6 Fatpack paperweights! Waaah!

[docnjoj]

Well i finally did something really stupid and left my controller and D/C converter on overnight. When I tried to charge I got red lights on both chargers (60 volt Ping and Bosch charger) and no response on my Turnegy meter. Looks like all 6 Fatpacks (4 parallel and 2 set for 18 volts in series) are Dead, dead, dead! Any suggestions?
otherDoc

 

[drewjet]

Check individual cell voltages. You may be able to force them up in voltage if using a power supply directly to the cells. Once they get up to a minimum voltage then you should be able to charge as normal. This doen't always work, but sometimes it will. Good luck.


Drew

 

[docnjoj]

Thanks drewjet. I just learned that a Ping charger will put a small but effective current into batteries and all parts of the pack are now charging! No premature celebration as I have no idea if they will hold the charge. I have the 18 (2 // packs) volt part on an Averatec PS( 19 volt) and the 1 36 volt pack on the Bosch charger. The 3 // 36 volt packs are on the Ping gradually charging at about 1.5 amps. Hmmm, Lipo in my future?
otherDoc

 

[neptronix]

Yikes...

Best of luck with those.
Sounds like you may wanna go lipo.. or lifepo4 because you can get bigger cells ( 10ah+ ) that ultimately require less maintenance.

 

[neptronix]

and something like an iCharger where you can balance the cells yourself and such.

Tool packs make me nervous because you never really know what's going on with them.. and they are not necessarily 100% maintenance free either.

 

[docnjoj]

Mine were maintenance free for over a year without any problems. My downfall was putting the converter for the Magicshine on and leaving both the controller and it on for almost 72 hours. I just forgot to hit the "off" switch at the end of our last ride. Certainly a BMS would have helped but the ease of use of these packs is really wonderful. I would buy another 6 if they were the original price of $45 each delivered. Alas they are now $90 and not a good deal any more. I have charged all of them up to approproate voltage and if they hold the voltage through tomorrow I will load test them. Maybe miracles really do occur!
otherDoc

 

[neptronix]

hm, did you test what voltage they were at?

 

[TPA]

Doc, Doc, Doc, Doc....

Read here starting at the 6th post:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=7569&start=525

Surprised you panicked since you know about this already, you posted a comment after all.

Your packs will likely be fine, mine are several months later.

 

[docnjoj]

Thanks for the encouragement, folks. Being a devout pessimist I will only hope for the best. Luckily I had my old Ping splitpack @ 36 volts which I had rebuilt over a year ago to put on the trike. We did a cold but full 15.5 miles without incident so I have backup. Will do a full discharge to about 50 volts @ 5 amps tonite and see what the damage is to Fatpacks. Nominal voltage is 54 volts at 15s 4P with 59 volts hot off the charger.
otherDoc

 

[docnjoj]

Possibly a resurrection! I was able to charge the whole shebang 15s system up to about 60 volts and it held the charge overnite. Now d/c at 5 amps to see what capacity is at 50 volts cut off. I normally could do 15 miles from 60 volts down to 52 volts@ about 5.5 AH. Sorry for not using W/hrs but it is easier(for me) to read amps and volts directly from the Whattameter and Turnigy. Stay tuned!
otherDoc

 

[docnjoj]

Well the news is OK but not superb. I got about 5.3 ah out between 60 and 50 volts cut off. Ceertainly not dead but perhaps a 10% loss. I will cycle them 2-3 more times and see if the ah number increases but this is enough for our usual 15 mile ride. The voltage started to decline faster as it approached 50 volts. This is about 3.33 volts per cell and it seems to me it used to hold it's voltage a bit better at that point in d/c. Any comments or suggestions would be greatly appreciated.
otherDoc
edit: For ID10Ts like me an LVC is a really good idea. Even thought everything is wired through the on/off switch if i forget to turn it off.....................

 

[John in CR]

Doc,

The capacity loss is most likely mostly due to an out of balance condition, and running them conservatively for a while should see some improvement. If you can, that's conservative on both ends, so it includes cutting off the charge before the top, since at the top some will be overcharged. If you know your consumption on each ride, and you know your charge current, then a timer cutoff for power to the charger works well for those extra conservative cycles. Definitely do not run them close to low for a while.

A key switch that includes all of your accessories is a good preventative solution too. If your house key is on the keyring with your bike key, it's harder to leave your bike on. Also making your ebike easier to charge so you plug it in for charging as soon as you get off the bike is good prevention too, since those accessories shouldn't draw much current and can't kill a full pack so quickly.

 

[docnjoj]

Excellent points all, John! I have now connected my Magicshine after the switch so the little green light is on when the switch is on. It should be enough of a reminder for my feeble brain. I will charge when we return, which is something I have neglected. I'm also going back to my Ping charger (2 amps) instead of my Bosch/ Averatec 4 amp series charge and will do a couple of more charge to 60 volts and D/c to 50 volts and keep track of the Ah. If it stays around 5 ah then they are ok to ride for our 15 milers. I never took more than 5 amps out (of 8 nominal amps) and always charged to 59.5 volts. Here's hoping! Actually if I charge on return, I have to break the circuit anyway as I don't have a separate charge port. This "should" be foolproof. Meanwhile the old Ping just keeps rolling along.
otherDoc

 

[docnjoj]

Well Good news! It looks like charging to 60 volts and D/c to 50 volts about 4 times got about 6 ah out of the Fatpacks. Seems OK to me. I have to put it back on the trike and remove the Ping but I can't do that for the next few days. The 36 volt 20ah Ping has a surprising amount of power, but the off the line "push" is much stronger with the Fatpacks @54 volts. It looks like I dodged this bullet and the Fatpacks don't have to be replaced. They do seem to recover even from the 2-3 volt readings that I got at first. Really great cells (Sony VT) and I wish they could be bought through "regular channels" and at a reasonable price. 90 bucks for 2 ah@ 36 volts sucks.
Thanks all for your advise and support.
otherDoc

 

[TPA]

I hate to say "I told you so"...so I won't.

Something to make you sweat a little...

...nobody that I know of has done it twice.

So, is it going to be you, or me?

 

[dnmun]

the controller should turn off when the pack dropped below 31.5V. since the light was off, the DC-DC converter was not pushing current out so it may not have been much more load when the cells got down to 2V, so that was why it did not show more damage. you should be ok, imo.

 

[docnjoj]

Hopefully, TPA, neither one of us will have to endure the 2nd round of the fickle finger of fate!
otherDoc

 

[docnjoj]

the controller should turn off when the pack dropped below 31.5V. since the light was off, the DC-DC converter was not pushing current out so it may not have been much more load when the cells got down to 2V, so that was why it did not show more damage. you should be ok, imo.

Thanks Dennis. I do hope you are right. The Magicshine has a "power on" led on the button and that probably drew some current too. It shouldn't have been much, though.
otherDoc

 

[dnmun]

the switch mode power supplies SMPS always have some current leaking on the output, through a big resistor across the output cap and that would use almost as much current as the LED. was the LED still lit when you got back to it?

 

[docnjoj]

the switch mode power supplies SMPS always have some current leaking on the output, through a big resistor across the output cap and that would use almost as much current as the LED. was the LED still lit when you got back to it?

It was not lit when I realized something bad happened. Now it is forward in the circuit so the main power switch cuts everything off. It is now a good indicator (if I look at it ) as to whether the main switch is on or off. It is right in front of the trike and is about a nickle size bright green when lit.
otherDoc