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Using lead acid batterys to power projects.

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Alex1M6

New Member
Hi, are lead acid battery's suitable to be used as a power supply for my electrical projects as I do not have a good power supply to hand and need around 5-7amps of current @ 12v, I can get hold of lead acid battery's very cheaply and have a charger.

And also I have read that they let off hydrogen gas, is this a safety concern if when connecting and disconnecting alligator clips from the terminals and sparks being created.

I plan to use this for powering my circuits and this includes things like flyback transformer drivers so again sparks and hydrogen could be a concern.

Any advice would be appreciated.

Thanks.
 

georgetwo

Member
as 4 me, Lead acid bat (I assume car battery). needs so mush attention, like maintain the acid level, hazard of over charging, weight and size. If you can handle them, dont forget to use diode for protection of cct.
 

georgetwo

Member
good, and make sure the charging system is automatic if it will be left permanent with electricity.
and that diode projection shuld be used.
 

georgetwo

Member
use a diode (big or small depending you) by foword biasing the vcc from the + terminal of your battery to the vcc terminal of the cct. this prevent burning of components during polarity mistakes.
 

MikeMl

Well-Known Member
Most Helpful Member
Alex,

When using SLAs, do not discharge below ~11.5V (measured at the battery terminals). When charging, use the information here.

I would use a fast-blow fuse between the battery and your experiment; not a diode.
 
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MikeMl

Well-Known Member
Most Helpful Member
use a diode (big or small depending you) by foword biasing the vcc from the + terminal of your battery to the vcc terminal of the cct. this prevent burning of components during polarity mistakes.

George,

How??? If you reverse the connections to the project, the diode still passes current to blow up the project.

If you short the diodes, you still draw an arc and likely blow up the diode.

USE a FUSE!
 
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georgetwo

Member
I agree with you, but i have fried some transistors due to polarity mistakes in the presence of about 0.2A fuse.
 

Alex1M6

New Member
Thanks for the replies, I will be sure to put some kind of protection in my circuits that I plan to use this battery to power. (Note I do not intend to use these battery's for always turned on type projects but rather stuff that I will be powering off after use such as fly-back transformer drivers).

So as far as using these types of battery's, is there any risk of the sparks of high voltage arcs igniting the hydrogen gas produced by the battery's?

I will be charging them in a safe vented place well away from any of my projects.

Thanks.
 

crutschow

Well-Known Member
Most Helpful Member
The reverse polarity protection diodes need to be on the circuit you are testing. As Mike noted, they don't do anything across the battery.
 

MikeMl

Well-Known Member
Most Helpful Member
Or in series with the battery lead.
 

Alex1M6

New Member
I will put a fuse in series with the battery's positive lead going to my circuit.

Could an arc/spark ignite any hydrogen vented from the battery when in operation.

Thanks.
 

MikeMl

Well-Known Member
Most Helpful Member
Unless you put the battery in a sealed box, I wouldn't worry about it. Besides, if you obey the charging restrictions in the link I posted, an SLA should never vent anything. Only if you abuse it by overcharging it would it vent.
 
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