Refrigerated Charging

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jmap
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Refrigerated Charging

Because I was very concerned about the high temperatures of the batteries in the charging process, I’ve decided to do an experiment called "Refrigerated Charging". The problem is even greater in longer charges which includes 4 hours of equalization. In the last charge, done by the traditional way, when I arrived to the bike she marked 41ºC.

As you know, the NiMH batteries have their ability affected when they reach high temperatures. From the 35ºC begins to be worrying and the higher the temperature the greater the danger of damage.

So, I’ve started an experiment with the following ingredients:
- A large plastic (7€);
- A portable air conditioning (AC) (300€);
- A Vectrix (8650€).

The idea is to provide cold air when charging the Vectrix. Since the air admission is made by the front, I’ve covered both the AC and the front of the Vectrix with the plastic, to reduce the space and increase the cooling efficiency. The hot air flow out of the AC tube was placed near a window.


The initial conditions:
- Ambient temperature of the garage: 29°C;
- Air temperature out of AC: 20ºC;
- Temperature of the battery (Vectrix indication): 35°C (after the deep discharge).

After the period of 30 minutes of ventilation (pre charging phase);
- Temperature of the battery (Vectrix reading): 30°C;
- Temperature measured at the outlet of the ventilation of Vectrix (rear end): 25°C.

After the full charge process (all phases) took about 10 hours. With 30 minutes of ventilation included, about 2.5 hours of charging, ventilation +1 hours, 4 hours of equalization, plus a few more procedures that that I could not trace because I was sleeping, produced:
- Ambient temperature in the garage: 26°C;
- Temperature of the battery (Vectrix reading): 25°C;
- Final stabilized voltage: 147V (Maximum noticed 149V, usually a normal charge produces 144V stable).

So I am happy to notify the success of my intents! Certainly it is not a convenient way to apply every day but for longer loads in enclosed and warm places, maybe can be a nice option to consider. This procedure can maintain the quality and expected life of batteries that worth much more than the cooling energy spent. Without the cooling system, I estimate that the batteries (in that conditions) would reached 45ºC (ie above 20ºC than what it was), this value make sense to me but I do not want to try it because it is known to be quite harmful to the batteries. The estimated value it is based on previous conditions (on the day before) that with a little more favorable and less loading time had reached to 41ºC.

This procedure is recommended for those who want to take care well their batteries in hot places. It is especially important when it is done a deep discharge as generally it does also the long equalization and a few more steps that I do not know what they are. This happens only in the latest version of the software (Oct 2008) and can last up to 10 hours.

In the next deep discharge (sometime in July), I will record on video all the phases and submit them here for us try to understand it. Until then, spare batteries for your Vectrix, I know I will.

(sorry my English)

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Re: Refrigerated Charging

- A large plastic (7€);
- A portable air conditioning (AC) (300€);
- A Vectrix (8650€).

-The smile on your Vectix's face....priceless!

Good work.

Simon

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Re: Refrigerated Charging

That's why I'm very happy to have my Vectrix in an underground garage where the temperature in the first floor is currently at 20°C, outside is 31°C. In the second underground floor, the temperature is even lower.

But yes, AC are really cheap now. I could get one for 200EUR. If it can extend the life of the battery pack, I'd do it also.

Edit: Thank you for the information about how long it takes to cool down the battery with pre-charge active cooling at 20°C. I'm getting a new software and a battery next week, so I know how to time my delayed charging.

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Re: Refrigerated Charging

Thank you for taking the time to do this and report it!

I've moved this thread to the Vectrix Collaborative Handbook, please stay on topic!

Undoubtedly this is an important topic.

Although the use of an air-conditioner will probably double the energy consumption for charging, and therefore reduce the efficiency by 50%, it might save energy overall if it increases battery life span.

In places where the air conditioner is occasionally used it will be useful. But in places where it is needed most of the time it might be better to get a different vehicle.

A small cooler / heater just for the purpose of battery management would be best. Like in the Prius, where the cabin air is used to cool the battery. NiMH batteries like the same ambient temperatures as we humans do!

