Battery Not Holding Charge

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Battery Not Holding Charge

I have a Honda CB500 1998

I have bought a new battery, one of these gel ones.

Charged it up as instructions.

Used the bike for a few days, but once I use the lights for about 45mins, it will only have enough charge for one more start.

I have to at the moment go home each day and charge the battery.

I have not done much fault finding yet, any ideas if this is the rectifier that I need to repalce?

Three possibilities: Bike not charging the battery, battery not holding charge, or something is draining lots of power off the battery.Lets assume the battery's OK as it's new, but that's not always the case. Before you start overhauling the charging system, are you sure you're not just asking too much of the electrics? Are you running obscenely powerful headlights? Are you using heated grips, vests, pants and ear muffs? Is the engine spending a great deal of time idling with the lights / other power drains on? Is there any signs of a short circuit somewhere - overheated wires etc?If the answer to all those is "no", then check the charging system. You need to check the voltage across the battery at say idle, 2k, 4k and 6k rpm. Then do the same with the lights on. Depending on the results you then need to check the unregulated output straight off the alternator, at the same speeds. But be careful - if all is well in there you'll be looking at up to 100V AC.

thanks for the reply, that will keep me going for a while

im naughty not had a chance to have a look at the battery issue yet.but i noticed a strange thing last night coming home from was dark so i had the lights on all the way home, its about a 35min drive home, half slow riding and lots of stopping at lights (central london) and the rest is nice and fast 3-6k rpm easy. by the time i got home  i turned off the bike, turned off lights, parked it up, and thought i would try to start it again, only heard a ticking noise then it stopped nothing from the electric startso no luck battery dead, so then i tried the lights, they worked fine nice and bright. so is it that my battery have some voltage but no amps???

Sort of.A battery's voltage is largely defined by the ph of the electrolyte (the acid), the electro-potential of the metal plates, and the number of them stacked together.Its internal resistance is related to its construction, but also to its state of charge.If a battery is barely charged then it might be able to deliver 12V at 5A, but when you start asking for much more current it loses most of those 12V across the internal resistance.The symptoms you describe are an effect of this: when you ask it to turn the starter motor (100A+) the voltage drops so much it can't even fire the starter relay, so the relay clicks off, so the battery voltage comes back up, so the relay clicks on, so the battery's draining thru' the starter motor, so the voltage drops, so the relay clicks off and so on, several times a second.Given that you're riding around on it in the dark OK it does sound more like the battery's not holding charge rather than it's just not charging.. Still worth doing those tests tho'.

its a gel battery. does that matter?

Quick check.

Start it up, put the light on then blip the throttle a few times. If the light goes brighter as you blip the throttle, charging circuit is probably ok. If it stays constant, charging circuit is likely fault.

tom joffe wrote (see)

its a gel battery. does that matter?

Hmmm. Interesting thought. It *may* do - they may need a different charge method when first charged. Did you charge it up before you first put it on the bike? I'll maybe do some digging around and have a think.

It is possible that the battery is no good. I bought a mid range Gel battery (Sprint I think eariler this year for my trackbike. Fitted it and it seemed fine however on the first trackday it started to mis fire occasionally and then wouldn't start on the button but bump started OK.Spent a couple of hours on the phone to an autoelectricain mate of mine going through everything with a multimeter and in the end he just said 'the battery is f*cked' I said it's new, he said 'it's f*cked'. Called the shop I'd bought it from 5 weeks earlier and told tjhem and they said 'it happens' bring in back so I did and swaped it for a Varta sealed, cost £3.50 more and it's now fine.So the point I am trying to make is don't assume the battery is OK beause it's new. Do you have another battery that you can try or can you borrow one?

ok got the old multi meter out today, its the regulator rectifer that is dead thats gonna cost me £80! 

What makes you think it's the reg/rec?What tests did you do?Did you check the alternator output too?

its the reg rec its a honda problem blades vfr and cbs eat them, ive fitted loads of them

Yeah, but for another 5 minutes you can check whether it's the alternator instead and thereby save yourself spending money on parts you don't need. It probably is the reg/rec, but why waste £80 if it's not?

battery is doing my head in. bought it new 12 months ago but left it sitting without disconnecting a terminal. now when i fully charge it, it doesnt seem to hold charge. thanks to post above, as im going to get the multimetre out and do some invesigating. 

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