NiMH reduced performance in cold weather

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undead
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NiMH reduced performance in cold weather

I have read about people on (I think) this forum and a few others mentioning that NiMH batteries suffer loss of performance in colder weather.

In terms of the Vectrix, would we be talking in terms of less range, less overall acelleration or both?

Cheers :)

mikemitbike
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Re: NiMH reduced performance in cold weather

It´s because of the chemistriy of NiMh-Batteries. The internal resistance of the batteries becomes higher at temperatures below 0°C so they "seem" to be empty earlier. Onother problem is that the batteries which are "hit" by very cold cooling-air "seem" to be empty earlier than the other warmer ones. This could maybe the reason for my battery-defect.

Greetings
Mikemitbike

retrodog
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Re: NiMH reduced performance in cold weather

I have read about people on (I think) this forum and a few others mentioning that NiMH batteries suffer loss of performance in colder weather.

In terms of the Vectrix, would we be talking in terms of less range, less overall acelleration or both?

Cheers :)
------------

Both.

Hands0n
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Re: NiMH reduced performance in cold weather
I have read about people on (I think) this forum and a few others mentioning that NiMH batteries suffer loss of performance in colder weather.

In terms of the Vectrix, would we be talking in terms of less range, less overall acelleration or both?

Cheers :)
------------

Both.

Yea, I've noticed a distinct drop in the range available on a given charge - I used to end up with 5 or 6 bars after a 25-mile commute, where now I am lucky to get 4 or even 3. And the new software [seems to] reduce acceleration performance as you get to those low numbers of bars! It is not especially cold where I am (SouthEast, just outside the M25), we've not hit the really bad stuff yet! But when it does that 25 mile run is going to be right on the edge I predict!

undead
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Re: NiMH reduced performance in cold weather

I have noticed the reduced acceleration when the bars get low as well, i am wondering whether it is to prevent people suddenly ragging it everywhere at lower charge levels so that the range is more accurate and the sudden drain on the battery is less?

Hands0n
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Re: NiMH reduced performance in cold weather

That sort of makes sense to me too, but I really wish Vectrix had warned me of it after the software update, if indeed that is what it is. I wasn't too ready and nearly put myself in front of a few "situations" on the London bits of the commute for the first day or so after the battery condition run-in process. The old software used to let you use the power until it had gone!

Now the brain has adjusted its not such a problem, just a bit pooey getting seen off at the lights where that was previously never going to happen! ;)

NickF23
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Re: NiMH reduced performance in cold weather

FYI

I have a 13AH 48volt nimh pack in my ebike. at 5 Celsius the drop in range and internal resistance is barely noticable alll though the final charge voltage is slightly higher. If temperature is an issue on the Vectrix it might be useful to time the charge so it finishes just before you use the bike. Normally the final stage of the charge will warm the batteries

Wotnopetrol
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Re: NiMH reduced performance in cold weather

I have my "markers" e.g. at this point when the first bar goes out then at this point when the next bar goes etc. and on a 24 mile journey to work and back, my indicated range has definitely dropped, or at least, I have a few bars less now at the end of the journey.

I'll try the timer approach so that it finishes just before I leave for work.

The best I ever managed on my commute was 9 bars left after the 24 mile run. It's now dropped to 6 bars. That's with a 420 foot climb/descent at the begining and at the end of the run.

The temperature has been around +5c to -1c lately and the V is stored/charged in my garage over night, which is at 11c pretty much all the time at the moment.

Simon

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Re: NiMH reduced performance in cold weather

You have to consider if you had the software update introducing the fuel-gauge recalibration feature. This might have an impact on the "remaining bars" at a given trip distance.
Because it cannot add any Ah capacity to the battery, it might have to count down faster when the Ah flow out of the battery.
Maybe some of this effect is blamed on the colder temperatures.

I guess the proof will be in the pudding when it gets warmer again in the northern hemisphere.

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Wotnopetrol
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Re: NiMH reduced performance in cold weather

You have to consider if you had the software update introducing the fuel-gauge recalibration feature.

I guess the proof will be in the pudding when it gets warmer again in the northern hemisphere.

I've not had the upgrade yet. From what I'm reading, I'm not sure I want it, but I suppose I could always ask for the original version to be loaded back on if I didn't like it.

