48v Battery in sleep mode - How to Wake it ? - iZip E3-Dash eBike

[mark-in-seattle]

(eBike model = E3-Dash (Currie 2014 IZip E3 Dash), model year = 2014)

Sleeping Battery = Tranz-X, Li-ion 48v, 8.7AH, 418wh battery seems to be stuck in dormant "sleep mode" due to not being used or charged for 11 months...dang. An answer for me hopefully will help other eBike users accessing this forum with "sleeping battery" issues.

Was stored at 35% charge after last use 11 months ago.

Battery still has sufficient energy to drive rear wheel motor and energize LCD control panel on handle bars. Only bottom two of 5 LEDs on battery light up: RED + Orange, other 3 OFF. Standard iZip 48vdc charger seems good however will not charge battery, LED on charger = green, => no current draw, but my Fluke dvm measures 54.7vdc at battery spade terminals (outside pair of terminals) with charger plugged into battery charge port. Other battery terminal pair combinations measure = 26v and 42v


NOTES:

Bike has been great for years and would love the be able to ride it again, this time avoiding low battery charge state.

What procedure might bring my iZip E3-Dash LiON 48v battery out of hibernation "sleep" state possibly due to charge on cells is below level considered safe by the BMS ?

The local Seattle iZip dealer has only one iZip bike in stock, sells mostly other eBike brands. Their service dept did not have any suggestions. I seemed to know more about this 2014 battery than they did.

I have Tektronix O-scopes, lab power supplies, Fluke DVM ...etc, EE background.

(photos attached of the battery connected to the iZip charger ..etc)





Any suggestions appreciated, thanks.

 

[amberwolf]

Sleeping Battery = Tranz-X, Li-ion 48v, 8.7AH, 418wh battery seems to be stuck in dormant "sleep mode" due to not being used or charged for 11 months...dang. An answer for me hopefully will help other eBike users accessing this forum with "sleeping battery" issues.

Was stored at 35% charge after last use 11 months ago.

Battery still has sufficient energy to drive rear wheel motor and energize LCD control panel on handle bars. Only bottom two of 5 LEDs on battery light up: RED + Orange, other 3 OFF. Standard iZip 48vdc charger seems good however will not charge battery, LED on charger = green, => no current draw, but my Fluke dvm measures 54.7vdc at battery spade terminals (outside pair of terminals) with charger plugged into battery charge port. Other battery terminal pair combinations measure = 26v and 42v

If it is driving the motor, it's not really in "sleep" mode, it's actively able to output power. If it were asleep, any load connected to it would not operate, and voltage with the load connected would be essentially zero.


If the output is enabled, the input should also be enabled. A BMS normally can't enable the output if the cells are in any state that would prevent enabling the input, *except* if the cells are too high a voltage--if it was only at 35% charge 11 months ago and has sat unused since then, that's virtually impossible.

The charger appears to be putting out the right voltage, so it's unlikely to be a charger or connection problem.

So it sounds like the BMS has turned off it's input. Finding out why is important, before continuing.

To do this, you should first check the actual cell (group) voltages. These are best measured at the many-wire harness from the cells on the connector where it plugs into the BMS, so you know what the BMS itself is seeing. Measure each pair of wires; a 48v pack should have 14 of them, and you will end up with 13 separate voltage readings. List those here and we can see if any seem problematic, and advise from there.


If any of them are too far different from others, or too low, it's possible the BMS has shutdown the ability to charge to prevent problems that can lead to a fire.

If none are actually below LVC (which they shouldn't be if the output is still enabled), but are just enough different in votlage to make the BMS not enable the charge port, you may be able to manually charge the low ones up to match the high ones, or drain the high ones to match the low ones.

If any of them are too far below the LVC, you would probably be safer replacing them than recharging them. Internal damage to a cell could occur that could eventually lead to a fire.

A BMS is designed to prevent using a battery that has dropped below a certain point. BMSs that don't do this, or have been bypassed one way or another, are one cause of battery fires, when the cells get damaged internally because of it..

 

[mark-in-seattle]

Thanks very much for your reply and insight regarding my "possibly" sleeping battery.

I will remove the battery cover and carefully measure the individual cell voltages and report back. The battery is indeed currently able to spin the rear wheel, though as you mention, perhaps the BMS is seeing an internal condition among the cells which is problematic and is correctly preventing the charger from putting energy in, until safe preconditions are met. I have a lab power supply and some load resistors which if warranted could be used to bring the cells into better balance.

Would be quite unfortunate to lose the iZip's Tranz-X battery after only very modest use these past years. Having owned an affordable Nissan LEAF of various models since 2011, I appreciate that Li-ION batteries can last quite a number of years with a reasonable percentage of original capacity if treated OK. We sold our original 2011 LEAF to a good friend and it has done very well for 10 years now. Should our iZip D3 Dash require a brand new battery, it honestly makes one wonder about the value proposition for folks like us who use their eBike modestly, not always daily or weekly. In contrast the old 2011 LEAF and our present 2019 model were/are used almost daily and their batteries given attention. If weekly use at a minimum is demanded of eBikes to support their batteries, I think eBike dealers should be honest with customers about this issue and concentrate sales toward eBike commuters.

Thank you again for your advice. I will report back and do my best to keep this LiON battery in use and safe.

 

[Mesanos]

Ebike batteries should be charged at least every three months, if not every month, to prevent self-discharge to below LVC. As you pointed out, your cars were given daily care so that wasn’t an issue. But it sounds like you have the tools to figure out what’s wrong with your battery and I hope you’re able to get it working again. I’ve recovered cells down to about 2.7V before, but I followed a procedure of charging, discharging, wrapping in plastic, freezing and thawing them before using again and then stored in an outdoor BBQ for years until I trusted them again, and still only charge them when I can keep an eye on them…