Electric scooters and batteries

Lead batteries yes, LiFePO4 well managed/handled not.

Lead-acid batteries are damaged a little bit with each deep discharge (below about 75%) while lithium batteries (especially the better chemistries like LiFEPo) don't suffer damage until discharge reaches 90% or more. In fact, lead batteries are only "happy" when fully charged, while lithium cells "prefer" to be between 20% and 80% charge. So lead batteries deteriorate much more quickly in scooter use than lithium cells. Lithium batteries deteriorate most when stored at full charge, in a hot environment. They also don't 'like' sub-freezing temps when low on charge, and can burst into flames if charged while very cold. Lead batteries deteriorate fastest when stored with a low state of charge, also in a hot or sub-freezing environment. Lead batteries are very stable compared to lithium cells, though...

If talking LiFePO4, most of the batteries with a short (2-3 year) service life are due to being undersized, poor charge profile, or being over discharged.

The battery in my own bike has done 110'000km and is down to 70% of original capacity (put into service in June 2010)
The original capacity was 8kwh (42 x TS 60Ah cells), with average discharge rate around 8kw at 100kmh (or bang on 1C discharge rate)

If the average continuous discharge rate is higher than this, you will have a poor service life (my first scooter had 19 x TS 40Ah cells, and average discharge rate was 55A or 1.4C - that lasted 20'000km)

The older ZEV scooters had batteries that were just too small for the application (like nearly all the bikes of their day)

The 7-year old 60AHX24 GBS (LiMnFePO4)cells are still doing fairly well on my Current scooter which has about 35K miles.

I have not tried a capacity check and I have never really pushed the scooter's range to cutoff at 85% dod - but the range can't be more than 10-20% lower than when new - and I have increased the motor controller maximum current settings. I never have done a pack current check though - I have meant to put laptop under the seat and log some data from the BCU to see how much current is being drawn drawing under various riding conditions.

The main effect of aging is reduced power output due to voltage sag (down to an average of 2.7 volts per cell from the nominal 3.0 to 3.2) when drawing probably 2-2.5C or so. Top speed is down to only 50-55 mph (80-90 kph) at best from the original 65 mph (105 kph).

I suspect the age is going to really show when the cool weather arrives in October. But unfortunately, in spite of a strong dollar relative to the yuan, GBS cells from the US's sole importer remain exactly the same price as 7 years ago. It will still cost about $2200 to replace the pack - before shipping across the US from California or Arizona.

Unfortunately, the battery tray simply will not work with any other cell. Without changing the whole BMS and charger setup (which due to Current being out of business for all practical purposes is basically a black box), I can't change to fewer cells of a different chemistry.

How about Silicate lead battery's?

There are two schools of thought on these. One says that they are just lead-acid batteries with some silicate (maybe even sand) added, and are no different. The other (mostly the manufacturers) says that because the sulfur is "replaced" with silicone, there is little or no sulfation. My 5000LA had Greensaver silicone batteries, but I didn't use the bike long enough to be able to say one way or the other. Generally, if you want lots of charge/discharge cycles, you want one of the more stable lithium chemistries like LiFePo4.

I have not tried a capacity check and I have never really pushed the scooter's range to cutoff at 85% dod - but the range can't be more than 10-20% lower than when new - and I have increased the motor controller maximum current settings. I never have done a pack current check though - I have meant to put laptop under the seat and log some data from the BCU to see how much current is being drawn drawing under various riding conditions.

The main effect of aging is reduced power output due to voltage sag (down to an average of 2.7 volts per cell from the nominal 3.0 to 3.2) when drawing probably 2-2.5C or so. Top speed is down to only 50-55 mph (80-90 kph) at best from the original 65 mph (105 kph).

It would be interesting to see what your continuous current draw is like

curiously, I wonder if your scooter just has cell level low voltage cut off to prevent over discharge, or whether it Ah counts to arrive at the 85% dod figure.

I too have seen increased voltage sag, although, and this is weird, the voltage sag I am experiencing this winter is not as severe as what I remember seeing during previous winters

I'm thinking with your reduced top speed, the discharge rate may have come down too, it certainly takes far less power to do 50-55mph than it does to do 65mph.
My bike takes 5kw continuous to do 50mph, which on your 4.2kwh nominal battery isn't too bad (just as pulling 11kw from my nominal 8kwh battery isn't too bad when I'm doing 70mph)

It's a shame it takes so many years to see how a pack will behave as it gets old.