So I set my timer to finish charging just before my commute this morning. The batteries were at 22c and there was NO increase in distance to the 1st bar going out, or the second or third etc.

I'm not going to complain. It takes me my 24 miles to work and back with plenty of spare juice for side excursions if I need, all on one charge. I would say I get 35 miles if I hammer it everywhere, 40 miles if I ride normally and 50 miles if I baby it until it stops, well 49.9 actually, I've never made the 50 miles. This is all in-town riding.

1,600 miles on the clock and all I do is plug it in at night and ride it. As long as it keeps doing that, I will be very pleased.

Simon

Simon

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Re: NiMH reduced performance in cold weather

I've not had the upgrade yet. From what I'm reading, I'm not sure I want it, but I suppose I could always ask for the original version to be loaded back on if I didn't like it.

Simon

I doubt that.
Vectrix Corp. are improving their product and want to keep it confidential how they do it. That makes it harder for the competition to bring an EV to market.

The updating of the software is the service mentioned in the warranty conditions, if you do not bring your vehicle for servicing, your warranty is technically void.

The training for new dealers and technicians is also a difficult and weak point, and in my experience the weakest link in the chain. They have had big difficulties getting any answers out of Vectrix Corp. I do not know if this has changed.

It would be even harder to get any answers / training / competent advice if the older software versions were allowed to stay around in some of the Vectrixes.
How could a new dealer possibly give competent advice if they are having a hard time knowing the current version well?

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Re: NiMH reduced performance in cold weather

I, too, have noticed a significant decrease in performance in my Vectrix in the cold weather. The temperature has been near freezing (35-40 degrees F). Twice I've had a sudden loss of power, similar to the loss of power that occurs at the 25-30% charge level. But this happened on a full charge! The red battery light came on as well. After slowing down to pull over, the battery light turned off and the power suddenly returned. The first time this happened I was riding at about 55 MPH, the second time I was only going about 40 MPH. I've also noticed the decrease in acceleration. I was surprised at how dramatically the NiMH batteries responded to the cold, but luckily it doesn't stay so cold for too long here in California!
(I do have the firmware upgrade).

moccasin
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Re: NiMH reduced performance in cold weather

My Vectrix definately suffers a lack of performance in cold weather. It hasn't moved in over a week now! HAHA!! :-)

I understand and respect the fact that some of you out there don't have a choice, but when it's raw outside, I put my health above my concern for the enviroment, and I take a nice warm truck to work. If I just take the V in on the good days, I'll still get 125 to 150 days of green commute per year, which is enough for the bike to actually pay for itself in gas savings over it's useful lifetime.

I'm proud to own it, and proud to ride it, but when it's cold, it's cold! ;-)

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Re: NiMH reduced performance in cold weather

I have read about people on (I think) this forum and a few others mentioning that NiMH batteries suffer loss of performance in colder weather.

In terms of the Vectrix, would we be talking in terms of less range, less overall acelleration or both?

Cheers :)
------------

The trick I find is to make use of the on-board time or a plug in time to make sure that (on a daily commuting basis) the batteries have just finished charging just before you hop on the bike. That way, they're fully charged and pre-heated (read; not frozen!). Otherwise you will notice the difference for the first five minutes of riding until the cells warm up.

Drew

BDI Drew

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Re: NiMH reduced performance in cold weather

Stranger and stranger... I'm riding to work in the freezing temperatures (32F/0C) and after riding about 20 miles (with about 5 bars remaining on the battery gauge), my red battery light comes on and the temperature light comes on and the 'bathot' message comes up on the left LCD display. I hope I make it home from work...

undead
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Re: NiMH reduced performance in cold weather

That is odd - best hope it is a malfunctioning sensor because in around 2c the other day, after a full 15 mile run at full speed down the motorway, the batteries were only just hitting 24c - and the bathot only comes on around 48c afaik...

I would contact Vectrix fairly quickly to find out first

Mik
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Re: NiMH reduced performance in cold weather

Stranger and stranger... I'm riding to work in the freezing temperatures (32F/0C) and after riding about 20 miles (with about 5 bars remaining on the battery gauge), my red battery light comes on and the temperature light comes on and the 'bathot' message comes up on the left LCD display. I hope I make it home from work...