This information may be used entirely at your own risk.

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

jmap
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Re: Refrigerated Charging

I don't know any very small AC, but if exists one that could fit above the front wheel and bellow the head lamp, ventilating directly to Vectrix air admission, would be perfect and very easy to use. Also the energy consumption should be a lot lower too. This could be an easy answer to the problem...

I will try too improve the method and report it.

Thanks for the critics :-)

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Re: Refrigerated Charging

I think that at least 9kBTU AC should be required. Consider; at CP charging, we're putting in 1.5kW of energy (1.8kW at the plug), at CC - 450W, at EC - 150W. Add all the fans, charger and airflow to the calculation and the fact, that you have to cool down 90kg of metal for at least 10'C.

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Re: Refrigerated Charging

I think you guys are wasting your time lowering temps to improve battery longitivity
Ian, Paul and I in Tassy rarely see temps over 20c... our bikes after a hard run would be reach 24c
my batteries charge at 18c-25c...well guess what fella's our batteries are all stuffed. Pauls range is 10klms, mine is 20klms,
dont know what Ians is?, the point is, whether you charge hot or cold, you live in a hot or cold climate.... makes no difference...the issue is balancing the cells.
sort that out and we are back on track to an awesome machine.
Peter

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Re: Refrigerated Charging

I think you guys are wasting your time lowering temps to improve battery longitivity
Ian, Paul and I in Tassy rarely see temps over 20c... our bikes after a hard run would be reach 24c
my batteries charge at 18c-25c...well guess what fella's our batteries are all stuffed. Pauls range is 10klms, mine is 20klms,
dont know what Ians is?, the point is, whether you charge hot or cold, you live in a hot or cold climate.... makes no difference...the issue is balancing the cells.
sort that out and we are back on track to an awesome machine.
Peter

I'm sorry but I don't understand your point of view... Temperature doesn't matter? Come on... Then why all the trouble that the new software has to pause and try to cool down? It is well known that in charge NiMH suffer above 35ºC. As Mik says, NiMH likes the temperature that humans like. If your place is cold enough to not reach these values, lucky you. This recommendation is for those who have to deal with high temperatures, right now I have 35ºC outside, if my Vectrix does equalization at these ambient temperatures, will reach 45ºC for sure. So please, keep that in mind, you are confusing different issues… Oh yes, and my range is actually 85km (last week mark).

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Re: Refrigerated Charging

I think that at least 9kBTU AC should be required. Consider; at CP charging, we're putting in 1.5kW of energy (1.8kW at the plug), at CC - 450W, at EC - 150W. Add all the fans, charger and airflow to the calculation and the fact, that you have to cool down 90kg of metal for at least 10'C.

That seems to be nice for the best results/ efficiency, but everything counts to sustain temperature of rising. Even extra ventilation can help... We must keep also in mind that people like to keep it simple... So if a small AC with 9kBTU is possible to find and place above the tire ventilating directly (or by a tube) to the air admission of Vectrix, would be perfect.

Unfortunately hot temperatures are a big problem for NiMH. If the batteries were lithium, that wouldn't be much of a problem...

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Re: Refrigerated Charging

A small cooler / heater just for the purpose of battery management would be best. Like in the Prius, where the cabin air is used to cool the battery. NiMH batteries like the same ambient temperatures as we humans do!

I was thinking of something to be permanently installed, that small!

Maybe a "Thermoelectric effect" device could be placed inside the battery compartment and then either cool or heat the air. See Wikipedia: http://en.wikipedia.org/wiki/Thermoelectric_effect

The air flow would need to be recirculated, rather than fresh air being sucked in all the time.

When the surrounding air is between about 15°C and 30°C it makes sense to just use this air.

But when it is very cold, or very hot, you want to keep the batteries isolated from the outside air.

Recirculating air, and conditioning it, would also help to avoid temperature gradients within the battery!

This information may be used entirely at your own risk.

