How to take out iZip Metro battery?

[JamesG]

How can the battery on iZip Metro be taken out?

Actually I am not sure of the model of the bike so pictures are enclosed. If you can identify the model from the pictures please do so.

Tried to access the battery from below the frame tube as shown in the pictures but not possible from what I see, unless everything is disconnected. I thought there surely must be an easier way to access it.

The battery has about zero voltage measured at the charging port. The bike must have sat for a long time (at least 6 months but probably more than a year). The charger won't turn on and I suspect it is due to not enough voltage at the battery.

Is the charger dependent on a minimum voltage at the battery to turn on?

Is there anyway to try to get the battery charged without taking it out? I have another used weak battery 37V 14A. I thought of charging this one and then connecting it to the charge port of the iZip bike to see if the voltage of the iZip battery gets high enough for the charger to start charging. Thank you.

 

[JamesG]

On second thought if the other battery is connected to the one in the iZip bike the amount of current going through the wiring will most likely destroy them. So I won't do that. But suggestions are welcomed.

 

[JamesG]

Also a picture of the whole bicycle for the identification.

 

[harryS]

If you google "Izip Metro Battery" for images, you get pix of the curved battery and old links to buy them, so it probably was designed to slide out of there.

It's not good to connect the output ends of two batteries together unless they're at the same voltage.

The charger won't charge the battery ... actually the battery won't let the charger run any current thru it, because it has determined via its internal circuits that one or more internal cells are below some threshold voltage.

You could leave it in there and put a battery on the rear rack, altogh the wiring is going to have to go in there somehow.

 

[JamesG]

The second time I opened the lower compartment of the bicycle's frame and yanked on the cables the battery gradually came out. It was fairly easy. I opened the battery after it was out but had to heat the case to soften the double sided glue inside to be able to open the 2 halves of the battery. Once the battery was out I checked the voltage at the BMS. It was about 7.6 volts. I took out anything that was glued to the battery and while doing that one of a pair of wires that was glued to the case of the batteries came undone as shown in the pictures. I think these are temp sensors and there were 3 of them.

The one that came undone still has its 2 wires attached to each other, I think what came off was only the protection and the temp sensor itself is good. Can this be verified?

Can this BMS be reused if this temp sensor has gone bad?

What are my options at this point? How can I check this battery further? Any link to video or text that would explain what needs to be done and how to test the battery would be useful.

The individual battery cells are not only welded to the strips on each side of them but are also glued to the battery holder. How can I disassemble this further in a way that I can reassemble it later?

Thank you.

 

[JamesG]

Actually there are 50 cells in the old battery not 40.

 

[JamesG]

IZIP battery voltage measurements

The pictures show how the voltages of each group of 5 cells were measured and link above shows what was obtained. The voltage numbers steadily decreased from the positive post to the negative post and all are very low. What does these numbers suggest?

Can the positive and negative wires of the battery be connected directly to the battery charger of the bicycle to see how far the batteries charge up WITHOUT the BMS? What are the safety risks if this is done?

 

[harryS]

Congrats on getting this far.

Just to be sure, we understand your data, you kept the black probe on the most negative end of the battery cells on the right side of the pictures, not on the negative lead of the battery. Then you measured each island of metal going to the positive lead on the left side.

If so, then your voltage data says the battery is dead, with just a few tenths of a volt across each cell as you go right to left. What you want to see is 3 to 4 volts across those cells.

The safe range of a lithium cell is between 3 and 4.2Volts. You can go lower than 3 volts as the manufacturere's limit is lower, usually 2.2 - 2.5 volts, but never lower than the rated limit. When a cell is discharged below its rated limit , It is ruined. Metal precipitates form in the electrolyte. These can link up if the cell is rechargd, and cause an internal short circuit that will overheat the cell and start a fire.

Some people will try to recover a fully discharged cell though, but they're playing with fire.

 

[JamesG]

The original way the battery voltage was measured was as shown below in the first picture. Which I now think was not the correct way to measure the voltage. But please advise.

I remeasured the battery voltages using the method in picture 2 below and got the measurements shown in picture 3. Please advise if the way the battery voltage is measured this time round is the correct way and what you make of the numbers obtained.

I understand that the risk of fire may increase due to Metal Precipitation in the Electrolyte Solution in a deeply discharged battery due to possible short formation as shown in picture 4. Thank you for that information. If I do charge this battery it will be on concrete and away from anything flammable.

Still, I do like to know how is it possible to rejuvenate this battery. Can the original bicycle charger be used? I suspect a constant current special type charger maybe needed with adjustable amperage output. If such a special charger is needed can you provide the name of it and a link to one?

Presumably IF the battery is rejuvenated then the metal is dissolved back into suspension form in the electrolyte and the risk of fire is back to near normal for the battery.

 

[harryS]

This video by Shawn McCarty might help you better understand how your battery is wired, using 10 groups in series, each group containing 5 cells in parallel. Incidentally, Shawn built me a pretty good 36V battery a few years ago.

Then you should understand that you were measuring the connectors on the bottom of the pack twice, .635 and .634 volts, 2.025 and 2.026 volts, etc. You had to move the red probe to the other side to get the other voltages.

Anyway, the final voltage on the other side of the final group (where you measured 7.90 volts) is not going to be much better than 9 or 10 volts, which still says all your cells are discharged well under 2.0 volts. Dead. Scrap. Junk, Dispose of it safely.

Trying to revive a $200 battery is not worth burning down your home.

 

[JamesG]

Thank you for the emphasis on possible fire hazard.
You say this is a $200 battery. Is that what Shawn McCarty charges for a battery such as this? That seems too good of a price perhaps, although saying that I do have a vendor in China that probably charges much less but with shipping and bank transactions it will probably be $200 or more.