Near disaster with my LiFePo4 battery

Footie

Esteemed Pedelecer
Jun 16, 2007
549
10
Cornwall. PL27
I got very close to damaging my Ping battery today.

Decided to try a bit more cycling this morning, as my hand has been feeling good the last few days (off work, recovering from carpal tunnel operation).

I got half way to Tesco's (just starting the big long hill) and the power cut out (all the power lights went out). Turning the key switch on and off did no good - it was totally dead. Freewheeling back down the hill I noticed the power lights lighting up (regeneration in the back wheel). This indicated to me that probably the bike was ok, likely to be a battery fault.

At home I put a voltage meter on the battery terminals, thinking it would be dead. To my surprise it was reading 26.5 volts. So the voltage had dropped for some reason and the controller was shutting everything down. That explained the “no power” fault, but not the “why”.

On removing the top of the case and looking at the battery I could see no signs of damage (no melted battery). However, when I turned the battery top over and looked inside I saw that the fuse holder was jammed between the switch terminals. Not only was it jammed; it had shorted its self to the live wire on the switch. When I prized the fuse holder away from the switch it was a molten mess.

Battery Short on Flickr - Photo Sharing!

Fortunately, I had a spare fuse holder lying around so I cut the old one out and wired it in. The key switch (other than being slightly melted) appears to have escaped with minimal damage. With it all assembled I checked the voltage (to see if the battery pack was ok). Thankfully, the reading was 40.4 volts indicating the pack could be ok.

A short seven mile trip has confirmed all is working fine and the battery is now on charge, as I don't know how much the pack was discharged by the short. I can only hope that no serious damage has been done to the pack by the short.

How did the fuse holder get jammed into the bottom of the key switch?

I can only presume it happened when I recently cycled the Camel Trail. At the time I found it very bumpy. It likely happened then but has only shorted now.

-----------------------------------------------
Cougar Mountain Electric Bike 36v 200w Hub motor (Jul07)
fitted with 10 Ah LiFePo4 battery (Apr08)
Maximum range (road/hills - Cornwall) 18 miles
Maximum range (on flat) 25 miles
.
 

Michael of Gwynedd

Pedelecer
Jun 30, 2008
39
0
Caernarfon, Gwynedd
Quite a nasty shock. I have often wondered whay would happen to a battery when shorted; they can heat up very quickly generating heat that could cause a fire.

I am thinking of investing in a Ping battery fro my Ezee Forza as the existing battery does not like to be stressed, but may last a while longer, especially on the flat.

Was the fuse holder something you wired in yourself, or was part of the Ping Battery??

Also how do you rate the Ping LiFeP04 Battery? I’m thinking of getting a 15 AH version and will mount it in a strong waterproof plastic box with 20 amp speakon connectors, fuses, and an isolation switch.

Glad you managed to salvage the battery without it busting in flames!!

Michael.
 

Footie

Esteemed Pedelecer
Jun 16, 2007
549
10
Cornwall. PL27
I've read reports of shorting LiFePo4 batteries melting their internal cell tabs. So I was very relieved to find it still works.

I retro-fitted the Ping battery when my electric bike was only 8 months old and it's SLA batteries were dieing. The battery is actually 12 months old this month. Perhaps it was just reminding me :)

It’s also interesting that after 12 months use it still chucks out a whopping 40 volts (It was putting out 39 volts when new) so it's bedded in nicely.

I think, looking at it, what happened was a freak accident. The fact that the holder was forced up between the terminals and then rubbed through the insulation is unusual. But it just goes to show, electric MTB bikes are not really suited to off-roading - even along an uneven fine gravel path. I think perhaps my high speed played an important factor, as I was going faster then everyone else, which gave the battery and me a good shaking.

I would highly recommend a Ping LiFePo4 battery to anyone looking for a replacement battery. In my case it tippled my powered distance (more powerful and lighter).

I'm satisfied that this hiccup was just that rather than a failure of the battery. As a leisure only rider I'm still hoping for at least five years usage (four now), but there's also the possibility I may get more :D

-----------------------------------------------
Cougar Mountain Electric Bike 36v 200w Hub motor (Jul07)
fitted with 10 Ah LiFePo4 battery (Apr08)
Maximum range (road/hills - Cornwall) 18 miles
Maximum range (on flat) 25 miles
.
 

Michael of Gwynedd

Pedelecer
Jun 30, 2008
39
0
Caernarfon, Gwynedd
Many thanks Footie for the info on the lifeo4 battery, and was pleased to learn its lasting well after a years hard use.

I am now seriously giving thought to getting a Ping battery as all the reports so far have been positive.

Michael
 

Phil the drill

Esteemed Pedelecer
Jun 14, 2008
395
6
TR9
In my case it tippled my powered distance (more powerful and lighter).

I'm satisfied that this hiccup was just that rather than a failure of the battery.
Careful, all these tipples and hiccups and we might end up like another esteemed forum contributor :D

Phil
 

Footie

Esteemed Pedelecer
Jun 16, 2007
549
10
Cornwall. PL27
What, what!
Tipples and hiccups?
None of the green stuff here please, just keep the wine and whiskey coming :p
A toast slur …. “God bless this glass and all who empty her”

(Is that off key enough?)
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Footie

Esteemed Pedelecer
Jun 16, 2007
549
10
Cornwall. PL27
Tests, this weekend, have confirmed that my Ping LiFeP04 battery is working fine.
I was concerned that the short could have damage it.
However, a 6-mile ride yesterday (in strong head winds) and a 16-mile ride today (lots of steep sections - making the battery work hard and me) have passed without incident :D

-----------------------------------------------
Cougar Mountain Electric Bike 36v 200w Hub motor (Jul07)
fitted with 10 Ah LiFePo4 battery (Apr08)
Maximum range (road/hills - Cornwall) 18 miles
Maximum range (on flat) 25 miles
.