Wednesday, June 30, 2010

Progress report on the 36/72V switch

I got some of the work I needed to do, done on the switch, however, the connectors I planned on using don't work as a screw-on connector for the switch so I only connected the copper pieces to the swtich. I first removed all of the screws, cut a small strip of copper and tapped and drilled holes into it to fit on the 3rd row to short out that section for the 72V configuration. I needed the copper to carry the current of the entire pack so wanted something really thick and solid copper.

W.B. Maske gave me a 6x8" piece approximately 3/16th of an inch thick. There's a gauge for this thickness. I think the person at W.B. Maske said it was 16 gauge.

This is how I used it on the 4PDT center off switch.

The screw posts are canted unevenly to each other so the copper wiggles a bit when the screws are tightened.

Second row is ready to connect the last few wires to the controllerso I've got the copper strip up in the air waiting for 2 cables running to the controller to connect.

Finally, as I was running out of time, I realized that I needed to have a working system of some sort in order to ride my bike to work so I hurriedly put the pack back together using some spare Y splitters for this 4x 4-to-2-to-1 configuration.

The picture is a little bit oversatured in reds, however, the packs are very, very bright red and look great in the sunlight.

Notice the mass of neatly arranged Anderson Powerpoles and cables? I moved the black connectors to show you how each group in the bag looks.

More later,

Tuesday, June 29, 2010

W.B. Maske for Copper!

During my lunch hour today, I went looking for a small piece of copper to act as a bus bar for my 4PDT center off switch so I noted a couple of shops to hit. I went to the first shop and it was closed. I went to the second shop and they didn't sell copper sheets. I was sadly disappointed and started to head back to work when I drove by W.B. Maske Sheet Metal Works in Bladensburg, MD. This was a pure drive-by-and-jam-on-the-brakes type of stop!

I walked into their customer entrance and saw a very clean, well run shop. A very nice gentleman came up and I told him what I was looking for. He came back with a small 6"x8" piece of copper and handed it to me. He didn't want anything for it even though I offered and so I went away very happy that I had found, by pure chance, the copper piece I was looking for. I highly recommend them for outstanding customer service!!!

Thanks W.B. Maske!

Reconfigured and slimmed down Bosch Fat Pack BAT836 batteries

I decided to go whole hog on my Bosch Fat Packs BAT836 36V batteries (BFPs) and fit 8 of them into my rear Topeak Expedition MTX bag. I took each of the 8 packs and disassembled them by removing the end bumpers which are plastic with a rubber coating and remove the extrusions that were not needed from the red shells surrounding the packs to reduce their size. I may do more, but with what I did, I was able to fit all 8 in.

First, the removal of all of the security screws, ends and protective end caps.

Then I used my Lie-Nielsen adjustable plane to shave off the parts I didn't need from the BFPs into a gardening planter bowl!

Then came the bundling of the packs together and of connecting the group of 4 Anderson Powerpoles that I needed for each pack. The configuration that worked the best was in a 1 flat pack over a 3 stacked configuration.

finally, putting them into my Topeak rack bag and zipping it up!

It fits snugly, but it fits. I intend to run the wires to the switch which I plan on installing tomorrow that allows for switching between 36 and 72V seen here

More later!

Friday, June 25, 2010

New GPS for my eBike

I've always wanted a GPS for my bike and have hesitated from buying one for various reasons: cost, complexity, another item to charge, etc. However, this popped up in my radar and I impulsively took the plunge and ordered it. It's a refurbished ASUS R300 GPS that is so small that it will be great mounted to my bike.

It sells/sold for $40 shipped and is the lowest price I've seen for a small GPS unit that's battery powered. Hopefully, it will work well and be useful on my ride!

More later,

Wednesday, June 23, 2010

Two new members of my Bosch Fat Pack BAT836 family!

I was able to pick up 2 more Bosch Fat Pack 36V BAT836 batteries yesterday unaltered so wanted to take a picture of them with their fellow BFPs. These two were inside a Currie battery pack where they replaced 3 lead acid batteries! I got them and the electric bike for $75!

They have small metal tabs inserted into the power connectors so that I could charge and check the voltages on them. I'll be running them through my LBD to see how much capacity they contain. 

The lovely duct tape pack to the right of the new BFPs is my home made pack constructed from 20x Doctorbass reclaimed Sony/Konion 18650VT cells. Essentially, the DTP (duct tape pack) consists of four groups of 5 cells from the good Dr. Doctorbass reclaims old Makita tool packs that contain the Sony/Konion VT cells and resells them as a service to the electronics community!

The good thing about my DTP is that it's ready made to check each cell individually and trouble shoot them very easily.

The individual 18650VT cells look like this:
They are nicely nickel tabbed so it's easy to solder them to the next cell. I hope to be able to make a tab welder in the future, but now, soldering is easier.

