Motorcycle battery question.

[cjchaps]

Let's say you have a battery that is 12 volts 20 amps. Would you measure the volts or the amps or both to tell when it is going bad?

 

[chusteczka]

I have not worked on a motorcycle battery in just over ten years, so maybe their design has changed but first thing to do with a motorcycle battery that is believed to be going bad is to check the water levels to ensure there is still water in the cells. It is possible the water could have evaporated out. I am not sure if an electrolyte is necessary.

 

[cjchaps]

This is a lead acid sealed battery and I don't believe you are supposed to open them...

Originally posted by: chusteczka
I have not worked on a motorcycle battery in just over ten years, so maybe their design has changed but first thing to do with a motorcycle battery that is believed to be going bad is to check the water levels to ensure there is still water in the cells. It is possible the water could have evaporated out. I am not sure if an electrolyte is necessary.

 

[Colt45]

measure voltage with a load on the battery

 

[malbojah]

When you battery dies on you 80 miles from home, you yank it and see that there's no water left. Then when you con a friend into bringing you a new sealed battery, only to find out it was never charged, then you know it's dead.

 

[Eli]

Batteries don't contain water, they contain electrolyte; a mixture of sulphuric acid and water.

If it's an SLA, there isn't much you can do to revive it.

To test the battery, fully charge it and measure the voltage with a load. The bigger the load, the more the voltage drop will be. But it shouldn't go below say, 11.5V even with a full load.

A lead acid battery is considered dead and in need of a recharge at ~10.5V.. or about 80% depth of discharge. You don't really ever want to go below this, as it will damage the battery. The deeper each discharge cycle, the less charge cycles you will get overall out of the battery.

For example, a car battery can start a car perhaps tens of thousands of times, because when you start the car the DoD is only like a few percent, at the most. But if you go 80% or more each charge cycle, you may only get a few hundred charges out of the battery.

 

[ta8689]

I always call it dead after your stranded at a resturant 15 miles from home. You can usually tell when its dieing by how much difficulty it has turning over the engine. If it has a leak.... big problem, get it the hell out of the motorcycle. ID say if its iffy, get a new one. I guarantee you will be happy with this fix (except spending the money)

 

[Eli]

Originally posted by: ta8689
I always call it dead after your stranded at a resturant 15 miles from home. You can usually tell when its dieing by how much difficulty it has turning over the engine. If it has a leak.... big problem, get it the hell out of the motorcycle. ID say if its iffy, get a new one. I guarantee you will be happy with this fix (except spending the money)

I agree, they're pretty cheap.

SLA/AGMs are more expensive, but worth not having to worry about leakage.

 

[GalvanizedYankee]

A real motorcycle is kick started, off the bike, while on the center stand.
It will not need a battery for operation. Like my 1977, 900SS Ducati

A wet cell generates 2.2V per cell, 6X2.2=13.2V. Charge the battey for 48hours at 1.5A.
Make sure all cable ends are clean & tight. Install the battery, cranks for 5 seconds w/o
starting. With the headlight on read battery voltage. If it's under 12.9V replace the battery.


...Galvanized

 

[Rubycon]

Does the headlight dim noticeably when the motor idles? Your dynamo or output regulator may be failing.

 

[cjchaps]

The motorcycle battery is actually being used in a Robomower. It's an electric lawnmower and it takes two 12 volt 20 amp batteries. The reason I asked is because the batteries are not lasting as long as they used to but the volts are still at 13.5 when I measure them...

It's this battery BTW.

It's also a deep cycle battery so I guess it can be discharged a bunch and still be charged up...

 

[Eli]

Originally posted by: cjchaps
The motorcycle battery is actually being used in a Robomower. It's an electric lawnmower and it takes two 12 volt 20 amp batteries. The reason I asked is because the batteries are not lasting as long as they used to but the volts are still at 13.5 when I measure them...

It's this battery BTW.

It's also a deep cycle battery so I guess it can be discharged a bunch and still be charged up...

Yeah, deep cycle batteries can withstand high depth of discharges better than normal batteries, but it is still damaging to them. In the future, try to charge aftereach use.. don't let them discharge too much, and certainly don't let them sit partially discharged. They will last much, much longer this way.

