LifePO4

YAVLiC - BMS blues

Last week the kit including the BMS arrived. No circuit or wiring diagrams, just a pile of parts. Hmmm...

The BMS consists of a module for each battery cell and a "control unit" if you can call it that.

The BMS components are from EV-Power. Here is a link: EV Power cell module.

The "control unit" seems to consist of a few relays and a butchered plugpack which floats around in the box. It seems that I am supposed to connect the mains to the Vectrix charger through this box. As far as I can determine without tracing the tracks on the PCB, it is supposed to switch off the mains when the battery is charged.

BMS-CM-sml.jpg

BMS Module Testing

Since I am not going to entrust a $4000 battery to a pile of components which I don't understand, I started by testing the BMS modules. I hooked up the modules to a Lab power supply. A Fluke multimeter was connected via separate leads directly to the module and a second multimeter was used to indicate the state of the Solid State Relay (SSR) on the module. Like this:
BMS-modules-testing20130826.jpg

It took about 2 hours to measure all 42 modules. Here is the data:
BMS-modules-data_0.jpg
BMS-modules-data2.jpg

  • VLL is the cell voltage lower limit (LL). Below this voltage, the SSR goes open circuit.
  • Vth is the threshold at which the module starts to shunt some of the charging current through itself. I measured the voltage at which the module starts to draw more than 10mA.
  • VUL is the cell voltage upper limit (UL). Above this voltage, the SSR goes open circuit as well.
  • IUL is the shunt current drawn by the module at VUL.

In retrospect, I should have also recorded the shunt current at maximum allowable battery voltage which is 3.65V for the CALB CA66Fi cells. However, the current rises rapidly from Vth and reaches around 0.5A at Vth+10mV.

The only parameter which approaches a normal distribution is Vth. For the other parameters the production process seems to be less well controlled.

A significant worry is VUL. As can be seen from the measured values, VUL is 3.965V (average). This is 0.315V higher than the maximum allowed as per the battery datasheet. This is also the voltage at which the SSR switches to open circuit (OC).

However, the real worry is that the control unit does not know when the first cell has reached it's maximum voltage and the BMS module starts shunting current. By the time the SSR switches to open circuit, at least one cell will have been cooked for a while.

The maximum shunt current achieved by the BMS modules is 0.8A, some only get to 0.73A.
I don't think that shunting 0.8A when charging with 10A or 15A is going to make much of a difference to a cell.

How it ought to work

To properly manage the battery and to be able to equalize the pack, the charging system needs to have at least 3 states:

  1. Nominal charging, e.g. C/4 until the first cell reaches the maximum allowable charging voltage and the BMS module starts to shunt current. The chain of SSRs must go open circuit at this time.
  2. Equalization phase. The battery charger reduces the charging current to a value not much higher than what the BMS modules can shunt, in this case 0.8A or maybe 1A.
  3. Charge complete. When the battery pack reaches VBatt = N × 3.65V, all BMS modules should be shunting current and all cells should be at SOC = 100%. The charger reduces the current to 0A.

A "real" charger should of course also have a state for the case where the initial VBatt is below the lower limit, timeouts, alarms, etc...

Conclusion

I have the wrong BMS modules. They might be designed for cells which have a Vmax=4.0V (maybe Thundersky?). They also switch at the wrong time.
The modules don't seem to be suitable for the cells I have because:

  1. The modules don't indicate when the first cell has reached Vmax and shunting starts.
  2. The SSR switches at the wrong woltage for my cells.
  3. By the time the module's SSR switches, at least one cell (but probably many) will have been cooked for a while with nominal charging current minus 0.8A

Grrr...

YAVLiC - Fitting the Li battery 2

I am trying to figure out how to fit the battery. The original plan was to put 32 cells arranged as 2 rows of 16 in the bottom of the battery compartment. However, they don't fit.
At the rear, welding lugs from the frame's rear casting are protruding. I am prepared to grind some of that away to make the cells fit side by side.
Battery-InterferenceRear.jpg

The interference at the front is more problematic:
Battery-InterferenceFront.jpg
I am not going to attack the frame with a big hammer or a hydraulic jack and I won't grind away material from the frame's tubing.

