Vectrix Stock Battery Problems - what goes wrong in there?

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Re: Vectrix VX1 Stock Battery Issues

This is the continuation of a discussion that went a bit off topic in this thread:
http://visforvoltage.org/forum/6535-maximum-kilometres-or-miles

I want to continue the discussion here to keep the original thread on topic and to start collecting information about the battery here, where it might be easier to find in the long run.

Here is the lead-up to it:

I wrote:
RaDy wrote:

Mik, thats the only thing we can do right now, Dream.

Nothing wrong with dreaming sometimes a bit, but I thought you were trying to collect actual data about achieved Vectrix range in this thread. Otherwise you could have called it: "How much range do you believe you will get on your Vectrix?"

You are of course telling this to the wrong man! It is hopefully quite clear that dreaming is NOT all that we can do! I have had the advantage of the canceled warranty, as a reward for my proactive gearbox repair attempts and the sharing of this valuable procedure. That made it obvious to me that the battery needed to be opened up, analyzed and improved to give it a chance to have some longevity. I am firmly convinced that I "caught it" just in time.
My battery was showing clear symptoms of problems, and the analysis confirmed that, and the installation of the manual BMS prevented further rapid deterioration. There have been numerous reports of similar scenarios, usually ending with ever decreasing range, bathot messages and finally a bad smell emanating from the rear end...

Quote:

Dream about the life expectancy of our battery. But there is a guy here in Bcn who im in contact with and he has done around 14.000kms. He did 4.000km with the first pack and then went for the recall and has done another 10.000km with the second pack, i dont think its dreaming for him to make another 5.000km. Anyway i last spoke to him a month ago, so i will ask him how its going. I know he was waiting for a gearbox replacement and had the Vec in the dealer for 2 months but had finally got the change done.
15.000kms with 1 pack looks possible.

I am becoming more and more convinced that the Vectrix VX1 NiMH battery is fatally flawed. Not because on NiMH, but because of poor design. Their business model might have been bad , but it's the failure of the heavy, expensive and dangerous (due to high voltage) batteries that really caused the most trouble and service costs. The battery recall was only one disastrous facet of this.
Read this description of how the Prius NiMH battery is designed: http://www.cleangreencar.co.nz/page/prius-battery-pack

It reads like a "Who-is-who" of the cardinal mistakes that were made in the design of the Vectrix battery!

The main problem is the temperature gradient which will be present due to the three layered design: This will either cause severe imbalance, or needs to be rectified with frequent equalization charges, like introduced in the Oct 2008 software update. The equalization charges probably increase the life expectancy of the cells that would otherwise fail first, but they reduce the overall theoretical life expectancy of the entire pack. Each equalization charge is a slow over charge and ages the battery! The avoidance of C/10 overcharging (and over-discharging) is the key to the longevity of the RAV4EV and the Prius packs.

With an equalization charge scheduled every 10 running hrs (or whatever the exact number is) you cannot expect anything like the promised 80000km or 10 years.

You can expect to make it past the end of you warranty, though! Without the "update", many more batteries might fail during the warranty period.

Then JDH2550_1 replied:

jdh2550_1 wrote:
Mik wrote:

I am becoming more and more convinced that the Vectrix VX1 NiMH battery is fatally flawed. Not because on NiMH, but because of poor design. Their business model might have been bad , but it's the failure of the heavy, expensive and dangerous (due to high voltage) batteries that really caused the most trouble and service costs.

That's interesting to hear. I agree with all your points - almost. While NiMH might not be the cause of a bad design it appears to make it harder to come up with a good design for a motorcycle. However, that's not why I posted!

What I wanted to ask for was clarification on your feeling that high voltage was a mistake and feeds into your conclusion of a bad design. Do you have a feeling what would have been a better system voltage? What about the trade-off of the associated higher amperage flowing from battery to controller?

I really hope you guys get access to the Vectrix technical manual and the all important software access.

I'll reply in the next post!

Re: Vectrix VX1 Stock Battery Issues

When I wrote:

I am becoming more and more convinced that the Vectrix VX1 NiMH battery is fatally flawed. Not because of NiMH, but because of poor design. Their business model might have been bad , but it's the failure of the heavy, expensive and dangerous (due to high voltage) batteries that really caused the most trouble and service costs.