You have to measure the voltage with a load. A volt meter doesen't present a load to the battery, so it will always measure "full", unless something is pretty seriously wrong with the battery.

The battery you linked to is a 18Ah battery.

Check on eBay. Search for "lead acid". There are gobs of them, realitivly cheap.. Many of the auctions say the batteries' dimensions. You might be able to find two replacement batteries that are higher capacity and the same or nearly the same size.

 

[funboy6942]

Originally posted by: Eli
Batteries don't contain water, they contain electrolyte; a mixture of sulphuric acid and water.

If it's an SLA, there isn't much you can do to revive it.

To test the battery, fully charge it and measure the voltage with a load. The bigger the load, the more the voltage drop will be. But it shouldn't go below say, 11.5V even with a full load.

A lead acid battery is considered dead and in need of a recharge at ~10.5V.. or about 80% depth of discharge. You don't really ever want to go below this, as it will damage the battery. The deeper each discharge cycle, the less charge cycles you will get overall out of the battery.

For example, a car battery can start a car perhaps tens of thousands of times, because when you start the car the DoD is only like a few percent, at the most. But if you go 80% or more each charge cycle, you may only get a few hundred charges out of the battery.

I guess that why they dont reccomend if your non sealed battery has low levels to fill it back up with distilled water? Because they dont contain water?????Im so

 

[Eli]

Originally posted by: funboy42

Originally posted by: Eli
Batteries don't contain water, they contain electrolyte; a mixture of sulphuric acid and water.

If it's an SLA, there isn't much you can do to revive it.

To test the battery, fully charge it and measure the voltage with a load. The bigger the load, the more the voltage drop will be. But it shouldn't go below say, 11.5V even with a full load.

A lead acid battery is considered dead and in need of a recharge at ~10.5V.. or about 80% depth of discharge. You don't really ever want to go below this, as it will damage the battery. The deeper each discharge cycle, the less charge cycles you will get overall out of the battery.

For example, a car battery can start a car perhaps tens of thousands of times, because when you start the car the DoD is only like a few percent, at the most. But if you go 80% or more each charge cycle, you may only get a few hundred charges out of the battery.

I guess that why they dont reccomend if your non sealed battery has low levels to fill it back up with distilled water? Because they dont contain water?????Im so

Well.. lol

The way people were phrasing it sounded funny to me. I just didn't want anyone to think that batteries run off water.

You can add more water to a battery in most cases because it has merely evaporated, increasing the concentration of sulphuric acid. Adding distilled water brings the electrolyte back up to the proper level on the plates, and the electrolyte concentration should be the same.

However, if the battery has actually tipped over and spilled, if you just fill it back up with water... you will lose capacity.

 

[MWink]

Originally posted by: cjchaps
The motorcycle battery is actually being used in a Robomower. It's an electric lawnmower and it takes two 12 volt 20 amp batteries. The reason I asked is because the batteries are not lasting as long as they used to but the volts are still at 13.5 when I measure them...

It's this battery BTW.

It's also a deep cycle battery so I guess it can be discharged a bunch and still be charged up...

I don't know of a simple way of testing them other than to see how long they run the device they're in. Of course if you didn't test them when they were new, you won't have anything to compare the results to. The biggest killer of SLA batteries seems to be time. They are usually only good for 3-5 years (even with minimal use), though some brands last longer than others (Panasonic's are by FAR the best I've used). Also some lose capacity slowly over time while others may give almost their full capacity and then just up and die with little/no warning.

Also according to what I've read the temperature they are exposed to (especially during storage) can have a substantial impact on their lifespan. And as others have already mentioned, the deeper the discharge, the shorter its life will be. It's best not to discharge SLA batteries any more than necessary (unlike most other types of rechargeable batteries).

If you decide to replace the batteries I would recommend Panasonic if you want batteries with the longest life span or Enersys if you want to save some money (also they have a slightly longer runtime, at least when new). I would suggest avoiding Powersonic and Universal Battery (UB).