You have probably damaged cells in the bottom layer - damaged during the Californian summer heat. Now, in the cold, they have even less capacity and tend to get charged in reverse when they are depleted of charge.
Getting charged in reverse creates heat, hence the bathot warning. At that stage at least one cell would have been more or less destroyed.

The internal resistance of the dying or dead cell/s will probably also be higher than normal, and this - together with the lack of 1.2V from each dead cell - causes the lack of power during acceleration.

It seems to me that the software upgrade came too late for your battery.....

Did you make it home?

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Rogresalor
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Re: NiMH reduced performance in cold weather

It does drastically.

I'm owning a electric bike with 24v 10 Ah NiMH GP cells and you're lucky the winter won't as long as here.
Here in Holland it will freeze from November till April.

In autumn when the outside temperature is around 15 degrees celsius I can run 20 miles on one load.
At this time the batterypack is loaded in house, because outside it is at this moment -6 degrees celsius.
In house the cells will charge at max level, but when mounting it on the bike and when I ride just up to 10 miles the red empty LED lits up hardly and they're empty.

I've red on a RC forum here in Holland that NiMH behave like this:

15-30 degrees Celsius (100% SoC)
10 degrees Celsius it is 80%
0 degrees Celsius it is only 60%
-10 degrees Celsius it is only 15%!!

At -4 degrees it is logical I can reach only 10 miles. The temperature outside in the batterypack drops insanely fast due too the cold freezing wind. Thus 10 miles is a reasonable distance when it is such cold.

I don't like that and when stalling the batterypack overnight in freezing temperatures the red LED lits up at just charged batteries.

I don't like that and I'm thinking to build a Li-ion sollution instead of these worse NiMH sollution which is nice when living in Spain or more south.

Is it possible to replace the 20 cell sollution with an 7 cell Li-ion pack of 10 Ah. Li-ion has a neglectable loss when it is so cold. Instead of 10 miles a can reach up 20 miles or even more.

And the cost? lower than a brand new NiMH pack, so a dirty marketing trick. The cost of 24 v 10 Ah Li-ion with seperate charger costs only 250 euro (320 dollar).

Is this possible for the controller on the bike which is made for NiMH? 24 volt is 24 volt whatever it cames from?

Like this nice pack:
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4257

I red on some sites it is impossible to fit Li-ion in a NiMH E-bike, even stronger, these are Li-Poly cells.

Everytime when stalling outside I've to keep the batterypack inside. I take it with meto acclimate.

Somebody with other arguments if it is possible, thanx in advance!

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Re: NiMH reduced performance in cold weather

It does drastically.

...........................

Everytime when stalling outside I've to keep the batterypack inside. I take it with meto acclimate.

Somebody with other arguments if it is possible, thanx in advance!

What's on your side is the large thermal mass of the battery pack. It also generates heat during the end of charging and during discharging.

All you need to do is insulate the battery pack from the cold. Wrap it up!

For the Vectrix owners: If I had to ride in a cold climate, then I would tape up the front air inlets during riding, and disable the fans during charging when not needed.
That can be tricky and dangerous, though.
But if you charge NiMH in a freezing environment you would have to be stupid to force-feed that cold air through the pack. But that is what it does, regardless of how low the temperature gets (I base this on the absence of any reports here that the fans do not run when charging in very cold conditions - someone would have mentioned it by now, right...???)!

The battery cooling fans are easily disconnected, and as far as I know it is impossible to determine if it has been done. It is fully reversible.....you would keep your warranty!

Just undo the two screws holding the front seat down, take the seat off, and pull off the 3-way connector on the battery cooling housing. You will also enjoy almost silent recharging that way! But do not omit to watch at least one full charging cycle and reconnect it when you charge in warmer environments.

Really cold environments could potentially be as detrimental to the bottom layer cells as really hot environments. The bottom layer cells might easily be 15°C colder than the top layer cells at times. Therefore they have lower capacity and get charged in reverse (and then heat up whilst getting damaged).

Once I have put the Vectux back together I will measure temperatures below and above the cell packs, as well as inside them. After that (if my hypothesis holds) I will install insulation to the underside of the battery housing.

