All about my electric van and the epic kwh bump

Back in November I purchased an all electric Ford/Azure Dynamics Transit Connect. At the Azure liquidation auction. I even made it on that weeks episode of evtv. Thanks for lunch Rich and Jack!

It's great. It's my everything. I drive it daily and love it dearly. The huge Siemens motor is butter over the entire rpm range but especially so down low. The ONLY gripe I have with the van is the limited range offered by it's small ~28kwh Johnson Controls battery pack.

Hence epic upgrade. An additional 46kwh of A123 prismatic cells.

Unlike most of my other projects this one needs to remain operational and not turn into a half working science project. The problem is my van's intelligence. It's much too high. The daisy chained CAN network flips its shit if anything is breathed on the wrong way. I don't want to mess with the JCI pack/bms at all for fear of bricking it. AdamVan (name_still_in_progress) isn't going to even know it has an extra 46kwh in the back.

 My modules are 13s6p A123 20ah prismatic cells for 42.9v nominal and 48.1v fully charged. That voltage matches up well enough to a high power solar inverter, maybe 5kw. I'm going to be putting the modules in parallel for ....1080ah. Over 1000 amp-hours. It's going to be fantastic. That way the Johnson pack can charge from the A123 pack through the Brusa when the car is parked. Having a bunch of AC power onboard will be nice too for heating/minifridge/powertools/welding/whatever.

Having the car charge itself is admittedly a bit of a silly way to use such great cells but I cannot think of a better way to interface them. I think I'm going to run it like this until the Johnson pack just dies (hopefully a long time).

The number of  local derpyvans just doubled. Read about the adventures of Mikuvan here: http://www.etotheipiplusone.net/?p=2711 . 

It's April. 2013.

And then it accidentally became April. 

Lipobike aka the big pile of Lithium Polymer batteries on wheels recently got running again. It has been out of commission primarily due to weather (my thermal regulation was previously calibrated for a Floridian environment and I've had difficulty adjusting the gains). Also due to some skewed motor parameters. The skewed motor parameters were a product of much rigorous labor done by the great Tony "Danger" Coiro and myself. We got the Curtis 1238-7601 AC induction controller to play nicely with an AC24LS motor.

The Curtis 1238-7601. This is my motor controller, there are many like it but this one is mine.  

 I need to stop here and simply proclaim my love for this motor controller. The block is a place I've been very much around. Motor controllers are usually the thing that breaks first and this one breaks... dead last. The Curtis 1238-7601 is a joy to use. It is as if it was purpose built for the application of motorcycle propulsion. If I had infinite time and money I would likely still use this motor controller. 130V (max) and 650A of joy. It can even auto-tune to your own motor like T-Pain.

Riding a silent electric motorcycle is the closest I have come to flying while not dreaming. My inspection sticker is expired so I only briefly blasted around the back alleys around the Artisan's Asylum but oh.. oh my..

I really do love this thing. It's highly recommended. Simply Choice. In other news...

Equals Zero Designs is open for business! It is a pack of hooligans and hoodrats led by my dear friend Charles Guan. We produce high quality powertrain components and accessories primarily for the robotics/small EV market.

Shiny things. 

That picture was taken with Charles' nice camera. I should get a camera. This feeling has been dubbed Camerapenis-envy.

The Ragebridge features a unique for of current control. Many other speed controllers have hard current limits but the Ragebridge has active current limiting in that the motor controller will not simply shutoff when current goes above some preset point, instead it will simply maintain that preset point by varying its output "voltage". This is useful in real world robotics where gearboxes bind, limit switches fail, and chassis flex.

When a brushed DC motor in a powertrain is in a stalled condition for an extended period of time...some shit is about to go down. Brushed DC motors have terrible thermal paths. The heat produced in the motor is all in the armature which is usually in a sealed can with only the shaft capable of conducting heat away from the armature. Eventually this motor will smoke due to the insulation on the windings being pushed beyond its thermal capabilities. That is fairly bad but far from the worst that could happen. In a properly balanced system (a debatable topic) I think the motor should be the first point of failure because it is generally the most safe and least expensive component to nuke itself here.

If the battery cannot sustain the high current demands of the stalled motor it may nuke itself here too. It's rare but thermal runaway can happen with lithium polymer batteries. This is a real safety concern that can be avoided with a fuse or some other form of current limiting.

Lastly the motor controller can nuke itself. Pretty much everybody reading this blog should have exploded as least one motor controller so far.

So. Here's the pitch. The Ragebridge is awesome because it has a trimpot that you can set the active current limit to. Whatever happens motor side, the controller will not allow more current to flow than the preset limit. This keeps everything alive motor, controller, and battery.

Blitz used the current limiting feature of the Ragebridge to have an electrically simple limited rotation actuator. By setting the current limit conservatively, hard stops and stalls became acceptable.

