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Battery Problems... Keep Going Flat?

53697 Views 89 Replies 22 Participants Last post by  CBR250RRINOZ
[align=center]Battery Problems... Keep Going Flat?[/align]

It's worth paying a bit of attention to keeping the battery in good condition... a bad battery effects performance. Just ask someone that got a new battery recently!

How do you know its going flat or not performing?
A battery in good condition and charged will quickly crank the bike and start it. If it's low on charge, you'll hear the starter motor rotate a bit slower and take longer to spin up to speed, and in the dark you'll notice the headlights dip a lot while cranking. Lower again, and although the bike still cranks over it won't fire up. This is because the voltage has dropped so low, that the spark plugs won't fire with a hot enough spark. Turning the headlights off (or pulling the headlight fuse if you don't have a switch) might be enough to get you started. Usually you can still roll start the bike. Even lower again, and you'll get this rapid clicking noise from under the seat, and the starter motor won't turn over. Even lower, and you have no chance of roll starting, as the battery will suck all the juice :mad:

BTW... that clicking is the starter relay, which switches on to power the starter motor, then the starter motor loads the battery up and the relay no longer has enough power. So it turns off again hahaha.... Hence it repeats, on-off-on-off... :(

A battery typically goes flat under the following conditions...
1. Old battery
2. Mis-treated battery
3. Left for months un-used
4. Not getting enough charge from the bike.
5. Loose battery terminals.

Old Battery
A battery can last 3+ years without too much problem, though expect less if you live in areas with particularly colder winters. Higher quality batteries can cost twice as much, but last longer under these conditions. However... you can kill a brand new $150 battery in a day if you try hard enough :lol:

Lead acid batteries 'hate' being discharged! Can't stress this enough! As a general rule, you should always keep at least 20% charge in there at ALL times. Let it go flat, and it will never be the same :(. Continually letting it go flat is just plain mis-treatment and likely to cost you in the end.

Don't leave the bike unused for an extended period of time (more than 4 weeks), particularly if you have an alarm fitted. Ideally you would plug in a battery tender. Otherwise, give the battery a charge and disconnect the negative terminal from the battery. The battery will hold out a lot longer, particularly with newer bikes that have more electrickry!

Not Enough Charge - Short Trips
Short trips can slowly lower the batteries charge. It takes a fair bit of power to start the bike, and while idling, the battery isn't getting much back - on a CBR250, at idle it may get no charge at all. If you do a lot of short trips, consider getting a battery tender to keep it charged. A battery tender is a low power charger designed to be continuously connected for long periods, which usually comes with a plug you fit to the bike and can convenient connect to. Just ask at a motorbike shop ;)

Not Enough Charge - Bike Problem
If your battery is going flat while riding, then you definitely have a problem that needs to be fixed before it gets worse. If this happens, your bikes battery is probably providing the power for the ignition... which won't last long. Symptons will be the headlights go dim, trouble idling and/or the RPM starts limiting / missing. I you ignore this problem, your punishing the battery and causing it to go flat.

Typically there are 3 things that can cause the bike to stop providing power to the battery, the alternator, the regulator/rectifier (reg/rec) and the reg/rec plug. The alternator rarely fails, but if you suspect it as the last cause, check the service manual for how to test it. You basically measure the windings of the alternator coils with a multimeter... which isn't as hard as it sounds ;)

The reg/rec does get quite hot, and a few problems have been due to the plug being melted and having the terminals short others, or fall out. You should also remove 10cm of the insulation and check the wires from the plug haven't melted/fused together. In some cases, the terminals are oxidised (charred) and don't conduct very well. They just need a good clean. The plug should look like this, with no meltage or black charring.

The reg/rec may likely be the fault. What is the reg/rec? It converts the alternator power to the power needed by the bike. If it fails, it will provide too much power (over-voltage) or none/little power.

You can check if the reg/rec is operating correctly with a multimeter. Measure the voltage with the bike off at the battery. A good battery will show 12.6V. If it's low on charge, it should still be above 12.2V. I'd just like to add... the battery voltage does not necessarily indicate how much charge there is!!! If you have recently charged the battery, it could be much higher, like 13.5V. Within a few hours, it will be dropping back down to 12.6V, which is function of the chemistry involved.