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

jmap
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Re: Refrigerated Charging

A small cooler / heater just for the purpose of battery management would be best. Like in the Prius, where the cabin air is used to cool the battery. NiMH batteries like the same ambient temperatures as we humans do!

I was thinking of something to be permanently installed, that small!

Maybe a "Thermoelectric effect" device could be placed inside the battery compartment and then either cool or heat the air. See Wikipedia: http://en.wikipedia.org/wiki/Thermoelectric_effect

The air flow would need to be recirculated, rather than fresh air being sucked in all the time.

When the surrounding air is between about 15°C and 30°C it makes sense to just use this air.

But when it is very cold, or very hot, you want to keep the batteries isolated from the outside air.

Recirculating air, and conditioning it, would also help to avoid temperature gradients within the battery!

Very interesting. That would be perfect and inexpensive (I think). Seems so nice, why not use Thermoelectric effect (inside the battery compartment) to cool or heat if needed during charging or even discharging. Is there any drawbacks?

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Re: Refrigerated Charging

Cooling down batteroes for those in hot climates seem to be a fair trick improving battery live. I would have one concern (only theoretically as I am living in the UK) that significantly cooler batteries (compared to exterior temperatures) could lead to condensation within and around the battery pack.

Norman

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Re: Refrigerated Charging

Cooling down batteroes for those in hot climates seem to be a fair trick improving battery live. I would have one concern (only theoretically as I am living in the UK) that significantly cooler batteries (compared to exterior temperatures) could lead to condensation within and around the battery pack.

Norman

I didn't noticed any problems about condensation (I think that Vectrix is yet too young) but if there are any problems in those conditions, you should try to dry the air with a desumidifier to keep low levels of humidity.

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Re: Refrigerated Charging

Such a shame a battery isn't like a fuel tank, not needing so much care to maintain.

ICE vehicles of course are fighting constantly to prevent themselves from overheating, seizing, over-revving (in the case of a rev limiter) radiators bursting in winter etc. But now it seems that the EV may need a charging environment of cooled and dried air in hot countries, or indeed, a warmed environment if kept in a sub zero garage in the winter.

But we still love 'em, how we still love 'em!

Simon

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Re: Refrigerated Charging

Such a shame a battery isn't like a fuel tank, not needing so much care to maintain.

ICE vehicles of course are fighting constantly to prevent themselves from overheating, seizing, over-revving (in the case of a rev limiter) radiators bursting in winter etc. But now it seems that the EV may need a charging environment of cooled and dried air in hot countries, or indeed, a warmed environment if kept in a sub zero garage in the winter.

But we still love 'em, how we still love 'em!

You are right, but many of this problems happen because it is used NiMH technology. For example A123 batteries doesn't have that much problems, to be true, they don't have almost any problem, so I've heard. Unfortunatelly, some day it won't be possible anymore to replace the NiMH batteries. Maybe then Mik (or another expert here) could try them and advice us to make the change...

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Re: Refrigerated Charging

Update:
Seems that refrigeration action is most needed on equalization... Temperature raises considerably during this phase.

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Re: Refrigerated Charging

Curious - my manual says that the Vectrix was designed to operate at temperatures from 14°F - 122°F (-10°C to 50°C). Although I can tell the difference in performance depending on the temperature - I haven't been concerned about it getting too hot. Has anyone had their Vectrix break down because of overheating? I live in San Joaquin Valley where the temperature routinely gets up to 110°F (43°C) in the summer. This is my 2nd summer riding the Vectrix and I've had no problems with heat issues...
Vctrx.jpg

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Re: Refrigerated Charging

Curious - my manual says that the Vectrix was designed to operate at temperatures from 14°F - 122°F (-10°C to 50°C). Although I can tell the difference in performance depending on the temperature - I haven't been concerned about it getting too hot. Has anyone had their Vectrix break down because of overheating? I live in San Joaquin Valley where the temperature routinely gets up to 110°F (43°C) in the summer. This is my 2nd summer riding the Vectrix and I've had no problems with heat issues...