Well, adversity is the mother of all innovation... So now I will be able to fit 33 cells instead of 32! See:
33CellsInbottomLayer.jpg

The whole pack will probably be arranged like this:
ConfigurationOfWholePack.jpg

YAVLiC - Fitting the Li battery

Received the battery. 42 CALB CA66Fi cells, 66Ah. 32 of them go into the battery compartment standing up as 2 rows of 16 and the remaining 10 will be stacked flat on top, most of them where the impellers used to be. Unfortunately the supplier forgot to send the interconnects. Next week then...

Battery cooling

I have satisfied myself that forced cooling will no be necessary with the cells I bought. As a contingency however, I have a plan B which will use conduction instead of forced convection. 2mm aluminium sheets between the cells would serve as the heat conductors. They would be thermally coupled to the bottom of the battery compartment. For the cells stacked horizontally, I would have to come up with a heatsink – maybe the plastic sides of the battery compartment could be replaced with aluminium sheet...

Battery mechanical fitting

I could not fit the cells side by side where the frame welds are. Some of the protruding welds will therefore have to be ground down by about 1 mm. Also interfering is the bracket for the rear temperature monitoring board and a rivet in the front center of the battery compartment. While I am at it, the big ventilation holes will also need to be covered – this will stop the battery from getting a shower when I ride in the rain.

will01's picture

Electric bicycle: Enjoy the responsibility

The threat of global warming looms large over the face of earth and is attracting war scale measures from various quarters. However there is also a unique way of fighting global warming which is really fun filled. The electric bicycle has emerged as a suitable alternative to traditional vehicles and can help you to reduce your carbon footprints while you enjoy a joyful ride through the beautiful countryside!

Electric bicycleis finding a lot of acceptability across the whole world although there are different rules governing the electric bicycle in different countries. Thus in Australia the electric bikes and electric scooter have to comply with the Australian Design Rules(ADR) before the vehicles can be legally allowed on the roads. The ADR covers a whole range of vehicles which include self powered as well as motor propelled bicycle.

According to the Australian ADR a pedal cycle is one which has one or more propulsion motors attached to it having a maximum output of not more than 200 watts. Thus an electric cycle is basically a cycle which can be propelled with the help of an external device. The source of energy in the electric bike is generally clean fuel cells which provide a constant supply of carbon free energy.

The different rules pertaining to electric bikes basically throw light upon various important criteria relating to electric bicycles viz :

* Identity: The type of vehicles
* Type: The type of the vehicle as per law
* Maximum speed: The maximum speed at which the bike can travel
* Maximum power: The maximum engine power permissible
* Helmet: Is a helmet necessary.

All the above factors determine the design of the electric bike that will be launched in the market.

Electric bikes have come a long way since their early days of inception. The present day electric bikes are sleeker and can pack many features together. They are distinguished by the use of super light LiFePo4 batteries which makes them super light and also highly portable. You can carry the bike around with you wherever you go! Also the motor bicycle kit makes it possible for you to assemble the bike right inside your home by following some simple Do It Yourself steps.

Electric Bikes and Batteries offer electric bicycle kits. The website http://www.electric-bicycle.com.au provides complete information about the company.

moveon70's picture

Upgrading from SLA to LiFePO4

Some of you have been following my project to upgrade my little 180W ebike.
I have all ready posted on upgrading the hub motor from the 180W 36V system to the 1000W 48V system.
I promised to post on the performance when I got my new battery, and it finally came in.

I ordered a 48V 15Ahr LiFePO4 battery pack with BMS and charger from China off ebay for ~$250 shipped.
I hooked it up to the charger after unwrapping. I found the charger shut off after only 10minutes, so that means it did not self discharge during the 6 week boat trip it took to get here. Thats good news.
Another note is how they made it. Its simply duct taped together, but over all looks fine. IF I want to change the shape, I should be able to remove the tape and change it how I like.

In just a few minutes, I had it in the scooter.
P1010375.JPG
There is nothing under the seat. That silver cube is the whole battery.
OK, its not pretty, but I will clean it up as time allows.