Witch Doctor is alive and well. Busted Nuts Robotics is planning on making a big comeback to the Middleweight division after taking a hiatus in 2012. Along with my electric motorcycle this robot is an electrically powered object I am most proud of. Witch Doctor has two 1st Place BattleBotsIQ championship wins under its belt. The contenders along the west coast are very different than back home in Miami. For one there are THIRTY-SIX middleweights registered. That is completely insane. In BotsIQ we were lucky to get 10 entries. I cannot wait.

If you know me then you know I love upgrades. Upgrades to WD include planetary reduction boxes for the drivetrain. Apex Dynamics boxes similar to the ones used to great success by Sewer Snake of Team Plumb Crazy. These boxes are smaller and lighter than out old whyachi spur boxes. With our indirect drivetrain the additional weight of a large and well supported shaft on the whyachi gearboxes was unnecessary. The Apex boxes are also about half of the overall volume. Witch Doctor 2013 edition also features a completely steel weapon assembly. No more hardened dowel pins and shoulder bolt shearing in the weapon assembly! An all new chromolly steel wedge is coming after the destruction of our mystery alloy titanium wedge at the hands of the ferocious Blue Flame at BotsIQ 2011.

A Black Melon. There's one in Witch Doctor.

Many more things are happening. 

/ End Buroguu

A practical look at BMS options for DIY EV use.

     The Battery Management System or "BMS" is one of the most debatable subjects in all of the Do-It-Yourself-Electric-Vehicle kingdom. The job of the BMS is to make the battery more manageable ie: make your life easier/safer. At times this goal gets lost in a pissing match between competitor's features and specs with actual ergonomics/user-friendliness/cuddliness/adoptability being completely blown out of the nonexistent exhaust on your EV. Note that I included adoptability, that includes cost. There are some nice and tidy options yet they remain prohibitively expensive often costing more than the battery itself. This overview covers BMS options for lithium batteries. Lead and nickel based battery chemistries are not considered due to their relative rarity now with cheap lithium on the market.

     So what are the lithium based BMS options available today for the EV enthusiast? 

1. NO BMS

     This is a completely legit option especially for a hacked together, weekend project, non legit EV. The style of execution varies on your particular cell's behavior under over-charging. LiCo (RC Lipo) for example is known to not handle overcharging well with swelling and even fire. In this (and every) battery pack build it's best to equalize each cell before pack construction. This is most simply done with a full charge using a single cell charger or even a lab power supply. Doing so creates an initially balanced pack. Most controllers these days have pack level low voltage cutoff, setting this conservatively high will reduce your available onboard energy while lowering the chance of an under-voltage condition on any one cell/P-group. Similarly, setting your bulk charge voltage conservatively low (say 4.0v instead of 4.2v) will again reduce your available onboard energy while greatly lowering the chance of an overcharge condition.

Sure, with this method you may reduce your overall cycle life and not get the most bang for your buck Wh wise but the money saved on not purchasing a BMS cannot be ignored. Over time the cells will drift apart.

2. Biologically based BMS

     Even with no BMS, you still have a BMS. You. Yes, the human BMS. Manually checking the individual cell voltages every once in a while and bringing up a low cell with a single cell charger is a good idea. The higher your system voltage is the more of a pain in the ass this becomes because of more cells in series.

3. The BMS from the Kings of Hobby

    Next time you see some guy in the park flying a little remote control plane kiss him directly on his face. The clever cats in the RC model community have been using balance chargers for a long time. You should use them too. 

A personal favorite for cost/flexibility/power. The HK EC06-10.

    You can find balance chargers that can balance up to 14s and up to 1300W.

    Balance chargers connect to battery packs through their main discharge leads and a small balance connector. They detect individual cell voltages through the balance connector and can simply shutoff when any cell reaches it's maximum or it can go into balance mode which attempts to bring all cells to the maximum by shunting the cells that get there first.

    For my 30s 40ah pack on my motorcycle I balance with five EC06-10's on isolated 12v power supplies. That setup costs about $175 with scavenged power supplies.

4. Actual BMS. 

    If running LiFePo4 then you have the option of running a small thing called the MiniBMS. It's difficult to really even call it a BMS. The MiniBMS is really just a big analog balancer, which is awesome. Especially for the price. No monitoring, no data, no adjust-ability, all analog, HVC/LVC, you get the idea. 

After here the price skyrockets. Any of these BMS systems costs more than my entire battery back and often 2x. For info regarding Legit BMS I will direct you here.

/end_BMS_rant_1.0

  

     

- written on the way back from DragonCon.

STOMPY!

So yeah Stompy. It's a real thing. I'm the TA in a class at the Artisan's Asylum in which this is being built:

Hi, I'm Stompy. What's you're na----*STOMP*

 

 

 

 

We've been focusing on updating things over on www.projecthexapod.com but I'll do a quick recap here. 

To get this project started and to get a feel of the team's skill/workflow we decided to hold off on Stompy and quickly whip together his awkward cousin, Gimpy. Gimpy features an all-electric powerplant consisting of a ADC 9" motor (a common electric car motor) and a huge bank of lead I put together.