I confirm the manual says that, but 50ºC (122ºF) is the prohibitive temperature. It is known that temperatures above 30ºC start to harm the batteries and their life expectancy drops. Specially when in the charging process (I don't know why).

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Re: Refrigerated Charging

Tonight I've left the Vectrix charging at my garage with 25ºC of ambient temperature. When I arrived in the morning she marked 43ºC! If I was suspecting that the long equalization (4 hours) were take place I would do the refrigerated charging! I confirm that without it, the long equalization have 20ºC above the refrigerated!

Since I was suspecting that had a bad sensor, the readings were the best way for detect it. I was thinking that the max temperature readings were right but they took almost 2 days to drop to ambient temperature and that I doubt very much of that, unless the batteries pack retain too much the temperature inside their protection…

I ran to the shop (for getting temperature readings) with the ventilation always on and arrived with 37ºC marked on Vectrix display (outside temperature was about 20ºC). Some minutes later, the computer readings were (all in ºC):

4D (I suspect that is battery 1):
Ambient: 25,4;
Calibration: 25,3;
Mod Temp 1: 31,1;
Mod Temp 2: 32,8;
Mod Temp 3: 34,7;
Mod Temp 4: 30,9;
Mod Temp 5: 30,9;
Mod Temp 6: 33,3;

4E (I suspect that is battery 2):
Ambient: 29,3;
Calibration: 30,9;
Mod Temp 1: 35,8;
Mod Temp 2: 35,8;
Mod Temp 3: 35,6;
Mod Temp 4: 31,1;
Mod Temp 5: 31,1;
Mod Temp 6: 35,8;

Motor controler: 34;
Cap 1: 34;
Cap 2: 33;
Cap 3: 33.

I verify some discrepancy in readings but I don’t know if it is normal or not…

(sorry for my English)

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Re: Refrigerated Charging

I was thinking that the max temperature readings were right but they took almost 2 days to drop to ambient temperature and that I doubt very much of that, unless the batteries pack retain too much the temperature inside their protection…

Yes, it takes that long! Hard to believe until you try it out. That is why I built the ABCool 12V power supply .

Where I live the battery would never get below 35degC in Summer if cooling it was left to the early 2008 firmware. It would be a bit better with the newer software (since Oct 2008), but the ability to run the cooling impellers as long as I like, totally independently of the stock electronics, is great and keeps the batteries much cooler than they would otherwise be. Running the impellers for extended periods will under most circumstances also help to equalize the cell temperatures and so help reduce imbalance.

This information may be used entirely at your own risk.

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

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Re: Refrigerated Charging
I was thinking that the max temperature readings were right but they took almost 2 days to drop to ambient temperature and that I doubt very much of that, unless the batteries pack retain too much the temperature inside their protection…

Yes, it takes that long! Hard to believe until you try it out. That is why I built the ABCool 12V power supply .

Where I live the battery would never get below 35degC in Summer if cooling it was left to the early 2008 firmware. It would be a bit better with the newer software (since Oct 2008), but the ability to run the cooling impellers as long as I like, totally independently of the stock electronics, is great and keeps the batteries much cooler than they would otherwise be. Running the impellers for extended periods will under most circumstances also help to equalize the cell temperatures and so help reduce imbalance.

Thanks I didn't know that. Very nice cooling system that you have...

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Re: Refrigerated Charging

Its fabulous, that just when i was about to post a question for high temperatues, this question appears.
So, in my Vectrix i have exactly the same problem as you Jmap, in the last week (2 days without it cause of gearbox change) i have been experiencing high temps, first i thought it was a bad sensor, cause the temp after recharging would go up to 38c then it would go down to 33 or 34 and not move from there.Then i realised that last week had been a very very hot week also for Spanish standards, so i started ventilating the Vectrix giving it half an hour to cool before charge and then unpluging it and doing it again. i managed to get the temp down to 28 and 29 but it never went down from there,ambient was 26 or so.
Then without advice it started equalizing one night when the temp was at 36 and i had to stop it cause i had to go to work!!!!
to be continued........(no battery left)

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Re: Refrigerated Charging

Its fabulous, that just when i was about to post a question for high temperatues, this question appears. ......Then i realised that last week had been a very very hot week also for Spanish standards,......

