The Perils of DIY Headway LifePO4 Battery Building

The Perils of DIY Headway LifePO4 Battery Building

Here are a few things to watch out for if you are building your own headway pack:

Charge All of the Cells . . . 

A headway cells can read 3.2v and be nearly empty or quite full. So just becuase the volatges are "balenced" it does not mean that the charge levels are.

Use a single cell charger to charge all cells individually to 3.65v. This makes things a lot easier, becuase when you connect up yout BMS, it will not have to do so much balencing.

If you do not charge individually the BMS may takes WEEKS to balence the pack.

Watch that BMS!  . . . 

Do not trust your BMS, headway cells have a low internal resistance apprently so the BMS somthimes gets confused and will discharge your headway cells compleltly which kills them! So after rigging up your BMS, check to see that it is not discharging the cells.

Spending more on a BMS (ie. choosing qaulity) will not prevent this behaviour. Even a high qaulity BMS will do this. I do not understand why, just watch out for it.

Work in a Clear Area . . . 

You will need a screw driver / allen wrench / allen key to put your pack together, also perhaps some pliers etc. Keep these well away from the pack when not in use. If you place you pack on top of a metal object, it will short the terminals and you will get a big flash (which is scary) and also perhaps damage the cells.

Watch Order of Balencing Wires.. . .

The order in which you connect the balencing wires from the controller will differ from BMS to BMS so make sure you get them in the write order. Read the instructions (if you are lucky enough to have any).

Always connect all of the balencing wires to the pack, before connecting the BMS.

Do not buy secondhand . . .

This wholeprocess of headway DIY batteries is confusing enough without using secondhand cells. Some will be bad, and this will cuase problems. . . trust me you will have enough problems.

Conclusions . . . .

Perhaps I am over confident but I have found building my own pack very difficult. I would recommend that you buy a preassessmbled pack, and learn by fixing it when it comes of age. Componenets are expensive and you do not need to damage many befor ethe costs equal that of a pre-built pack.

Save youself the hassle and buy a ready made battery pack.

Environmental Consultants

Using a Step Up Transformer to Run Ebike Motor

Using  a Step Up Transformer to Run Ebike Motor

Swaping from a 24 volt system to a 48 volt? Well that means a new battery . . or does it?

Can you use a step up transformer to turn 24v or 36 v in to 48v?

Yes you can but you may run in to trouble with supplying enough amps.

This is the kind of transformer which can be had on ebay. It is rated at 2000w but the this is a maximum wattage under ideal conditions.

If you were to input 46v anf take out 48v not doubt this transformer would provide close to 2000w but with alarger step up it will provide a lot less . . just 500w stepping up from 24v to 48v.

A 2000w Step Up Transformer Fresh from Ebay

Wiring and Adjustment is Easy - You will need a volt meter

The Transformer would not provide enough amps.

The problem lies in that a ebike motor rated at 250w will use perhaps double this when climbing a hill. A 500w motor such as the one I have will then use 1000w.

This transformer might wrok if you were stepping up fron 24v to 26v on a low wattage motor. But a step up of more than 12v and you will likley have trouble on high amp applcations such a electric traction motors.

Here are the specs copied from the sellers listing on Ebay:

 Output Current: 20A(MAX) More than 18A, please enhance heat dissipation,

 Constant current range: 20A(max)

 Output Power = Input voltage * 20A, such as: input 12V * 20A = 240W, input 24V * 20A = 480W, input 48V * 20A = 960W, input 60V * 20A = 1200W

As you can see the 20a max input means that at a given input voltage the watts are resytcited by the performance of the transformer.

(If you need more power, you can use two modules in parallel, such as the output to 30A, two modules can be used in parallel,the current per module can be adjusted to 15A.)

 Working temperature: -40 to + 85 degrees (ambient temperature is too high, please enhance heat dissipation)

 Operating frequency: 150KHz

 Conversion efficiency: up to 95% (efficiency related with input,output voltage, current and voltage difference.)

 Overcurrent protection: Yes (With current limiting adjustment, adjustable output current limit, current exceeds the current limit, the output current is automatically reduced to a minimum 5A, according to the nature of the load current will be different.)

Short circuit protection: Yes (input 30A fuse) double short circuit protection, the use of more security.

