How to get the most from your Cordless Power Tool Batteries
Here`s the basics.
- High Temperature is the enemy of any Li-ion Battery.
- Li-ion batteries take DAMAGE at TEMPERATURES ABOVE 50 DEGREES.
- Batteries get heated according to how fast they DISCHARGE and where they are STORED.
- Over Discharging can also damage Li-ion batteries. They should NEVER BE RUN UNTIL DEAD FLAT.
- Constant Deep Cycle Recharging Reduces the Lifespans of Li-ion Batteries.
- Charging Li-ion Before They are Flat is better for a battery than full Deep Cycle Recharges, they have No Memory Effect.
We have all felt a tool battery after it`s been discharged from full charge to empty in 5-10 minutes.
They get very hot.
Ni-Cd and Ni-Mh power tool batteries can take more heat than Li-ion before taking damage and hence they can be discharged very quickly, usually as quick as the tool will allow and will still work fine for 100`s of cycles.
Fully discharging a Li-ion battery really fast, repetitively, will reduce the number of cycles it gets. Most Li-ion powered tools have circuit protection either in the tool or the DEWALT DW988 Power Tool Battery to stop it discharging too quickly and over heating. That`s why they maintain more constant power.
Here’s the problems:
Firstly
There isn`t much information about batteries taking heat damage being advertised by manufacturers, it`s certainly not emphasised in any great manner when you buy a battery or a tool kit.
Well that is unless you buy one from us, I Tell Lots Of People How To Use Them Properly.
They are all quick to talk up all the good points and slow to educate consumers about the bad point.
- They are not like Ni-CD`s, forget what you know and learn how to treat li-ion batteries. Change your habits.
- The operating temperature ranges from approximately 4 to 50 degrees for Li-ion and going outside this range Will Cause Damage!
- In Aus on a 40 degree day just leaving them in the boot of your car Will Do Damage. Let alone sticking it in a power tool.
- Direct sunlight is something to be avoided. Don`t leave batteries and tools laying around on Hot Concrete slabs or just sitting in the sun. Once again the battery will hit way over 40 degrees on a 40 degree day. Especially since most brands of batteries are black, that doesn`t help.
- A pack can easily hit 40 degrees in Australian summertime in around 5 minutes in a high load tool.
- Same goes for extreme cold, in wintertime you need to be careful not to leave packs where it can get below 4 degrees, batteries loose performance and don`t hold load or charge as well and shouldn`t be exposed to very low temperatures.
Solution: Store them in the fridge but above 4 degrees, or low on storage shelves at floor level in the coolest place you can find in summer and the opposite in winter.
Best Solution to Over Heating: Cycle your batteries at 1/2 to 3/4 Discharge, take it out of the tool and let it cool down, go grab another cool battery. Keep an eye on the temperature of your packs when doing fast discharges under heavy load. Feel the pack and use your common sense to judge how hot it is. It`s not hard to do.
Another Problem Is
Some manufacturers have put circuit protection in the tool, rather than in the battery to protect them, so most user`s think when the tool switch’s off that they pushed the tool to hard, not realising it just switched off to protect the battery.
It`s simply a matter of switching off and on again and away you go, you can continue to over heat your battery and most people do exactly that.
Large high load power tools battery heat evry quickly
You`ll notice all new chargers have fans in them and some packs are vented to reduce heat build up.
The fan in the charger will not help a battery that has already exceeded it`s heat level, the damage is already done.
So Ni-Cd & Ni-Mh have a higher INITIAL power output, a higher discharge rate, a total reduced run time, less cycles and weigh twice as much almost. From the moment you start to work the output declines rapidly until gone. But you can heat them right up to 70 degrees and they usually keep on working.
Li-ion will give you longer run times with slightly less power output, but power at a constant rate throughout the charge, holding load right up until its almost flat. This also highly increases the total work done from one battery charge. Of course they also get more cycles, so they last much longer and are better value for money in the long run IF TREATED WITH CARE.
Up to 2000 recharges for Li-ion (Dewalt`s Average Claim for Nano Phosphate), vs 500 for an average Ni-Mh or Ni-Cd cell. 900 FOR AN XRP NI-CD.
This is all determined by the user mostly and how they treat the pack.
- Bad storage and regular strain, excessive heat from fast discharges, regular full cycle recharges & over discharging will all add together to make shorter and shorter lifespans for your batteries.
- Use them for heavy work and discharge quickly all the time and that will mean significantly less cycles.
- These batteries are better charged at half cycle rather than full DEEP cycle constantly, They have no memory effect, you can charge them at anytime with no ill effects. 1 full cycle roughly equals 6 half charges. Now you see what i mean, i hope.
Another difference is the self discharge rate.
The Average Ni-Cd cell will loose 20% of it`s charge approximately 24 hours after charging.
This will usually pan out at 10% per week after that until it`s totally flat.
Pick up a ni-cd pack you charged 2 weeks ago and it will have around 60-70% of it`s charge.
Li-ion cells are different and do not suffer with this problem in nearly the same way.
They self discharge approximately 5 times slower, at about 5% per month.
Batteries left in tools and on shelves for really long periods can discharge to the point of death. Once below a certain level the internal fire protection switching may prevent the MAKITA 1220 Power Tool Battery being recharged due to the risk of explosion. Yes, they Can Explode. Internal switching and bad tool circuitry can also drain a battery slowly, so they are best stored with 40% charge as the optimum level and best left not inserted in tools, long term.
Charge at least every 6 months if in long term storage.
An accidentally depressed trigger can kill a battery by discharging it too far.
Never leave lithium ion battery in a power tool with trigger taped down
In a nut shell, someone who uses their batteries in high load tools will get less cycles than someone who uses their battery in Low Load tools. The hotter they get the less cycles they`ll get.