With a CBR250 idling, the voltage should be around 12.5V, though can still be a bit lower if the battery needs some charge and the headlights are on. Basically the battery is loading the alternator. If you turn the headlights off, the voltage will probably go up a bit higher. Newer bike are usually around the 13.0 to 13.5V at idle.

The important thing is, one you get above 3,000rpm you should clear 14 volts. Revving higher, it shouldn't go above 15 volts, and will be more like 14.3 - 14.5V. If it's going up to 16V, then you have a big problem :dodgy:

The figures I've mentioned are general, as it primarly depends on what speed your idle is, if the headlights are on, the condition of your battery and how much charge its holding - and of course the bike/model.

Although the battery may be 12.6V by itself, it actually needs more to actually 'accept' charge at a descent rate. At idle, it will still be charging a little, but no where near what it will while your riding.

Loose Battery Terminals

Yep... I've seen it a few times. Clean the white crap off the terminals with a wire scrubbing brush, and make sure the bolts a tight enough!

Charging the Battery

These batteries for the CBR250 are a 6 or 7 amp-hour capacity. Thats tiny compared to a car battery. So if you put it on a big car charger, it's going to be choked with electrons :blush: A 3 amp charger is too much. It will heat the battery more than necessary, and not do it any favours. A 1 amp charger is ideal for these, 2 amps is still fine! The batteries usually specify a full charge takes 3 to 4 hours, but for a 1 amp charger, I'd go a few more hours than that. 8 hours is good, but as always, if the battery starts getting hot, take it off charge and let it cool down before charging further.

Battery Conditioners

You can buy chemicals to add to the battery to help reduce the lead sulphation buildup on the plates. Without getting too technical, it helps restore the capacity of the battery. Getting slightly more technical, the ions in the solution bind to the plates covering them, reducing the solutions charge capacity and reducing the plates ability to supply strong current. I've heard good things about these conditioners from a few people now, though never tried it myself. It doesn't cost much either, so worth a shot. When my battery is starting to get a bit old, I'II be dosing it up myself hehe... Here is one you buy...

INOX Lead Acid Battery Conditioner
Jaycar NA1420, $8.95 www.jaycar.com.au
Supercheap Auto, $8

You can also get 'battery refreshers', which as I understand, pulse the battery with very short high current bursts. These electrical shocks cause the sulphation to crack and fall off. I've never tried one or heard any reports from others, but personally... not that keen on the concept. I can see why it would work, but I can't see why it would do as good a job as the chemicals. Besides... $8 of chemicals will probably do 2 of these batteries, and these refreshers are a lot more expensive!

Battery Refresher
Jaycar MB3660, $49.95

A lot of people are having battery and reg/rec problems lately, so here is a bit more info to help with understanding the problem and what to do about it...

A battery is a device based on chemistry and it's a much bigger topic to understand than most people first realise. The voltage at the battery "does not tell you everthing". You absolutely cannot tell how good a battery is by the voltage, or how charged it is by the voltage alone. Lead acid batteries have two primary things to describe there status. If you were to use a multimeter, the nominal readings would be 12.6V (good) to 12.4 (average). If you have recently charged the battery or ridden (where it gets a charge), then it will be higher... like 13.6V, but wait over night and re-measure and it will stablise back down to 12.4 to 12.6V. This is the chemisty stabilising.

State of Health (SOH) and State of Charge (SOC) --> these are industry terms, not something I've made up. You can have a battery that is fully charged, but in poor SOH. This would be like having a fuel line that shrinks as it deteriorates. It can still supply fuel, but don't go wide open throttle for long, as then engine will get starved of fuel. If the SOH is low, the battery is probably barely coping with running the headlights, then trying to start the bike is way too much for it. Might even get the odd backfire :)

What to do if you're having a problem?

