Motorcycle Battery FAQ’s (frequently asked questions)

A few common (and not so common!) questions that have been asked about scooter and motorbike battery care and maintenance.
Not sorted into any particular order, but covering many areas of battery care in including parts number questions, topping up questions, fault finding questions, battery charging questions and much more!

Click on a question below to view the answer…

~How do I charge my motorcycle battery?

~Do I have to charge a motorcycle battery?

~Can I put my battery straight on the bike to charge it?

~Can I use a car charger or a high rate charger?

~Why do I need to top up my lead acid battery?

~I need to top up my old battery, what should I use?

~What battery does my bike use?

~What is the popping or fizzing noise I can hear when I charge my battery?

~My battery says CTX9-BS on it, is this the same as a YTX9-BS?

~How can I check if a motorcycle battery is fully charged?

~I’ve put a new battery on my bike but every time I go to use it the batteries flat?

~My motorcycle battery has gone flat, can I recharge it?

~How long does a motorcycle battery last for and why don’t they come with long warranties like car batteries?

~When I put the battery on the bike, which terminal do I connect first?

~What will happen if I connect the battery terminals the wrong way round?

~What is the white stuff that collects in old batteries?

~What causes sulphation?

~How do I keep my motorcycle battery from sulphating?

~Is it true that you shouldn’t leave a motorcycle battery on a concrete floor because it loses it’s charge quicker?

~If I disconnect the battery terminals, will the battery still go flat?

~Why are some batteries bigger than others?
~I have just connected the battery terminals the wrong way round?

~How tight should the battery terminal bolts be?

~What is battery acid & is it corrosive?

~I have accidentally drunk some battery acid I left in a lemonade bottle?


Do I have to charge a motorcycle battery?
Motorcycle batteries are dry charged to about 80%. If you don’t give the battery a top up charge (3-4 hours) the battery will only ever be 80% efficient (which will greatly shorten the life span of the battery)

Can I put my battery straight on the bike to charge it?
Unfortunately, this method of charging a battery will also mean the battery is only ever 80% efficient & may damage a new battery.

Can I use a car charger or a high rate charger?
NOOOOOOOOOOO!!!!!!! A car or high rate charger will force a higher rate of charge into the battery, which can result in permanent damage to a motorcycle battery. Because of their size, motorcycle batteries cannot take the same high charges or abuse that car batteries can.

Why do I need to top up my lead acid battery?
Lead acid type batteries use electrolyte (battery acid) which is a mixture of water & sulphuric acid. When the water evaporates this makes the acid concentration stronger. If the acid becomes too strong it will corrode the batteries internal components which will cause loose particles to collect in the bottom of the battery & short it out

I need to top up my old battery, what should I use?
Top up old batteries with distilled water. The electrolyte (or battery acid) is a mixture of water & sulphuric acid. When the battery reacts to produce electricity, only the water part of the mixture is used up so adding distilled water dilutes the electrolyte mix back to its correct strength.

Which motorcycle battery fits my bike?
You can find motorbike battery fitment lists on the page below:
Motorbike battery application list

What is the popping or fizzing noise I can hear when I charge my battery?
As your battery charges, the electrolyte (battery acid) reacts with the lead plates inside the battery to produce lead sulphate & in the process the electrolyte releases some of it’s hydrogen, which causes bubbles to be produced inside the battery which can produce a popping or fizzing noise (similar to the bubbles in a lemonade bottle!). This noise can also be produced for a short period after the motorcycle has been ridden as the chemical reaction which produces electricity is still occurring. BUT, the noise should be fairly quite, so if your 50 meters away from your bike & it sounds like someone has put a firecracker under your seat, our advice would be ‘RUN LIKE F**K!!!’.

My battery says CTX9-BS on it, is this the same as a YTX9-BS?
In most cases, yes, the batteries are the same. The first letter is a manufactures mark & different makes of batteries use a different letter. For example a Sprint battery would be YTX9-BS, an Exide battery would be CTX9-BS & a Delco battery would be GTX9-BS. This applies to most models of lead acid, sealed & gel filled motorcycle batteries.
A couple of exceptions to the rule are Westco & Yuasa batteries, who seem to make up their own battery listings, more to make life difficult & to p*ss people off then for any practical purpose! If in doubt, we can usually confirm a battery if you send us the dimensions or the make, model & year of motorbike a battery is from.


How can I check if a motorcycle battery is fully charged?
The best way to check a battery is with a volt meter. A healthy 12 volt battery should be between 12.5 & 13.5 volts & a healthy 6 volt battery should be between 6.5 & 7.2 volts (although this is only a guideline, once a battery drops below 12.4 volts it will struggle to start most bikes).

