Vectrix additional 'fuel'

It is a nice idea, but the more I know about vectrix, the less possible it seems to me to do mods like that...

How do you pretend to connect these batteries to the main system? when one battery runs on empty and the other one is half-empty, how do you prevent it from getting damage? Any ideas?

Not being very electronically inclined, I'll pass on speaking to the possibility of connecting up a battery in these two locations, but I will chime in with a note that most "trunks" are only rated for holding 10kg or so (if that).. I would think ditching the second seat would be the best option (I've thought it might be fun to transport our small dog in there), but you'd probably want it swappable so that you could regain the storage space and/or re-charge the unit separately.

Extra miles just may be feasible

We have already condemned a few notions of adding extra high voltage batteries, but on thinking differently why not add a 'relatively safe' low voltage battery.

The working principle is that a 12 volt 40 Ahr lead acid battery has a usable capacity of perhaps 384 Watt hrs. This is about 12% of the Vectrix's NiMH working / useful capacity.

If this 12 volt battery were used to power a 500Watt inverter at 230 volts output and this output used via 'Universal Freddy' to 'top up' the Vectrix NiMH battery (it could commence at the start of a journey), then there is a potential to get a range increase in the order of some 10% to 12%. The 'fuel transfer time' would (by design) be something between 1hr and 3hrs.

The 12 volt battery and the invertor plus Universal Freddy could all be fitted under the passenger seat (it might be a bit of a squeeze). Safety issues are minimised by the use of the 12 volt battery. If the invertor is efficient then there should be little heat to get rid of and this might just be a workable system.

Total cost should be less than £150. I am allowing £45 for the invertor, £50 for a 12 volt 40Ah battery and £30 should cover the parts for 'Freddy', there might just be enough change to buy an ice cream after the job is done :-) But, is it really worth the effort?

Come on folks, your critical comments are awaited. Sufficient good comments could result in a working design. Sufficient negative comment will consign this one to the scrapyard along with all other dumb ideas.

Keep smiling,

The Laird.

For the universal Freddy to work, it has to maintain a battery voltage above the actual battery voltage. Will this not confuse the Vectrix electronics regarding cutoff voltages as battery runs low?
If not, I would probably replace the 12V lead with at least 24V or 48V NIMH or LifePos and a more powerful inverter. I use a regulated power-supply in place of the Universal Freddy. I can readily deliver 1A or even 3A currents. Even though at 3A one would replenish nominally 10% of the charge over a 1h petriod all a while one depletes the whole batery in less than 1h. The gain is almost insubtantial and easily wiped out by the increase in weight.

No new batteries in the horizon.

Here's a question for the engeneers on this board. What if instead of using battery and inverter and the freddy as decribed above one were to add a 10Ah 130V NIMH or LifePo4 pack and connect it to the battery the same way the Freddy is coupled via lets say 40A diodes on both legs. charging of this pack occurs seperatly as needed. Yet once the voltage of the main pack saggs below 130V, this pack will passively feed current into the main battery (one-way only). A current limiter needs to be inserted that limits current flow to <40A. This way the extra battery would indeed serves as an extra fuel tank.

What if instead of using battery and inverter and the freddy as decribed above one were to add a 10Ah 130V NIMH or LifePo4 pack and connect it to the battery the same way the Freddy is coupled via lets say 40A diodes on both legs.

I'm not electrician, but the simplicity of this system makes sense to me.

Let's take a kokam lipo cell:

http://www.kokam.com/product/product_pdf/high_energy_density/EL-301_SLPB60216216_25Ah_Grade.pdf

max voltage 4.2v
weight 0.620 per cell
dimension: 220x215x6.3mm
capacity: 25Ah
max discharge: 25A

how many cells? 143v/4.2v = 34 cells
nominal voltage? 125.8v (when vectrix battery starts to be really empty)
min voltage? 91.8 v
weight? 34x0.620kg = 21.1 kg
dimension? 220x215x(6.5x34= 221 mm). It's a cubic pack that can be easily fitted inside the V's trunk!
capacity? = 25Ahx3.7vx34 cells = 3145 Wh

Diodes should limit current flow at 25Ah. The pack will need a BMS. Around 30% of the energy inside the battery wont be used due to mismatched voltages between the two chemistries.
Effective capacity with the extender pack:
1h ride: 2800wh NImh+25Ahx125.8vx0.7 efective= 2800wh + 2200wh = 5000wh!!
Range at "low" speed is extended from 60 km to 105 km.

Mik, would this work? Anybody want to have some extended range?

pd: jeanmi has sent us this news:

Esini, the company in charge of distribution over france said the lithium pack would be ready by the end of april. The max speed would be 125 km/h and max range 125 km .
these 2 last news are only rumors of course but the source is not so bad (esini) .
thing tend to go in the right direction so .
regards.

Oh... well, probably I missed some post....if the battery , SW etc are ready... what is missing?

