ups 650 12 vols 7ah battery

[SMAUH]

Hello everyone,

i have ups capacity of 650 VA it consists of 12 volts 7ah battery which gives backup for approx 10 mins for 1 pc.

Please let me know,

1. can i replace 12 volts 7ah battery and connect 12 volts 100ah battery to same ups?
2. will it charge from the ups?
3. will it give more backup time instead of 10 min?

Thanks & Regards,
SM.

 

[BradtheRad]

It is okay to use for backup purposes, since it's the same voltage. The larger capacity will give you longer backup time.

However the charger function will not necessarily provide more current than it already does. Therefore you can expect charging to require a longer time.

gives backup for approx 10 mins for 1 pc.

Your UPS may be built to operate only for 10 min. After that time components may heat up, even though you are not drawing overmuch current. Therefore you should be alert for signs of overheating which could lead to failure. Consider adding a fan, or cooling fins, or vents, etc.

 

[kam1787]

You need not replace the existing battery. It is fairly common to add an additional battery - in parallel.

 

[tanveerriaz]

it can not charge from the ups. use a external charger for high a/h battery.

 

[chuckey]

Kam1787, you NEVER connect lead acid batteries in parallel with out a voltage sharing resistors between them. Compared to the 100 Ah battery the 7 Ah battery is just an embarrassment and should be dispensed with.
Frank

 

[kyrietec]

Get inverter

 

[Audioguru]

I have used MANY batteries (carbon-zinc, alkaline, Ni-Cad, Ni-MH, silver-oxide and Lithium) but in my entire electronics career I never used an old lead-acid battery.
I never needed a UPS because my mains electricity is reliable.

 

[SMAUH]

Thank you everyone for the suggestions :-D

Please let me know if i want to charge 12 volts 100ah battery(20hrs), how much should be the charging voltage(DC) to the terminals is required to charge the battery?

For ampere and charging time Please let me know the below calculation is correct?,

100ah battery 10% = 10 amps
100/10 =10 hours

considering losses during charging,

100 ah x 0.4 % =40
100+40 = 140 ah
140/10 = 14 hours

If possible please provide me a schematic diagram to charge 12 volts 100ah (20HRS) battery.

Thanks & regards,
SM.

 

[--BawA--]

HI SMAUH
If you go through the chemistry behind lead acid battery,u'll find that the nominal charging current for a lead acid battery is 1/10 of its AH capacity, so as you witnessed that your ups has 7AH battery so the charging current for that battery is approx 0.7 ampere , and for 100AH battery ,the charging current required is approx 10amps , so it's really not a idea to charge 100AH battery with your UPS , however if backup is intended to increase ,you can connect 100AH battery with your UPS, but for charging purpose, u have to use approx 10amps charger.

you NEVER connect lead acid batteries in parallel with out a voltage sharing resistors between them.

Hi chuckey,
could you please explain a bit more , actually i didn't know about this thing so please through some light.

 

[Audioguru]

Kam1787, you NEVER connect lead acid batteries in parallel with out a voltage sharing resistors between them.

It is normal for us to do it each time we "jump" a dead car battery on another car with our good battery. There is a HUGE spark then the good battery charges the dead battery, then both parallel batteries can start the dead car.
Maybe the very thick "jumper" cables are a resistor?

 

[dick_freebird]

I have tried this out (attaching a bigger battery to a small
UPS) and for a while it worked. But one time I let it run the
battery down, and the charging circuit got fried trying to
recharge the big battery.

Home UPSes (like use those little SLA batteries) are made
as cheap as possible and are not meant to leave anything
on the table, for you the consumer.