Hi Javier, do You truly reset original Makita chip on the BL1830 battery? Please contact me, [email protected]

SOURCE: Makita 18v Lithium-Ion BL1830 Battery Won't Charge

If you have been a bad boy and managed to short the battery by using it for non-proscribed purposes, the fusible link will blow (kind of like a fuse) To fix it, open up the battery (use a Torx 10 security bit, or a small flathead in a pinch) On the battery connection nearest the spring-loaded white catch there is a small bridge of metal with a hole in the center. If this is melted you can solder it back together by sanding the two pieces and putting a glob of solder on them. This will void your warranty (duh!) and remove the battery's fuse protection, but it WILL work again. If the link is intact and nothing else is obviously wrong, you almost certainly have a bad cell. I recommend pulling out the bad cell ( it will be the one that does not read between 2.5 - 4 vdc) and replacing it with one from another dud battery- this requires some fudging and re-soldering. Or do what I did, pull the cell, toss the electronics and the short pink wire, add a cigarette lighter socket and voila! you have a portable power supply giving around 14 volts. Charge it up by wiring two cigarette lighter male ends together (check polarity , + to + and - to -) and plug it into your car, but only while it is running or you will be charging your car battery with it! Hope that helps.
Matt Binns GiantGlobes.com

SOURCE: I have a li-ion Makita BL1830 18V 3.0Ah battery

Sorry Mate your battery is dead...
The makita lithium batterys dont like getting worked hard quickly.
There is a chip in them that recognice each battery to each specific charger. Try another charger. This has not worked for me. Try anyway

SOURCE: hi both red and green

If both lights are flashing it means the battery is defective so it won't charge it. By defective it could mean the battery is just worn out or there may be a short in the battery. If the battery is under warranty you can get it replaced at a Makita Service Center, if not you have to buy a new battery.

Testimonial: "thank you verry helpfull"

SOURCE: MAKITA LXT BL1830 18V LITHIUM-ION 3.0AH BATTERY

If the charge count on the batteries is under 300, Makita will replace them. Makita has a known defect in this battery that causes the battery to shut down before it is dead. So as of now they are exchanging ones with low use.

If they are truly defective and makita won't replace, you have to open them, find the dead cell or blown fuse, and replace. Search youtube makita battery for a video on repairing this battery. But once the red and green lights on the charger flash, the the battery can't be charged on a Makita charger -- it's been locked. So use a third party charger.

SOURCE: can my makita bl1830 battery

This battery has a known design defect that causes premature failure. The battery is still probably good, but the safety circuit n the battery spuriously locks it, due to a bug. Once locked, it won't charge in the Makita charger (flashing red and green lights). Makita knows about this problem but so far is not actively recalling the batteries. Makita will replace the pack if the charge count is under 150 (some people say 300?) regardless of warranty status, but you have to take or mail it to a Makita Service Center -- the dealers won't handle this unless it's in warranty.
http://www.makita.com/en-us/Modules/Service/ServiceCenters.aspx

If Makita won't fix it, you can try to repair it. If the red and green lights are flashing, the battery is probably locked and cannot be repaired in a way that will let it be charged in the Makita charger (but it can be charged in off brand chargers). Buy a clone charger on eBay for $60 and try it. If it charges, just use it, no repair needed.

Be aware that lithium batteries do lose capacity permanently at a rate of about 20% per year. So, 3-6 years is about the best battery life you can expect - from date of manufacture, so if it sat in the store a while that adds. Makita derates the cells to allow for some shelf life (down from 2400 Mah to 1500 Mah rating).

If the battery is weak, and only gives brief usage, you can replace some of or all of the cells in the battery. These are expensive and worth repairing. See this video:
http://www.youtube.com/watch?v=Z5taguEdlkY

If just 1 or 2 cells are weak, you can replace them with the same Sony 18650 size 2400 Mah capacity battery, green sleeve. The Sony's are not sold retail, and are hard to find other than from another Makita pack or from some laptop packs. If more are weak, you're better off just replacing all of them with new 18650 2400 Mah (or higher) batteries with tabs. Look for Tenergy or other quality brand.

Hope that helps.