Input reverse polarity protection: None (if necessary, please enter the string into the diode)

Output prevent reverse irrigation: Yes, for charging plus blocking diode is not required.

Installation: 4pcs 3mm screws

 Connection: solderless;terminals output

Module dimensions:86*63*68(L*W*H)

 Weight: 350g

Pin define:

CV: Output voltage adjustment

Adjust to CV potentiometer, according to your battery or LED to set the required output voltage value.

CC: Output current adjustment

Adjust to CC potentiometer counterclockwise about 30 laps, the output current is set to the minimum,then connect the LED,adjust to CC potentiometer to the required current. (Please adjust the converter after the battery have already been discharged when charging. )Please do not use the short-circuit way to adjust current.

Package Include: 

1 x 1200W 20A DC Converter Boost Step-up Power Supply Module IN 10-60V OUT 12-80V

Environmental Consultants London

Bafang BPM Review

Bafang BPM Review - Intro

I you are looking for a large heavy duty hub motor at a relatively low price then look no further then the bafang BPM. At nearly 20cm (8") in diameter it is large. But is is also powerful, with lots of torque.

The Bafang BPM comes in 48v and 36v offering at 350w and 500w power setting, although in reality, these motor can be run at all sorts of wattages and voltages.

In a 20" wheel, the spokes will be short -  110mm approx. 

If you are reading this having noticed that your ready built ebike has a Bafang BPM installed then well done, you worries are effectively over. Spares (yes spares) are available for this motor, including gears and clutch assemblies, so it should last along time. Your main worry would be overheating the motor on a long up hill.

Bafang BPM Review - In Use

In use the most noticeable thing about the BPM is the torque, and how quite it is.

There is a little lag between applying the throttle and starting to go, but the acceleration is rapid, and hill climbing is strong.

Disc Brake Mounts are available.

Bafang BPM Review - RPM Variants

The revs per minute of the motor will ultimately dictate the speed at which you bicycle travels. I have opted for a 230 rpm variant, which with a 20" wheel will give a top speed of approx 14 miles per hour. 15mph is the legal maximum in the UK. So if you are using this motor in a 26" wheel, then you will require a a lower rpm version.

A simple excel sheet can be used to give speed vs rpm.

This RPM vs Speed Spread Sheet can be down loaded here.

Bafang BPM Review - Choosing Voltage

Typically a higher voltage battery pack is more expensive. But if you live in a hilly area it is probably worth it. Here is why . . .

A motors wattage, is obtained by multiplying the volts by the amps it uses, so for example, my 48v motor will use approx 10A of current to produce 500W, a 24 volt motor would have to use 20A of current to produce the same power output.

So if you use lower voltage you will require:

1. A higher performance battery.
2. Thicker wires to connect everything up.

Add to this that fact that a motor normally produces far more power than advertised, and you end up with a powerful 24 volt system drawing 30 Amps sometimes.

Bafang BPM Review - Choosing Wattage

Always choose the 500w variant. If you are legally required to use less power then, use a smaller controller. I have read there is no difference between the 350w and 500w versions. I have also read that the 500w version has wider stators (part of the motor). . .  either way the 500w version is normally the same price.

Clearance for mounting brakes etc. is limited.

Bafang BPM Review - Batteries

I have tried to assemble my own battery pack, and wish I have never started. It is not easy. Read my guide on buying a ebike battery. But ignore the last chapter, building a battery is waaaaaaaaay hard.

Again clearance is limited for forks with wide stanchions. 

Bafang BPM Review - Fitting

Forks. Do not use aluminium. There is a guy on youtube who did this, the torque will split the dropout.

The axle on the BPM is a funny size, it is 13 - 14mm on outer edges, but 10mm on the "flats". I presume this is to stop the axle turning in the fork. The BPM comes with torque washers, and various other wasters.

Steel forks are best. But try and choose forks with narrow stanchions. I had to squash by stanchions in a vice to provide clearance for the hub body and disc rotor, which was not very nice.

So chunky BMX forks, are not a good choice, especially if you choose to use disc brakes. 

Bafang BPM Review - Conclusion

There are better hub motors out there than the Bafang BPM (MAC for example), but I do not think it will be beaten on value. 

It offers bags of power. 