Yeah, no coincidences there! That is why I wrote: I still believe that the Vectrix is the best production electric motorbike available at the moment, and that many of the scooters perform superbly well, although summer in the northern hemisphere might hold some surprises.

In the absence of cool air (i.e. heatwaves or hot climates) it can be a bit of a chore to look after a Vectrix.

I am amazed how easy it is right now to keep the battery happy, when the Gold Coast Winter temperatures (0°C to 25°C, usually over 10°C when I head off for work) are ideal for the Vectrix. Even the stock March 2008 firmware would do a reasonable job under these conditions!

Re: The "overheating" during the equalization charges: The easiest fix remains a timer that turns off the charger after a time sufficient for charging. I have also used a simple timer recently to just let the Vectux charge to 16/17th, repeatedly, with no obvious ill effects.

I think someone wrote this: The equalization charge starts again each time after the normal charging if it was not completed at the last time when it was scheduled to occur. If that is correct, then you can just delay the EQ charge to a time when it is cooler and when it can finish completely. Just interrupt the charging process each time with a timer, at about the time when the heating of the battery would begin. When you want the equalization charge to occur, plug in without the timer and leave it alone for 12hrs (or however long it takes). That also reduces the power wastage due to the chargers standby current consumption of 0.5A.

Just remember that the software is written to be distributed into every Vectrix VX1 on the planet. It will not deliver optimum results for most people. With some intelligent tweaking you can achieve much better results for the circumstances in your particular location / climate / work roster etc.

This information may be used entirely at your own risk.

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

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Re: Refrigerated Charging

I have received the answer from Vectrix about my readings. I share you what they told me…

They say that: NiMH batteries should not work with temperatures above 40ºC. Damage can happen in these cases. But, the NiMH batteries used on Vectrix can work with temperatures above 50ºC, and damage can only happen above 60ºC. Above 80ºC, the damage will be permanent.

So, I must not worry because my readings are perfectly normal…

What about that? Do we have special NiMH batteries? I will continue trying to keep temperature bellow 30ºC. That will not hurt them for sure.

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Re: Refrigerated Charging

Its fabulous, that just when i was about to post a question for high temperatues, this question appears.
So, in my Vectrix i have exactly the same problem as you Jmap, in the last week (2 days without it cause of gearbox change) i have been experiencing high temps, first i thought it was a bad sensor, cause the temp after recharging would go up to 38c then it would go down to 33 or 34 and not move from there.Then i realised that last week had been a very very hot week also for Spanish standards, so i started ventilating the Vectrix giving it half an hour to cool before charge and then unpluging it and doing it again. i managed to get the temp down to 28 and 29 but it never went down from there,ambient was 26 or so.
Then without advice it started equalizing one night when the temp was at 36 and i had to stop it cause i had to go to work!!!!
to be continued........(no battery left)

Glad I could help. I advise you to do refrigerated during long equalizations at least. That's when the temperature raises the most.

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Re: Refrigerated Charging

Exactly, it is equalizations, that actually heat up the Battery so badly and then its hard to cool them down without a source of cold air.
So at then end what i have done is to put the bike inside an airconditioned place/shop, that i can do so at non working ours and let it refrigerate for half an hour bringing the temp to 25c. It works fine. Then i drive home and keep the garage well ventilated, because my wifes car sits there emanating hot air and heating the garage´s air, which is why when the Vectrix tries to cool down, it cant because of the lack of normal air.
Ok,so i dont know if i explained very well, but to summarize, the Vectrix doesnt cool down easily if it doesnt have a source of normal ambient air(even if air is at 30c) while its just finished charging and its equalizing. These three events together are deadly for the temp of the Battery, it will go up to 40c and amaizingly conserve a 35c - 38c temp during a long while. So if you happen to mix those three ingredients it is a good idea to use Jmap´s idea of Refrigerated Charging.
Rag

