Honda CBR125RW Battery Doesn't Hold Charge

eoinzy · L Plate Warrior Joined: 10 Jun 2014 Karma :

Hi

I'm having problems with my CBR125RW battery. The bike wasn't used for a while and the battery was dead as expected. I charged it off a 4amp battery charger and that seemed to do the trick.

However the battery doesn't hold its charge. The bike will start, I can go for a ride for an hour plus, and then the next day the battery will be dead again. I'll charge it again, the bike runs, then either later in the day or the following day it's dead again and needs charging. I've even had it not restart when I'm out on a trip.

Is my battery dead or is there a way that I can save it? I'm pretty broke at the moment and really don't want to spend £60 on a new battery if I don't have to.

Your help is much appreciated. Thanks.

J.M. · World Chat Champion Joined: 27 Mar 2011 Karma :

I'd measure the voltage over the battery with the bike running first. With poor connections, it is possible that your battery charges enough to run the bike, but not enough for the starter to work.

But I'd definitely want to measure the voltage over the battery to ensure I was getting around 13-14v at 5000rpm.

It is possible to save a battery sometimes, but the charger will likely cost a similar price to the battery itself. Take a look out for some independent shops. I recently paid around £60 for a new battery as it was from Halfrauds and I needed it now, but the battery I bought before that was from a lesser known shop my dad told me of, and that cost £30.
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2004 R1 & 2018 XSR900

eoinzy · L Plate Warrior Joined: 10 Jun 2014 Karma :

How to I measure the battery voltage with the bike on? Do I need to buy a special instrument?

J.M. · World Chat Champion Joined: 27 Mar 2011 Karma :

With a multimeter, such as this one: Digital Multimeter - eBay

In all likelihood, your charging system is probably fine. I just like to check things. A friend/parent/neighbour may have one of the above tools that you could borrow for a couple of minutes.
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2004 R1 & 2018 XSR900

eoinzy · L Plate Warrior Joined: 10 Jun 2014 Karma :

OK I've just ordered that from eBay. Thanks.

So just incase it is worst case scenario can you recommend that cheap battery seller you mentioned previously? Would rather save some money there rather than buy from Halfords. Thanks.

eoinzy · L Plate Warrior Joined: 10 Jun 2014 Karma :

Also the battery is a YUASA YTZ7S.
[VLRA 6.3 Ah (20HR)/130 CCA, 12v 6ah (10HR)].

I can't find this battery at any reliable seller. Does anyone know any other battery models that are compatible with the Honda CBR125RW?

Cheers!

Vincent · Banned Joined: 16 Oct 2006 Karma :

Take the battery off the bike and charge it up. Then, with your newly acquired multi-meter, check the voltage every half hour and take a note over about 6 hours. You don't want it to drop more than 12.4V, if it does, the battery is kaput.
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Robby · Dirty Old Man Joined: 16 May 2002 Karma :

Replace the battery. Remember that a new battery will need charging at more like 0.8A - a 4A charger is too much for a small bike battery to take, unless it's a smart charger that steps down to something appropriate.

For a cheap battery that will last a couple of years:
https://www.ebay.co.uk/itm/Powerline-Honda-CBR-125-R5-2005-Battery-YTX5L-BS-/271385728746?pt=UK_Motorcycle_Parts_13&hash=item3f2fd996ea

£16 delivered.

For a battery than will last as long as the bike:
https://www.ebay.co.uk/itm/Honda-CBR-125-R6-2006-CT5L-BS-CTX5L-BS-Motobatt-Motorcycle-Battery-Upgrade-/271006398785?pt=UK_Motorcycle_Parts&hash=item3f193d7941

£39 delivered.

doggone · World Chat Champion Joined: 20 May 2004 Karma :

They really don't like being let go completely flat, if you often aren't using it for a couple of weeks or so you're going to need a trickle charger.
Chemical changes occur when fully discharged, and they are not usually reversible.

Some bikes will hold charge longer than others, but if you've got an immobiliser, clock, or alarm fitted the drain is significant on what is a fairly small battery. Cold weather makes things worse.
Performance starts to fall off after a couple of years anyway.
It's unusual to get much more than three years even if you do everything right.

eoinzy · L Plate Warrior Joined: 10 Jun 2014 Karma :

eoinzy · L Plate Warrior Joined: 10 Jun 2014 Karma :

Vincent · Banned Joined: 16 Oct 2006 Karma :

eoinzy · L Plate Warrior Joined: 10 Jun 2014 Karma :

J.M. · World Chat Champion Joined: 27 Mar 2011 Karma :

eoinzy · L Plate Warrior Joined: 10 Jun 2014 Karma :

The Shaggy D.A. · Super Spammer Joined: 12 Sep 2008 Karma :

andys675 · World Chat Champion Joined: 08 Feb 2007 Karma :

4 amps? for how long?

90 mins would be ok, but more than that there's a valve inside that opens permanently and the fluid inside will evaporate

need to charge at 0.5 amps for 14 hours on a new 7ah battery

to get the best from it, buy an optimate, honda do one and doble's sell them on ebay for £37 delivered, this will test, charge and maintain you battery
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gavcarter · Could Be A Chat Bot Joined: 28 Mar 2009 Karma :

eoinzy · L Plate Warrior Joined: 10 Jun 2014 Karma :

doggone · World Chat Champion Joined: 20 May 2004 Karma :

If you're still on about the old one then no.
It might improve things slightly but once it's damaged that's it.

A decent charger is a life-long investment so you really ought to get one sooner or later. It will save you money long term - if you keep batteries well maintained you could double their lifespan.

But for now you just need a new battery, then you'll forget all about it for a couple of years.

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

I provided links to a couple of batteries on ebay 10 days ago. Have you bought one yet?

You don't need to go to a bike shop to fit a battery.