What Ryobi batteries p103 or p104 will a battery charger that came with my p100 batteries charge? Or will the charger work with these batteries?

After looking at the manual for your charger, it looks like most of the Ryobi chargers like the P113, P114, P117, P118 will charge your battery. The connector on the battery looks the same as the P103 and P104 used here in the U.S.

The motor may have overheated and burned open. Use a multimeter to check resistance across the battery contacts in the tool with the switch closed. If it reads open, the motor has failed.

This WEB site show how to install the nylon string.
http://www.ehow.com/how_6326062_string-ryobi-trimmer-plus.html

If you have your receipt, check with Ryobi to see if it is still under warranty. It comes with either a 2 or 3 year warranty, depending on when it was purchased. If it is still covered, get it replaced/repaired. If it is not, buy the P117 charger. $30 at Home Depot. It has a 90 day satisfaction guarantee. If it charges your batteries properly, you're good. If not, bring it back if you don't like/want it. My P113 won't get out of test mode now, or charge Lithium batteries anymore. So I bought the P117 yesterday. Works great, and it's a lot cheaper than new batteries! And it has a 3 year warranty.

The physical differences between two models of Ryobi batteries is:
- The P103 (Part Number 130429008) is a 1.5 Amp/Hour (a measure of how long a battery lasts on a charge) battery. If totally discharged it takes about 15-20 minutes to charge back to full. It is lighter than the P104 because it has half the cells inside. Lighter, quicker to recharge, quicker to discharge, shorter lifespan.
- The P104 (Part Number 130429017) is a 3.0 Amp/Hour battery. It takes about 30-35 minutes to charge it to full if fully discharged. Slightly heavier, longer time to discharge & recharge, longer lifespan.
Considerations:
- No difference between batteries in the performance of your tools.
- The number of times you discharge and recharge a battery determines a batteries lifespan. That's why most manuals will tell you to fully discharge a battery before putting it on a charger.
- If you only have one battery you cannot use your tools while it is recharging. On big projects you have to have two batteries.
- The weight difference between batteries is negligable unless you are working with the tool in your hand for extended periods.

p103 is name of the battery. p106 is the kit with 2 p103 batteries. same thing just 2 times. the p104 however is bigger and holds more juice.

That is true the One+ 18V Li-Ion battery packs will work in any One+ 18V Ryobi tool. However the Lithium ion batteries will not charge in the original P110 NiCd charger. You will need one of the the new series Ryobi One+ 18V "dual chemistry" chargers for that. The will charge both types of battery packs.

You need to have the charger tested, if you know that batteries are good then what else could it be. This LIon charger has a logic circuit in it like a computer.

If you are sure your charger is working properly then your one battery may be shot.. i even had a new battery quit charging and had to replace it. they do not come cheap.

Please provide the part number.