Is 46 V to much ?

[jackhammer 550]

Been following and searching some of the older posts made. I am working on a '83 blacknose with a '79 16hp K341AS. It used to be a 17hp but was replaced by the PO. I'm not mechanically inclined and usually tear more up than I fix.

I have a problem with the ammeter not showing 0 . After mowing for an hour or so (at the battery) dc shows a drop with the multimeter, and ammeter is a fuzz below 0 also.. It's showing as a drain and over the past 6 months it pulled the old battery down, finally to where I didn't feel comfortable charging it. I bought a new one with more CCA than the old. After reading different posts I'm attempting to fix it so I can use it this winter with the snowblower.

I have changed out the ignition switch with another compatible one. Ammeter didn't change , negative side of -0. Then

Pulled out the rectifier and was put on a rectifier tester. Showed bad. Bought one and tested it while I was there, now I am afraid to hook up the stator for this reason.. ---> I've seen where it's been said to have at least 28v coming from a running engine at full rpm. When I use the multimeter with Vac on the 2 A stator leads my reading is 46Vs . I'm afraid I'll burn the new rectifier up. Any thoughts on the maximum Vs output from the stator??? or is the 46Vs within a given range and acceptable???

The old rectifier is grounded to frame of this 165.

Do you think I have a problem or am I good to go and plug in the new one.

jackhammer

rick

[Save Old Iron 1,571]

Remember,

 

whatever AC voltage you see across the stator gets rectified or "cut in half" by the RR unit. There is also a measurable loss across the electronics in the RR unit.

 

 

46 VAC would get halved to 23 VDC available to charge the 12 volt battery to 14.5 volts. This is perfectly acceptable and you should feel comfortable hooking up the new RR unit.

 

28 VAC is the minimum allowed due to this halving effect. With 28 volts from the stator halved by the RR, only  14 VDC would be left to charge the battery - that's bare minimum.

 

 

My experience is the higher HP C series era stators seem to produce these higher outputs.

 

Most defective RR's I have seen are usually the result of jumping starting a dead battery. Sparks go flying and electrical spikes ride thru the RR units and destroy them.

 

RR units do contain transistorized electronics

 

Edited November 15, 2013 by Save Old Iron

[sorekiwi 761]

Apologies to Jackhammer here - I am going to hijack your thread for a second, in an effort to protect some of us from damaging our Regulators!! 

 

Most defective RR's I have seen are usually the result of jumping starting a dead battery. Sparks go flying and electrical spikes ride thru the RR units and destroy them.

 

RR units do contain transistorized electronics

 

 

 

I don't think I remember ever seeing this as being a possible problem with regard to our tractors.  I have to jump start tractors reasonably regularly, as it seems that buying 3 or 4 batteries a year still isn't enough to supply the fleet.

 

I was an Automotive mechanic apprentice in the mid '80's on the other side of the world.  As fuel injected cars became the norm, they started selling jumper leads that had a magical box in line with them that was supposed to be a "surge suppressor".  I've never seen jumper leads like that in this country,.  I asked a smart guy once why that was, and he told me that most modern electronics had surge suppression built into them.

 

So, is there a safe way to jump start our tractors?  Or do we need to resign ourselves to the fact that we have to charge the dead battery, either by plugging in a charger or by hooking up jump cables to another running vehicle and let it charge up via the donor vehicles alternator?

 

I assume that it is still safe to jump start a starter/generator tractor?  (due to a mechanical regulator with no sensitive electronics.)

 

Is there some sort of plug in "magic box" that can be used with jumper leads to avoid the voltage spikes?

[leeave96 490]

"So, is there a safe way to jump start our tractors?"

 

This was my fix on the 314-8...

 

[jackhammer 550]

 Going to take it out and put it to the test on the remainder of leaves..

 

I will have a couple more questions concerning the above sometime this weekend if you both could check back -  - rains a coming gotta go.

 

Thanks for the input  fellas

 

jackhammer

Rick

[ARK 9]

First- never uses running engine that is in line and charging to charge a smaller tractor battery.  Stop the engine, then with jumper cables + to + terminal and - to a good ground.  When the dead battery is jump connected DO NOT START OR RUN THE ENGINE from the charged battery.  Try a kick, no more than 3 seconds and no more than 3x spaced out to allow cooling.  When the dead battery engine starts let it idle a few minutes, then remove the cables, DO NOT SHORT THE CABLES, remove from the good battery then start that engine and re-charge that battery.

 

Removing the + and - cables hang on to them, do not let them dangle around metal frames, fenders etc.  Carefully remove the hot end and then put cables down.

 

That said a dead battery is best charged by a low amp charger 2A for an hour, then do 6 A.  The dead battery has residual charge but not enough to crank a series wound starter motor.  

