Check Battery drain with Multimeter Q.

My Yuasa battery currently reads 12.5 volts, 1 week after a 110 mile ride and a 12 hour charge prior to that ride. This is 50% charged according to Yuasa. The battery is almost 2 years old. I believe it needs replacing but I could be wrong.

I tested for amp drain by disconnecting the positive lead cable and then touching the + lead to the + batt terminal and the - to the disconnect cable end. Reading = 0.00 amps

Am I to assume there is no amperage drain on the battery doing it like this?

Other blogs say to disconnect the negative side instead.

Your opinions would be appreciated. Thanks

Either side in theory should give you a proper reading since you are inserting the meter into the entire bike's circuit at the power source. Sometimes the drain, if any will be in milliamps. I start with the meter in the 20 A range and then switch down one range at the time until I get a reading, or none at all on the most sensitive range.

I've never trusted open circuit voltage as an indictor of battery charge. If it is a non-sealed battery, a specific gravity check will tell you the state of charge. Otherwise, I'm happy with open circuit checks of 12.4 to 12.7 or slightly more. YMMV

I starter at 20amps and worked down. All readings were 0.00. Should a battery drain down to 12.5V after sitting 6 days? Seems like a large loss for such a short period of time.

I would disconnect one (or both) battery terminals and then measure resistance across the wiring harness positive battery lead & negative battery lead. Multimeters are much better at measuring large resistances than tiny currents.

Some information that I have compiled:
Voltmeter Reading State of Charge

• 12.84 Volts or higher 100%
  12.50 Volts 75%
  12.18 Volts 50%
  11.88 Volts 25%

Warning: Gel and AGM (Absorbed Glass Mat) batteries
require a voltage-limited charger. Charging a Gel or AGM
battery on a typical shop charger – even one time – may
greatly shorten its life. It is imperative not to exceed 15.0V as this will cause the pressure valves to open and out-gas hydrogen, oxygen and water from inside the battery. This will shorten the life of the battery and cause premature failure.

Recommended charging information:

• Alternator: 13.65-15.0 volts
  Battery Charger: 13.8-15.0 volts; 10 amps maximum; 6-12 hours
  Float charge: 13.2-13.8 volts; 1 amp maximum (indefinite time at lower voltages)
  Rapid Recharge (Constant voltage charger): Maximum voltage15.6 volts. No current limit as long as battery temperature remains below 125°F (51.7° C). When current falls below 1 amp, finish with 2 amp constant current for one hour.

All Limits Must Be Strictly Adhered To

Recharge time (assuming 100% discharge - 10.5 volts):

• 100 amps - 35 minutes
  50 amps - 75 minutes
  25 amps - 140 minutes

Recharge time will vary according to temperature and charger characteristics. When using constant voltage chargers, amperage will taper down as the battery becomes recharged. When amperage drops below 1 amp, the battery will be close to a full charge. (all charge recommendations assume an average temperature of 77°F , 25°C)


* APPROX. BATTERY CHARGING TIME *
STANDARD OF TO FULL CHARGE AT 80°F/27°C

Maximum Rate at

• 12 V ---------- 50 Amps 30 Amps 20 Amps 10 Amps
  12.6 100% – F U L L C H A R G E –
  12.4 75% ---- 20 min. 135 min. 148 min. 190 min.
  12.2 50% ---- 45 min. 175 min. 195 min. 180 min.
  12.0 25% ---- 65 min. 115 min. 145 min. 280 min.
  11.8 0% ------ 85 min. 150 min. 195 min. 370 min

Still sounds fine to me. It is a 12V battery. Regardless of the Yuasa chart, I would still expect to see open voltage of about 12.4 to 12.7. I just checked 2 of three charged batteries I have on hand and got 12.01(needs a float charge) on the oldest battery, and got 12.7 on the newest sealed AGM battery.

You have 2 years use on the battery. I expect 3 years out of a battery based on 40 years of riding experience. After that, it doesn't owe me anything. Since lead acid batteries degrade over time, I think you are reading too much into the voltage readings - it seems normal to me. That's just my opinion, but its free (and worth exactly what you're paying for it ) I also think you can probably expect another season or year out of that battery. Of course becasue I said that you will have it die suddenly with the next major temperature change to extreme cold or hot. Batteries are sneaky that way.

If it makes you nervous and you have the money, replace it. I think you can get some more time out of it myself.

The reason why people are advised to use the negative lead - it is safer!

----------------
Is your current meter working? If it reads 0 on all ranges .. there is an internal fues thata has probably been blown .... could be becasue you used the positive lead ...

