bendiazclegg Posted November 26, 2011 Share Posted November 26, 2011 i have a dead battery and decided to take it to the local garage to get it charged and they said it wont charge, they cheked that the alternator was charging the voltemeter and said that bosch batteries are c**p as they run out of charge very fast and do not like to retain voltage when charging, ive been looking arround the net and found a NUMAX and a YAUSA battery that fits, i was just wondering wether anyone had anything to say about this battery will i have another crap time with it running out in 3 weeks ? also looking at my battery ive seen that i must keep to the 12volts and 4ah but it has another value of 30A is this amps ? and how would buying a battery with a different A value change performance or would it not work ?i know im asking allot of questions on this forum but im fairly new to motorbikes and id rather be safe than sorry Quote Link to comment Share on other sites More sharing options...
eastanglianbiker Posted November 26, 2011 Share Posted November 26, 2011 yausa batteries are normally fine a lot of japanese bikes are fitted with them as standard Quote Link to comment Share on other sites More sharing options...
TC Posted November 26, 2011 Share Posted November 26, 2011 Yausa are decent batteries.Get yourself an Optimate to plug into your battery when you are not using it, it will keep it charged and in good condition. (just don't leave it pluged all winter) re-charge about every 3 weeks for a day. Quote Link to comment Share on other sites More sharing options...
bendiazclegg Posted November 26, 2011 Author Share Posted November 26, 2011 thanks for the help when im buying the battery i know i must keet to the voltage and the Ah but on my old battery i have another A figure....it reads like this 12v4 Ah 30 A do i have to keep to the 30A value as i have seen many that match the top to figures but not the last Quote Link to comment Share on other sites More sharing options...
Fozzie Posted November 26, 2011 Share Posted November 26, 2011 So 12 volts and 4 ampere/hours and can deliver 30 amps full current is what I make out of that...It's best to find one that matches the specification of your current battery. A battery too big for your bike power wise might cause problems. Quote Link to comment Share on other sites More sharing options...
Bogof Posted November 27, 2011 Share Posted November 27, 2011 So 12 volts and 4 ampere/hours and can deliver 30 amps full current is what I make out of that...It's best to find one that matches the specification of your current battery. A battery too big for your bike power wise might cause problems. My understanding (which may be wrong, it does happen occasionally) is that the 30A relates to cranking power available. Just 'cos it's available don't mean it's delivered, so it'd be OK so long as it physically fits. The only time you woulld have a (potential) problem is if there is a fault on the starting circuit and it demands more power than the circuit is designed to take at which point the fuse would blow. Most Firestorm owners uprate their battery to a higher cranking power battery 'cos they occasionally need an extra kick to start them. Mine used to flatten the battery if it didn't start 2nd push of the button. Since uprating the battery it starts everytime first push. Quote Link to comment Share on other sites More sharing options...
bendiazclegg Posted November 27, 2011 Author Share Posted November 27, 2011 the only reason why im asking is because.....the yausa battery fits exactly has 12 volts and 4ah but has 80A'sand the numax battery is exactly the same appart from the fact it doesent even list the A value so thats why i was guessing it didnt matter ??? Quote Link to comment Share on other sites More sharing options...
Colin the Bear Posted November 27, 2011 Share Posted November 27, 2011 Voltage and physical size is the most important. Cos if it's the wrong size it won't fit on the bike and if it's the wrong voltage , nothing will work.The ampage is the total output available from the battery. Each component only draws what it needs. The battery can't force more than is needed into the component. The amp /hour value is how long the battery will last under a constant load. 4 amps for an hour, 1 amp for 4 hours, 8 amps for 1/2 an hour.This is under test conditions. In the real world it's only a guide, because temperature, electrolite level and strength vary with age and weather conditions. Quote Link to comment Share on other sites More sharing options...
cyberwolf Posted November 27, 2011 Share Posted November 27, 2011 The battery can force more than is needed into the component, thats why the say dont put lets say 8v bulb into a 12v system as it well burn out Quote Link to comment Share on other sites More sharing options...