Baawwww...

 Maybe a kAH? aka my new stick welder!

 

 

 

 From CAD to reality!

Oh yeah, the coolest thing about stompy is the kickstarter. Almost at $90K!

Summer update

Here's the overdue epic summer update.

Like an annual pilgrimage I can never seem to escape from, I ended up attending this year's BattlebotsIQ event back in Miami. Instead of fighting Witch Doctor (forced retirement) I instead built this:

Hey, this would totally save your life.

It was part of the first annual College Design Challenge held at USATL/Battlebots/BotsIQ/BotsWorldwide/BattlebotsIQ/305/Nola's event.  The event consisted of a 48 hour buildathon with the overriding theme of disaster relief. The specifics were revealed at the beginning of the challenge. We were to build emergency flood rafts that could easily fit in a closet (24"x24"x96") and be assembled quickly by anyone. Luckily there wasn't really anything too exciting going on in the combat robotics area. I hand selected the best possible teammates with a completely empty resume of boat building expertise including fellow combat robotics veteran Eric Mueller, another engineer guy named Eric, and Jennie, a graphic designer who created an epic set of ikea-esque assembly instructions. The box of parts were to be assembled by "ordinary Americans". At the end however, I was very impressed and satisfied with our achievements. There was no box-o-parts. Instead each team got $500 worth of Lowes (Home Depot) gift cards.

I could say much more about this event but I'd rather you just look at that picture of the boat again.

Moving on....

Now that's more like this blog. 

I finally got a Turnigy emblem on my Turnigy lithium polymer powered motorcycle! Thank you Joe Schlesinger! He's one of LipoBike's new fans. I'm also a big fan of his company Arcbotics. Check out his robot Hexy on Kickstarter. 

Free charge/parking near the Boston Commons.

It was hard to resist whipping out my leatherman and taking this sign with me.

A fun picture to take.

Cambridge Mini Maker Faire. The next EV generation?

It happened, and I loved it. 

 That big green box there is a big battery charger. Not just any big battery charger, it's THE big battery charger. A Manzanita. Boosted to. I don't know why but these things make me so happy in life. The PFC20B is capable of 30a out aka fast. That on my bike combined with my DeltaQ, I'm charging at around 3.5kw! That reduced my charge time from ~5 hours to ~2 from empty. I also used the manzanita to charge something else....

It's got nanotech. I think.

My working-until-I-crashed-it-too-many-times Tricopter!! This little guy was intended to be a crash course in building quickly and building flying things quickly. Things that worked well:

Square nuts in 3D printed parts. You'll likely see me do this forever. 

- The Turnigy 9X aka my wannabe 9CAP. The menus are not very intuitive at all but once programmed it has proved to be a rock solid 9 channel 2.4ghz TX for 45 bucks.

Active hinge on tilt mechanism. Plastic on plastic. This just worked.

I was pleasantly surprised by the stability of the multirotor in flight.

Ok now onto what didn't work.

Pulltruded Carbon Fiber .5" OD tube from dragonplate. This stuff was cheap. I mean cheap. When you imagine CF I would be willing to bet you're thinking of some shiny honda civic hood with a woven pattern. Pulltruded is a process in which the carbon strands are pulled together in a single direction with no weaving. This creates an incredibly stuff and rigid tube. However, once any significant torsion becomes present it fails. Woven CF tube is considerably more expensive and outside the scope of this project. A simple, cheap, and bulletproof aluminum rebuild is planned.

The Hobbyking KK board. I know many have had good luck with them but I've found mine to be very temperamental. I ordered a replacement which performed admirably, I'm just not sure what was going on with the first one. Still, $15 for a mixer like that is unbeatable.


OOOkkk so I've covered things that roll and fly. Now onto walking. Have you met Stompy?

He Stomps. 

Those red chairs are for people.

Made the Boston Globe Sunday.

Stompy is being build in a class at the Artisan's Asylum. I'm one of the 4 instructors. More info: http://projecthexapod.com/blog/

Email me with anything, I'm around.

DangerScooter

Because DangerScooter.

It hasn't snowed yet.

I was lucky enough to be called by my good friend Ted Dillard to go visit another EV enthusiast, Jeff Disinger aka Dice23 on the Elmoto.net board. I consider my motorcycle fast but it's simply not in the same league as Jeff's Predator. It's a sick and twisted machine of electromechanical mayhem.

The "Pred" in action!

The sleeping Predator with Jeff and I

If you want to go really really fast, flip this switch.

The new controller for the "sport bike". 

As you can see, I'm in love with the Soliton1.

Don't think I've ever had more power on tap.

Check out Ted's EV Grin!

So it hasn't snowed yet. I'll keep riding till it does. 

Photo credits to Ted on pretty much all of these. If interested, there are even more on his blog: www.evmc2.com.