First thing is it would be good to confirm if your reg/rec is stuffed. With a fully charged battery, get the bike started and pick the revs up as covered in the info above, to measure the reg/rec voltage output (at battery). If it's too high... don't ride the bike. It's probably already boiled the battery - the start of your problems. Next things to go are things like headlight bulbs, brakelights and instrument bulbs. There is also the risk of the ECU dieing (which has happened) and also things like the tacho might fail from the over voltage (which has happened). It gets REALLY expensive at this stage. A brand new Honda reg/rec costs a far bit. You can buy second hand CBR250 reg/rec's, but people are getting ripped off and being sold one with the same problem of late. The economic solution is to get one off another Honda bike... usually the wreakers know what model fits what. Some might not have the same connector (fine if you want to wire it). Essentially you're looking for a 5 wire reg/reg, with the same plug and same bolt hole spacing.

Once the reg/rec issue is solved, then you can either get the battery tested or replace it. You can take a charged battery (must be charged) to a battery shop and get them to load test it. They'll tell you what the state of health is. You can test it yourself, by monitoring the voltage as you crank to see how low it gets. Hard to say what level, but after a few seconds of cranking, if the voltage isn't back above 11V it might not be in the best of shape and will be more difficult to get a hot spark.

For a new battery, the common model is the Dynavolt YTX7L-BS which are around $70..$80. You can get expensive batteries, but these batteries are perfectly fine for condition in Australia. Look after the battery and it will last over 3 years.

If you get a new battery, make sure to fully charge it before use.... i.e. 2amp charger, 8 hours. Don't use a big charger... it will charge too fast and overheat it (doing damage in the process). It's silly to charge a new battery by going for a ride... you're not doing the battery any favours and it's going to take a while and stress your reg/rec. BTW... some people get the bike shop to fill the battery with the acid for them and charge it. But they might think 2 hours on the charger is enough and call it fully charged. Do it yourself to be sure. If you don't give it a full charge, it starts it's life by sulfating the plates and you'll be lucky to get a year out of it.

Also, if you have a charger with a the famous red/amber/green or fully charged light... ignore it. They are nothing but a crappy gimmick, and not a good indication of battery charge. Ignore it. If you have a multi-stage battery tender, then that is something you can rely on for knowing when it's charged.

Often people will charge a new battery before putting it in the bike. It's really important that you don't charge it while it's sitting on cold concrete. Sit it on some wood if needed. The concrete otherwise sucks the heat out, and the battery/solution has a hot and cold zone... bad karma for chemistry trying to properly charge the solution.

Often people putting up with with a bad battery will notice a difference in the power when they fit a new battery. Probably because the ignition at idle was crap before with weak sparks.

Above all... get off your arse and fix the problem. Otherwise, you'll be another one that is left stranded on the side of the road because they thought the problem would go away or not get any worse.

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Testing a Regulator/Rectifier...

The easiest test is to see if your getting appropriate voltage at the battery, as previously described. But sometimes when this power is on the weak side, it becomes a grey area.

Ideally... if you have a friend that you can swap reg/recs with to test, it's the easiest way to determine if there is a problem with the reg/rec. Alternatively, you can test the diodes in the rectifier stage.

There are six diodes to be tested. You are looking for one that either shorted, or open circuit.

The reg/rec has 5 wires. Two go to the battery, the +ve and the -ve. The other 3 are from the alternator.

Set your Multimeter to the Diode Test Function...

First Test...
This will quickly show if any of the diodes have shorted.

This is testing between the two battery wires. Note the reading on the multimeter. One appears as open circuit (because the diodes are blocking the current) while the other reading is showing the resulting forward voltage through both sets of diodes. If you have a short, you'll get a reading about half what my multimeter is showing.

Second Test...
The next test will check each diode on the top row of the diagram separately. Both to check it blocks current one way and conducts the other. So for these 3 diodes, it's six tests. Note the readings on the multimeter.

Third Test...
This is the same as the previous lot, except now we are testing the 3 diodes on the bottom row of the diagram.

This sort of test isn't always conclusive, as often the reg/recs start to fail intermittently. So it may only be when the reg/rec is hot, that it starts to fail.

Checking the Alternator Windings...

Unplug the reg/rec. The plug has 3 yellow wires, which are the 3 wires from the alternator.