Read www.batteryfaq.org/ for more info on batteries .. lots more...

------------------
Measureing the resistance will not give you a good idea of the drain current .. the resistance reading is done using a different source voltage/resistance.

Frank, you hit it! I kept thinking in terms of electrical theory, which says no difference.

In shop practice disconnecting the ground side definitely saves on sparks and exitement!

Definitely some informative information. Thank you all.

Now, let me toss this question at you. A battery on a dual sport bike takes a heck of a beating compared to a street machine. Washboard roads (Saline Vally, DV Nat'l park) is one example. 80+ miles of washboard. knocks your teeth right out of your head.
Does the battery degrade or plates come loose during this beating? What effect if any does it have on the battery?

With all the tight restrictions on charging gel and AGM batteries, how is the bike's charging system going to maintain within those parameters. Don't know about the newer bike these days. Older bike charging systems are pretty crude.

The first thing is to let the vehicle sit for a few minutes. How long depends on the individual machine. Some take longer to power down electrical components. Make sure everything is off. Remove key. Set m/meter for m/amps. Most m/meters will take 10a. on this setting. The key here is to not break the battery connection. Working on the neg. side, attach one lead to the neg. cable. Attach the other to the battery's neg. post. Carefully remove the connection of the machines neg. cable from the battery while maintaining the multi meters connections. So you will be using the m/meters cables to keep the connection to battery when the cable is removed. If you loose the connection, start over.
This is the only way to verify the actual drain on the battery.

Ah a new yet interesting twist. Maintain a circuit at all times. Can you please explain why you need to do it this way. Seems to me a drain is a drain. If my heated grips switch were to malfunction slightly it would be a constant drain. Connecting the MM should detect this either way it is done.

Makes a bit of sense to me, if it is something like a relay stuck on removing the battery voltage completely could cause the relay to open fully and remove the evidence. A drain the size of heated grips would drain the battery completely in a couple hours.
I have heard of the layer of crud builtup on batteries may cause a circuit to form on the outer case of the battery. This was probably more of a problem with older style batteries but I wouldn't entirely rule it out. A clean battery is a happy battery.

It's for complicated electronics that stay switched on when the ignition is turned off. Clocks, alarm systems, that sort of thing. The idea is they might get into a strange state where they draw more current than usual, but would reset themselves and start working properly after they are disconnected and reconnected to the battery.

That's the theory. Never seen it matter, myself

Neg side due to lack of sparks etc. Either side will work.

Do not loose continuity in the circuit...
Because the clock etc will require a reset. (not a problem for the reading)
Any element in the circuit that is "stuck" on may completely turn off when power loss happens. (problem in reading)
When you reconnect the circuit by placing the meter in the loop, "things" may power up! Large amp draw initially may blow meters fuse.

Newer bikes may take up to several minutes to power down some elements and the reading will not be legit until after that time.

Bad meter fuse? Use the ohm meter function to check the Amps function. Most meters you can place the Pos. lead in the Amps connections while on the Ohms setting to check the fuse inside the meter without opening the meter. You should be able to see this on the Schematic that is on the meter by the lead inputs.

All of the above reasons apply. Thanks for the help, guys.

Makes sense to me. Thanks for the explanation.

Oh, one other thing...

Before you perform a parasitic load test...
You are supposed to start the vehicle and turn every electrical component on and off then stut it off and test.

This is to be sure that is something is "sticking" on that you recently had it on and it may still be stuck!

Make sense?

Of course you determine what is stuck by removing fuses until the reading is OK.
Remember that any fuse that powers an OK parasitc load should be left until last.

Your suspension needs work.

Any of that and more can happen .. most battery holders have some rubber damping on them to minimise the risk.

Best performance improvment on most dirt bikes is suspension work.

I've had an ongoing problem with my RID and last winter bought another used one to replace the first. Now it's doing the same thing, locking up or going dead. If i unplug the fuse it resets for a while. Sometimes it might be with the ignition switch, sometimes I just look down and it's frozen up. I've also been having a battery draining issue and finally got the multimeter out and found fuse 3, the one for the RID to have a large drain on it. It's around 2.65 when the meter is set at 20. I unpluged the rid and it's down to 1.2 ish which seems where the other fuses rest at.

I reinstalled my old RID and it does the same thing. Are both RID's bad or is it in the wiring harness somewhere and when I plug it in it causes the drain. How can i find out if both RID's are now bad? How can I check each of the 8 wires that plug into the RID, what would I look for, a short or something?

Totally puzzled with this and really would like to sort it out.

Thanks