It's missing the issue that caused the vast majority of NIMH problems: lack of time doing intense test drive...
Vectrix launched the bike without doing enough testing, and you all know the result... I hope this time the lithium battery is going to be infallible.
Anyway, the kokam pack looks promising, what diodes and BMS should we use?

are we all going to get lithium ion pack to test i think it would be good idea and i am shour we wouldent mind the change
also we love to ride our bikes . and i don't mind doing the odd thousand miles hear and there ..
kev

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Mik, would this work? Anybody want to have some extended range?
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There are a number of different questions in that one question! It depends on what you mean by work and what safety level you want.

As you might recall, I have actually built and tested a parallel battery pack for the Vectux. Just about everyone says you cannot do it, the negative delta V of NiMH cells will cause problems with cells in parallel, etc etc.

But, alas, it worked just fine! The weakest cells in the Vectux pack got a buddy which reduced the work these cells had to do. I ran it for several months with careful monitoring.

First I used a single 9Ah NiMH cell, like this:

The resistors in the diagram represent the cabling and several connectors and fuses, not a deliberately introduced resistance.

After testing this single auxiliary cell, and finding no problems, I built, tested and used this:

It also worked well, as in: it reduced the workload for the weak cells and extended their life span. And did not cause any problems.

However, the range was not really extended, it was maybe even reduced. Range on the Vectux is defined by when the weakest cell is nearing empty, and I try to stay well clear of that situation most of the time.

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Now to the other important aspect of an auxiliary battery pack (or really any battery pack for that matter): Safety!

I cannot think of a reasonably safe way of attaching an auxiliary 150V battery pack to the Vectrix.

My "virtual crash test" for an electrical scooter is this: Imagine lying in a salt water puddle, with one leg trapped under your severely damaged scooter. Maybe after a car ran over part of the scooter. This is a very common scenario, although most riders like to deny it!

With an unmodified Vectrix you would have a reasonable chance of remaining electrically safe in that situation; so you "only" have to deal with not getting run over by the next car coming around the corner, bleeding out etc.

But if you have an additional battery with more than a few dozen volt attached to your scooter anywhere outside the safety container, then you and any helpers/rescuers will be at extreme electrocution risk!

The same problem exists with a 24V battery, an inverter and a "Freddy" charger - unless you manage to mount the inverter and Freddy inside the safety container. That might just be possible in the small space in front of the batteries, but a very close fit!
"Freddy will actually increase the safety risks by boosting the voltage to 340V!

Most inverters seem to be the type that does not like inrush currents, and "Freddy", from the point of view of an inverter supplying it with power, is just a big capacitor waiting for a massive inrush current! So you better build an automated ICL as well!

I think you are barking up the wrong tree! It is much harder to add a battery pack safely than to build one safe pack from scratch!

8x TS 60Ah pack in the boot , something like this (but with about 10A capacity):

http://axiomatic.com/step-up-converter.html

In the battery box, paralleled to the battery through diodes.

Why not?

what are you going to do with 2A? That's not going to help. It'll take 5h to deplete your 10Ah battery. You need a 10Ah or larger pack that has at least a 128V and connect it via diodes directly limiting current draw to about 3C.

like I said, "Like this but with a 10A capacity".

We are tryng to avoid having high voltage outside of the battery box to improve safety. So having a low voltage pack in the boot (storage box for non-australians) that you can plug in and out at will, safely, and converting that to Vectrix voltage inside the battery box might be a safe, workable solution.

I think at least a 25% range increase would be needed to bother with it. That'd need about 1 kWh of storage. A 48v 40Ah pack would do it easily, including conversion losses. If 60V ia acceptable, then then 20 A123 20Ah pouch cells would make a nice light pack. (Expensive though)

I am new to the grid and have been following everyone on all of the vectrix blah blah. I just got my "NEW" 2008, and found that driving this to work, I'm short by "THAT MUCH!"(maxwell smart). What I came up with, is I added a nice hitch design to the back and under the tail for pulling a tiny trailer with a safety cantainer and a battery power-pak. WOW! IT'S COOL! I noticed that everywhere, everyone talks about the weight, why not pull it, it's the same as a second rider. So what I need from you all is some help in where to tap/in-line splice, a connection for this prototype trailer pwrpak with a twist-lok 50amp connector,like a large travel trailer. I've been an electrician for over 20 years, but do not have the know-how that you all have in this field of power and electronics please help and blog between you all for a suitible idea.

Stu

I don't know much about the strategy you are pursuing, but some advice after reading this group for a while, take city streets, you'll make it farther.

If you think you can just splice into the bike you have some surprises coming, people on this group who spliced in a light on a storage box behind the seat caused the bike to freak out. It really knows where all the energy is allocated and will reject modifications without changing the software that runs the bike.

I know they say that Vectrix was working on an under-seat range extender (fuel cell), but they also had control of the software so they could make it do things like not shut down the bike because it was plugged into 110v. Otherwise I would just have a Honda portable generator with me on long trips, charging as I drive.

-Randy