General failure issue

Batteries, Chargers, and Battery Management Systems.
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LogRaam   10 mW

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General failure issue

Post by LogRaam » Aug 10 2010 4:52pm

Hi,

I'm having trouble with my LiFEPO4 setup. Can you help me about diagnostic?

I have 2x pack of LiFEPO4 48v/20A. Each pack have "pouch" cell of 20A each. These packs were purchased at eCity. Packs are connected together to give a total of 48v/40A.

This summer, both chargers stopped working during a charge. Haven't noticed that the chargers died, I went on a ride thinking I had a full charge.. until all system shutdown.

Then, I purchased 2 chargers from PING (detail below). But when I connect them to the battery packs, both charger's lights stay green, and one of them start smoking after 2 minutes.. I disconnected them before everything goes on fire.

When I try to start the controller, the CA start briefly, showing 26.x volts, then shutdown.

So, From there, I don't know what to do.. is this my LiFEPO4's cells that doesn't work? Or the BMS? .. or my chargers? Controller? Did I purchased the right chargers for my packs? .. well, I'm stuck.. pretty well indeed..

What do you think?

LogRaam
LogRaam
-----------------------------------------------------------
Surly Pugsley + Shiver SC... cooked the Ezee hub :-( upgrading to X5 Cruiser or Brute with 2x LiFePO4 48V/20Ah.

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LogRaam   10 mW

10 mW
Posts: 29
Joined: Oct 23 2008 9:05am
Location: Quebec, Canada

Re: General failure issue

Post by LogRaam » Aug 10 2010 4:53pm

Charger details:

2A Charger for 48V(16s) LiFePO4 Battery Packs
SKU: CHR060020001

48Volt 2.0Amp LiFePO4 Charger

Handling Time: 1-2 working days

Specifications:
Size: 150x64x38 mm / 5.9x2.5x1.5 inches
Weight: 400g / 0.9lbs (weight of AC power cord is not included)
Charging System: CC/CV
Input Voltage: 80-260V AC
Output Voltage: 60V
Working Current: 2.0A
Type of DC Output Connector: 3 prong XLR
Changeable AC input cable
Convenient LED status display
Built-in cooling fan & fuse
LogRaam
-----------------------------------------------------------
Surly Pugsley + Shiver SC... cooked the Ezee hub :-( upgrading to X5 Cruiser or Brute with 2x LiFePO4 48V/20Ah.

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liveforphysics   100 GW

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Re: General failure issue

Post by liveforphysics » Aug 10 2010 5:25pm

Check the pack voltage. If it's abnormally low, gotta do what it takes to access the BMS wires on the packs, and probe them with a multimeter to see what cell voltages you've got. This often means cutting into the tape, finding a big ribbon cable (sometimes multi-color), and poking the meter leads on each set to check. You want to be seeing voltages in the 2.5v-3.6v range per cell.
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cell_man   100 kW

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Re: General failure issue

Post by cell_man » Aug 11 2010 2:26am

As Luke said.

It could also be incorrect polarity of the charger plug. However, when this happened to me, there was a big spark from the plug to let me know something was wrong. Plug in the charger and see if you can measure a voltage on the connector. Some chargers have a circuit that isolates the charge voltage until it detects it is connected to a pack, so this doesn't always work

You should be able to measure the pack voltage on both the charger plug and the output connector. If you cannot the BMS is isolating the pack voltage. If you can measure a voltage on both Charger and Pack, make sure they are the same polarity before connecting them.
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dogman dan   100 GW

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Re: General failure issue

Post by dogman dan » Aug 11 2010 4:43am

One common cause of a false charged reading on a charger is a bad connection somewhere, often the plug to the charger or the charge plug on the pack. This will cause no charging, but a green light. The only explanation I have for the smoked ping charger is shipping damage, or other defect. Smoking two minuites later doesn't sound much like polarity reversed.

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