batHot, Flashing Temp light and red Battery light during charge.

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procrastination inc
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batHot, Flashing Temp light and red Battery light during charge.

After ridng 33km through hilly terrain, limiting throttle use and speed underload, I lost 8 bars and red battery light came on, speed restricted to about 50km/h. I limped 3km to my uncles house for a Boxing Day do. Great food, great company as usual :)

Temp in the high 20's at midday, I put the bike on charge. bat temp 32 degrees at the start of charge.

1hr later, 1/3 full bat temp 36...

another hour later a little over half full, batt light on, temp light flashing bathot on the LCD :( ambient temp might have been low 30's.

I turned off the power and switched the ignition on, this seems to fire the fans up. I let it sit for an hour like that then restarted charge. batt temp 44... shut it down againg and let it sit for another hour with the fans running, bat temp 36 after that. restarted the charg and it completed without the fault recurring.

As the evening air cooled, I turned on the fans again for a few hours, then topped up the charge and left at 10pm.

I was really gentle on the return trip and got to withing 6km from home with 9bars left. (Almost all downhill I think) so I nailed it and ran 100km/h all the way home without a hiccup. 7 bars left as I pulled into the drive. I noticed the battery fans weren't running as I pulled up and thought that was a bit odds. Put it on charge, fans spooled up , bat temp 34 and went down to 32 in the first 15 minutes of charge.

I wonder how lithiums would behave in these circumstances?

antiscab
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Re: batHot, Flashing Temp light and red Battery light ...

i was running my vectrix at 44 deg c all christmas eve as well.

heres how the loss of bars works for me:
if you leave you vectrix sitting for more than 12 hours after a charge before use, bottom 2 bars don't exist.
if voltage at start is less than 142v, or pack temperature is above 30 deg C, another bar or two doesn't exist.
if you haven't full cycled in the past 24 hours, another 4 bars don't exist.

the overheating while charging would indicate at least one reduced capacity cell. in my experience, cell heating is not significant until near full charge. if you are lucky, your whole pack was just under-charged, but this would not be consistent with only having put 1/3 of the Ah pack in.

if just a couple of cells were behind due to un-even self discharge (temp again?) these would have the red batt light. if by Ah you pulled less than 5Ah after the lowest cell reversed, then it will probably be fine.

when you were at 9 bars, did you still have most of your accleration capacity?
when your battery is getting low, you lose acceleration capacity long before you lose top speed.
if you still had decent acceleration, chances are your pack is still in good nick.

my suggestion, if you know your going to need full pack capacity, full cycle the day before.
if it gets nice and cool at night, set a charge delay so the fans run through the night, and charging starts so its finnished just before sun up.
if starting with an indicated fully charged pack, set the delay so there is an hour or 2 for charging before sun up.
this gives the 3A constant current charge till 3 deg C temp rise time to replace all that is lost via self discharge.

Lithium batteries don't self discharge nearly as fast. seriously, i fully charged a lithium pack then put it in storage for 6 months, after 6 months even the surface charge was still there. i miss my lithium traction pack.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km

procrastination inc
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Re: batHot, Flashing Temp light and red Battery light ...

not sure about the acceleration, I was running very carefully because I expected the trip to be very close to the bikes capacity at a 60km/h max speed. Turned out I was right.

I charged the night before and topped it up just before I left, but I hadn't deep cycled it for a week and hadn't ridden it for 3 days prior to this run.

I still have the old program, no charge delay available.

Getting closer to putting thundersky cells in it. Using 42 of the 60AH cells will mean some mods. 36 of the 90AH cells will fit in the same space + a 6pack in the luggage space might mean 100km/h for 1hr capacity...

we can dream :)

R
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Re: batHot, Flashing Temp light and red Battery light ...

emp in the high 20's at midday, I put the bike on charge. bat temp 32 degrees at the start of charge.

Voltage is as important as temperature. What voltage did you get? Did you charge it in the middle of the sun? In hot season never park a vectrix in the sunlight!

another hour later a little over half full, batt light on, temp light flashing bathot on the LCD

Usually happens when a battery temp sensor board fails or when there's a huge temp difference between the sensors. You may have a cell with reduced capacity that got it's voltage inverted, getting very hot, blocking the flow of electrons and dropping down the voltage of the battery. If equalization does not balance that cell, you'll have find it and shunt it, or replace it (if you are able to find a replacement), otherwise your battery will quickly die.