 

With a dead battery, now is the time to do work with it.  After an indication of full charge, voltage at 13V, light indicator…check a wet cell battery cells for proper electrolyte level and top up with distilled water only.  Now with a battery hydrometer test each cell…1.25 S.G. (specific gravity)  If the battery tests full charge now equalize that battery.

 

Equalization is over charging a battery a few minutes and then reading max voltage.  The equalization will increase the top up voltage and will mix the electrolyte and get rid of portions of electrolyte that are insulators and make them back into conductors.  The easy explanation, the chemical explanation is lengthy.

 

When equalizing a 20AHr battery which is small stay with the battery in a safe location, no kids, no pets, fire extinguisher handy, safety gear on.  Never leave the battery on high amps, 50A when equalizing and never be away from the battery.

 

Depending on the battery condition, a PM of equalization will bring it back to life.  Long charges of low amperage will eventually kill a battery, an occasional kick in the pants will keep it up.  I equalize all lead acid batteries 2x a year and get 8-10 years of life.

 

In the meantime routine PM must be done like clean and secure terminations, battery completely, compartment.  Never over crank a starting engine, if it doesn't start in 1 or 2 tries there is something wrong.  heck and test all cables, all grounds and the starter every 3 years at least.

 

Second…with a running engine, warmed at idle and up, test the battery terminals while it is running with a good meter.  A 12 V battery fully up all off reads 12.7 VDC any lower the battery is discharging.  At idle terminals should be 12.7-13 VDC, at full RPM 13.7-14.4.  Readings are around these numbers but the range for a 12 V system is 10-15V nominal and this includes starting the engine.

 

As tractor owners we can get into full wave, ½ wave, pulsating DC, smooth DC, but in reality we really want to know if the battery is being charged by that AC alternator.

 

As an aside rectification lowers voltage, batteries in cars or tractors have the ability to smooth out pulsations and because of this the smoothness from an AC source being rectified than regulated or not is a concern for the maker.  Costing is a bit cheaper when you use ½ wave, or non 360 degree set ups because they still work.

 

And it doesn;t hurt to check your battery voltage, S.G., and charge it every so often.  A fully charged battery can do its job.

[Save Old Iron 1,571]

Apologies to Jackhammer here - I am going to hijack your thread for a second, in an effort to protect some of us from damaging our Regulators!! 

 

Is there some sort of plug in "magic box" that can be used with jumper leads to avoid the voltage spikes?

Mike ,

 

there are devices that protect electronics from voltage spikes. Essentially, they chop spikes off "at the knee" and shunt any excessive voltage on the positive cable directly to ground. Most AC powered household appliances and electronics have these surge protectors on their circuit boards.

 

The battery cable version is just a 12 volt version of the surge suppressors box you can buy for your computer. Instead of cutting off any voltages in excess of 120 AC, the battery cable version may cut off any voltages in excess of 30+ DC.

 

These devices are called MOV (metal oxide varistors) - check on google for more info.

 

http://www.toolsource.com/antizap-service-minder-auto-surge-protector-p-78350.html

Edited November 16, 2013 by Save Old Iron

[sorekiwi 761]

Thank you Chuck.  It will take me a while to digest that.

 

From what you wrote, it seems that I do everything exactly wrong when I jump start a tractor! 

[jackhammer 550]

I think all of my questions for now have been answered . . 12.4 v on battery  prior to mowing.

With the engine running and lights on, I checked and was showing  a little less than 13v, - added pto at the same time and it took it up to 14 .

But ammeter is still on the left side of 0

Went out and used it mainly with leaf sweeper and idling in between while I burned each load, probably over a hour I would say.

When finished I took a reading with the engine off. --> 12.4

 

Thats all I can ask for  

 

Thanks everyone

Edited November 17, 2013 by jackhammer

[ARK 9]

To help you sort voltage and current with a lead acid battery.  Nominal voltage is 12V.D.C. but the range is 10-15 V.D.C. since the alternator, regulator have to charge at over 12 V. because each cell needs higher than its nominal point of around 2 V.D.C.. The low of 10 V.D.C. happens during the starting of the motor and lead acid automotive style batteries can only be discharged 20% then there considered dead.

 

To test the battery and alternator and regulator the battery should be fully charged.  This charge is best done by a stand alone off the vehicle charger.

 

Now with a known good charged battery, with everything in the tractor, car, truck, bike, with all off, the battery voltage should be around 12.7 V.D.C.

With a voltage meter on the battery terminals, start the engine and while doing so, check the voltage at the battery.  While starting, the battery voltage should go no lower than 10 V.D.C.  Anything lower, there is a problem.  And that could be the battery itself, terminations, cables, starter relay or solenoid.  Because all these things are in series with shoving lots of current into the series wound starter motor.  And when in series the voltage can drop drastically via bad joints, dirty joints, corroded cables not to mention weak cells in the battery that can be caused by weak electrolyte, shorted out bottoms of the battery, internal resistance of the battery and the electrloyte itself becoming an insulator chemically from prolonged low charging rates.