My first choice will no longer be heat reflective paint, but rather something that offers a combination of blocking heat radiation as well as convective heat transfer. What I will therefore probably try first is a type of sarking used inside walls: It's like an extra-thick bubble-wrap with reflective metal foil on each side; one side is silver, one side gold colored. I happen to have some leftovers from a shed-insulation project. I'll test first which side of the foil should go towards the outside.

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tom5007
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Re: NiMH reduced performance in cold weather

The cooling fans run regardless the battery temperature. This morning I charged the bike with batteries at 2'celsius and the fans kept running. Disconnecting the fans sounds like a dangerous idea as long there is no mechanism that ensures no overheating can occur while charging/riding.
Norman

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Re: NiMH reduced performance in cold weather

The cooling fans run regardless the battery temperature. This morning I charged the bike with batteries at 2'celsius and the fans kept running. Disconnecting the fans sounds like a dangerous idea as long there is no mechanism that ensures no overheating can occur while charging/riding.
Norman

There is a safety mechanism: siai47 had to try it out involuntarily for weeks...

AndY1 ran his Vectrix with just one fan running, also for weeks.

The charger stops charging when the temperature gets too high and waits for the fans to cool things down.

During riding there would be a problem if you continue to ride even if you get a bathot and temp and battery warning telltale whilst your fans are disconnected.
This is not likely though if the outside temperature is really cold. Your battery will barely warm up I guess. But that is something for people in cold climates to try out, I cannot be sure.

I'll let you know about the heat issues with measurements, soon.

This information may be used entirely at your own risk.

There is always a way if there is no other way!

Rogresalor
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Re: NiMH reduced performance in cold weather

Yes, wrap it.

But I'm asking if it is possible to replace that cells by Li-Poly or Li-ion.

We're living here in a very cold climat and I'm bored to carry in and out that pack every day. If I let it outside; the bicycle works, but with every acceleration trhe red lights lits up. Even when fully charged.

At this very moment it is in California around 10:57 and here it is 16:57 and the temperature lies around -6 degrees Celsius. When I fit the batterypack on the bike, the first 10 kilometer it works wel, but as soon the whole pack become lower than 5 degrees the performance drops terrible. 3 month ago when the outside temperature whas 14 degrees I can ride 30 kilometers with one pack and now it is empty after 12 kilometer. No cells are damaged because the charging time calculated with the adapters output is 133% of the capacity which indicates a good state and this pack is merely 3 month old.

My reason to look at Li-ion is the temperature outside and the circumstances where I rode in. I'm using pills like Prednisolon and my weight is 95 kilogram so if my sister ride with the bicycle she cames much further and the more you drain from NiMH teh quiker it drains (Peukert effect).

With the same wattage Li-ion (24 v 10 Ah) I can ride up to 40-50 kilometer even in mid winter!

I only watch to my phone equiped with a Li-Poly cell and I blowing my everyday joint outside in the freezing cold and the phone can handle it easeally. Laying on the gardentable right in the freezing cold. I'm glad I don't have a phone with NiMH cells!

So my question is the possibility to replace the NiMH cells by Li-Poly ones. I don't do it myself so I know a very kind specialist batterylabatory who can do it for me in Utrecht (Holland). I know the boss of this centrum who cares my E-scooter for know and this one gets Li-ion instead of stupid Lead-Acid.

I ride nearly every day and if Li-ion has and age of 3 years I charge this one 312*3= 936 times in 3 year so I take the most out of Li-ion or Li-Poly.

I'm riding still 2 years full electric and I don't have a car! I living in Oss (Holland, Google maps, so there's one Oss on the world) and I rarely drive any further than 20 kilometer at one day, but a good friend of mine live 15 kilometers more east and 30 kilometer is my command. In summer no issue, but in winter a hazzard. I've parkinson and I can ride that long without any help on the pedals.

A new Sparta ION of 2500 dollar is too much money for a parttimer. I've a electric bike, a nice one and my wish is to fit Lithium technology and the sum is much lower than a Sparta ION so I can decide my capacity by myself and not the manufactorer.

Is this possible?
Controller: when he cuts of power? Could I stop the support when the red led spots on? Is this early enough?

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