I’ve put a new battery on my bike but every time I go to use it the batteries flat?
There are a few reasons why this type of fault can occur. A few of the most common are:

  • Faulty alarm systems can flatten a battery in a very short space of time as can motorbikes left for long periods with an alarm armed.
  • A faulty regulator/rectifier (or reg/rec) can flatten a battery. The reg/rec regulates the direction of the electrical charge & how much charge is produced from the engine, they do tend to fail occasionally & will flatten a battery if not working properly. A simple test to check if the reg/rec is working properly is to rev the motorbike or scooter with the headlight on, if it’s working properly, the light will get brighter as the revs increase, if the light gets dimmer as you rev the engine, the reg/rec is probably faulty & may need replacing.
  • A common & often overlooked problem is loose battery terminals which can cause running & starting problems. Check the battery terminal bolts are as tight a possible & recheck them occasionally to ensure they haven’t worked loose.

My motorcycle battery has gone flat, can I recharge it?
Although motorcycle batteries are being constantly recharged while the engine is running, they are only receiving a ‘top up charge’. motorcycle batteries are not rechargeable like mobile phone batteries, which run almost completely flat then can be recharged. Once a motorcycle battery drops below the level required to start a motorbike (usually around 12.4 volts), it means that the battery is starting to fail.

How long does a motorcycle battery last for & why don’t they come with long warranties like car batteries?
Most motorcycle batteries are at their best for about 3 years. Because of their size, motorbike batteries don’t last anyway near as long as car batteries so warranties tend to be alot shorter.

When I put the battery on the bike, which terminal do I connect first?
Always connect the positive (+) or red terminal first. Make sure there are no flammable substances (i.e. leaking petrol!) around the bike as connecting the battery can produce sparks which can ignite flammable materials.

What will happen if I connect the battery terminals the wrong way round?
Your local dealer will be laughing all the way to the bank with the money they made from all the spare parts you had to buy! You might be lucky & just blow a fuse. We, however, work on the sods law theory (if it can go wrong, it will go wrong!) which usually means replacing lots of expensive electrical parts like the CDI.

What is the white stuff that collects in old batteries?
The white stuff is lead sulphate which is the same compound the lead plates in the battery turn into when they discharge. Lead sulphate is a crystal & can destroy a battery if allowed to build up. This process is called sulphation.

What causes sulphation?
In normal battery operation, lead sulphate never has much chance to build up on the plates because the charge cycle returns the sulphur back into the electrolyte & turns the plates back into lead. But a battery that discharges too deeply can develop sulphation.
Another cause of sulphation is low fluid or electrolyte level in the battery. When the fluid level drops, the lead plates are exposed to air. Under these conditions, the lead plates will oxidize & sulphate & the battery will no longer hold a charge.

How do I keep my motorcycle battery from sulphating?

  • Make sure your motorcycle’s electrical & charging systems are functioning properly so that any charge lost during starting or by the running of lights or accessories is replaced.
  • If it’s a lead acid/conventional type battery keep the levels topped up with distilled water.
  • Keep the battery terminals clean & disconnect them if possible when the motorcycle is in storage. Most importantly, charge the battery with a motorcycle battery charger regularly if the motorbike isn’t being used regularly to maintain a healthy charge in the battery.

Is it true that you shouldn’t leave a motorcycle battery on a concrete floor because it loses it’s charge quicker?
You’ll really believe anything you read, won’t you? I suppose you still believe in Farther Christmas & the Tooth Fairy as well!? It doesn’t matter what kind of surface you store a battery on, concrete, metal or wood as long as the battery is kept level, not stored in excessively high temperatures & charged regularly.

If I disconnect the battery terminals, will the battery still go flat?
A battery will still carry on discharging, even if it’s not connected to a motorcycle although it will lose it’s charge at a much slower rate. 

Why are some batteries bigger than others?
The size & number of lead plates in a cell depends on the output of the battery. The more plates in a cell, the bigger the battery & the more current it produces & capacity (amp/hours) it has.

I have just connected the battery terminals the wrong way round?
1) Call White Dog Motorcycle Accessories & get ready to part with vast amounts of money!
2) Lie down & cry for a bit when you realise how much it will cost
3) Don’t bother applying to MENSA

How tight should the battery terminal bolts be?
Use a screwdriver or spanner to make sure that the bolts are as tight as they can possibly be. A common problem that occurs with bikes (even brand new ones!) is that the battery terminal bolts are not tight enough (basically, when you think you’ve tightened the bolts up enough, tighten them a bit more to make sure!). Battery terminal bolts that are not attached securely will work loose & cause erratic & rough running problems as well as starting problems.

What is battery acid & is it corrosive?
Battery acid (or electrolyte) is a mixture of sulphuric acid & distilled water & is highly corrosive, please handle with extreme care. Try to avoid contact with skin & eyes & don’t put left over acid in empty lemonade bottles!

I have accidentally drunk some battery acid I left in a lemonade bottle?
1) PANIC
2) Don’t stray too far from a toilet
3) Make sure your life insurance is paid up
4) Don’t bother applying to MENSA

Maintenance free battery

Disclaimers:
The information provided on this page is ‘to the best of our knowledge’ and should not be taken as 100% accurate!!

To keep this page as a free resource for people to use, there are affiliate links (mainly Amazon) throughout the article. These affiliate links help maintain the cost of running this blog (basically, if you visit Amazon through one of the links and buy something, we make a few pence!).

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