I finally got to go on a real test ride.
Here are the results:
Top speed is ~20MPH using a GPS.
It goes about the same speed up or down hill, so the speed must be governed by the controller.
It has plenty of torque. If I put my feet on the ground and pull the throttle, the front wheel will come up (but no, it wont wheelie while moving).
I can go up pretty steep hills with out loosing speed.
So far, I have gone about 8miles on the battery, and there is no noticeable drop in performance.
I pulled over and checked, and nothing (motor, controller, BMS or battery) was hot.

The only downer is that some times when accelerating from a stop (and pointing up hill) the current shuts off and then back on and off making a jerking motion. Since it did not do the same with the SLA batteries, I am sure that this is the BMS which came with the LiFePO4 system. It is protecting the battery from over current, or under voltage.
This tells me that I should have bought the 20Ahr battery, not for the additional range, but for the increased supply current under heavy load. Still, this issue is not common, and over all the bike is very ride-able, and I do not feel the need to order a larger battery.

So, the verdict:
Fun little scooter. Since I started with such a small frame, it is really light and maneuverable. The small LiFePO4 battery in the floor does not weigh much. The whole scooter weighs 32kg. It seems like is has plenty of range, and is fast enough to be usable. Also it is an e-bike, not a scooter. Only need a bike helmet, not license or registration. I am happy enough with it to want to finish off all the details like new lights and key switch. Get the regenerative breaking working and so on.
-Mark

juanito's picture

EV's Rule

Overview

I've been comparing many different technologies concerning EV's (electric vehicles) and have been finding that they really do rock. Simple, efficient and practical EV's could be the next wave of the future. They have many many advantages over ICE's (internal combustion engines). They don't pollute as you drive them. You can even run them from solar panels and wind mills. They are so efficient that they can go over hundreds of miles on the equivalent of a single gallon of gasoline. They are reliable, having only one moving part in their motors and don't need in reality things like transmissions and driveshafts. The can slow down the vehicle and charge their batteries at the same time. They don't need oil changes or antifreeze. They can be made just as fast and powerful as any ICE out there and have the potential of doing more. What were we thinking all these years?

However, EV's have some drawbacks. Nearly all of them are related to batteries. EV's can't store enough electricity to travel long distances. They can't "fill up" very fast, perhaps taking all night to recharge. They can be affected by hot and cold weather. Some battery packs wear out rather quickly and can be quite expensive to replace. Prices seem to be quite high for the moment for all parts of EV's.

What will the future bring? Will EV's improve and adapt to the expectations of society? Will society realize that they don't need the range of ICE's and adapt to EV's? How would you picture the future?

History

In the beginning of the automobile industry EV's were the car of choice. They were quiet and easy to operate. Women would drive them to visit their friends and have a cup of tea. No starter, no gearshift, no smell, no dirty gasoline nor oil. You could just get in and go.

Many people think that EV's are slow dinosaurs of the automobile industry. Although that may be true of many EV's many people don't realize that it was an EV that was the first car to reach 60 MPH (100 kph). 60 MPH EV Even today some have reached record speeds and acceleration.

Back in those days you had three choices of automobiles: 1) gasoline, 2) steam and 3) electric. Gasoline engines were difficult and dangerous to start since they had to be cranked. They were also much harder to shift since automatic and synchromesh transmissions didn't exist yet. Steam cars were fast and powerful, some crusing at 60 MPH, but at the time they used more fuel than gasoline cars and cost more. Most of them also took a several minutes to reach boiling temperatures and couldn't be let freeze. But EV's didn't have any of these problems. There main drawbacks were their limited range and long charging times.

But however people wanted to go faster and further. Electric starters and better transmissions made gasoline cars more practical. Now that they were easier to use and could go a lot further they started to take over. You didn't need to wait all night for them to charge. And so the EV was left in the dust.

But as the years rolled by we started to see problems with ICE cars. Air pollution, oil dependency, gas prices and repair prices. Recently we also have seen a trend of people who don't care. Bigger, more powerful and faster seem to be what many look for in a vehicle. Safe, reliable and efficient seem to not really matter.

