Battery Discharge

[albertaduke]

Fit a voltmeter and ammeter. A voltmeter is generally enough for normal use - Ammeters help if you show high volts but don't charge (sometimes the charging cable and charge warning cable have different feeds). Mine charges at tickover. My 33 year old Guzzi charges at 1100 rpm.

We have regulated Alternators not Dynamo's. A good alternator with a magnetic stator charges from almost nothing. A wound stator requires power - it's why car alternators are "geared" to spin faster.

In fact most charging systems become challenged OVER a certain rpm band. - Why? because they've reached their maximum amperage - but the engine load (sparking) increases. Under full electrical load - I've seen the R3 charging drop away at about 80mph. It's why I started converting to LED lighting.

and all this time I believed your above average knowledge of electrics/electronics was geared toward better night riding..!!
happy new year

 

[mully95]

You can with the switch off take the negative battery cable lose from the battery and place a test between the cable and the negative post of the battery. If the test light is really bright then there is a high drainage of the battery. If the test light is really dim then that is probably the ecu, clock, etc.... The trick is to get the test light as dim as possible.

 

[barbagris]

and all this time I believed your above average knowledge of electrics/electronics was geared toward better night riding..!!
happy new year

Nope - I'm simply an über-geek. Maths, Physics and Chemistry. And mechanical engineering comes naturally to me.
I could have pursued all sorts of stuff academically - but I'm to easily distracted and go off at tangents.

Very obsessive if faced with a "problem". Once it's solved I NEED another. Others have put my success rate at 98%.
This makes be bloody useless for pure research - **** good at applying solutions across boundaries.
It's why I was able to rise fast as a Systems Engineer. I could apply solutions for entirely the wrong reasons.

I can often "feel" problems. Often I can find errors just by staring at things. Freaky and very occasionally (for others) disturbing.
Also makes me VERY conflictive when I KNOW and others are still catching up. To the point of violent unless chemically suppressed. I'm not a team player.

Hence my signature line.

 

[captain jack]

I have a small device that flashes the on-board alarm LED - draws approx 1ma. It's the only un-switched feed I have on. After a week of disuse the led flashes slower - indicating lower battery. 7ma would (extrapolated) suggest voltage drop after a day.

That's interesting Chris, could well explain my previous battery problems & confirms my need to have the battery tender connected when parked up.

 

[captain jack]

Nope - I'm simply an über-geek. Maths, Physics and Chemistry. And mechanical engineering comes naturally to me.
I could have pursued all sorts of stuff academically - but I'm to easily distracted and go off at tangents.

Very obsessive if faced with a "problem". Once it's solved I NEED another. Others have put my success rate at 98%.
This makes be bloody useless for pure research - **** good at applying solutions across boundaries.
It's why I was able to rise fast as a Systems Engineer. I could apply solutions for entirely the wrong reasons.

I can often "feel" problems. Often I can find errors just by staring at things. Freaky and very occasionally (for others) disturbing.
Also makes me VERY conflictive when I KNOW and others are still catching up. To the point of violent unless chemically suppressed. I'm not a team player.

Hence my signature line.

Yea that's the problem with beards Chris, Samson's hair & academics facial hair, keep it growing for your own sanity or even the drugs won't work.

 

[barbagris]

Yea that's the problem with beards Chris, ---, keep it growing for your own sanity or even the drugs won't work.

Since it's grown - the drugs seem not to work

 

[Dawg68]

Please dont forget that all batteries naturally drain wether they are connected to a circuit or not (This determines shelf life of a battery) and that said, not all batteries should be considered as equal, even if they are the same brand. Unfortunatly it is a process to determine how much a battery will drain on a daily basis when it stands alone. Just a little battery theory. Im asuming that most of us use a wet cell battery. All this means is that the electrolyte solution is a liquid (Mixture of water and sulfuric acid) One of the factors that can affect the ability of a battery to preform at its optimum is the specific gravity of the electrolyte solution. If the solution is off either to the high or low end of the recomended specific gravity for the designe of the battery, performance can be affected. This can be measured with a hydrometer. Normal electrolyte mix for a battery is less than 1.350.

To put it simply, when a lead acid battery is discharged, the amount of acid is reduced in the electrolyte and replaced with water (the acid, suplhat combines with the lead of both electrode plates, electrodes) . When it is charged (applying current flow in the opposite direction), the opposit happens, the sulphate is driven from the lead plates back into the electrolyte and increase the specific gravity of the electrolyte solution, this continues to happen until all the suplhate is driven from the plates back into the electrolyte, then the battery if fully charged.

Batteries can also suffer from shorted cells which can be caused by several different conditions; faulty separators (lead particals of other metals froming a circuit between the positive and negative plates of a battery), buckling of plates, sedements forming in the bottom of the battery etc....some of these occurrences are due to overcharging and or overdischarging of the battery which causes the sediment to build up due to flaking and buckling of the plates. As each cell is shorted in the battery, the battery capacity is reduced.

Batteries opperating at temps higher than the normal band 60-80 Deg F will produce more capacity but the life of the battery will be reduced. Batteries opperating at lower temps will have an increased life span but will have a lower capacity and as we know, extreamly cold temps can freeze the electolyte (only if the specific gravity is low, more water than acid).

