Will this charger kill my battery?

[jetblack]

I've got a car battery charger and i'm Not sure if its safe to use on my bike battery. I've heard they can be too powerful and kill them off...

Its a sparkrite one and printed on it is:

Suitable for cars up to 1200 cc
output 12-15VDC
4 amp (max output)
current 2 amps or 4 amps peak

The battery (yuasa) says STD: 0.7amp X 5-10 hrs OR QUICK: 3.0amp x1hr on it.

Any thoughts?

Don't want to shell out for an optimate/ctek if this will be fine.

[oldgreyandslow]

If I remember rightly the battery charger will only deliver the current that the load (the battery) demands so I'd put it on low, 2A, and if it has an ammeter see what it reads, as it gets to full charge the current should reduce

[jetblack]

you cant set it. There is no hi/low setting. its just 'on'
i gues it delivers the ful 4 amps if the battery needs it and then drops to 2 once the battery is charged?

[magg]

Your charger will be satisfactory, its output is insufficient to present a problem to the battery. As indicated in the other replies, the battery will only take what it needs from the charger and in this case the charger is claimed to be limited to a max of 4 amps. The type to avoid are the quick charges and heavy duty car types, if their their outputs cannot be tightly controlled, they can be detrimental to bike size batteries.

[Neosophist]

Some of the replies above are a bit confusing.

Stating that a battery will only draw what it needs but 'don't use a big battery charger' kind of conflict, if it will only draw what it needs then surely any charger would be ok?

The problem is that a bike battery WILL accept a charge upto quite a high-ampage rate, the problem with this is that damage to the plates occur becuase of the rapid charge, which is why you want a smaller charger that will supply less current.

Since your charger outputs 4/2 amps I wouldn't use it for more than an hour as stated on your battery.

Even 4amps is a lot for a motorcycle battery, to be on the safe-side and prolong the battery, in future don't supply more than 1 amp of current and perform a slow charge.

Since the battery allows for 'quick charge' connect it up for just under an hour and see how you get on.

You would be best investing in something like an optimate / dedicated motorcycle charger, they usually supply upto 1 amp max of current and go into a float mode when the battery is fully charged, saving the fluid in the battery as you can leave them connected.

If your not using the bike slow charge it with a bike charger once every two weeks to keep it in the best condition, also if it's cold where you are it would be beneficial to keep the battery in-doors while not using the bike for a long time.

[jetblack]

Quick charge with the sparkrite then maintain with a CTEK/optimate it is then. thanks.

[mick.mh2racing]

I've cooked bike batteries before with car battery chargers. Worth an investment in an optimate. Got my bike charger from machine mart. Think it was only about a tenner so it's not worth risking in my book.

[Morespeedvicar]

If you have a multimeter just keep checking the voltage doesnt go over 15volts. Youd be surprised how much current a battery charges at the 14volts it charges at on the bike!
Cheers
Ian
PS is it a standard battery not one a them LiPo racing battery?

[magg]

A flat battery will draw as much current from a charger as is dictated by its internal resistance. A charger rated as 4 A peak max will only supply 4 amps no matter what the internal resistance of the battery and therefore will not cause any damage. Car battery and quick charge chargers have very high current limits because car batteries are large energy storage devices that may require large current flow to recharge.

This means that when these large capacity chargers are connected to a bike battery with a low internal resistance ie flat, the charging current can be quite a lot higher than is desirable for the small battery structure. This is why manufacturers provide a guide as to the charging requirements for their bike batteries.

[dgunthor]

I got a CTEK charger that was suitable for motorbike and car, it seems more useful than the optimate (which i still have) which didn't do much for my flat car battery - the CTEK brought it back to life :-)