For EV's to be a part of our future either society needs to realize that most people only need the range of an EV or EV's need to become bigger, more powerful, faster and as good as, or better, than ICE's. Let’s look at how things are turning out so far.

EV’s today
Today, however, some folks have taken interest yet again in the electric car. In the 1990’s some automobile manufactures even started producing and leasing EV’s for a few years in California, USA. Although they didn’t continue, it did give rise to the hybrid car, a car that was both gasoline and electric powered. As people started to notice the advantages of driving these hybrid cars some have asked themselves what would the world be like if we be like if we all went all electric. What have they done about it.

NEV’s

Although today it is hard to find an EV on the market that would replace a regular sedan, some companies have started to manufacture cheep and efficient NEV’s (neighborhood electric vehicles) and scooters. These vehicles are slow and have a limited range of about 30-40 miles (depending on car, scooters are usually less), which is still plenty of range for the average driver. To double that range they can be charged at work before coming home.
A variation of the electric scooter is the electric bicycle. Just put a motor kit on your own bike and go.

Cars
In the 1990’s many car manufacturers, such as GM, Ford, Honda and Toyota, started to produce electric cars, pickups, and SUV’s that had up to a 100 mile range and could accelerate quickly up to a governed 80 MPH. Sadly, most were destroyed by their own makers. There seems to be quite the controversy as to why. (For more information see the documentary video, Who Killed the Electric Car?)

Today most electric cars are homemade conversions. In the future some manufactures have promised that there will be electric cars like the GM Volt and the Aptera 1 and other plug-in hybrids.

Sports Cars

It may seem strange that the next step up from a slow moving NEV is a sports car but it is true. The Tesla Roadster is a fast nimble convertible for those who have a wild side. I does 0 to 60 MPH in less than 4 seconds and has a range of 200 miles. Others have made homemade electric sports cars that are even faster. With these advancements the EV may someday surpass the ICE car in every way.

But how does an EV work? What makes it different from other cars? EV’s have three main parts for their drive train: 1) the battery, 2) the motor, and 3) the controller. All of these parts play an important part in making the EV go.

Batteries

In the EV world probably the most important part for determining the performance of an EV is the battery. The battery is the fuel tank of the EV and its size and type set out the range of the car. What sets out its capabilities? EV batteries are composed of cells, like the AA, AAA, C and D size batteries which really aren’t batteries, rather cells or piles. Each cell has a certain voltage. To get a greater voltage the cells have to be connected end on end (positive to negative) which makes a series. For an example six 2 volt cells in a car battery are put end on end in a series to produce 12 volts. You can make up to hundreds of volts this way. The size of the cells determines how much current they can produce over a certain period of time. You can also increase this by connecting series of cells with other series in a parallel connection (positive to positive, negative to negative).

But another important factor is the type of battery that is being used. What kinds of batteries are out there and what kinds may be part of the future?

Lead acid

Lead acid batteries have been around as long as the EV itself. They are cheap and durable. But lead acid batteries don't hold a lot of energy for their weight and don't last very long. They also contain sulfuric acid which can burn, although GEL and a few other types can't leak. They also produce an explosive mixture of hydrogen and oxygen and are harmful for the environment when disposed.

Lead acid batteries are used in many NEV's and small vehicles and were the original batteries on the EV1 electric car. Even though they are rather low quality batteries compared to others, they do have plenty of power to fuel a car up to double the average 30 mile range that 90% of Americans need for their daily lives.

NiMH

NiMH (nickel metal hydride) batteries hold more electrical energy than lead acid ones. They also last some 5 times longer. What else I like about them is that they aren't as harmful for the environment. They also seem easier to recycle. They do however have some strange charging characteristics and can be easily damaged by overcharging and discharging which means they need a special BMS (battery monitoring system). An older battery that is similar but contains toxic cadmium is the NiCad.

NiMH batteries are used in many hybrid cars including the Toyota Prius and were the battery of choice for many EV's of the 1990's.

