Battery maintenance: discharging to red regularly?

First a question: Has there been any instances of packs failing that can't be directly related to temperature?

With the Oct 08 firmware, I discharge to the red on average once a week - and I mean down to about 118 - 120 volts. It keeps my range at an average of 35-42 miles per charge. This is on a pack that has just ticked over 9,000 miles in two years. I've been on this forum for around 18 months and can't recall a reported failing where battery temperature hasn't been involved. Here in the UK the temperate climate keeps the [reported] battery temp low. The highest I've seen on mine was 32 degrees after a full charge from the red during a hot spell. The rest of the year the highest is usually low to mid twenties. I also travel mostly on country roads at an average speed of 30 - 50 mph with no hard accelerating so my route driven riding style also helps to keep the battery cool.

My gut feel is that an accurate SOC of the battery is beneficial to the software. If you live in a cool climate then I think it is ok to discharge to the red. In a hot climate, then much, much more care needs to be applied not only to discharging and charging but also to riding style - if you tear around then that will stress and heat the battery just as much.

I stress that this is only a non-techie opinion based upon nothing more than myself as a case study.

Hi Sparker,

First a question: Has there been any instances of packs failing that can't be directly related to temperature?

I got my V in Okt. 2008 the battery failed during November 2008. Weather and Charging conditions were good (cool battery).
Failure began during one of the 5 deep discharges which you should do with the old handbook. It began with the dropping
bar sysndeome (5 Bars to zero and 20 km est range to zero). Because of the lack of a real BMS in the vectrix I avoid
deep discharges to the red light. I usualy drive the V more carefully the emptier the battery is and recharge when the
pack is down to 125v not lower.

Greetings Mike

Happening so soon after you bought the bike, you have to question whether the battery was damaged before it even got to you. I know there were a lot of packs damaged in transit to Australia due to some major issues where the batteries weren't maintained properly prior to the bikes being sold on. I had a temperature sensor replaced but apart from that mine is running very well. I'll keep monitoring temp, voltage and keep my 'relaxed' riding style, though am not that concerned about avoiding deep discharges. I seriously hope that I'm right on this one as the bike is now out of warranty!

Any other instances of non-temp related battery failure?

You out there, Steve Scott or Winged Racer? Perhaps you know of any?

Happening so soon after you bought the bike, you have to question whether the battery was damaged before it even got to you. I know there were a lot of packs damaged in transit to Australia due to some major issues where the batteries weren't maintained properly prior to the bikes being sold on. I had a temperature sensor replaced but apart from that mine is running very well. I'll keep monitoring temp, voltage and keep my 'relaxed' riding style, though am not that concerned about avoiding deep discharges. I seriously hope that I'm right on this one as the bike is now out of warranty!

Any other instances of non-temp related battery failure?

You out there, Steve Scott or Winged Racer? Perhaps you know of any?

As far as I know all the bikes running in Tasmania have suffered battery failures - but they would have been from the same stock that was sold in Australia. Apparently it barely gets above 20degC in Tassi....

Do you know anything more about the Australian battery failures?

...
...

Mik recently discovered that cell reversal is possible inside normal vectrix voltage parameters.
...

That's not much of a discovery, really! If you have a damaged cell, then it could reverse at 140V Vectrix battery voltage, too!

It all depends on the damage of the affected cell. It could even happen with a good, but imbalanced battery. In that case, it will soon turn into a damaged battery, though....unless it gets equalised.

Yeah, but I think, that's the point of this thread. What is the best way to keep the battery pack balanced?
1. By regular discharge to red and letting do a full charge afterards?
or
2. By doing discharge to red only couple of times a year?

Yeah, but I think, that's the point of this thread. What is the best way to keep the battery pack balanced?
1. By regular discharge to red and letting do a full charge afterards?
or
2. By doing discharge to red only couple of times a year?

That depends on circumstances!

My suggestion is to develop an automated system to do the deep discharge to exactly the point when the first cell reverses. Saves you from getting run over, too. And it would work for every Vectrix, regardless of battery health, season, terrain etc!

In the absence of such a system, and if you have a known good battery, I would suggest to always do the EQ charge first - just in case part of the battery is SOC imbalanced. That will prevent the deep discharge from causing capacity imbalance. But if I had a good Vectrix, unless I really needed the full range, I would not use it, anyway! If you need the full range of the Vectrix regularly, then it is not a suitable vehicle for you.

If you have a damaged battery, then the stock Vectrix BMS is utterly incapable of looking after the battery. In such circumstances repeated deep discharges will cause rapid decline to the point where some cells are completely destroyed and the battery becomes unusable. Therefore, if you have any capacity-reduced cells in your battery, you should avoid all rides until the red light. The weak cells would be screaming for help long before the red light comes on! But the stock system is deaf to those screams....

The more damaged your battery is, the more you need to avoid stressing the weak cells by deep (uncontrolled) discharges.

As a rule of thumb, use at least 1 or 2 bars less than what your Vectrix can supply without a BALPOR occurring.

If an unexpected (new) BALPOR occurs, do a full charge and a full EQ charge, then try again - but only once! If you do not get the expected range before the red light appears, then do not try again and again (unless you are angling at a battery replacement under warranty).

For those people without warranty, the price of the replacement is 3800+IVA = 4500 Euros + installation, = 5500 euros. And the price of a new bike is 6500... What's going on with the vectrix replacements? they're quite expensive...

1000 E just for installation, wow thats steep.
replacing the whole battery is easy, its replacing individual cells thats a pita.

4500 E is about what you would expect to pay for a 60Ah Lithium conversion.

If anyone has a truly dead battery, don't replace it with another nimh, go to your local EV workshop and ask if they can install a Lithium pack for you, if you supply all the parts.

Matt

Hi Mik,

In the absence of such a system, and if you have a known good battery, I would suggest to always do the EQ charge first - just in case part of the battery is SOC imbalanced. That will prevent the deep discharge from causing capacity imbalance. But if I had a good Vectrix, unless I really needed the full range, I would not use it, anyway! If you need the full range of the Vectrix regularly, then it is not a suitable vehicle for you.

If an unexpected (new) BALPOR occurs, do a full charge and a full EQ charge, then try again - but only once! If you do not get the expected range before the red light appears, then do not try again and again (unless you are angling at a battery replacement under warranty).

What's an "EQ charge?

What's the difference between a "full charge and a full EQ charge"?

Thanks!