs and riding style, they may not be a deal-breaker. If you have any other questions about dual-battery for e-bikes or range extenders, feel free to contact us for further information.
Thank you for reading! We hope this article has helped inform you about the advantages of dual-battery E-bikes. Stay safe and have a great ride!
ebikes should support dual-batteries to encourage longer trips
Napier Lopez is a writer based in New York City. He’s interested in all things tech, science, and photography related, and likes to yo-yo in (show all) Napier Lopez is a writer based in New York City. He’s interested in all things tech, science, and photography related, and likes to yo-yo in his free time. Follow him on
Range anxiety isn’t just an issue for electric car drivers — electric bike riders suffer from it too. That’s a bit of a problem if we want ebikes to serve as veritable car replacements, as too often consumers have to choose between an affordable, lightweight ebike and something with more range.
Barring dramatic advancements in battery technology, this isn’t likely to change anytime soon. But there’s another way to deal with this problem: every ebike should let you latch on an extra battery. Too few do.
I test a lot of ebikes for TNW, and I love going on long rides on whatever ebike I happen to be reviewing a given month. I go on 15-40 mile routes regularly, and because ebikes take the edge off of long trips, my average distance increases every month.
The problem is, most of the bikes I test can’t actually take me as far I’d like to go. It’s no fun pedaling a 70-pound no-longer-electric bike if you overestimated how long your battery would last — I know from experience — and unless you have a folding bike, it’ll probably be difficult to find public transit options to get you back home.
Most journeys are round trip after all, so while you might be able to travel 20 miles one way, you might not be able to make it all the way back if you couldn’t recharge your battery at your destination.
Sure, there are single-battery ebikes with super high range out there, but they are usually super heavy, which works against you if you do deplete the battery. They can also get pretty expensive, as the battery is often, if not usually, the most expensive component of an ebike. Among lighter, more affordable ebikes, dual battery support is almost non-existent.
It’s a shame. If range extender batteries were more common, users would have a lot more flexibility with how they use their ebike.
For one, riders could save money by initially opting for a bike with a smaller battery and buying the range extenders when they’re financially prepared. The more people ride ebikes, the further they go, but they can also hit a wall once they start pushing the limitations of their battery’s capacity. Offering range extenders would be an easy way for riders to ‘upgrade’ their ride down the road without having to buy a new ebike altogether.
Of course, you could always just buy a second battery if your ebike offers a removable battery. But many do not, and in any case it can be awkward to carry a heavy second battery in a backpack or on a frame that isn’t designed for it. Making dual batteries an intentional feature, rather than something users have to jerry-rig, encourages these longer trips.
Bikes like Biktrix Juggernaut Duo and Juiced Hyperscrambler 2 offer more flexibility by allowing you to carry two batteries right on the frame. It means you can save some weight for smaller trips where you don’t need the second battery, or carry both for the longer rides.
Range extenders are arguably even more useful for the lighter ebikes, which often sacrifice range and/or power in the name of ride quality, and which often use integrated batteries that are hard for riders to remove. The VanMoof S3 and Specialized Turbo Vado SL, which both use fixed primary batteries for a more stealthy design, address these issues by offering range extenders. In these cases, the availability of a range extender battery means apartment dwellers can leave their bike in a storage room and only have to carry the range extender up five flights of stairs.
And it’s not always about going as far as you possibly can; you might also appreciate the option for a second battery if you need more power from the motor — say if you have a distant commute, if you live in a very hilly town, or if you are a larger rider like me. On most ebikes, range can vary dramatically depending on the assist level; you might go 50 miles on the lowest assist levels, but just 15 in assist level 5.
I know some of you are twiddling your goblin-esque fingers as you prepare to comment ‘jUsT rIdE a NoRmAl BiKe.’ That misses the point.
We all benefit from getting more gasoline-powered cars off the road, and ebikes actually appear to be replacing more cars than they are regular bikes. Studies have also shown people tend to ride farther and more often on ebikes. In other words, people are taking trips they wouldn’t even consider on a regular bike.
With ebike adoption rapidly increasing, it’s only reasonable to assume that more people will want to take even longer trips on two wheels, especially if cities continue to build the infrastructure necessary to support these journeys. Making these long journeys more viable for riders helps make our cities greener and lessens our reliance on cars even further.
All this is to say that an ebike’s range can make or break a purchase; it doesn’t matter how much you like an ebike if it can’t take you as far as you want to go. Making dual batteries the norm would give consumers more flexibility in what they buy — and how far they ride it.
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