Battery recharge

[johnw11]

Hi,

I need to recharge my battery, and reading through old emails I see it needs
a slow trickle charger of 1amp. Went into Repco and lowest they had is a
2amp. Looking at miata.net and I found an article saying use a 2amp charger.

Before I unpack it and start using it do you think it will be OK or do I
need to swap for the 1amp version when they get one in stock.

Regards

John

From jifjif@gmail.com Fri Apr 27 17:33:33 2007
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Date: Thu, 1 Sep 2005 20:46:15 +1200
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To: MX5List <mx5list@mx5club.org.nz>
Subject: Re: My MX5 won't go, ECU?
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The NA models sometimes had issues with bad grounds in the engine bay -
presumably it's about time the NB's had it as well ...

On 9/1/05, The Simpsons <grant@simtronics.co.nz> wrote:
[...]

[EricW]

Hi John,
Obvious question I know, but I assume that your battery is the genuine
sealed acid battery?

If so, yes, it needs a long, slow charge to get it going again from flat and
a two amp charger would be OK Most standard slow chargers run at about 5
amps, so two amps is a very low charge. Many older batteries have quite high
internal discharge rates, and you might find that a 1 amp charger is
struggling to put any real charge into the battery. Even at 2 amps it is
likely to take between 36 and 60 hours to bring the battery up from flat.

Once there is a reasonable level of charge in the battery you can raise the
charge rate, but I would not go over 5 amps until the battery is fully
charged and back in the car.

If it is anything other than the genuine battery, or similar, it would
accept a higher charge from flat anyway so there is no issue.


Eric

[EricW]

Hi John,
Obvious question I know, but I assume that your battery is the genuine
sealed acid battery?

If so, yes, it needs a long, slow charge to get it going again from flat and
a two amp charger would be OK Most standard slow chargers run at about 5
amps, so two amps is a very low charge. Many older batteries have quite high
internal discharge rates, and you might find that a 1 amp charger is
struggling to put any real charge into the battery. Even at 2 amps it is
likely to take between 36 and 60 hours to bring the battery up from flat.

Once there is a reasonable level of charge in the battery you can raise the
charge rate, but I would not go over 5 amps until the battery is fully
charged and back in the car.

If it is anything other than the genuine battery, or similar, it would
accept a higher charge from flat anyway so there is no issue.


Eric

[poison]

An old trick that can else be used on motorcycle or jet ski batteries is to
put a standard 230V/100W or 75W bulb (lamp, globe or whatever you like to
call it) in series with the battery during charging (on the 12Volt side) ,
this will barely reduce the voltage but will give very cheap current
limiting. The reason is that if you charge with too higher current then the
battery can boil and lose some of the electrolyte, a sealed battery can go
pop if there is too much gas discharge. Bt not too likely at 2 amps. But the
bulb is a good solution.

Gazza
"PO1SON"

[poison]

An old trick that can else be used on motorcycle or jet ski batteries is to
put a standard 230V/100W or 75W bulb (lamp, globe or whatever you like to
call it) in series with the battery during charging (on the 12Volt side) ,
this will barely reduce the voltage but will give very cheap current
limiting. The reason is that if you charge with too higher current then the
battery can boil and lose some of the electrolyte, a sealed battery can go
pop if there is too much gas discharge. Bt not too likely at 2 amps. But the
bulb is a good solution.

Gazza
"PO1SON"