Put it on charge, fans spooled up , bat temp 34 and went down to 32 in the first 15 minutes of charge.

It has been said in this forum that when temp is over 30 degrees the batteries must be cooled down before recharge. Nimh don't like hi temps, as they shorten their useful life. Do you know hot to set a charging delay to cool them down before recharge?

I wonder how lithiums would behave in these circumstances?

Lithiums can afford a wider range of temperature, hot temperatures should not be an issue any longer. On the other hand, the BMS will prevent all these cells with slightly reduced capacity from falling under safety voltage, and getting further damage... Your battery is dying because of lack of that BMS: Nothing prevents your damaged cells from getting more damage every time you do a deep discharge...
Aircon
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Re: batHot, Flashing Temp light and red Battery light ...

Do you know hot to set a charging delay to cool them down before recharge?

I don't. How?

Aircon
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Re: batHot, Flashing Temp light and red Battery light ...

Do you know hot to set a charging delay to cool them down before recharge?

I don't. How?

antiscab
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Re: batHot, Flashing Temp light and red Battery light ...

Put it on charge, fans spooled up , bat temp 34 and went down to 32 in the first 15 minutes of charge.

It has been said in this forum that when temp is over 30 degrees the batteries must be cooled down before recharge. Nimh don't like hi temps, as they shorten their useful life. Do you know hot to set a charging delay to cool them down before recharge?

while i would agree with keeping ni-mh cells cool, we generally kill them through reversal or overcharge long before they get old.

if you are planning on using the battery straight after charge, don't bother with pre-cooling.
i regularly charge with the pack temp north of 40 deg c (on days where ambient is north of 30 deg c) when i need the bike again almost as soon as its done charging.
self discharge is only an issue if the cells are hot when they are both hot and charged. if they are at less than 50% soc, they won't be doing much self discharging (actually this is another way of balancing)

another hour later a little over half full, batt light on, temp light flashing bathot on the LCD

Usually happens when a battery temp sensor board fails or when there's a huge temp difference between the sensors. You may have a cell with reduced capacity that got it's voltage inverted, getting very hot, blocking the flow of electrons and dropping down the voltage of the battery. If equalization does not balance that cell, you'll have find it and shunt it, or replace it (if you are able to find a replacement), otherwise your battery will quickly die.

there are 4 possible stages of ni-mh cell discharge.
stage 1 is where you always want to be. voltage will be above 0.9v.
stage 2 is where voltage has fallen to ~0.1v, heat buildup within the cell is still the same as all other cells. it will stay in this stage
for 20% of rated Ah or in our case ~6Ah. This is why no bms works for so long with cells with cells with such large self discharge,
you need more than 6Ah difference to 0 SOC between the lowest cell and the average before you can do rapid damage.
stage 3 is where the voltage is now ~-0.1v, heat buildup is twice that of the rest of the cells.
stage 4 is where the voltage is now -1.2v, heat buildup is 12x that of the rest of the cells. This is where real damage happens.

given temp before starting charging was only 34 deg c, stage 4 (and maybe stage 3) is unlikely.
given pack voltage caused a batt tell-tale, at least some of the cells got to stage two.
given pack temp rose significantly 1/3 the way through charging, its likely a significant number of the cells were already close to full charge, suggesting significant pack imbalance.

overcharging at 1/3C will raise temp rather significantly, though given you pulled out at least 9 bars (~15.8Ah) im at a loss to explain how some cells could already be full after only putting 6 (~10.5Ah) back in.

given it took an hour to recharge 1/3, it is likely the software still thinks pack capacity is 30.0Ah.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km

procrastination inc
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Re: batHot, Flashing Temp light and red Battery light ...

"if they are at less than 50% soc, they won't be doing much self discharging (actually this is another way of balancing)"

Tell me more Matt.

This sounds like a very useful, modification free routine to protect the batteries.

Tell me If I have this right.

Charge the bike, immediately ride it down to 50% capacity, let it sit for a period of time so the higher cells self discharge closer to the lower cells, recharge and repeat?

thanks

Jason

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Re: batHot, Flashing Temp light and red Battery light ...

given it took an hour to recharge 1/3, it is likely the software still thinks pack capacity is 30.0Ah.