I meant this: It seems to me that the battery problems will not be able to be solved (by whoever might take over Vectrix) without a major redesign of the battery.

This is not an inherent problem of the NiMH chemistry of the battery, but a problem related to poor thermal management of the battery and practically absent individual cell management.
Any chemistry other than NiMH would get destroyed in short order with this treatment. That is why other battery types usually have a BMS! NiMH can take the abuse a lot longer, but it is not good for them, and they fail after several thousand km where other battery types would have failed after a few full charge cycles under the same, mismanaged conditions!

The approach to equalize NiMH cells by C/10, C/15 or C/20 overcharging used to be the accepted way to do this, but it is the wrong way and is not being done in the successful NiMH batteries in the Prius and the RAV4EV, AFAIK.
This type of over charging to equalize NiMH cells needs to be kept to a minimum to ensure long battery life. Deep discharging also needs to be minimized, or better, completely avoided.

In an NiMH battery the cells need to be either actively monitored and balanced on an individual or near-individual basis, like Li chemistry cells, or the development of imbalance must be prevented as much as possible.

The Vectrix battery fails on both these requirements!

A) There is no active monitoring, let alone transfer of charge between individual cells. All cells get charged with the same current, all the time. No balancing other than over-charging is possible. Only three sub-sets of cells are being voltage monitored: 27 cells, 48 cells, 27 cells.

B) The thermal management is flawed in several ways, causing the predictable development of severe cell imbalance within the battery.
This imbalance is usually completely "invisible " to the stock-BMS because of the particular arrangement of cells in three layers within the battery. Each voltage-monitored sub-string (27-48-27) is made up of equal amounts of cells from the top, middle and bottom layer of the battery. The cell imbalance develops due to this "stratification" of the battery in three layers, and usually each monitored sub-string contains about equal numbers of low, medium and high State-of-Charge (SOC) cells; therefore they all "look" the same to the stock-BMS and the battery appears to be balanced even when it is severely imbalanced.
The main cause of the imbalance which develops are temperature differences between cells.
Batteries use chemical reactions to produce electricity. Chemical reactions happen faster at higher temperatures. The self discharge of batteries is a chemical reaction and happens faster at higher temperatures. (NiMH cells are particularly affected by this phenomenon, but I think it affects all types of batteries to some degree.)
If some NiMH cells are a lot warmer than others, they will spontaneously loose their charge much faster. If those cells are much warmer often or even most of the time, then they will soon be severely undercharged in comparison to the usually cooler cells, even if the pack gets charged and discharged regularly. The higher temperature of the affected cells also ages those cells faster.
What happens next depends on the exact circumstances:
If the Vectrix is driven further than the low-SOC cells can go, and if no recent equalization charge has occurred, then the usually warmer, low-SOC cells will start to get charged in reverse when they are empty before the rest of the pack. The voltage of the pack then drops very suddenly and causes the "disappearing bars syndrome". This heats and damages the empty cells further.
If the pack gets recharged before the Low-SOC cells are empty, then the High-SOC cells (the ones in the usually cooler positions in the battery) will get over-charged. The stock-BMS can only see the average voltage of the pack, so it continues to pump current into the battery because the sum of the Low-SOC and High-SOC voltages is still below the desirable end voltage at the time during charging when the High-SOC cells are full. In extreme cases this might lead to bulging of the High-SOC cells and possibly even to venting of hydrogen and oxygen gases with resulting severe capacity loss. It always causes heating up of the High-SOC cell and ages them quicker.
In most cases there will probably be some damage to the usually-warmer-Low-SOC-cells from reverse charging, and some damage to the usually-cooler-High-SOC-cells from over charging.
The whole pack ages relatively quickly that way, but a few cells will be the weakest link and develop runaway damage due to their eventually permanently reduced capacity.