Li ion

Li ion (lithium ion) batteries can hold tremendous amounts of electrical energy for their size. But they tend to wear out quite fast. Even if not used they can lose some 20% of their original capacity per year. They are also explosive and can be bad for the environment.

Li ion batteries are used in small portable devices like cellular phones and laptops.

Li ion batteries are good for drag racing applications.

LiFePO4

LiFePO4 (lithium ferrous phosphate) batteries are right now about the best battery for EV's you could buy. They have a high energy density and last 10 times as long as lead acid. They don't explode nor do they leak acid or explosive gases. They also don't contain harmful elements. If I were to build an EV right now I would use LiFePO4 batteries.

Thin cell

Thin cell lithium batteries are rather new but may hold a bright future. They hold twice as much energy as Li ion batteries of the same size and last 200 times longer than lead acid batteries or better.* Beat that!

Thin cell li batteries are currently used in things like pacemakers.Thin cell

Ultracapacitors

Ultracapacitors are unlike any conventional battery. Instead of using a chemical reaction to generate electricity they store electricity by capacitance. This means that they can be charged almost instantly, granted that you have a charger that can put that much electricity out. Many ultracapacitors sold today will last tens of thousands of times longer than lead acid batteries. They are also non toxic and don't explode. The only disadvantage (beside cost) is the fact that they don't hold a lot of energy.

So for now they could find a use only as supplementary sources of energy to batteries for those moments that you want to accelerate quickly. Or possible be used in drag racing applications.

But improvements are under way. Already ultracapacitors have been made to equal the energy density of lead acid batteries. Ultracapacitors At least on company even has promised that by the end of this year, 2009, it will have in production ultracapacitors that will far surpass even the best lithium batteries out there.Zenn Cars In the future I suspect that electricity could be stored in gigantic ultracapacitors at fuel stations. They could charge up each vehicle's capacitor bank in minuts, even seconds as long as wires are designed to withstand the amperage. But if you wish you could still charge them up overnight at home.

COMPARISON OF BATTERIES
....................KW/h..........Life
....................Per............In
Type...........Kilogram........Cycles
Lead acid..........30.........200
NiMH ..............90.......1,000
Li ion............155.........500
LiFePO4 .........100.......2,000
Thin cell.........300......45,000
Capacitors.........30*...1,000,000

*Best as of now. But with leaps and jumps in technology who knows what we’ll have next.

Motors

Hate changing oil? Hate trying to find out which part of the motor is not working right? Well look no more! Electric motors don't need oil changes and only have one moving part. What's cool about E-motors is that they work perfectly for vehicle purposes. An E-motor can start from a stop and go in reverse. Unlike an ICE they also have max torque from a stop, when you need it the most. They don't need a transmission. They even can be made as part of the wheel itself. You can also use them to slow down your car and at the same time partially charge the battery. E-motors can also be temporarily run on over-volt which supercharges them for fast take offs until they over-heat. Motors

Each kind of motor has its own characteristics but they all work on the same principal, magnets. In school you probably remember your teacher showing you the effects one magnet can have on another. If you put two of the same kind of poles together, north north or south south, then they push apart. But if you put a north and south together they attract. Well in any electromotor electro magnets push and pull on stationary magnets. Just when two magnets meet up the current is reversed, changing the poles of one of the magnets, and therefore making them repel each other. So as you can see, even though many motors are called "DC motors", all E-motors run on AC on the inside. AC or DC just refers to the kind of current entering the motor or its controller.

Now generally speaking, E-motors follow these basic rules:

1 At a stop the motor has the greatest torque. The faster the motor goes the more the torque diminishes.
2 At a stop the motor draws the most current. The faster it goes the less current it draws.
3 You can raise the current and torque by raising the voltage (electric pressure) as long as it doesn't overheat.
4 If the voltage is lowered or the motor is spun fast enough the motor will push electricity backwards back into the batteries. (A motor and a generator are the same thing.)