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Re: Refrigerated Charging

Hi all ,
I have been reading all posts and it was very instructive thanks .
however I think I could add a small contribution to this topic even if I am all but qualifiied to speak.
I think we mabye mix up two different notions : temperature and heat .
My english beeing very poor I must make it clear that by heat I mean energy not high teperature .
I think that temperature does not give us an accurate idea of the amount of heat (energy) contained in the cells .
the temperature sensor just allow us to know the exteriror temperature of the cells,
in my case yesterday after one hour ventillation temperature had passed from 32° to 27°, so I have stopped ventillation to see what happend, one our later , in night time (air was 25°c), batt teperature has risen back to 30°c while nothing heats it .
It shows that the heat/energy contained in the cells have not been removed after 2 hour ventillation, and it shows that we are mixing up temperature and heat/energy.
I have continued the ventillation process for 2 extra hours , after one hour temps could not get under air temp : 25°c, so I une plugged again and check one hour later : the temperature had remained at 25°c, there energy had been properly removed from the batt pack .
then I started charging process and went to bed, the mornig after at 8 the equalizing charge was taking place and the temp was 28°.
all of this shows that you are perfectly rigth to cool the batt pack with a cooler, but it also shows that the one who can't do this to accelerate energy/heat removal have to program at least 4 hours of cooling before charging .
just my two cents
regards
jean michel urbani
Cannes France

vectrixhoper

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Re: Refrigerated Charging

it might just be cheaper to move to england nice n cool.
lovely scenery .

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Re: Refrigerated Charging

Hi all ,
I have been reading all posts and it was very instructive thanks .
however I think I could add a small contribution to this topic even if I am all but qualifiied to speak.
I think we mabye mix up two different notions : temperature and heat .
My english beeing very poor I must make it clear that by heat I mean energy not high teperature .
I think that temperature does not give us an accurate idea of the amount of heat (energy) contained in the cells .
the temperature sensor just allow us to know the exteriror temperature of the cells,
in my case yesterday after one hour ventillation temperature had passed from 32° to 27°, so I have stopped ventillation to see what happend, one our later , in night time (air was 25°c), batt teperature has risen back to 30°c while nothing heats it .
It shows that the heat/energy contained in the cells have not been removed after 2 hour ventillation, and it shows that we are mixing up temperature and heat/energy.
I have continued the ventillation process for 2 extra hours , after one hour temps could not get under air temp : 25°c, so I une plugged again and check one hour later : the temperature had remained at 25°c, there energy had been properly removed from the batt pack .
then I started charging process and went to bed, the mornig after at 8 the equalizing charge was taking place and the temp was 28°.
all of this shows that you are perfectly rigth to cool the batt pack with a cooler, but it also shows that the one who can't do this to accelerate energy/heat removal have to program at least 4 hours of cooling before charging .
just my two cents
regards
jean michel urbani
Cannes France

Thanks for your contribution. It seems that you are right and that precooling is a good procedure. Unfortunately I've concluded from my tests that the Vectrix only refrigerates very well when is using it's own ventilation (absorbing the cool air). I think that a pre delay of 4 hours doesn't grant that the ventilation will be working during that period. In either case refrigerating is always a good measure especially during long equalizations and hot weather (>28ºC).

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Re: Refrigerated Charging

it might just be cheaper to move to england nice n cool.
lovely scenery .

:-)
I only do it in hot days and when I suspect that long equalization is going to happen... not every time.

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Re: Refrigerated Charging

Hi
during the predelay , the dsp maintains ventillation as long as temperature is above 25°c, when temperature reaches 25°c it stops cooling , the soft seems then to check temperature every 20° or so and in case temperature rises back above 25°c the cooling starts again so I think a 4 hours predelay does provide a loog cooling if not a continued cooling , when the bat is 30° or more after a ride, loosing 5° takes at least 3 hours at the time beeing (given the summer nigth time temperature) .
regards
jean michel

vectrixhoper

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