If there is a problem with the windings, it's often an open circuit or a short circuit. Those 3 wires go to 3 windings, which are all joined together. So you have to test 2 windings at time. Set the multimeter to the lowest resistance setting (often it's the 20 ohm scale) and measure all 3 pair combinations for the yellow wires.

For an alternator without a winding fault, all three readings will be the same. Text book reading is 0.3 to 0.4 ohms. But practically, most multimeters aren't very accurate at such a low end of the scale. Even touching the multimeter leads at the time can influence the reading. Even so, all three measurements should be around the same value.

If there is a short between windings, then you'll might get two low readings and one high one. If there is an open circuit, two of the readings will be very high (off the scale).

Again... this type of fault can be intermittent and temperature dependent. If your suspicious there is a problem, it might be worth checking when the engine is cold, and again when it's hot.

Catching an Intermittent Fault...

Connect a multimeter to the battery terminals, and tape the multimeter to your tank. Check the multimeter every now and then. Apart from at idle, where the voltage will normally drop, the reg/rec should be pumping out ~14V consistently, across the RPM range. Irrespective of whether the engine is hot or cold. It might register a little lower if your battery is flat, as it'll be loading up the system.

If you have a Shift-I fitted, then you can use it to monitor the battery level. Hold the bottom button, turning ignition on and release. It will now stay in battery voltage watch mode. At idle, you'll probably have 4 lights. While riding 5 or 6 lights. If you are only getting 3 or 4 lights... or it's going to 7 or flashing the last light, then there is a problem. Press a button or turn ignition off to exit battery watch mode.
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Fantastic thread.. I missed this one, thanks mate.
jlyall said:
Fantastic thread.. I missed this one, thanks mate.
Awesome thread eclipze, very in depth and descriptive, +rep, also, grats on 50 +reps!
Hey Eclipze, so I've read your post and thank you very much, it was very very helpful. I've conducted the test on my Rectifyer/regulator and using the diode mode on my multimeter it shows relitively similar current through the device. (.3 something, which is a bit lower then what you're is doing), I then tested the three pairs of alternator wires and they show a reading around .3. I've checked the battery and its between 12.3 - 12.6 V however i can only get a single crank out of it and its dead. Its constantly dying at lights or in low RPM and i have to use the bikes momentum to roll start it before I get stuck at lights... When the bike is running the battery shows a reading of around 15V... Im guess my battery is wrecked, but i don't want to buy a new one if its going to get stuffed up again strait away, is 15V to high and how do I change that... What do you make of it mate?

Thanks, 2Fiddy
Regulator/Rectifiers have two parts. A rectifier and a regulator. The diode test would have shown if the rectification circuit was functioning normal. Testing the voltage output when the bike is running is checking the Regulator. It's obvious that your reg/rec isn't regulating the voltage. Left for a while, it will boil the battery and the plates. You might even see dried powder marks from the battery where some of the fluid has boiled out. Once the battery has degraded too much, it just won't hold much charge. It might still measure above 12V, but that's because the chemistry dictates the potential... but when a load is put on it, it just cannot supply the current.

Unfortunately you need a new reg/rec and a new battery. But the important thing is... you've got an A+ for due diligence and you know what's needed to fix the problem and have a reliable system once again. If you only got a new battery, forgetting about the reg/rec and not checking it, then you'd just kill a new battery in a couple of months and be back at square one.
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Thanks Eclipze, I appreciate the advice. I'll have to look into purchasing a new rectifyer/regulator. The MCA near me quoted it for $250. I might try Red Barron on Hoxton Pk drive and see if they can get me one cheaper. Does anyone know of a place I can get one for a fair price? The battery is ruined I suppose so should I just dispose of it then?
find a second hand one of a cbr 250 that is wrecking
You can get cheap ones from China. Search for "cbr250 regulator" on ebay. They have been a bit of a lucky draw thing in the past, as some haven't lasted long. But they are definitely cheap. Make sure to get one with the cooling fins, as they will likely run cooler.

Getting a second hand CBR250 regulator is a big gamble. They've reached their shelf life and a very common part that fails. Chances are you'll get a second hand one that's already dead or near the end of it's life.