Matt

He still has the old software, which doesn't measure the pack's capacity and always assumes it's still at 30Ah.

procrastination inc
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Re: batHot, Flashing Temp light and red Battery light ...

"He still has the old software, which doesn't measure the pack's capacity and always assumes it's still at 30Ah."

Serious andy? that sounds like a reciepe to cook low capacity cells.

If that is the case, why does the factory recommend the 5 cycle deep discharge at the start of use?

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Re: batHot, Flashing Temp light and red Battery light ...

Yep, even though my pack was deteriorating rapidly, it still tried to put a lot of electricity in. When it reached cut-off voltage, it would just cycle through CC and TR until it reached full bar scale.

I think that was because they wanted users to eliminate memory effect or voltage depression if the battery was standing still for a long time, not to actually measure pack's capacity. IMO that feature was added with the new software.

antiscab
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Re: batHot, Flashing Temp light and red Battery light ...

"He still has the old software, which doesn't measure the pack's capacity and always assumes it's still at 30Ah."

Serious andy? that sounds like a reciepe to cook low capacity cells.

If that is the case, why does the factory recommend the 5 cycle deep discharge at the start of use?

the 5 deep discharges recommended right at the start is to "wake up" the chemistry.

after a long period of inactivity (or even shallow cycling) the actual capacity of the cells starts to dimminish.
this, however, is not due to damage. the capcity can be recovered by deep cycling.
This is at the cell level.

at the pack level, the chemistry allows for a 20% variation between cells (Ah to 0%). after this, the lowest cells start to heat up faster than the rest. after another 20%, the lowest cells start udergoing significant damage.

as for balancing, when a pack is new and all cells are similar balancing is easy.
all that is required is all cells are at a very similar state of charge.
so balancing at 100% has the same effect as balancing at 50%.

balancing approach 1:
so charging at 3A till theres a 3 deg c temp rise lets the low cells catch up,
and letting self discharge at 50% pulls the higher cells down (you need to be able to cool the cells after a bout of self discharge balancing).
but yes, charging, then riding till 50% (in you case id wait till 5-6 bars are gone), the let it sit somewhere shady for ~18 hours or more (over a weekend perhaps?), the charge at night when its cool, the full cycle to get some capacity back, then full charge.
just letting the pack balance on charge is fine, just make sure its cool if not using straight away. this is very important with the old software. if you aren't planning on getting the new software, get an ABCool from mik, so you can use the fans.

balancing approach 2:
however, for a pack that has aged (cells with different capacities), this does not work.
the easiest way is still to balance at 100%, since the software is already setup for it.
as long as the lower capacity cells don't also have accelerated self discharge, this approach will still work fine.

balancing approach 3:
for a pack with a couple of damaged cells, the best way is to shunt them out (or maybe replace them).
if this isn't possible, then frequent overcharging at 0.3A (say overnight when you can get rid of the heat) will keep the damaged cell up.

as for working out if there is a low cell in the pack, without taking the whole pack apart:
my way relies on the sudden 1v drop when a cell changes from stage 1 to stage 2.
fully charge the whole pack, with 3A til 3 deg C rise, then 0.3A overnight.
then discharge slowly, (less than 3A) - almost all consumer products are powered through a SMPS these days, so they will all run directly off the pack (even here in Australia).
use an Ah counter if you have one, otherwise, just use a timer.
watch the pack voltage, when you see a ~1v drop over a short period to time, stop discharging.
use (or borrow) a multimeter with data logging if you don't want to hang around for hours on end.
the slow discharge rate should mean that if the low cell gets reversed crossing over to stage 3, the heat buildup won't be to bad.

make note of that Ah pulled.

if its above 20Ah, none of the cells are damaged, just a few with reduced capacity (probably), so balancing approach 1 would probably work fine.
if its between 15Ah and 20Ah, at least one of the cells has aged for some reason. balancing approach 2 would be better

if its less than 15Ah, you may also have a faster than average self discharging cell aswell. time for balancing approach 3, or better still, do a Mik style M-BMS. (im far to lazy to do this)

in all cases, you will have to try and predict how many of the bars are actually there on each day, based on what you have done in the past 24hours.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km

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Re: batHot, Flashing Temp light and red Battery light ...

i was running my vectrix at 44 deg c all christmas eve as well....
...
...

I'm keeping mine parked for now. It's been three weeks or so since I last took it for a ride.