Frequent equalization charges, as introduced in the later firmware versions, can prevent this from happening in mild conditions, and will age the whole pack gently but steadily, as mentioned before.
In extremely hot weather, especially when parking daily in full sun, these equalization charges will in my opinion most likely be insufficient to prevent severe imbalance.
In addition, it will be difficult to "offload" the heat created during the equalization charges, because it is usually hot all the time during such weather events. There is simply no cool air available when it is needed most!

Before this post gets bigger than "Ben-Hur", I better get to answer Johns question!

JDH2550_1 wrote:

What I wanted to ask for was clarification on your feeling that high voltage was a mistake and feeds into your conclusion of a bad design.

I did not mean it that way, but I can see how it can easily be misunderstood.

What I meant is this: Because the battery is very heavy and has a dangerous voltage, it is expensive to transport replacement batteries and suitably trained personnel to work on the batteries. You cannot tell owners or untrained people to service the batteries or exchange them, because sooner or later someone would get killed because they do not have the training and/or skill to do it.
As a corporation, you could not even expect to get away without multiple workers compensation claims and lawsuits for back injuries, if you asked your technicians to fly to the scooters which need service, and lift the batteries out of the scooter without a hoist. The rear battery is heavier than the front battery and needs to be lifted out of the frame to replace the main fuse! About 47kg, no center stand in most cases, lifting the battery out with the scooter leaning on the side stand, it's no fun at all! One wrong move could damage your back, or the motor controller!

I believe that mature future EV's will have lower "hardware-voltages" and higher supply voltages to the actual motor. What I mean with this is a battery that produces no more than maybe 50V max, whatever the best compromise between actual safety and safety rules and regulations might be. The highest voltage that allows many people with a bit of training, preferably the owners, to perform simple repairs and maintenance without risk of electrocution, and legally! And small battery modules which can be lifted by hand, one by one, weighing no more than 20kg each.

In case of a multi-g deceleration event this would also make it much safer for rescue workers to peel the rider/driver out of the mangled remains of the EV.
Imagine using hydraulic cutting equipment to free bleeding passengers out of an EV when you know that there are 320V cables running somewhere through the twisted mess!

It might be much better to have a battery which only produces a lower "hardware-voltage" and then use some type of highly efficient transformer to turn it into a variable high voltage. This high voltage should instantaneously disappear whenever the EV is not operating normally.

The battery current would still be able to weld any metallic rescue equipment to the vehicle if the cables were cut, but the rescue workers would survive and could continue their efforts.

Re: Vectrix VX1 Stock Battery Issues

Thanks for the clarification. I see where you were going with that statement now - and it ties into "the failure" of the intended service model.

A couple of observations:
1) Another very robust battery technology is the venerable flooded lead acid. Just like you can balance NiMH by controlled overcharging - you can do the same with FLAs. The downsides of course are the need for regular maintenance of electrolyte, the inherent safety concerns and the poor energy density. However, for the right situation, properly maintained FLA's are actually hard to beat. This is not really that germane to figuring out the best EV battery but I always think it's kind of neat that the oldest form of battery still has some very nice characteristics.

2) Your description of a step-up transformer rather than a high voltage pack is interesting. I don't know enough to comment on the pros and cons - but I'm going to ask Erik (chief engineer at CuMoCo) about it.

3) In terms of solving some of the weight and service issues I think LiFePO4 large format prismatic cells go some way to solving the issue. Each cell is 3.2V nominal and a 60Ah cell is about 2.5kg / 5.5lbs and can be easily and safely handled individually. Of course putting 30 in series does cause a high voltage pack with the need for appropriate care by service personnel.

4) I think BMS's in the most general of terms are going to be important with whatever battery chemistry comes along. The monitoring and control required to achieve the most out of the most expensive subsystem in the vehicle should always be at the forefront of the vehicle designers mind...

It was a great write up and an interesting read. Thanks!

Re: Vectrix VX1 Stock Battery Issues

I think the different thermal environment for top layer batteries vs bottom layer batteries is very interesting.

Obviously, having a cell-by-cell BMS is a major step forward on this issue, since you can make sure that every cell is charged correctly. However, I wonder if there is still a differential aging effect even with a good BMS? Would it make sense to take apart your battery pack once a year and rotate the cells, much like we do with car tires? Obviously, that's a big task, and a dangerous task as long as the cells are all connected together.