If you want to get a really good regulator, get a FH008 model. You'll have to do some re-wiring and the bolt holes probably have a different spacing. Not cheap though. They were used on a few bikes. I got a second hand one off a wrecked CBR600RR and fitted to my Daytona 675. There is one on ebay at the moment ~$AU110, although they don't show shipping for overseas. $90 to $100 is probably the best you'd get for one of those.
Just paid $20 for a cheap chinese one with fins. I won't lie, I am only getting for experience I expect to be buying a genuine one eventually. I do hate going cheap skate on essentials but we'll see how this pans out. So, lets say I get this regulator soon, put it in and re-test the current at the battery terminals while it is running. What should it read, or perhaps, what shouldn't it (ie, 15V)? Also, will I damage my bike further if I ride it with a crap battery and faulty regulator, because I need it to get to work and may have to result in push starting it and riding... But if Im going to wreck other components I will have to start getting public transport.
If you have a crap battery, then the new reg/rec is going to get punished a bit. It will have to sink current into a battery everytime you go for a ride, as the battery will go flat. You'll still have trouble starting your bike too. The new reg/rec won't fix that. In addition, getting reasonable voltage readings will be difficult, as the alternator will be loaded up by the flat battery. You'd hope to get around 13.8 to 14.2V (defnitely not 15V), but I'd expect to be on the low side with a bad battery fitted. Best thing would be to get a new battery... and make sure to fully charge it to start with... 8 hours on a 2 amp charger.

I bought 20 reg/recs a few years ago. 2 of them failed within a week. Unless they have improved their manufacturing, it's probably a 1 in 10 failure rate for the cheap China regs.
Eclipze said:
If you have a crap battery, then the new reg/rec is going to get punished a bit. It will have to sink current into a battery everytime you go for a ride, as the battery will go flat. You'll still have trouble starting your bike too. The new reg/rec won't fix that. In addition, getting reasonable voltage readings will be difficult, as the alternator will be loaded up by the flat battery. You'd hope to get around 13.8 to 14.2V (defnitely not 15V), but I'd expect to be on the low side with a bad battery fitted. Best thing would be to get a new battery... and make sure to fully charge it to start with... 8 hours on a 2 amp charger.

I bought 20 reg/recs a few years ago. 2 of them failed within a week. Unless they have improved their manufacturing, it's probably a 1 in 10 failure rate for the cheap China regs.
Thanks mate, my charger is on its way from Melbourne as we speak. The moment I get it, I'll go buy a new Reg/Rec and Battery.
I have 2 regulators from bigger bikes belived to be from 1000rr
Currently I have installed is a FH008 works wonders on a battery that I brought from work.

Took 5mins to re-wire :D
Yeah that sounds like a great idea. You said you have 2, does that mean you have one spare you could sell?
2FiftyR said:
Yeah that sounds like a great idea. You said you have 2, does that mean you have one spare you could sell?
Hey where did you guys get the mosfet fh008? I can't find any.
^^ Just picked up a regulator and stator from http://www.regulatorrectifier.com

I have bought stuff from them before and to date (touch wood) nothing has gone wrong.
That's not saying that nothing will happen though.
In the past I have bought original Honda r/r's and as Eclipze said, there is always a chance that 1 in 10 or similar will shit itself.

Hi, today i was riding and out of nowhere my cbr 250rr started making a weird noise when i was revving, it eventually died out. When i tried to start it back up nothing at all was happening, the indicator lights wouldn't even work so the battery was really flat. I tried to push start it and it worked but after 20 seconds it died out again and after that it wouldn't push start.

So my mate picked me up, went back to my house got my other bike (yamaha) and a fully charged battery off my mates bike and doubled him back to the cbr. Installed the new battery and it started first go. Then after about 20 minutes on the way back to my house the cbr died out again. We had to keep switching the batteries from my yamaha (fully charged battery) to the cbr, and put the dead battery in the yamaha which was able to push start with the dead battery and charge it back up.

What is wrong with the cbr and how should i go about diagnostics?
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