Environmental Consultants London

Thorpy's Guide to Buying an EBike Battery

Thorpy's Guide to Buying an EBike Battery - Intro

There is only one thing worse than shopping for shoes with your wife or girlfriend, and that is buying an ebike battery. The variety of shops to buy from is large with branded systems (think Bosch) costing a small fortune, and cheaper "brand x" (i.e. unbranded) batteries still costing a painful amount but having no warrantee or support of any kind.

So what to do? I have been looking at batteries for around 2 weeks on and off, and I have found the choice a difficult one to make, mainly because lithium batteries are so expensive, and I am not used to spending that much money on bicycle components.

A good lithium based battery can cost upwards of £250 ($400), even if purchased direct from China, so its worth taking time to consider. Expect to pay a minimum of £300 for a quality battery purchased in the UK.

Thorpy's Guide to Buying an EBike Battery - Capacity (AH)

Summary: Bigger is Better

The capacity of a battery (think range or size of fuel tank) is normally given in Amp Hours (AH), typically the bigger the capacity of an ebike battery the more you pay. But before you spend a fortune on getting the biggest battery you can find it is worth considering how far you need to go.

Luckily for us somebody have developed an ebike range calculator for using to determine capacity required. Just fill in the boxes, and you will arrive at your required AH capacity. For me that was 15 AH.

This required capacity relates to a 48 volt system. If you did the same journey with a 24volt system you may require double the capacity.

I am not too hot with electronics so just use the calculator and you will soon realize what is going on!

Thorpy's Guide to Buying an EBike Battery - Voltage (V)

Summary: Must Match Existing if Replacing - Choose 48v if building from New

As mentioned above if you run a lower voltage you will require a higher capacity battery to travel the same distance, this is because a lower voltage ebike motor will use more amps, than a higher voltage motor to do the same amount of work.

A low voltage motor is probably OK in  flat areas where is does not have to work very hard, but if you require lots of power for hill climbing etc. the current flowing through a low voltage hub may damage the motor. The lower the voltage the higher the current needs to be to provide the same energy to the motor.

For example my 24v 500w motor draws 30A when climbing. The wires get warm, the motor is hot to touch. If you consider a vacuum cleaner runs on 13A or less, we can start to see that a high power motor at a low voltage is not very practical.

So if like me you wish to travel 20 miles over hilly terrain you will likely need a 15 AH battery if you are running a 48 volt system, but 30 AH if you are running a 24 volt system.

If you are building bike from scratch you can choose whichever voltage you think suits best (36v is the most widely used), 48v  for heavy going.

If you are replacing a battery you will have to stick to the same voltage, although some good quality motors can be run at higher voltages. But without getting too technical, just replace with a battery of the same voltage.

A final word. It does not do a battery any good to run it down to flat every time you use it. So buy a battery a little bigger then you need. For Sealed Lead Acid Batteries you should only use half of the marked capacity! For most lithium batteries 80% - 90% is OK. Yet another reason why lithium batteries are so much better for ebikes.

Thorpy's Guide to Buying an EBike Battery - Types of Battery (Chemistry)

Summary: For Reliability Choose LiFePo4

Most ebike use some type of lithium battery. Lithium batteries hold lots of power for their size. Although if you are on a very tight budget you might consider sealed lead acid batteries, but these are very heavy.

For proven track record a "LiFePo4" Lithium Battery will be your best bet, although there is now a growing number of  "NMC" Lithium Batteries coming on the scene. These "NMC" batteries are lighter although they are likely less reliable over longer time periods.

Thorpy's Guide to Buying an EBike Battery - Manufacturers (Brands)

Summary: For Value Choose Samsung for Reparability Choose Headway

If you are buying an ebike battery choose known manufacturers. To be clear this is not for the battery itself, it is the "cells" within the battery.

As above; a battery is composed of many small cells, and you should choose a known manufacturer. For example you might find the battery described as 48v 10ah Samsung. If the battery does not include a known manufacturer in the description then it is probably made with cheap no name cells that may not last very long (although you might be lucky!). Look for:

• Samsung
• Sony
• Panasonic
• Headway

Most cells are 18650 type this number relates to the shape of the cell. We are used to describing cells as AA or AAA or even (gasp) LR6. 18650 fits in with these names. 

Thorpy's Guide to Buying an EBike Battery - Output (A)

Summary: Divide the motor wattage by the voltage and multiply by 2.5 for required.