Re: Vectrix VX1 Stock Battery Issues

jdh2550_1 wrote:

1) Another very robust battery technology is the venerable flooded lead acid. Just like you can balance NiMH by controlled overcharging - you can do the same with FLAs. The downsides of course are the need for regular maintenance of electrolyte, the inherent safety concerns and the poor energy density. However, for the right situation, properly maintained FLA's are actually hard to beat. This is not really that germane to figuring out the best EV battery but I always think it's kind of neat that the oldest form of battery still has some very nice characteristics.

But it cannot take one particular type of abuse very well at all: It needs to be charged immediately, any time left standing around in a discharged state causes trouble. NiMH has no problem with that, actually lasts longer if stored at 40% full. The Vectrix unfortunately has a "permanently on" motor controller and drains even more quickly due to this. The Vectrix battery is better stored full because of this.

Quote:

2) Your description of a step-up transformer rather than a high voltage pack is interesting. I don't know enough to comment on the pros and cons - but I'm going to ask Erik (chief engineer at CuMoCo) about it.

I'll be very interested to hear his reply!

Quote:

3) In terms of solving some of the weight and service issues I think LiFePO4 large format prismatic cells go some way to solving the issue. Each cell is 3.2V nominal and a 60Ah cell is about 2.5kg / 5.5lbs and can be easily and safely handled individually. Of course putting 30 in series does cause a high voltage pack with the need for appropriate care by service personnel.

If batteries produce much heat, then they need to be supported in a structure which allows forced air (or other coolant) flow evenly past all cells; hence the engineering of larger aggregates of cells with a common air flow. But smaller modules would not be rocket science! The individual cells in the Vectrix weigh less than a kilo each.

Quote:

4) I think BMS's in the most general of terms are going to be important with whatever battery chemistry comes along. The monitoring and control required to achieve the most out of the most expensive subsystem in the vehicle should always be at the forefront of the vehicle designers mind...

As we, as a species, come to realize that the "throw-away-society" is unsustainable, we will have to find many solutions to the same principal problem. The solution is to build things to last and to remain useful, and recyclable. I believe that NiMH batteries have a great, and so far largely untapped potential in this respect. But most likely not all by themselves, of course!

Re: Vectrix VX1 Stock Battery Issues

MikeB wrote:

I think the different thermal environment for top layer batteries vs bottom layer batteries is very interesting.

Obviously, having a cell-by-cell BMS is a major step forward on this issue, since you can make sure that every cell is charged correctly. However, I wonder if there is still a differential aging effect even with a good BMS? Would it make sense to take apart your battery pack once a year and rotate the cells, much like we do with car tires? Obviously, that's a big task, and a dangerous task as long as the cells are all connected together.

Rotating the cells might make sense in rare circumstances, but I do not think it is worth the effort most of the time.
Individual cell monitoring might be overkill for an existing Vectrix battery pack, but I hope it will be used in the future. That would also allow logging of data and targeted replacement of weak cells before they damage the rest of the battery.

Re: Vectrix Stock Battery Problems - what goes wrong in there?

Notes on the Vectrix Battery – (Use, Improvements and Charging)

The NiMH battery chemistry is a topic which, for most of us, is shrouded in mystery. Myths seem to form a large part of what this chemistry is about and how it should be treated or not treated as the case may be.

The following script lists and explains a number of items which have been fished out of the muddy waters surounding the use and maintenance of NiMH batteries and particularly the battery used in the Vectrix VX1 Maxi-scooter.

First of all, some observations made whilst investigating the Vectrix battery application.

The 'New' Battery as supplied by G.P. Batteries

The battery as supplied by G.P. Batteries of Hong Kong to Vectrix, consists of 102 cells of (nominally) 1.2 volts per cell providing a total voltage, when charged, of about 138 volts (1.35 Volts per cell).

The cells have been selectively matched for capacity, open circuit voltage and internal resistance before being built up into the pair of batteries (front battery of 48 cells and the rear battery of 54 cells)

The batteries were supplied to Vectrix as paired, matched batteries with a long life expectancy.