All electric motors are similar in these respects. But E-motors come in many shapes and sizes and kinds. What are some of the basic differences? Here are some of the basic options:

AC (alternating current) motor or DC (direct current) motor
PM (permanent magnet), wound field or induction motor
On wound field motors: series type, shunt type or compound type
Brushed or brushless

PM Motors

Permanent magnet motors are simple motors, and can be made to be very powerful as well as efficient. Their only drawback is that they are usually efficient in only a very small RPM band. But continuously variable transmissions and modern electronics have the potential to make PM motors efficient in a larger RPM range.
PM motors come in two main types: brushed and brushless. Brushed types use regular DC current and convert the DC current to AC by contact between the brushed and the communicator. Brushless DC motors (BLDC’s) need a special AC current in order to run. In order to do this they need a special controller that uses DC current. Brushless motors are maintenance free whereas brushed motors will need new brushes after a while.

Most toys us PM motors.

AC Motors

AC motors are very useful in vehicle applications. But they need a converter that converts DC current into regular AC current. AC motors come in basically two types: brushless (induction) or brushed. The brushed type is like the field wound motors that we shall discuss next. The brushless type, on the other hand, is very different. They contain coils around a rotor composed of bars of iron. As the alternating current passes through the coils the magnetic field produced induces a magnetic field in the iron bars. This causes them to push and pull against each other and spins the rotor.

AC motors are used in household appliances like blenders and vacuum cleaners.

Field Wound Motors

Field wound motors don’t have permanent magnets in them. Rather they have electro magnets that use the same current as the rotor to produce magnetism. They come in three types: series, shunt and compound. Each behaves differently due to the way they are wired. Of the three, series type motors seem to be the best for EV applications. They have a fairly good efficiency in a broad RPM range and are great for EV’s.

Future Motors

Even today, highly efficient high powered super-conducting motors have been developed. These motors are usually a third of the size of other electric motors and have the same power. This is astounding since even modern electric motors are already powerful for their size. I can just imagine busses and large trucks with little tiny motors as powerful as the big diesel motors they have now!

Motors come in many different sizes and are built for many different purposes. Some are already designed to couple directly to the existing driveshaft of some vehicles. Others are designed to replace the hub and turn the wheel directly. However, many homemade vehicles have to be home fabricated for a commercial motor to fit.

Controller

The controller is like the carburetor on you ICE car (or fuel injectors). It controls the amount of electricity that goes to the motor. In an EV the throttle pedal or twist grip is connected to the controller. When you let your foot off the pedal the controller is signaled to cut off the current to the motor. Flooring it makes it turn the current on completely. Anywhere in the middle and the controller rapidly turns on and off the current to the motor and therefore limits the speed. Some have a voltage converter inside which causes the motor to act like a generator and slows down the vehicle and charges the batteries when you step on the brake pedal.

Compared with carburetors and fuel injectors and transmissions, motor controllers are easier to install, are universal for any specific type and size of motor and, since they have no moving parts, should last longer. Plug this into the battery; that into the motor; here’s the throttle; who cares if it’s a Ford or Chevy?; and let’s go!

Conclusion

So hope you’re a little more familiar with EV’s. They make so much more sense than gasoline, diesel, hydrogen, nitrogen, sterling and steam cars. Most people don’t need to drive much more than some 30 miles a day. If that is all you need, then why don’t you go down and buy a NEV for less than $10,000 and drive it for a tenth the price it would cost you in a gasoline car? You wouldn’t have to change the oil, nor spark plugs nor filters. No carbon monoxide poisoning nor spilt fluids. No more going to the gas station and cringing at the sudden changes in prices. Maybe later you could put up some solar panels on your roof and drive for free and save the environment. Could it really get any better than that?

Has anyone used a Shockley LifEPO4 Battery Pack??

Hello,
I am looking into a getting a 36v 10AH pack from Shockley. They sell there stuff on ebay and on http://www.EcoForumZ.com/.

It comes with a nice case, charger and BMS. I asked about the cells used, and they said they are new foil pack 3.2v cells. Has anyone heard of them? Is anyone using this pack? I attached a picture.

