MOTOBATT Battery

[Azer]

Hey up,

Got a bright yellow "MOTOBATT" battery on mine which doesn't want to turn the engine over properly. Sounds like it is flat.
Ok, so I take it off and get a multi-meter on the terminals.
It reads 16V. Which seems very high to me.
The only technical info. I can find on the battery is: 190CCA 8.6AH
Which I understand as Cold Cranking Amps and Amp Hours.

Am I doing something wrong here or is this battery knackered?
I'd expect a 12V battery to show 8 or 9 V when flat.

Any clues please?

[sirch345]

Not sure how you're getting 16V on your multi-meter.

So you have the battery on the bench, or at least disconnected from the bike?

If you've not got a battery tender/charger connected to it while you're checking it, did you have the bike running prior to checking it with the multi-meter?

Check your multi-meter with another if none of the above is applicable.

I would say your thinking is right,

Chris.

PS.Is the battery brand new or older? Has it been sitting in the bike for a long spell not being used?

[firestorm_al]

Sounds like your regulator rectifier unit is knackered and is not limiting the charging voltage to 14.4V.

That will have "cooked" your battery. You may get a static high voltage reading off of it representative of the overcharge voltage but the "cooking" will have damaged its ability to hold any meaningfull charge and hence can't deliver enough current to start the bike.

If you can get hold of another battery to try and get the bike running then measure the voltage at the terminals with the bike running at both idle and with some rpms on. If the voltage goes much over 14.4v then stop the bike immediately and get the regulator recitfier replaced before you damage the new battery.

Unfortunatly battery issues and R/R unit faults go hand in hand and means a double hit on your wallet.

Al.

[tony.mon]

I can't think of any overcharging situation that would allow the battery to put out more volts than before, when the battery is off the bike and not connected to the charging system.
Can anyone corroborate this?

[purgeraptor]

I can't think of any overcharging situation that would allow the battery to put out more volts than before, when the battery is off the bike and not connected to the charging system.
Can anyone corroborate this?

A fully charged, unconnected, battery cannot produce more than 12.6V

[firestorm_al]

Who knows what is going on inside the battery if it has been subject to a high charge voltage from a knackered RR.

A multimeter has a very high internal resistance so will not be loading the battery so you could be getting the strange reading due to the messed up chemistry inside the thing. That's why measuring the voltage of a disconnected battery is pretty meaningless.

If you were to apply a load to the damaged battery and then test the voltage it will drop and loose its charge fairly quickly.

Al.

[firestorm_al]

A fully charged, unconnected, battery cannot produce more than 12.6V

I would completely agree for a healthy battery subject to a normal charge.

[Azer]

Hey up,

Thanks for all the replies and info.

I did have the battery off the bike when measuring with a meter.

It had sat since about May/June last year, untill....Feb this year. I pressed the start button and the engine whirred slowly and without much conviction.
I knew from that it was flat. Though I'd get the meter on it to see just how flat. Was expecting around 9 or 10 volts. Maybe 8.
Really surprised to see 16.

I now have a new battery which is currently on charge. Purchased from a bike-breaker I trust. He had it in for somebody else, who didn't show. Filled and sealed it for me.

I'll get it back on the bike during the week and try starting up.
I will take the meter with me and measure it once I get the engine running.

Ta.

[tony.mon]

Hey up,

Thanks for all the replies and info.

I did have the battery off the bike when measuring with a meter.

It had sat since about May/June last year, untill....Feb this year. I pressed the start button and the engine whirred slowly and without much conviction.
I knew from that it was flat. Though I'd get the meter on it to see just how flat. Was expecting around 9 or 10 volts. Maybe 8.
Really surprised to see 16.

I now have a new battery which is currently on charge. Purchased from a bike-breaker I trust. He had it in for somebody else, who didn't show. Filled and sealed it for me.

I'll get it back on the bike during the week and try starting up.
I will take the meter with me and measure it once I get the engine running.

Ta.

Check as soon as it's running, if more than 16 volts best to turn it off straight away.

[Azer]

Check as soon as it's running, if more than 16 volts best to turn it off straight away.

How sure are you about that?

I don't really have much of a clue when it comes to electrics/electronics. So please bare-with me.
I have a multimeter which I have used to check this new battery of mine, along with the old one.
Having charged the new battery for 5 hours, which is the minium reccommended on the side of it.

Both it and the MOTOBAT are now showing ~16V when isolated.

This evening, about an hour ago, I put the new battery on the bike. Thinking that I didn't have anything to loose.
After some strong cranking with a bit of choke, it fired up. Everything seemed perfect.
I quickly put the meter on it, as reccommended and it was showing ~23V!
Slightly pannicked, I turned it off.

[tony.mon]

Try another meter, it could be that.

[purgeraptor]

Make sure the meter dial is set to the 20 Volt DC range.
Test it with a standard 1.5V AA torch battery,

The meter is either set wrong or broken.

[Azer]

News: borrowed a meter and just had on the bike now.
Showed 12.63V with engine off.
Showed 14.34V with engine running.

So now I need a new meter.
Any suggestions on what to look at/for greatfully recieved.

Cheers All.

[sirch345]

Not sure how you're getting 16V on your multi-meter.

So you have the battery on the bench, or at least disconnected from the bike?

If you've not got a battery tender/charger connected to it while you're checking it, did you have the bike running prior to checking it with the multi-meter?

Check your multi-meter with another if none of the above is applicable.

I would say your thinking is right,

Chris.

PS.Is the battery brand new or older? Has it been sitting in the bike for a long spell not being used?

I'm glad you got there in the end

I got my multi-meter from Aldi a good 10yrs ago, there are obviously more expensive ones available, but the one I have has been very good so far,

Chris.

[tony.mon]

Damn!
If you'd found a way to get 16 volts out of a 12v battery I was going to patent it

Glad it was something easy to find rather than a bike problem.