You should check the battery's output is OK for your motor. We are looking for an Amps (e.g. 30A) figure here. A normal 24v 250w motor should draw about 10A, but in reality this could be as high as 15A. For a rule of thumb divide the wattage by the voltage and multiply by 2.5. Then you will never be disappointed. 

It is the continuous or 10min peak amperage you should be looking for. 

The output of a lithium battery is largely determined by the BMS (battery management system), most modern lithium batteries can put out massive currents (amps), so it is the BMS  (the small computer that controls the charging and discharging (output)) from the batteries that is the controlling factor here. 

Sealed lead acid batteries do not require BMS. 

Thorpy's Guide to Buying an EBike Battery - Where to Buy

Summary: Anywhere you like just make sure cells are branded. 

I have not included non branded cells in my search. If you are going to spend a lot of money on a battery then buy something good, that will last (hopefully).

BMS Battery - Sell some batteries made with branded cells, but others are not branded.

Green Bike Kit - Sell some good quality batteries (Headway - £300 for 48V 10AH plus shipping).

AliExpress - Search for branded cells only.  So this page shows a seller who has some samsung celled batteries for sale (£300 for 48V 20AH). Just be sure to read the description carefully.

Eclipse Bikes - Sell good quality batteries based on headway (£500 48v 15AH) & samsung (£300 for 11AH) cells.  The headway batteries they cells can be repaired and have cells replaced easily. Eclipse bike also offer a repair service.

Thorpy's Guide to Buying an EBike Battery - DIY or Bodge Up

Summary: Make Do and Mend for Savings and Satisfaction 

If you do not like spending money and have spare time do some research. You can build your own battery! Or you may be able to repair the one you have. For example a poor quality battery may be filled with 18650 cells which you may be able to replace. You could re-use the case or the BMS at the very least. 

If in my case you are swapping from a 24V to 48V system, can you use a step - up - transformer. To change 24v to 48v. Although you will need a transformer capable of handling high amperages, and a high amperage battery to account for step down in current. I may try this as this costs £18 insted of £300!

Thorpy's Guide to Buying an EBike Battery - Physical Size

Summary: Make sure it fits!

All bikes have limited space where a battery can be placed. For typical bike you are limited to a "bottle" type battery or one that fit on the rack at the rear of the bike.

Just be sure to check the battery you are getting for it size. Measure you bike to make sure it will fit, and that you have the correct mounting points.

Environmental Permit Application Consultants 

Vitamin C Content of Fruit Juices

Vitamin C Content of Fruit Juices - Intro

Although you can find out various Vitamin C Contents for Fruit Juices, on different web pages, there is no single place where you can compare a good number of differenet juices. Please find below table which I hope is handy.

Vitamin C Content of Fruit Juices - Comparison

All the below are based on 100ml of juice. A normal glass holds about 200ml, a pint is roughly 550ml. A typical serving size would be 200 ml.

Orange Juice - 50 mg

Apple Juice - 0.9 mg

Pineapple Juice - 44 mg

Tomato Juice - 18 mg

Grapefruit Juice - 38 mg

Cranberry Juice -  9.3 mg

Vitamin C Content of Fruit Juices - Longer List 

Orange juice, frozen concentrate, unsweetened, undiluted -137.9
White guava, frozen pulp  - 136.0
Red guava, frozen pulp - 56.0
Grapefruit juice, white, frozen concentrate, unsweetened, undiluted - 119.8
Papaya raw -  61.8
Orange juice, raw - 50.0
Pineapple and grapefruit juice drink, canned - 46.0
Lemon juice, raw - 46.0
Cranberry juice cocktail, bottled - 42.3
Grapefruit juice, pink and white, raw - 38.0
Orange juice, canned, unsweetened - 34.4
Orange juice, chilled, includes from concentrate - 32.9
Grape drink, canned  - 31.4
Grapefruit juice, white, canned, unsweetened - 29.2
Mango raw-  27.7
Lemon juice, canned or bottled - 24.8
Pineapple and orange juice drink, canned - 22.5
Tangerine juice, canned, sweetened-  22.0
Apricot raw - 10.0
Pineapple juice, canned, unsweetened, without added ascorbic acid - -10.0
Kiwi raw - 9.3
Lime juice, canned or bottled, unsweetened - 6.4
Passion fruit frozen pulp - 4.3
Prune juice, canned - 4.1
Apple juice, canned or bottled, unsweetened, without added ascorbic acid - 0.9

Vitamin C Content of Fruit Juices - References

Self Nutrition Data 

USDA

Wikipedia 

Effect of Dissolved Oxygen 

Vitamin C Content of Fruit Juices - Conclusion

It would appear that orange juice has the most vitamin c out of the commonly drank juices. It is worth pointing out that the peel of the orange that we usually throw away contains 136 mg, and if the fruit is organic is perfectly OK to eat if chewed well.

