Will not hold charge / shuts off

What device are we talking about? I assume it has a battery..the device will not stay on until the battery is fully charged,especially if it has a lithium ion battery.If the battery does not fully charge in the amount of time it normally takes to charge it to full charge and it doesnt operate as long as it always has once fully charged,then you need a new battery.

Check its battery. If the battery have not enough charge on hold, this fault can occur. Re-charge it full, and check. If it too do not help you, replace the battery with a new one.
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Cell phone batteries have what is called a "memory" over time if they are charged without being fully drained they can start to not hold a charge. Unfortunetly the only fix for an issue like yours is to purchase a new battery. Your local retailer / service provider should have batteries in stock or they can order one for you.
It is recommended to allow the batteries to drain completely before charging, then allow at least 8 hours or more to fully charge. Most cell phone will show a full charge after a few hours, but this is more a fault with the software that check the batteries charge, then an actual indication of the battery being fully charged.

Bike has magneito (thats spelled wrong ) On line youtube veido shows how to fix that.

The camera shuts itself down to protect itself for further damage since it detected a problem. Make sure your battery is fully charged. If yes, then do this little trick. Hold the camera with your right hand with the lens facing the ground. Next, tap the camera's base as you turn ON the camera. This aims to remove any grit of sand or dust stuck in between the camera's base and the side of lense barrel. You may have to do this several times and see it it works.

Please let me know how this goes. Thank you for using FixYa.

it needs a new internal battery

I had a similar problem which I finally fixed. You did not say if any of your phones registered.
First try the following recommended by Uniden Support:
Your phone(s) should be fully charged before putting them on the main base.
Unplug the battery from the phone by removing the battery cover and removing the connector. Then, push the # and * key together and hold while you plug the battery back in (requires some dexterity). Continue to hold the two keys until you hear a confirmation tone. This will force the phone to reregister. Put the phone on the main base (if you are sure it has a fully charged battery) and see if it will reregister it to solve the problem.
That did not work for me. So, I followed the instructions to de-register the handset (even though it hadn't really registered). But, I also pretended like the Base was not available (because using the base in this step also failed).
1) Press and hold the hang up and # keys for at least 5 seconds.
2) Move the cursor to select Base Unavailable and then press Select.
3) Select the base you want to deregister from, press Select and then move the cursor to Yes and select.
This causes the phone to delete any of its base information.
At this point, again insure that your phone shows the battery is fully charged and if it is not, put it on the stand alone charger base (not the main base). With the battery fully charged, place it on the base and try registering again by placing it in the main base.
If neither of these approaches help, contact support at Uniden.com.
However, my problems were cleared when I cleared the handset with the second set of instructions.

try wiping off the connections n hold button down for a min.

Hold down on the center button while hold down on the menu button. The apple logo will appear. Your Ipod is now rebooted.

Is the new battery fully charged? Usually it takes 6 hours on a new battery.

If you have two identical handsets, try swapping the batteries. If the problems moves with the battery, then it is old or weak and not holding a charge. That what it sounds like to me.

Hope this helps, and please rate my answer, good OR bad.

Good luck!