All this to say is that according to the service manual for the Rocket it recomends that we do not use more than a 1.2amp charge rate other than for a boost charge of 5 amps for no longer than 1 hour. The alternator rating is 37 amps/min at 2000 rpm and 41 amps/min at 6000 rpm. So, depending on what your current draw is while running compared to the charge rate we could be either overdischarging the battery or overcharging while in use thus reducing the efficiency of the battery over time. The discharge of a battery is proportional to its CCA but the charge rate is dis-proportional meaning it can take longer to charge a battery than discharge. This may be the reason that everyone has different experiences with respect to how their bike starts on colder days etc....you may be in effect, discharging more than you charge. This is why your bike will start soon after its been running vice not starting after an overnight sit with cooler weather in the morning. Small current draws on the batter just might be the tipping factor on an overnight sit to give you a hard or not start. This makes sence when you read posts that state the operators were having the same problem until the started connecting the bike to a battery tender overnight, problem solved or they ride the bike more, longer run times allows the battery to charge.

One last though, consider a 2.3 liter car engine, how big is the battery??? Bigger than the Rockets? Larger batteries = larger cells = longer discharge time, higher capacity. The Rocket has a large engine, I think we may be asking a little too much out of the small battery it is provided with, just a thought

Cheers

 

[barbagris]

The alternator rating is 37 amps/min at 2000 rpm and 41 amps/min at 6000 rpm. So, depending on what your current draw is while running compared to the charge rate we could be either over discharging the battery or overcharging while in use thus reducing the efficiency of the battery over time.

What however is not quoted is what the beast consumes - my experience suggests the engine will use those 4 extra amps and then some as low as 3500rpms - so the overall effect is LESS available amps for other stuff.

In theory OVER CHARGING whilst running is not going to happen - it's what the regulator is for. A proper battery tender continually discharges and recharges to prevent sulphating etc.

Batteries serve 2 functions.

1) To smooth momentary differences in supply and demand and also to maintain a near constant circuit voltage whilst running. You could do this with 1-2Amp hours more than happily.
2) But the main function is Starter. The Starter motor on an R3 (iirc) is 1.2KW. or nominally 12V*100amps. if we say we need 5 seconds - this is (on paper) - 500amp seconds. Way short of 20aH. Forget CCA it's an artificial number. It's true that cars have larger batteries and alternators - but as often as not to compensate for folk who leave lights on or the radio without the engine running. Bigger still on diesels where you need a BUCKET LOAD of watts to heat the Glow-Plugs before turning over. And even so it's shown that car batteries in sever cold can be just as reluctant to turn over.

Here's the thing - What matters is the WATTS. Not the amps or the Volts (for the starter motor alone).

But as you crank over the chemistry of batteries has to generate the power. Note that a bigger starter may well be necessary to turn over a higher compression engine - but also requires more battery power. Fatter cables won't harm - they'll reduce resistance to current flow. Good connections are naturally paramount.

Lead acid batteries TEND to try and push out amps in preference to maintaining voltage - this circuit voltage drops fairly fast and then the remaining electronics sense undervoltage and simply do not react. And as the voltage drops - the battery attempts to pump out more amps to compensate. It has to produce those WATTs.

LiFePO4 batteries try to maintain volts rather than amps - so as they drain they are not able to pump out amps to turn the engine.

I personally feel the failure to start in the cold may lie elsewhere like failure to spark properly or vaporise fuel adequately. Even if on a tender until seconds before you can hear a different firing sound from the intakes.

But the high volts from LiFePO4 and high amps from Lead acid in parallel seems to work.

 

[captain jack]

What however is not quoted is what the beast consumes - my experience suggests the engine will use those 4 extra amps and then some as low as 3500rpms - so the overall effect is LESS available amps for other stuff.

In theory OVER CHARGING whilst running is not going to happen - it's what the regulator is for. A proper battery tender continually discharges and recharges to prevent sulphating etc.

Batteries serve 2 functions.

1) To smooth momentary differences in supply and demand and also to maintain a near constant circuit voltage whilst running. You could do this with 1-2Amp hours more than happily.
2) But the main function is Starter. The Starter motor on an R3 (iirc) is 1.2KW. or nominally 12V*100amps. if we say we need 5 seconds - this is (on paper) - 500amp seconds. Way short of 20aH. Forget CCA it's an artificial number. It's true that cars have larger batteries and alternators - but as often as not to compensate for folk who leave lights on or the radio without the engine running. Bigger still on diesels where you need a BUCKET LOAD of watts to heat the Glow-Plugs before turning over. And even so it's shown that car batteries in sever cold can be just as reluctant to turn over.

Here's the thing - What matters is the WATTS. Not the amps or the Volts (for the starter motor alone).

But as you crank over the chemistry of batteries has to generate the power. Note that a bigger starter may well be necessary to turn over a higher compression engine - but also requires more battery power. Fatter cables won't harm - they'll reduce resistance to current flow. Good connections are naturally paramount.

Lead acid batteries TEND to try and push out amps in preference to maintaining voltage - this circuit voltage drops fairly fast and then the remaining electronics sense undervoltage and simply do not react. And as the voltage drops - the battery attempts to pump out more amps to compensate. It has to produce those WATTs.

LiFePO4 batteries try to maintain volts rather than amps - so as they drain they are not able to pump out amps to turn the engine.

I personally feel the failure to start in the cold may lie elsewhere like failure to spark properly or vaporise fuel adequately. Even if on a tender until seconds before you can hear a different firing sound from the intakes.

But the high volts from LiFePO4 and high amps from Lead acid in parallel seems to work.

I'm with you up to your mention of the LiFePO4 battery. - what is it?

 

[barbagris]

I'm with you up to your mention of the LiFePO4 battery. - what is it?

Lithium Iron Phosphate. Not to be confused with simple Lithium Ion or Lithium Potassium. These latter two can actually offer MORE volts and to a certain extent Amps - but can also go BANG in a big way. Often used in rechargeable torches etc - but shunned on by electro-Automotive mfrs. Mid term I expect to see Graphene rise in popularity in batteries - Charge VERY fast. But Carbon is hardly known for fire retardant properties.