batteries - Add old lead acids to parallel or replace them

\$\begingroup\$

Check now

I agree to what is posted on this forum with the same question as yours:

Where westbranch said:

Mixing batts of different ages is not recommended as they interact between themselves

He also makes a suggestion of using a marine battery switch. That way you can leave the old battery charged up and on standby while you use the new battery for your initial demands of power. Whenever you need to, you can switch to the other (older) battery.

And Cariboocoot described some aspects of the issues that can appear as well:

CH Tech contains other products and information you need, so please check it out.

The problem is that a "perfectly good battery" is not the same as one that still has 100% of its capacity as the new one would. As a battery ages it inevitably loses capacity. The deeper it is discharged, the more cycles it is run through, and the time that passes all take their toll. The trouble is there is no practical way to determine how much the capacity has diminished.

Why it is bad to put an old and new battery together is the same as why it is bad to put two batteries of different capacity together (because that's what you've got): the charge will be wrong for one, the other, or most likely both. Too little for the higher battery, too much for the lower one. The greater this difference is the greater the risk of either frying the old battery (in a possible sudden failure) or cutting years off the life of the new one.

Another matter: do you have enough recharge ability to add more battery capacity? Chances are even if the system was properly designed to recharge one 160 Amp hour 12 Volt it can not do the same for two (320 Amp hours).

Since you are thinking of buying a new battery, needing to expand capacity, and inevitably will have to increase charge capacity it is time to re-evaluate. You probably would be better off buying one new battery of greater capacity (or two 6 Volt units) than adding another of the same on to the existing.

Re: 12v sealed lead acid battery, recharge or repl

Gell cell batteries on float charge do tend to last only about 5 years. Keeping them charged keeps the acid at it's strongest and the usual failure mode is for the plates to dissolve (positive plate, IIRC) in the acid. They don't last much longer (if any) on cyclic charge since they usually are left partly charged (often) and therefore sulfate. The other main failure mode is loss of water from overcharging - that can happen on float charge, also.

Your alarm is expecting you to have a back up battery and in fact has to have one to meet certain fire codes. It's not uncommon to loose your electricity when there is a fire, especially since the electrical system is often the cause. Most of them show some kind of signal when the battery isn't there. Mine for example has an LED that lights up (I don't recall exactly what it does). Anyway, I can tell when the power has been off OR if it is running on the backup battery OR if the battery is dead (run down, not necessarily DEAD). Obviously, your alarm won't work when your power is off (without the battery), including if your burglar disconnects your power (Hey, it happens!).

Home Depot usually has them and any electronic place should, even Radio Shack, as well as electrical distributors since they supply the alarm installers.

For more Lead Acid Replacement Battery(el,hu,it)information, please contact us. We will provide professional answers.