There will, of course, always be minor variations in the individual cells because, no matter how close the tolerances are in manufacture, there will always be some difference between the specific characteristics of the individual cells. Also, the internal resistance of each cell increases with ageing and cell 'ageing' can itself be increased through miss-use, resulting in some cells of a battery ageing more quickly than others.

If this characteristic of the battery is not catered for in the design of the charge / discharge system, the inevitable result will be battery failures.

The Vectrix Design

Vectrix were in total control of the design of the scooter in terms of the mechanical, electronic and electrical side of things. Unfortunately, there have proved to be some deficiencies in the design of the electronics which have resulted in some problems with the batteries. Some of these problems have now been overcome, some are still to be dealt with. The problems are listed below along with some possible remedial actions.

The main problems experienced by owners of the Vectrix VX1 have been connected with the power source i.e. the battery and it's performance. Basically, complaints have been about poor range (Low mileage), blown fuses, failures of the battery cooling impellers, battery overheating, during riding and whilst on charge, the appearance of the 'red' battery indicator (low battery Voltage) and the BATHOT (battery hot) symbol and occasionally the BUSULT (Battery under safe Voltage) warning.

All of the above has been investigated and the following script contains the findings of that investigation.

Uneven individual cell heating and Battery overheating.

It has been noted that under conditions of high power discharge (hard riding / hill climbing) some of the cells within the battery suffer a greater heating effect than others.
It has also been noted that, on long hill descents, regenerative braking also results in the heating of some cells more than others (and all cells when the battery is near to 'full').

This has the effect that those cells which are hotter suffer from greater internal losses than the cooler cells and this in turn creates an imbalance in the individual cell charges i.e. some cells have more or less ampere hours stored than others.

The 'knock on' effect of the above is that the situation just gets worse and the cells become further imbalanced over time. This imbalance, if allowed to get out of hand, results eventually in low range and/or the appearance of various warning symbols and, at worst, a damaged battery.

The reasons for these heating effects

The basic reason that the cells heat up in use is because each cell has a voltage, a capacity and an internal resistance. The voltage and capacity are both of great value to us but the resistance is the unwanted feature of all batteries.

The resistance of a battery limits the current that can be drawn from the battery. When the voltage at the terminals drops due to the current being drawn, you are seeing the effect of the battery's resistance. The higher this resistance the less current can be drawn for a given voltage drop.

When current is passed through a resistance heat is generated. This heat can be measured or calculated. The heat in watts is equal to IxIxR (the current squared, multiplied by the resistance). In the Vectrix battery the cell resistance is quoted at 'less than 1.2 milli ohms' i.e.0.001 ohms.

If we assume that the actual figure is 1.0 milli ohms then when 100 amperes is drawn from the battery the internal heating effect will be '100 x 100 x 0.001' = 10 watts per cell or 1020watts (1.02 kWatts) for the whole battery. This is a considerable amount of heat and it all has to go somewhere.

Heat effect whilst riding

On a single ride using the 'full' battery capacity (say 24 Amp Hours) at an average speed of 40 MPH, the Vectrix draws (on average) 25 Amps giving a range of just under 40 miles. At 25 amps drawn the heating effect is (IxIxR x 102 cells) 25x25x0.001x102 = 63.75 watts.
A total of just under 63 watt hrs.

On the same ride, but at 50 MPH the Vectrix draws 40 Amps and the range is about 30 miles. At 40 amps drawn the heating effect is 40x40x0.001x102 = 163.2 watts. A total of 97.92 watt hrs.

The heat generated within the battery increase rapidly as the current drawn increases. It also has less time to dissipate as the riding time becomes shorter with increased current drawn.

Heating effects whilst charging

When the battery is charged, current is passed through the cells and the chemical process of discharge is reversed. During charging, the cells again generate heat and this heat is also the result of the internal resistance and the charging current ( IxIxR). In addition to the IxIxR heating is the 'extra' heating which occurs in the final stages of charging. This heat is generated due to the chemical processes 'slowing down' as the battery becomes more full. At this point the cell voltage begins to rise more quickly and heat is generated more quickly. The usual practice is to reduce the charging current to a lower level where these effects are minimised (they cannot be removed altogether) with more of the energy ending up in the cells and less of the energy creating heat.