I wonder what the new leaf and Tesla modules will be like when they too are 7 years old

I sure hope it isnt a battery. I just replaced them at the tune of $900. Because that is what the factory said was my charging problem. i got home and still cant charge.

well, if it's not the battery, or the charger, then probably the bms

I'd temporarily bypass the bms to see if the charger starts up.
if the charger still doesn't work, then the charger is dead.

btw - if the connection between the charger and the bike is similar to the one I had - it is possible to accidentally plug it in backwards (as the plastic connector gets worn)
The charger also doesn't have reverse polarity protection
Worst implementation of a DC connector I have ever seen

If the charger is dead, and needs replacement, I'd suggest swapping that connector for a basic Anderson SB50

What is the BMS?
I have ordered another charger. Not from ZEV for shure! So hope that takes care of it.

The BMS is the battery management system
On the ZEV it's implemented such that there is a little circuit board on each cell, between the battery and charge port there is a relay that turns off if any cell voltage goes out of bounds, and it communicates with the Motor controller to prevent discharge if any cell voltage is out of bounds.

If the BMS breaks, it will stop you from charging, or riding (depending upon how it broke)

Matt (is that you name?),

It has both cell level LVC and SOC-based over-discharge protection.

Under the old firmware, a cell going below 2.5 volts or lower as the temperature goes lower, would trigger an instant shutdown of the motor and a warning code would flash. Needless to say, this was a dangerous setup - in a left turn situation (right turn out your way) it could leave you right in the path of an oncoming truck should a LVC occur!

Thankfully, good old John Harding changed the firmware thankfully just before he was kicked out of the company under-presumably some kind of gag order and vanished from this forum. With the new firmware, there is just a momentary stumble, followed by the warning flashes - still not an ideal situation. It has happened a couple times on colder riding days (below zero c) over the last couple years.

It also counts either amp hours or watt-hours (I'm not sure which) - charging or discharging - resetting it to full pack capacity (60 AH or 4608 wh)for each full charge. This is used to drive a SOC "fuel gauge" on the scooter and also goes through a sequence of more severe measures - warning lights, reduced throttle, shutoff as the SOC approaches 20% SOC (default) or 15% SOC (the way I set it in in the configuration utility) - similar to electric cars.

With age, my pack seems to have good spells and bad. It's not quite bad enough to justify the big outlay on a new pack quite yet.

I wonder what the new leaf and Tesla modules will be like when they too are 7 years old

The 30kwh 2016 Leaf modules are performing remarkably poorly so far, losing reported capacity much faster than expected.

The 30kwh 2016 Leaf modules are performing remarkably poorly so far, losing reported capacity much faster than expected.

This is a shame

are these modules installed in a leaf? or another project?

faster deterioration is a shame, hopefully tesla modules fair better

This is per LeafSpy reports from leaf drivers. The "state of health" which is believed to represent capacity, drops quickly from near 100% (if it's that high when the car is new) well down into the mid or even low nineties, pretty quickly.

This is true with LEAF's, but I've read or heard nothing about problems with Teslas - they are reporting almost no degradation on 5 year old, >100k mile, Model S's

The key seems to be managing the pack so it stays in the golden 20% to 80% SOC range. Pack life is almost indefinite if this is done - but at a usable range penalty of course...

I'm not sure that Tesla packs report their actual capacity in the BMS data. You may be seeing the result of reserving some capacity for use as the pack degrades, as GM likely does with the Volt. Not to say that Tesla packs are as bad as Nissan's for degrading, just that no degradation at all would be akin to magic...

Leftie, what Tesla drivers have been doing even way before OBDII-port readers for those cars were available was drain the pack down to 0, i.e. car declines to move, then recharge to 100% and report on the RATED RANGE reading at this point. Of course there is degradation in Tesla packs, especially noticable during the intial few thousand miles, but the curve appears to bottom out after a while with only marginal further degradation. Check out Ben Sullen's latest Report on this data in his Teslanomics utube channel:
https://youtu.be/Gb_i4ihsJ1w

If the BMS is programmed to reserve capacity, making it available only as usable capacity declines, then you would see the same thing. I'm not making any judgements about what is happening with Tesla packs, beyond noting that lithium batteries do degrade over both time and cycling.