Planning Consultants

Fastest CPU for XW6400 and XW8400

Fastest CPU for XW6400 and XW8400

Whilst on ebay a week or so ago I noticed that there were some used processors for sale that I might try in my XW8400.

This page might also be interesting if you have a Max Pro 2, as these use the same generation of processors as the XW8400, also the Dell Precision 490. However I do not own a Mac or  Dell!

In the quick specs document, the XW8400 and the XW6400 are shown as using:

• Intel Xeon 5100 Series 
• Intel Xeon 5300 Series

At present I am using 5160 which is a 3 GHZ , 1333 FSB, 4 MB, 771 Processor

52XX (5200) and 54XX (5400) Series CPUs in XW8400 and XW6400

Since the release of my XW8400, HP have launched the XW8600, and its little sister XW6600.

These use the processor families (THEY DO NOT WORK):

•  Intel Xeon 5200 Series
• Intel Xeon 5400 Series

Now the faster of these newer processors use a 1600FSB which I thought might cause problems, if I were to try it on my XW8400. But some of the newer processors use a 1333FSB. So I thought I would try one of those.

The cheapest I could find on ebay that would have improved performance on my machine was the X5260, which is a 3.33 GHZ , 1333 FSB, 6 MB, 771 Processor. I bought 2 for £5 each so throw away money really.

THEY DO NOT WORK. I tried both just to make sure and the machine will not start, I replaced the original processors and she booted. So that is a shame no upgrades for me. I would 99% assume therefore that all 5200 series processor will not work. And I would 95% assume that all 5400 processors will not work.

So what are the fastest Xeons for the XW8400 and XW6400?

So to conclude the fastest processors for the XW8400 and XW6400 are:

• Dual Core - 5160
• Quad Core - X5365 

BUT BUT BUT What is this I see? HP mention a processor - Xeon 5170 at 3.33GHZ . . .  .

Well it is not listed on the Intel website so rather disappointingly this is either a typo, or a ghost CPU!

Thorpy's Recommendation

If you are undertaking very CPU intensive operations such as video rendering or such like, then it may be worth getting quad core processors. However, the XW8400 at least works very well with a 5160 processor. This is very noticeable when doing normal computer use (opening and closing apps etc.) A 5160 can be had cheaply on ebay as can a heat sink.

If you are thinking of installing one quad core, I would recommend installing 2 dual cores. This will not only be cheaper, but it will help cooling. You will spread the heat load over two heatsinks.

I have not tried the 5365 (quad 3.0ghz) processor, but I have tried the 2.66 ghz 5355. I found them to be noticable slower during open cloase working, and they run much hotter. In fact I think I burnt out a mother board on one of my xw8400's due to over heating*.

*Rebuilding 16GB outlook data base unattended, on a hot summers day with non-standard low noise CPU fan.. . . your choice. 


 Environmental Consultants Bristol

NVS 285 vs NVS 300

NVS 285 vs NVS 300 - Intro

I couldn't find a straight comparison of the NVS 285 vs NVS 300 on the web so have made this page.

NVS 285 vs NVS 300 - Bench Marks 

www.videocardbenchmark.net gives rating of 34 and 196 to the NVS 285 and  NVS 300 respectively.

NVS 285 - (From PassMark)

NVS 300

NVS 285 vs NVS 300 - Compared

Feature	NVS 285	NVS 300
Bus Interface Memory Size Memory Interface Memory Bandwidth MEmory Speed CUDA Processor Cores Display Connectors OpenGL Power and Cooling	PCI-Express 128MB DDR 64-bit 4.4 GB/s 350MHz NA 2 21 Watts (Passive)	PCI Express x16 PCI Express x1 512MB DDR3 64-bit 12.6 GB/s 16 2 3.3 17.5 Watts (Passive)
Picture
Video		Sunlight and Daylight Assessment