Heating effects whilst standing

A heating effect which can easily be overlooked is that of 'solar radiation' as in, Sunshine.
In a cooler climate, the problem is minimised and conversely, in a warm/hot climate the problem can become serious. Heat from direct sunshine on the top of the walk through covers will generate a lot of heat which will find it's way into the upper battery cell layers. Heat from a hot roadway will tend to heat the lower battery cell layers.

Heating effects of Regenerative Braking

Regenerative braking is a wonderful way of 'putting fuel back in the tank' free of cost. However, regenerative braking is also just another way of charging the battery and, If heavy regenerative braking is used when the battery is near full (say over 80% full), then the heating effects, (which occur in the later stages of charging), can produce serious overheating. Even short bursts of regenerative braking can result in serious heating and damage.

Dealing with the problems

First of all, the causes of the excess heating should be removed or reduced where possible.

Secondly, where the causes cannot be removed, the resulting heat should be removed or reduced as effectively as possible.

Finally, the results of the remaining heat 'damage' i.e. the resulting 'imbalance' of the cells. must also be dealt with as effectively as possible.

The following lists the causes of the excessive heating and some ways to correct this.

Excessive current demand:-
Reduce the current demand. This could be as simple as advising riders to adopt a more easy riding style and make them aware of the effects (shorter battery life) of 'aggressive' / 'enthusiastic' riding.

It is feasible but highly undesirable (and commercially suicidal) to reduce the power available through the scooters software. This could however, be an option where the owner requests it (perhaps on scooters for hire etc).

Regenerative braking:-
Regenerative braking has the sole purpose of 'putting fuel back in the tank' free of cost. It is therefore both practical and desirable to re-arrange the software to restrict the energy generated when braking to a level which the battery can accept without causing damage. The 'new' behaviour could be 'learned' by the rider and should not be a problem. Regenerative braking is NOT a substitute for friction brakes, it is an added extra and should only ever be treated as such.

Charging the battery:-
The charging process, as programmed into the Vectrix, is flawed.
The initial part of the charge where the charge current is at 'C.P. (constant power) is correct. It is the later stages that present the problem.

The '3 Amp top-up' which follows the initial charge appears to take no account of the temperature rise which occurs when the battery is in an unbalanced state. There is no reason why the software should not detect an abnormal rise in temperature (as caused by any group unbalanced cells) and, instead of proceeding with the 'top-up', move on to an 'equalising' charge but not at the rate currently used..

The 'equalising charge' set at slightly under 3 amps is excessive. At 3 amps considerable heat is generated.

Note
Some literature states that 'equalising charges' should not be applied to NiMH batteries and that 'charging at low current is undesirable'. These well meaning statements do not take into account the problems of unbalanced cells as occur in the Vectrix battery. There is no practical reason why the imbalance cannot be corrected as suggested here. In fact there is no other way to correct the imbalance. The Vectrix needs an equalising charge.

In terms of the level of current suggested (0.3 amps). Bench tests have shown that 0.3 amps will correct any imbalance without generating excessive heat. Duracell's literature states that a continuous current of 0.3%C can be used to 'float charge' NiMH cells for use where the cells must be maintained in a fully charged state. The 0.3%C is to balance the cells internal losses and to maintain it in a 'fully charged' condition. This statement shows that low current charging is NOT damaging to the cells.

Solar Heat:-
Where solar heating is a problem it may be feasible to simply park the bike in shade or cover the bike with a heat reflective cover when parked. When riding, the effects of direct sunshine and road radiation will be largely negated by the airfow over and under the bike. What cannot be avoided is the high ambient temperatures, but remember that the higher temperatures in themselves are NOT necessarily a problem. The problems suffered by the Vectrix batteries are caused by the uneven cell temperatures, within the battery pack. This 'uneven cell temperature' is the major cause of damage and eventual failure of the battery.