Stu Posted November 27, 2011 Share Posted November 27, 2011 if the yuasa fits get it prob one of the best batteries for a bike and used by many manufacturers and get an optimate too and keep it charged Quote Link to comment Share on other sites More sharing options...
Fozzie Posted November 28, 2011 Share Posted November 28, 2011 So 12 volts and 4 ampere/hours and can deliver 30 amps full current is what I make out of that...It's best to find one that matches the specification of your current battery. A battery too big for your bike power wise might cause problems. My understanding (which may be wrong, it does happen occasionally) is that the 30A relates to cranking power available. Just 'cos it's available don't mean it's delivered, so it'd be OK so long as it physically fits. The only time you woulld have a (potential) problem is if there is a fault on the starting circuit and it demands more power than the circuit is designed to take at which point the fuse would blow. The starting issue is what I was referring to. Whilst on a training course for work last year we hooked up a car battery with 110 amps crank power as part of an experiment. The starter motor stalled and full current was drawn across the wire melting it. That was fairly impressive to see If there is a battery in close prox to your current values go for that. As said early physical size is most important. Quote Link to comment Share on other sites More sharing options...
Bogof Posted November 28, 2011 Share Posted November 28, 2011 The starting issue is what I was referring to. Whilst on a training course for work last year we hooked up a car battery with 110 amps crank power as part of an experiment. The starter motor stalled and full current was drawn across the wire melting it. That was fairly impressive to see And now kiddies, we all know what fuses are for, don't we? Quote Link to comment Share on other sites More sharing options...
Fozzie Posted November 28, 2011 Share Posted November 28, 2011 It was fused, but it had a 20amp crank rating and was hooked up to a 110amp crank battery to show what can happen, the fuse actually blew but an arc managed to melt the fuse down to the blades and took half the fuse box with it as well as allowing the wire to melt... All to simply show what can happen with the wrong supply And saw it happen to a 125 before as well A better block is a breaker but thats trailing off from the subject. Quote Link to comment Share on other sites More sharing options...
Guest Posted November 28, 2011 Share Posted November 28, 2011 did the starter motor stall by coincidence or did it stall because the bigger battery had the ability to supply more current? I don't think a bigger capacity battery could cause a motor to seize/stall but if it stalled all on its own then the bigger battery would have the ability to give the fireworks display it did if it wasn't fused correctly. Quote Link to comment Share on other sites More sharing options...
Tango Posted November 28, 2011 Share Posted November 28, 2011 The Yuasa sounds like a good bet.... The starter motor will only pull as much current as it is rated for unless it has a fault:Ohm's Law. I=V/R. ie. 12v/1ohm=12ASo, a starter motor with winding resistance of 1ohm will only draw 12A from a 12v battery. Even if the battery is rated to supply a maximum 80A instantaneous current the starter will only draw 12A steady state current. BUT....because the windings form an inductance the maximum in-rush current will be determined by the cross section of the wire used in the windings and the number of turns in the windings and the core material that the wire is wound around. But this in-rush current is for an extremely short period of time (milliseconds) until the starter motor starts turning. So, unless your starter motor has a fault the higher current capability of the Yuasa battery should be a benefit. Quote Link to comment Share on other sites More sharing options...
Fozzie Posted November 29, 2011 Share Posted November 29, 2011 did the starter motor stall by coincidence or did it stall because the bigger battery had the ability to supply more current? I don't think a bigger capacity battery could cause a motor to seize/stall but if it stalled all on its own then the bigger battery would have the ability to give the fireworks display it did if it wasn't fused correctly. It stalled by coincidence, it was a old motor though. The lecturer had been expecting the fireworks at some point to make a point as we all sort of laughed at the fuse thinking it would snap very easily and safely. As it turns out fuses arent fool proof. Thats why I worry about a battery of a much greater ampage being used as if the situation ever reproduced itself for whatever reason then it was our reccomendation the op went off Quote Link to comment Share on other sites More sharing options...
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