When charging my battery it will reach 95% and the battery charging light will turn solid red and battery meter will show plugin not charging.

During charging, RECHARGE indicator turns red, when the indicator is fashing,

that means battery is almost full and turns OFF when fully charged.

There's some Manual sites here...
https://duckduckgo.com/?t=ffab&q=PWMA1050BT+low+battery+blinking+red&atb=v159-1&ia=web

Mine is an Invacare M51 Pronto Surestep with an onboard Winsunny battery charger. My charging lights are solid red and green/ yellow. Depending on if it is charging or not. What kind of charger do you have?
I have to replace my charger because it is not working. My green light is staying green while charging even though my joystick is showing my batteries are depleting and I just got new batteries. sigh.

First, tell what charger is it?

EXAMPL
1- RED shows charging and GREEN means complete charging.....on most vacuum cleaners.

2- Blinking RED or GREEN means charging while solid RED or GREEN means charging complete on thigs like standalone battery chargers, like screw/drill driver.

If you put a cool battery in a camera and the camera says it is too hot. you have a critical problem with either the battery or camera.

There are a few things to check. The LED lights can tell you a lot. This will tell you more about the battery:

1. On the taskbar, double-click the power cord icon or battery icon to open the Power Meter dialog box. Note: If the power cord icon or battery icon does not appear on the taskbar, click the show hidden icons button.
   
2. Press Fn+STATUS to view the power status box, which opens in the upper-left corner of the screen. The power status box shows the current power source, the battery charge level, and the power management mode.
3. Look at the battery charge indicator (if applicable).
   • LED green - Battery is fully charged.
   • LED orange - Battery is charging.
   • LED blinking red - Battery charge is very low.
   • LED solid red - Battery is malfunctioning. Note: This LED only lights up when the notebook is connected to AC power.
     
4. Press the battery meter button on the battery. The battery meter lights indicate the percentage of battery charge remaining.
5. Wait for a Low Battery warning message to appear.

If your battery charge indicator displays what looks like an inaccurate charge, you may need to recalibrate the battery.

To recalibrate the battery as mentioned, try this:

1. Connect the AC adapter and then turn on the notebook.
2. As soon as it starts and you see a startup screen, press the F2 key.
3. In the BIOS Setup utility, use the TAB key to select the Advanced menu.
4. On the Advanced menu, select Battery Auto Learning, and then press the SPACEBAR to select Enabled.
5. Use the RIGHT ARROW key to select the Exit menu. On the Exit menu select Exit Saving Changes, and then press ENTER.
6. At the Setup Confirmation prompt, select Yes, and then press ENTER.
7. The battery recalibration process begins and a screen opens showing you the progress.
8. When the recalibration has finished, and the message "Press [Esc] key to exit" appears, press Esc. The battery charge indicator now displays an accurate battery charge.

Hope this helps!!

according to manualslib type site for the wg540, solid red means charging for the wa3840 and wa3838. After 30 minutes if battery has not reached 10 volts (of 18), the red will begin flashing meaning defective.
Just green? Ready to go. Green flashing? Overheat.
Tangent; sometimes a discharged battery needs a little coaxing - have to get a little voltage into the battery for charger to try to charge. Different company, electric drill. I plead ignorance if this applies for the 3840 since they mention the half an hour time.

Batteries have electronics data that software has to get to properly charge it. Newer lithium batteries maybe different. But apparently, you have a work around for a lengthy use of the new battery.

When the charger blinks it indicates is either charging or trying to charge.
A solid red light indicates a bad battery.

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Ok, just because the battery is 95% charged doesn't mean that it has 95% of the charge it's supposed to have. When a battery ages it holds less and less of a charge so it can have just a tiny bit of power and show as 95%. You can check the health of the battery on this Dell by removing the battery, pressing and holding the status button. The more lights that light the worse the battery is. Dell recommends a new one if 5 or more light.

Also, check the battery charge by just pressing without holding. This time the MORE lights the better. It may be that powermeter is lying.

i have same camera.. but i dont think this is a problem.. while charging light keep flash.. when it completes charging it shows u solid red light..