 

The battery is a chemical storage tank, the alternator, a source of electrons via the rectifier and regulator but the alternator needs time to recharge a battery since lots of electrons leave the battery to start the engine and only a small amount, 3, 15, 25 or even a 150 amps are delivered by the alternator.  And to boot that alternator must be spinning at its maximum RPM.

 

So if you have a tractor that has a 24 AHr battery and it takes 100 A to start the engine but you have a 15 A alternator, it will take time for those 15 A to meet the 100 A loss + the amps needed to keep things running…and if it's not ideal temperature 65F, being hotter or colder, more time is needed to get things back to full state of charge.

 

After the engine is running the battery voltage should be at least 12.7, with a small amount of choke, running less than max RPM..As the engine warms, choke off and RPM increased the battery voltage should max out around 14.7 or slightly less and then around 13.7.  At 13.5-14.5 the battery is fully charged according to the regulator, but a battery hydrometer will test the specific gravity of the wet cells and be around 1.25-1.3.  This tells that the electrolyte is fully charged.

 

As the battery puts out more current than comes back in while charging, it depletes its charge and as that happens the closer to water the electrolyte becomes and the specific gravity of pure water is 1.0.  As water, electrolyte can freeze but as a battery acid, H2SO4, sulphuric acid, it takes a very low temperature to freeze.

 

Batteries, electrolyte, cells are dynamic as electrons move in and out.  The state of charge changes, the composition of the battery, electrolyte changes from water, to acid and an insulator to a conductor.  The change is subtle but very evident.  A good battery as opposed to a dead battery.

 

Maintenance is critical, PM is crucial to long life of a battery.

 

Ammeters

An ammeter is an electrical gauge used to indicate current flow.  Ammeters are left to right, right to left and/or centre mount.  Centre mount meter can indicate a positive flow or a negative flow.  A positive flow with our tractors is from the alternator through the cabling, through the ammeter to the battery, or charging the battery.  Negative flow is backwards.  The amount of flow will will deflect the needle.  Greater flow more needle movement whether positive or negative,

 

A direct mount in-line ammeter is connected in series with the flow and carries all the current as does the cables, connections and alternator and battery.  It handles that same load, whether small or large and must be able to carry the rated amps of the complete charging system and battery.  Most ammeters in vehicles are by-passed during starting of the engines because of large currents.

 

An ammeter is not a volt meter.  Volt readings offer little current to the circuit.  Ammeters are in-line to the circuit.  There are other types of ammeters that are not in-line but are really voltage meters calibrated in amps which is a whole different discussion.

 

DO NOT WIRE AMMETERS LIKE VOLTAGE METERS and vice versa. 

 

A battery needs both amperage and voltage because both are needed to do work and starting a cold massive engine from a dead stop is a lot of work.  Automotive 12V batteries have the ability to take on a large charge and deliver a large charge but are considered discharged below 10 V.  Some batteries will indicate 11.5 V but have no useful amperage so they will be discharged.

 

Starter motors

For the most part, series wound motors are used to start ICE, internal combustion engines.  Series wound are electric DC motors that have their field and armature in series.  Thus these motors can be over loaded without damage.  Typical car engines have a 1-1-½ HP DC series wound motor rated at 746 W per HP.  At 12 V nominal that's about 62 Amps.  But these motors will draw up to 250 amps while starting an engine.  That is why they are used, but that work comes with a downfall, the D.C. motor needs cooling time.  So hitting the start button for too long or not letting a cool off time between starts will burn out the starter motor.  Also that amperage is flowing through the cables, the joints, the solenoid and the battery and its terminals.

 

You can extend the life of the battery system by PM, knowing what is taking place and knowing like us, it likes a moderate temperature, but life being what it is ideal is not always present.

[Save Old Iron 1,571]

Thats all I can ask for  

 

 

 

Rick, one last check.

 

Engine off, key in Run, turn headlights on.

 

Which way does the Ammeter deflect?

 

If it deflects into the + side, the ammeter is wired backward. The headlights act as a drain on a non charging battery and should force the ammeter into a fairly high (5 amp or higher) reading on the gauge.

 

If the wiring is backward, just reverse the wiring on the back of the gauge.

[jackhammer 550]

SOI,

 

With the battery reading 12.32v today sitting in the cold garage, .

 

The ammeter deflects negative

 

If each one of those marks on the ammeter is in increments of 5 then with the lights on and engine off .... the ammeter shows about a -6 .

 

Starting the engine and while its running full throttle + putting on the lights is almost 13v at the battery,  while the ammeter is still showing a negative .

 

I think everything might be good because the cold battery has set  a day +1/2 and only dropped .10.  Was 12.42 Wed morn

 

I believe that rectifier was the culprit before.

 

Thanks Chuck

 

Rick

[flyovrcntry 115]

The problem is with the gauge.