keeping batteries topped up

[Raj]

If I had to store my batteries, and i could do that while having them connected to solar power to extend their life. Should I (is it beneficial)? And what technologies I should? And at what voltages?
I know lead acid can be stored this way at 13.5v &I cant store lithium. What about nimh? nicd? etc
I'm thinking of this mainly to extend lifes and have them ready for when they're needed.

[Audioguru]

You should not and do not need to trickle charge Li-PO and Ni-MH batteries.

Rechargeable lithium batteries that have cobalt and have a fully charged voltage of 4.20V per cell can be stored at 3.7V to 3.8V per cell for many years. I have the Lithium battery from my daughter's first cell phone that has been stored at 3.7V for 20 years and it still works fine. I store the Li-PO batteries for my RC airplanes at 3.7V per cell each winter.

Ni-Cads are toxic and are obsolete. They also become weak or shorted.

Ni-MH cells made within about 5 years can hold a charge for one year. You can top-them-up for a few minutes each year.

[KL27x]

IIRC, Ni-Cads can be stored fully depleted. Just charge them before you intend to use them. This is how I always used them in practice, anyway, because they lose charge so fast.

[Audioguru]

Ni-Cad batteries are very toxic and obsolete. Ni-MH has replaced them years ago. Ni-Cads shorted when they were discharged and shorted when trickle charged.

[FrankE]

You have charge controllers for each chemistry?

[Audioguru]

You have charge controllers for each chemistry?

Of course. Learn about battery chargers for all the different chemistries on the charger ICs datasheets and at www.batteryuniversity.com .

[grifftech]

ni-cd, nimh, and lead acid are less likely to explode/ignite when abused than lithium

[Raj]

Thanks,
That pretty much sums it up