Frequent Usage of Flooded Lead Acid Battery Without Fully Charge

What information was forthcoming during the telephone call to the UPS vendor's technical helpline?

Hello PWSlack;

The major concerns of UPS vendors is to sell their product whatever the way. This is our engineering corner where the participant shares their knowledge/experience and many times I solved many problems in machines by asking questions here whereas the vendor/supplier could not provide sufficient information. So I prefer to ask questions here first then move to others.

Many thanks to all my colleagues/participants.

For lithium battery, shallow charge/ discharge is beneficial to battery life. I don't know whether this applies to lead acid battery.

Only those chargers that have an equalizer setting will charge the battery to about 100%. Most chargers fall short of charging to 100%. This is to keep from over charging a cell. 80% is a little low at that state it will cause sulfating. This will reduce battery output and life.

The 80-40-80 percent charging numbers are not bad, actually are good numbers for a lead battery. Cycling between these numbers however in one and two hours period is DISASTROUS for the battery and you will have VERY SHORT life. For this kind of load I would use four times your battery capacity. I calculate that you will then eventually go to about 88-78-88 percent with the same charger, if it can handle the heavier duty. S.M.

I'd think you'd need the specific rate of charge and discharge to determine is there's any potential battery damage.

I can't imagine a UPS charger cooking a battery. Discharge maybe.

Agree we need more details, but the data already given by OP is bad news:

"Power-in time 2hours, UPS charges the battery up to 80%" (charged from 40% to 80% in two hours pretty high rate, very stressing to most deep cycle lead batteries)

"Power cut-off time 1hour, UPS works and battery discharges at 40%." (discharged from 80% to 40% in one hour, no lead battery will live through that for too many charging cycles)

(Not to mention no settling and/or cooling time in between.) S.M.

Hello friends,

That was just an example to use the battery for one hour and charge it for 2 hours. The main concern is that in such a case like 80%-40%-80%........ (or 60%-30%-60% i.e not full charge every time) would it be ok for lead acid battery or harmful?

Lead-Acid batteries give low life if cycling in Partial State of Charge. PSOC is major area where research and also improvements are being done.

It is better to charge these batteries with equalizing charge periodically ,say every 3 months.( depends on actual usage and state of charge)

If depth of discharge is more than 40%, it is better to have higher capacity of battery,if you can not reduce usage of power.

I find it good, no gassing, so no explosions (assuming not SLA type).

The battery life will be extended and as good as it can get!!!