Battery charging issue

[Tamb]

Hello, I have a MagicPie 5

All of a sudden, yesterday my battery will no longer charge. The charger is a Mebo GY200-48AL. The battery is a GRE48V 11.6Ah. When turned on, the red (on) light is on but so is the green (fully charged) light. It doesn't go double red like it should when the battery is not full. I've tried leaving it on overnight but no dice. The charge is slowly draining (speed = slower and slower). The voltage is set correctly on the charger (230v - in AU)

Not sure what I ought to do. Thanks for your help

[Bikemad]

Hi Tamb,

Have you measured the output voltage at the charger's plug to make sure that the charger is outputting the correct voltage? (The charging voltage is usually stated on the charger label).

Some batteries require the power switch to be in the ON position while charging the battery, so it might be worth trying to charge it with the battery switched ON and see if it makes a difference.

If you cannot find an obvious fault with either the battery or the charger, you may have to contact your supplier for further assistance, assuming it is still under warranty.

Alan
 

[Tamb]

Thanks, I will get a tool to check those #s but from reading around it sounds like it's likely to be the BMS since the battery is fine (i.e, supplying juice to the bike) and the charger is alive (i.e., lighting up). Does that sound likely to you? Any recommendations for a BMS to buy from ebay (I am in Aus) to use?

[Bikemad]

The BMS would obviously need to match the chemistry and series count of your battery cells, in addition to the constant current capability and physical size limitations that might affect its installation.

Your battery is likely to contain one of the following configurations:

• 16 LiFePO₄ cells in series with a maximum charging voltage of 58.4V
• 13 LiMn cells in series with a maximum charging voltage of 54.6V
• 14 LiMn cells in series with a maximum charging voltage of 58.8V

Your charger will probably have the respective maximum charging voltage marked somewhere on the label.

Alan
 

[Tamb]

The BMS would obviously need to match the chemistry and series count of your battery cells, in addition to the constant current capability and physical size limitations that might affect its installation.

Your battery is likely to contain one of the following configurations:

• 16 LiFePO₄ cells in series with a maximum charging voltage of 58.4V
• 13 LiMn cells in series with a maximum charging voltage of 54.6V
• 14 LiMn cells in series with a maximum charging voltage of 58.8V

Your charger will probably have the respective maximum charging voltage marked somewhere on the label.

Alan

Yep battery charger reads 54.6v

Are there any reputable sources for these BMS or it is just hit and hope on ebay?

[e-lmer]

Just because the battery reads the right voltage does not mean it is good.
In a cell goes bad it may read the full voltage, but under any load drop to zero. 
 
A smart bms would detect this and not charge.