How to charge a 6v sealed lead acid battery

[threedee]

I have one of them ride on car toys thats been sitting for a while, decided to try to revive it but cannot find a charger. It was just a phone charger sort of affair...

Anyone can tell me how to recharge this battery ?
Markings
NJenne 3-FM-7(6v 7Ah/20HR)
Constant voltage charge (25c)
Cycle use 7.2-7.5v
Standby use 6.8-6.9v

I have here an adjustable power supply that i use to sun some small projects of mine. Skytronic IC1200 Stable (660.190UK), 9-12-15-18v step switch. Output: 1200mA 21.6VA(max)

Anyone care to educate me ?

 

[Monkeh]

How long has it been sitting?

 

[threedee]

'bout a year...

 

[Monkeh]

'bout a year...

Chuck it. Lead-acids do not sit.

When you buy a new one, buy a suitable charger.

E: And by 'chuck it' I mean take it to a recycling centre.

 

[threedee]

Pretend battery is good. Can i charge it using the power supply i described and how ?

 

[Monkeh]

Pretend battery is good. Can i charge it using the power supply i described and how ?

No.

 

[threedee]

No what ?

 

[Monkeh]

No what ?

No, I won't pretend it's good, and no, you can't charge it with that.

 

[threedee]

why not ?

 

[Monkeh]

why not ?

Look at the (actually excessive) charge voltage printed on your battery. Now look at your power supply.

 

[endecotp]

[quote="threedee";p="3165426"Constant voltage charge (25c)
Cycle use 7.2-7.5v
Standby use 6.8-6.9v[/quote]

Like it says, you need to apply a constant voltage of 7.2 to 7.5 volts (or the lower voltage range for "trickle" standby charging).

It might be sensible to start with a lowish voltage e.g. 7v if the battery has been discharged for a long time. Keep an eye on it in case something unpleasant happens.

It doesn't sound to me as if the power supply that you have is suitable.

That assumes that you're going to remove the battery from the device and connect it directly to the charger. It's more likely that previously it was charged "in situ" i.e. the charging regulator was in the toy and the external power supply that you've lost delivered a different voltage.

These batteries don't last forever, but I would expect that after just one year on the shelf you should be able to get some charge into it.

 

[threedee]

This is what i want to hear... Constructive criticism..

I cannot find original charger and i'm not sure there is much if any electronics in the car. Need to check again (tomorrow).

I might be able to scrounge a pot to dial down from 9v to something more suitable ? Would it charge the battery this way ?

 

[Monkeh]

Pots do not dial voltage down. You'll just release the magic smoke.

 

[threedee]

So explain it to me without being a dick. Or dont.

 

[endecotp]

I might be able to scrounge a pot to dial down from 9v to something more suitable ? Would it charge the battery this way ?

No. It will get hot, and might burn down your house if you leave it unattended. It will also fail to correctly charge the battery.

Question: did the lost charger plug into a socket on the toy? Are there any markings on the toy next to the socket? If so, they will give a clue about what voltage (etc.) the lost power supply delivered.