Finally got around to install the diode protected connection from tab 103-001 into the boot. It replaced tab 28, which was unused. Tab 1 is not diode protected (but has a 20A and a 10A fuse) so that discharging of cell 103-102 can be done for reconditioning / exercising.

It was scary reconnecting the tabs to different locations: I had covered them with "liquid electrical tape" when everything was ready, just to be sure to be sure, and indeed, nothing has rattled loose or shifted. But loosening it without shorting anything is tricky!

Anyway, with a lot of precautions (temporary shrink-wrap over exposed cable ends etc) it all went well, and the M-BMS has had it's second modification done (the first having been the installation of the ICL connection points. It was sooo nice to just use it!).

Now I can charge the entire battery externally at will, using "Universal Freddy".
//i281.photobucket.com/albums/kk217/Mr_Mik/Vectux/Battery/Battery%20Rework%208%20M-BMS%20with%20Freddy%20access/th_DSC01287.jpg) //i281.photobucket.com/albums/kk217/Mr_Mik/Vectux/Battery/Battery%20Rework%208%20M-BMS%20with%20Freddy%20access/th_DSC01284.jpg) //i281.photobucket.com/albums/kk217/Mr_Mik/Vectux/Battery/Battery%20Rework%208%20M-BMS%20with%20Freddy%20access/th_DSC01256.jpg)
I am not looking forward to replacing that ailing cell 103-003 - dis-assembly of the M-BMS modified battery is a nightmare.

.

Whilst I had the cover off, I installed the long overdue heat shield:
//i281.photobucket.com/albums/kk217/Mr_Mik/Vectux/Battery%20Insulation/th_DSC01406.jpg)

Careful if you want to repeat such an exercise, the metal film on both sides of this "Bubble-wrap"-style high-tech product is conductive!

This information may be used entirely at your own risk.

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

R
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Re: batHot, Flashing Temp light and red Battery light ...

R wrote:

Do you know hot to set a charging delay to cool them down before recharge?

I don't. How?

hve a look at all pages: http://www.voltforum.cat/voltforum/YaBB.pl?num=1257336941

Aircon
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Re: batHot, Flashing Temp light and red Battery light ...

R wrote:

Do you know hot to set a charging delay to cool them down before recharge?

I don't. How?

hve a look at all pages: http://www.voltforum.cat/voltforum/YaBB.pl?num=1257336941

thanks

R
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Re: batHot, Flashing Temp light and red Battery light ...
R wrote:
Do you know hot to set a charging delay to cool them down before recharge?
I don't. How?

hve a look at all pages: http://www.voltforum.cat/voltforum/YaBB.pl?num=1257336941

thanks

you're wellcome!

procrastination inc
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Re: batHot, Flashing Temp light and red Battery light ...

my poor battery is still 32 degrees 36 hours after a quick blat to get doown to half charge :(

I'll plug it in at 5am for a bit

Mik
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Re: batHot, Flashing Temp light and red Battery light ...

...
...
...
just letting the pack balance on charge is fine, just make sure its cool if not using straight away. this is very important with the old software. if you aren't planning on getting the new software, get an ABCool from mik, so you can use the fans.
...
...
...

Sorry, but I do not (try to) sell ABCool's any more. Never sold one, actually. Can't be bothered with the licensing and insurance issues involved!

But maybe it's legal for yourself to make your own where you live.

This information may be used entirely at your own risk.

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

antiscab
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Re: batHot, Flashing Temp light and red Battery light ...

ah yes, insurance is always a bundle of joy

its a good thing you demonstrated just how you made it Mik.

jason - if the temps dont get low enough at night, you could have a go at refridgerated cooling.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km

Mik
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Re: batHot, Flashing Temp light and red Battery light ...

ah yes, insurance is always a bundle of joy

its a good thing you demonstrated just how you made it Mik.

jason - if the temps dont get low enough at night, you could have a go at refridgerated cooling.

Matt

And it can of course be made in a much less complicated fashion! A simple DPDT 12v 10A rates switch will do!

The switch should have a "Centre Off" position to avoid any reasonable risk of the two circuits "making contact" with each other.

Or, even easier, unscrew the seat each time and plug in a 12V supply (4A continuous minimum). But you will soon realise just how good it is to run extra cooling at will, timed for the coolest hours of the morning etc, and you'll want to build something automatic, like the ABCool. The screws for the seat will soon wear out if you undo them every time!

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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