Incidentally:
The NiMH battery specifications (according to Duracell) allow for a 'recommended temperature range' of 0 to 40 Degrees C and a 'permissible temperature range' of -20 to +50 degrees C on discharge and for charging they 'recommend a temperature range' of 10 to 30 degrees C and a 'permissible temperature range of 0 to 45 degrees C. (Needless to say, the nearer the middle of the 'recommended' temperature range the batteries are operated the longer they will last.)

Heat removal:
Heat removal is essential where heat is generated but not wanted. That said, in cooler climates some heat generated within the battery housing could prove beneficial especially in near freezing conditions.
For most places where the Vectrix is operated, heat removal is necessary. Also necessary, but not much considered, is the idea of keeping the temperature of all of the battery's cells as even as is possible. Both of these objectives would be largely achieved if the Vectrix's plenum fans were run whenever the scooter was in use. Therefore it would be desirable for the plenum fans to run whenever:-

a/ the scooter was in use, either being charged or being driven and,
b/ the cell temperatures differed (from each other) by more than a few degrees.
c/ any of the cells were at (say) five degrees above the ambient temperature.
d/ and whenever any combination of a/ plus b/ and/or c/ exists.

All of the above improvements could be programmed into the software.

The Damage limitation – Dealing with the imbalance.
None of the above 'corrections' will prevent the problems of imbalance, they will simply reduce it to one of manageable proportions.
The imbalance can only be corrected by overcharging some cells whilst bringing the remainder up to a fully charged condition.
The overcharging of cells will inevitably reduce their life and the more current during this overcharge the more will be the resulting damage/ageing.
The only practical way to equalise the cells is to pass a low current through the whole battery until the battery voltage stops rising and remains at a steady level for a predetermined time period.
In view of the above it has been found that an equalising current of 0.3 amps is far more effective and far less damaging to the cells than the present 3.0 amps used by Vectrix.

The above suggestions could be incorporated into the charger software. The actual equalising current provided by the charger (via it's software) would have to be increased to account for the current being drawn to run the two plenum fans. Estimated 'equalising' current would probably be 0.3 amps for the battery Plus the current required by the plenum fan power converter (I am assuming that it is taken from the battery rather than directly from the charger)

Without access to the software.
Most of the above would be difficult to achieve and some of it impossible.
However, I have already fitted my own Vectrix with an input system for the purposes of providing a 'safer' equalising charge. (It also allows me to resurrect the battery if it ever falls below the voltage necessary to start the charger)
It is also possible to provide the plenum fans with an alternative source of power and therefore have control over them.
The regenerative braking can be dealt with by 'learning' when it is safe to use it and equally, when it is advisable not to use it.

Finally,
If anyone has access to the software writing programmes, I could make good use of a copy. ( pirated or otherwise) I do not condone software piracy BUT I bought an electric scooter and I expect to be provided with all possible information whereby I can maintain my property. I now require this software and if a 'pirate' copy is all I can get, then so be it. Please contact me via the forum

Re: Vectrix Stock Battery Problems - what goes wrong in there?

hear hear. all needs to be addressed.
and how many will make the move to lithium ion batteries.
i for one am watching very closely at this technology.
and am needing 100+ miles so my vectrix can go futher afield .
and would find this very useful on wekends.could the currant v charger be converted?
and could the currant fan system be striped out to make way for more batteries.
and and an old for cooling like the old 4 strokes used air when moving.
and have some type of meshing so air can easily inter in the compartment and cool and no grit but any water can drip out hols in.
bottom of compartment.kev

Re: Vectrix Stock Battery Problems - what goes wrong in there?

When you look at the advertised performance for GOLD PEAK lithium 30 AH cells versus the supplied Ni-Mh cells, you see that the internal resistance "Per Volt" is LESS for the lithium cells, therefore more of the battery power will be available for vehicle use, and less than 1/2 as much heat would be produced at 100 ampere load. (If it is actually possible to fit TWO parrallel sets of the lithium cells in the space, heat production and resistance will be cut further, generating less than 1/4 as much heat, and producing a VERY efficient and practical vehicle, which should EASILY travel 50 or more miles per charge!) (80 KM!!)--That type of performance would make ME very happy!---Robert M. Curry

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