The Makita packaging includes a nice rubber pad underneath the cells to give them a bit of cushioning. Here's a shot of a pack minus one cell showing the rubber pad.

Even with this pad, the pack comes out much smaller than a BFP which saves a lot of room. Here's a comparison of the thickness of my DTP vs. a BFP.

With 10 packs it can save a considerable amount of room and a little bit of weight. The DTP is also much easier to stack and arrange since they are flat. The BFP has rounded corners and big rubber end bumpers.

The reason the BFPs are so thick is that the cells are staggered instead of side-by-side. There's also considerable amounts of plastic "fins" which give the packs extra protection from abuse and some heat dissipation.

More later,

Tuesday, June 22, 2010

Free Mongoose Electric Bike?!?

In my never ending search for more Bosch Fat Pack batteries, I spotted this used equipment ad on which listed 2 Bosch Fat Packs.

Stiffi had posted 2 BFPs and a Mongoose branded Currie electric bike. I made an offer on the BFPs and charger and he countered by essentially throwing in the bike if I came to pick up the whole enchilada!

I made it over there today and I now have a total of 10 BFPs and a new (almost) electric bike! I plan on refurbishing it and selling it on Craigslist. I need to desulfate the SLA batteries and to clean up the bike a bit. I also need to rebuild the slide-in battery holder. Stiffi had opened them up and replaced the SLAs with the BFPs so some work may be needed there. He was also missing the SLA charger so I'll need to come up with one.

The bike looks like this one:

More later,

Friday, June 18, 2010

LBD! Light Bulb Discharger

I had a spare 5 minutes so I put together my brand new Light Bulb Discharger courtesy of YPedal's design. I found it on his website here:

I couldn't find the exact same fixture as he used so I just improvised and looked around to see what was at the hardware store.

I saw the overhead light sockets first ($1.50/each):

Then I saw the amazing 300W 120V utility light bulbs next ($3.98/each):

Then I used a spare piece of wood to mount the two sockets. (free!)

After that, I wired it up with a couple of short lengths of red and black wire I had laying around terminated with a couple of Anderson Power Poles (what else!). (free)

I then hooked up my now spare Drain Brain battery analyzer in series between the battery and the LBD.

I first tested a single Bosch Fat Pack battery by itself which barely turned the bulbs on and were only drawing around 58-60W.

Then I put a series pair of Bosch Fat Packs and saw a dramatic increase in light brightness and in the amount of power being drawn from the batteries. The setup was drawing over 300W with the battery's 80V when first plugged in.

I then used a couple of "Y" Power Pole connectors and hooked up my digital voltmeter (DVM) so that I can watch one pack at a time. I cut off the test probes from the DVM and added some APPs on the DVM's test leads just for this purpose. Of course, I kept the test leads and added some APPs to them as well so that I can reconnect them and use it as a conventional probed meter if I needed that. However, I've found very little need for the probes since the change.

This will be a very useful device to diagnose any battery issues I may have.

More later,

Wednesday, June 16, 2010

Using a 4PDT Switch for 36V/72V switching

I've been researching how to add a switch to my current configuration to ease the switch between 36 and 72V configurations. I looked at DoctorBass's drawings on how to add the switch and just couldn't figure it out. I already had the switch. (see below) I just needed to figure out how to hook it up.

After a bit of ruminating, this is what I will implement. If it works well, I'll add the 4th pack to each 36V pack so that I have more AH to work with.

More later,

Possible Remedy

Looking at my power problems with the Bosch Fat Packs (BFP) in series has caused me to rethink why this is happening. It seems that if one battery out of the two in series is lower or less capable than the other in the pair, it may cause the weak one to drain to near zero. In order to minimize this lower pack issue, I'm going to first rewire the setup so that the batteries aren't in series with only one other BFP. This is how I had the packs when I was having all the issues:

I'm going to rewire the packs so that the cells can't draw from only one pack at a time by connecting and distributing the power this way.
See the connection in between all of the packs at the common junction point? Hopefully this will take care of the problem.

More later,

Wednesday, June 9, 2010

More power problems!

I again had a low voltage cutoff on my way home last evening.  This is getting very frustrating. I had ridden into work that morning and it was a very satisfying, high-speed, no problems trip in. I let the BFP (Bosch Fat Packs) cool off a bit (they weren't even warm) but I thought it would be wise.

I charged the whole pack and let it complete on its own. I then double checked by putting each pack on the charger to make sure they were full. I reconfigured the packs again into the 72V configuration I use for my ride home and let the pack sit for about 4 hours at my desk. When I got down to my bike and connected the packs to my DrainBrain meter, the pack only showed 75.7V when they should show 83.8V! I knew I was in for a short ride but took the bike anyway. I made it about 1 mile from work when it died. I checked each group of 3 72V packs and found that they were all down to LVC of approximately 63V. I took the bus home and then checked each pack. 2 of the 6 batteries were drained down to almost nothing <5V but I was able to charge them back to their usual 41.8V float charge setting.