From Ebay:

NEW - 36v 10ah Shockley LifePO4 Battery Pack Kithttp://visforvoltage.org/imce/browse#b5e9_1.jpg

*
Kit Includes The Following:
*
Shipping within 24 hours insurance included
*
3 Amp Charger
*
Battery Management System (BMS)
*
Aluminum Alloy Case With Fuse
*
Lock & Keys with On / Off switch
*
3C rating with 50a amps max

Shockley Lithium Iron Phosphate LifePO4 battery packs are sold exclusively by EcoForumZ.com at this time. We do have a few resellers that will be selling our packs in the near future if you wish to verify if a seller is authorized please visit our website at EcoForumZ.com Others may use the same case but only Shockley LifePO4 battery packs are guaranteed to be brand new LifePO4 cells. Many of the duct tape packs you see online are purchased from the manufactures at a discount because they did not pass inspection, are used, returned, or are defective. I myself have been offered these cells but refuse to sell them even at a discount.

Can I run my LiFePO4 Battery with no BMS?

Hello,
I am a newbie who just purchased my first e-bike conversion kit. I picked up the Phoenix 5304 hub motor with a 40 amp controller. The battery been used is a duct tape 48v 20ah pack. I converted my bike and everything worked fine my first time out........until I started to smell smoke :(. I looked over the battery pack it was fine, not even warm. I then inspected the BMS which basically melted. The solder was dripping off the BMS like water!

I did some testing, and believe it or not the BMS still works. After my testing I decided to do the following.

I created harness for the BMS. I am only using the BMS during the charging process. After a complete charge I remove the charger and the BMS via the harness. i then ride the bike with just the battery and an in-line 50 amp fuse. The bike seems to run great. Is this is a safe configuration? Am I in danger of damaging the battery? I assume that the BMS is only used for charging purposes, but I could be WAY off. Thanks for helping the new guy :).

engr_scotty's picture

Ping - Brushed Kollmorgen Tests

IMG_4452.jpg
10/11/2008: 3rd test ride: Farther. Went on a 5 mile loop. Very windy, long rolling hills for the most part. I adjusted the pedaling gears so that I could contribute from about 15mph-22mph. Everything went very smooth. This thing is really fast! Scary fast!

10/9/2008: Second test ride: This time with another rider with a spedo. Flats: about 23mph. Slight downhill hits about 28mph. Almost too fast for the 'hood. Ordered a ecrazyman brushed controller and throttle. This should make a big difference. I noticed that if I flip the switch too early (big current draw), the battery cuts out. I don't think this is a problem with the battery or BMS, just the BMS doing its job (I guess...).

10/6/2008: First test ride: Tightened everything REALLY good and installed the torque arm. Found a good, flat straight away and got up to about 20mph (estimated). Flipped switch and it took off...probably mid 25mphs...very strong pull. No noticable heat or general breakage. Will try it again and get a controller.

10/4-6/2008: Prepped Raleigh aluminum bike with Kollmorgen rear brushed hub motor. Motor is rated at 24V, so a bit worried about running it at 60V. Don't have a controller either, so this will be a "flip-switch" test with a 20a automotive switch. Have a 30A inline fuse too. Using somewhat small gauge wire 18ga.(?) so that there is a voltage drop to wheel. Have an old EV Warrior kickstand that I'm using, which is needed cuz this thing wants to fall over all the time with the batt. on the rack. First test: spun wheel with pedal and flipped switch: Wow. Went strong and very fast. Then I smelled burning and shut it down. The wheel had torqued itself loose from the mounts and nearly came out. Need to tighten things down....

Note that this is a pic of the Kollmorgen hub mounted in a "pusher" vehicle (see this photo if interested --> 122.jpg (32.78 KB) Didn't work great. Lots of wheel hop, and weirdness when turning. But it was easy to go from ebike to regular bike...)

124.jpg

10/1/2008: Hooked up charger and ran it over night. Charger ran RED for just a few minutes, then to green. No noticed "balancing" (turning red again). Charged voltage for this 48V pack is ~60V (!).

9/25/2008: Received Ping battery. 48V, 16ah, ~17lbs. Packaged well and arrived apparently safely with 2A charger. Was headed out for a 5 day trip, so had to leave it be :(

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