Battery maintenance/storage?

[wotan]

I've had some issues with my hitachi cordless batteries. The first batch I went through, I left in the unheated shop over the winter and they didn't charge again come spring (my fault.)

This year, I decided I'd leave them on the charger, in the house, and plugged in. Imagine my surprise when I pulled them off the chargers and they were dead. Plugging them back into the chargers causes all of the lights to go out which indicates a fault. These are batteries that are less than 2 years old.

How should I be storing these if they are not being used? Any other tips to prolong the lifespan of these batteries? It seems incredibly wasteful to be pitching them (and the tools.... since it is cheaper to buy new tools w/ batteries) into a landfill every 18-24 months.

 

[Cope]

Batteries and Bulbs told me that the batteries need to be charged once a month or so. If you use them every day, this is a non issue, but for home use it's easy to forget. Don't pull them off the charger as soon as they are charged, leave them on for a few minutes.

 

[AllDodge]

Agree with Cope, periodic charging is best (I don't do it but it's best)

Will add, I'm surprised the batteries were dead being left on the charger. Hitachi makes some good stuff. Dewalt states if you can to leave them on charge for hours afterwards for best charge. Have left mine on for a couple days because I sometimes forget about them, but have not had an issue.

 

[The Cobbler]

sometimes batteries that wont take a charge can be resurrected by repeatedly putting them in & out of the charger several times . also you tube videos showing how to flash them with 12 volts to get them to charge. might be worth a try, but unlikely they will ever be as good as new now...

 

[Ign]

I don't think anyone can accurately answer your question without knowing battery chemistry.

I'm guessing these are ni-cad?

 

[wotan]

I don't think anyone can accurately answer your question without knowing battery chemistry.

I'm guessing these are ni-cad?

Lithium Ion -- BSL1815X batteries.

They have been sitting this time for about 3 months. I just don't find much time or energy in the winter to tackle projects.

 

[apdxyk]

Lithium likes current going through them. Don't keep them on the charger for too long and discharge them with a normal load. There is a battery cell and there is a micro-chip that may easily be confused while recalibrating the levels on the dormant battery.
Long term storage - half-charged/discharged

 

[jkwilson]

Many chargers just shut off when the battery reaches full charge and never come back on to check for a battery that has self-discharged. Effectively leaving them on the charger is like leaving them on the shelf.

Often you can get around it by hooking the charger to a programmable timer that comes on once a week for several hours. Look for a 7 day timer. Should be able to get one for $12-$15.

 

[bigroomboy]

Li-ion batteries are great because they have such high capacities, are light weight, have less memory effects and self discharge more slowly. The last one is critical along with another one that the cells can completely collapse if over discharged. Therefore they still self discharge over months and if they do discharge too far they will die. They also suffer from loss of capacity from storage which is why li-ion are best in constant charge discharge roles like phones etc.

The rate of capacity loss is related to how charged they are when stored. The more charge the faster the loss. Off the top of my head I think this may be as high as 40% per year if fully charged. Which is impossible due to self discharge. The best is to store at around 50% but should be charged and partially discharged every few months to avoid over self discharge.

I hope that helps.