Seriously considering buying a reviver

[MTOBATTERY]

Originally Posted by HugoBoss

What I meant to say was that I bought two seperate "dead" batteries . The first one has arrived and I am still waiting on the second one. The question is wheter to wait for the second one and replace the two batteries at the same time ( as recommended) and see if the luck of the Irish holds or do I go ahead and try the one I have.

Here is a picture of a voltmeter that was on the ebay site . Will I have any luck ??
Attachment 1902

I think if you check between the two large contacts in the middle you will find the voltage will increase approximately 4V. Based on the numbers I see that battery should be fine to start the Segway "as is". There is always the potential that it will have a huge voltage dip under load but you have a chance of using it without doing any reconditioning/reviving.

[dale@thecoys.net]

Here's a recent experience. Please note that this is "one observation".

We have two X2s. They have been "parked" in the garage for the winter, perhaps under somewhat-cold conditions at times, and continually plugged in for charging. Each had both charge lights blinking every time I checked. Let's call them SegA and SegB

Saturday, I tried starting them up, and SegB started fine, but SegA would not power up. Plugged SegA back in, and the front charge light did not come on. Swapped the two SegA batteries (front/back), plugged it in, and the back charge light did not come on.

Put the SegA battery that was originally in the rear, back in the rear. Swapped the front battery from SegB to SegA. SegA now seemed OK. Put the battery that had been in SegA front, in the front of SegB. SegB front charge light would now not come on.

Conclusion: Bad battery, formerly in SegA front. Pulled that battery off of SegB, and put it on the test bench. Voltage reading (between 2 diagonal large sockets) was 8.6 volts. Aha! Too low to charge (don't understand why that happened, but...).

Now, I happen to have a DC supply that is variable-voltage and can be current-limited to not more than 2 amperes. That's not a common item, but would be fairly easy to cobble together for someone with the right knowledge.

I hooked that up to the battery, and slowly increased the voltage, while keeping the current limited. Surprisingly, this was a rather rapid process. It only took about 10 minutes to get the voltage up to about 73 volts with a "charge current" of about 1 ampere. Then the "charge current" rapidly dropped off to roughly 100 ma. I left it that way for 3 or 4 hours, and then disconnected the "charger", and read the battery voltage as about 73 volts. I left it that way overnight, and checked the voltage the next morning, and it was still about 73 volts. !!! Obviously, this was "good voltage", and clearly the battery could not have been anywhere near fully charged.

Put the battery back in the front position of SegB. Plugged it in. Front charge light steady green, back light blinking. Front light stayed steady green for several hours, and then switched to blinking (mostly green), and slowly went to the briefly-blinking state that shows fully charged.

OK, so let's see. Good to do the "recalibrate" operation. Do that on both SegA and SegB. Put them in riderless balance mode against the wall, wait 36 hours or so for shutdown. Both did about the same time before shutdown. Put them back on charge, both did roughly the same number of hours before indicating full charge.

I'm sure time will tell, but my initial feeling is that, in this one case at least, I managed to resurrect this battery.

Comments and/or questions invited.

[KSagal]

Dale, you indicated that it only took 10 minutes to get to voltage, and also indicated that you believed the battery clearly could not have been near full charge...

I am not too sure if I understand the relative context for these two statements.

If the battery got to a point of charge that no longer took amperage (reduced to 100ma) in just 10 minutes, then I feel it may have actually been close to charged, but some other factor choked off the voltage available.

I wonder if the voltage read across those two terminals reflected the whole battery, or possibly one single bad cell. If the whole battery is charged, but one cell (or more appropriately, one series of cells) is only producing 8 volts then this may explain why the whole battery went from 8 to 73 volts so quickly.

I am surely not knowledgeable enough to analyse anything here other than my understanding of your statements, but from them I wonder if some thing other than the whole battery was undercharged was really your problem.

Any way, it surely seems you have nipped this one in the bud, and have averted more damage, and more expense.

If I were you, I might swap locations of all batteries, but also mark this particular one. See if a problem arises again, if it is related more to that particular battery, or the position it was in.

Good luck.

[dale@thecoys.net]

Originally Posted by KSagal

Dale, you indicated that it only took 10 minutes to get to voltage, and also indicated that you believed the battery clearly could not have been near full charge...

I am not too sure if I understand the relative context for these two statements.

If the battery got to a point of charge that no longer took amperage (reduced to 100ma) in just 10 minutes, then I feel it may have actually been close to charged, but some other factor choked off the voltage available.

I agree that from the first observation, I couldn't clearly make that conclusion. [Certainly, there were not enough ampere-hours to actually fully charge it, though]. I could speculate about adding "surface charge", but...

The second observation was that, after I put this battery in the front position of SegB, and plugged it in, the front charge light went steady green for several hours (the "normal" time for a full charge from "empty").

In summary - it wouldn't charge on either Segway, then I put just a very small "charge" in, the voltage increased by about 64 volts, and it would now charge. A significant factor is that I could do this with a DC supply that could go up to 73 volts (but with relatively low current limits).

I am not necessarily able to explain any of this. And there's a lot of circuitry inside the battery case that's involved. Perhaps one of the folks who have (literally) dug into the battery internals can help explain.

I thought about putting this battery back in SegA-front. However, I think I'm going to leave it in SegB. If there's something wrong with the SegA-front charger (or with this particular battery), having this configuration should eventually reveal something. (This was what you were suggesting, I think).

[KSagal]

Yes, your final statement is what I was trying to suggest. One diagnostic tool that I use is to change the conditions in a controlled manner. In this case, that would be to identify the suspect battery, and then remove it from the suspect charging location. Then wait, keep your fingers crossed, and have as much fun as you can tolerate while waiting for the next step in this adventure. (Then have just a bit more fun )

[dale@thecoys.net]

...and, as far as possible, change only one thing at a time.

[KSagal]

Originally Posted by dale@thecoys.net

...and, as far as possible, change only one thing at a time.

Exactly. It is amazing to me how many technicians and engineers I work with who will do 6 modifications at once, and then no one really knows which one did the trick.

Glide on, good luck.

[Gihgehls]

Very true, although sometimes you pull something open and see 6 things that are not how they should be!

[GLIDE4FUN]

I think the folks at MTO should just rent the revivers for $50 to $75 a week.

[KSagal]

Originally Posted by Gihgehls

Very true, although sometimes you pull something open and see 6 things that are not how they should be!

This is a good point. When something works, it may be the result of several patches that are overlapping. Then when it breaks, there are a number of things to do to get it back to spec, before you can further diagnose.

Often in my career, just bringing it back to spec will get you a positive result. In this case, 6 repairs at once may be warranted.

But in the case presented, where all seems to be in spec and not modified, and one particular failure occurred, the diagnostic for the next step would be to try to change only one pairing, in that the specific questionable battery aught be swapped to a new location.

This would not be a good time, relatively speaking, to also swap in a new power supply, or start using a timer, as examples.

Sometimes, context helps us to understand a statement, which in other circumstances may not be as accurate if it were to be forced to stand alone. I do not believe it is possible for a person to make each and every statement in a conversation to be able to be taken out of context, and still be as accurate.