I'm thinking that my current configuration of 3 72V 2S packs is not optimum for my situation. I am going to rewire the packs for 2 groups of 3 BFPs in parallel and then series the 2-3 cell packs for the 72V configuration. This should help spread the load from 3 groups of 72V packs to one 72V pack. I'll be very careful to wire each pack with the same lead lengths so as to not cause any balance problems and to double check the configuration before loading it on my bike.

This is a great learning experience!

More later,

Tuesday, June 8, 2010

Power problems solved! For now...

I spent some time this weekend and checked all 6 of my Bosch Fat Pack batteries and found one that was very low. I recharged each pack individually so that they were all topped off. I then rewired the pack so that the many connections would be more stable and not disconnect easily. Gorilla brand duct tape is very useful here, although a more convenient method of keeping single connection Anderson PowerPole connectors needs to be found! One that doesn't require that I stick on and remove duct tape!

Something like the Blok-Lok but for only one set of connectors not a pair of connectors.

The ride in this morning was fabulous. The weather was perfect (70 degrees and sunny) and the bike had tons of power. I averaged about 25 mph and topped out at or over 40 mph on the downhill straight sections. A wonderful ride!

More later,

Friday, June 4, 2010

Power problems this morning

I have a light day at work on Fridays so decided to ride in. Everything was going fine until about 3 miles in when I noticed that my power was sagging fairly dramatically. In fact, I was down to LVC (low-voltage cutoff) on my bike. I checked everything and noticed that I had used only about 2.2 AH which is about a 1/3rd of my expected power. I rode for about a mile and took the pack apart to see if I was having battery issues or motor issues. It looks to be that it is a battery connection issue. I am charging my packs now one at a time and seeing that 2 out of the 5 so far have come up to full charge very quickly. That tells me that they weren't used on the trip in!

I'm going to have to double check all of my Anderson Powerpole connections to make sure they are all VERY solid. I may need to tie them together somehow to prevent them from coming apart. If you think about it, a bike is a fairly high vibration environment and I'm hoping that my tying everything together will minimize my power losses in the future!

Wish me luck on my trip home.

More later,

Thursday, June 3, 2010

Over 2000 Watts!

On my way home last night, I kept an eye on the DrainBrain's Watts readout and noticed it going over 2,000 watts on several occasions. This is a huge amount of power considering the motor is rated nominally as a 500 watt motor! I need to limit (somewhat) the amount of power going to the motor to not burn it out. Speed is important, but longevity and safety of the motor is even more so! It's amazing to think that the controller is only rated for 35 amps which doesn't sound too significantly different than my current 22A controller, however, the power difference once you add the higher voltage (72V vs. 48V or 36V) is really dramatic. With the battery at 72V, 2000 Watts is only 28Amps!

Of particular note was the fact that I rarely ran at WOT (wide open throttle). Instead, feathering the throttle so as to not overexert the battery. I am currently running with the 6 Bosch Fat Packs wired as 2S3P configuration to achieve the nominal 72Volts needed.

In this configuration (2S3P), I was able to get to work and home but did notice that the batteries were essentially exhausted. The DrainBrain was showing between 62 and 63Volts for my BFP and the controller was cutting out power by cutting power in pulses to the motor. I need to wire the additional 2 BFPs I have in order to increase capacity. I'm also planning on testing each BFP for capacity since they should give me 2AH at a minimum each and I'm only getting around 1AH each. YPedal has a nice light bulb discharger (LBD) that he uses to test battery packs.

I need to add a thermometer to the motor to keep an eye out so as to not overheat it too badly. It was very hot to the touch on my way in and I didn't have time to check it when I got home last evening.

More later,

Wednesday, June 2, 2010

Finally at 72V and 40+ mph!

I went over to my friend, GCinDC from the Endless-sphere forums who helped figure out my 72V configuration. I bought a 72V 35A controller from Lyen in California back in March of this year and it has taken me this long to figure it out. First, the wires for the throttle were reversed. I figured that out by carefully looking at the color of the wires. However, GC figured out that the phase wires were reversed and so that it made a grinding noise when power was applied. He reversed the outside leads and the motor immediately quieted down and gained incredible speed. Here's a shot of the new controller all wrapped up and tidy under my Thudbuster.

With the batteries fresh off the charger, I was at 83.8 volts!

Here's how the bike looks with the new controller mounted on my bike and the new front fork and wheel. Overall it's a very tidy bike without too much fuss. I rode it into work today and it was amazingly fun. I almost popped a wheelie when I first started off!

More later,