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90mm 12 volt generator charging question
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vdubmyk
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PostPosted: Tue Nov 18, 2014 6:02 pm    Post subject: 90mm 12 volt generator charging question Reply with quote

I am currently using a 90mm 12 volt generator along with the new style solid state voltage regulator on my stock 40 hp engine. The other day while out and about, the car would not start up and I had to push start it. I got it home and put it on the battery charger. The idiot light has always come on at idle but turns off when the car is under load. The battery reads 12.65 volts at idle and goes to 13.95 volts when under load. Should the voltage be higher? Or is it that I need to drive it for longer periods of time while under load to charge the battery? It is not my daily driver and gets driven once every few weeks. The builder I got it from sold the items as a pair and says the VR wil work just fine. Thanks in advance for any advice.
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Cusser
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PostPosted: Tue Nov 18, 2014 6:58 pm    Post subject: Reply with quote

Charging voltage is right, measured across battery terminals. So get that battery tested UNDER LOAD.
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61SNRF
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PostPosted: Tue Nov 18, 2014 7:51 pm    Post subject: Reply with quote

In theory,
Generators aren't made to charge a dead Battery. Their primary task is to supply all the current that the car consumes under normal use, and only trickle or slow charge the battery to rebuild what it lost during starter cranking.

The battery is only a storage unit or reservoir of potential energy. It's main job is to supply the power to start the car and to dampen the surges and dips in voltage during RPM/load change.

So, to be accurate, the battery should be fully charged to test the GEN output. Every manufacture's specs will state this.
Given it's a Solid State VR, no chance of adjusting it that I know of, so you get what you get. Ask your vendor if they can supply some sort of output specs to expect.

Good, solid wiring connections are another first step before charging output test too. Voltage drop in both the positive and negative battery cables should not exceed 0.2V. High resistance can prevent starting as well as limit recharging of the battery. If you want to know how to test this, just ask.

All that said, if you had that one time odd or unusual no start, it could be that the battery is aging or has a weak/dead cell. They can test fine for voltage, and work great 80% of the time, but give up at random moments. A cheap hydrometer is handy tool to have for testing lead/acid battery's both for state of charge as well as overall health.
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vdubmyk
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PostPosted: Tue Nov 18, 2014 9:27 pm    Post subject: Reply with quote

Thanks for the advice. The car itself has had the battery cables changed, new wiring from the generator to the VR and new wiring from the VR to the dash area via the B pillar and down the A pillar. The battery itself is just over a year old but the car really doesn't get driven all that much. I used non insulated double crimped terminals as original as well. My main reason for asking was I know that car charging systems should be around 14.25 to 14.5 volts. I did notice the battery has a built in indicator light that when new illuminated green. It no longer is lit even when fully charged. I will get the battery load tested to see if it has a bad cell first and go from there. Thanks again.
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herbie1200
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PostPosted: Wed Nov 19, 2014 12:59 am    Post subject: Reply with quote

Just a little question: the "solid state" voltage regulator is for a standard 14V-30A generator (115mm diameter, the bigger).

Your generator is a smaller "90mm" unit.

You have to check if it has the same electric specification, 14V-30A. I suspect those units have less amperage, so your regulator does not perfectly fit your equipment.
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Aussiebug
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PostPosted: Wed Nov 19, 2014 1:20 am    Post subject: Reply with quote

herbie1200 wrote:
Just a little question: the "solid state" voltage regulator is for a standard 14V-30A generator (115mm diameter, the bigger).

Your generator is a smaller "90mm" unit.

You have to check if it has the same electric specification, 14V-30A. I suspect those units have less amperage, so your regulator does not perfectly fit your equipment.


Whilst that is sort of true, in fact so long as the rating of the VR max amps is the smae or HIGHER than the generator output, it should work OK.

As an example, the BUS generator is 38 amps, and if you try to use a bug VR (30amps) on it, it will probably fail if the amperage load exceeds 30 amps to the car and battery. But you can use a bus VR (38 amps) on a bug (30 amps) and it will work OK.\

Vdubmyk,

As Cusser says, the voltage output is OK - it's at the lower end of OK (14-14.5v is ideal), but it should charge the battery with a reasonable run. The battery will still charge if the charging voltage drops to 13.8v (some brand cars are set to this - never understood why), but it will charge much slower - need a longer run.

And as 61SNRF says, generators are better at maintaining a battery at full charge rather than charging a very flat battery, so a car which is not used often will benefit (battery life) a LOT if it gets a bench charge every month or so.

The chemistry in lead acid batteries is such that if the battery is allowed to go flat, one set of lead-compound plates will go soft and start to slump off the matrix holding them in place (ruining the battery). Car batteries use many thin plates (for maximum starting amps), and the thin plate allow for more slump than deep-discharge batteries like golf cart batteries etc - THEY have fewer/thicker plates, so the lead compounds are held in place more easily and the battery wont suffer so much from deep discharges, but fewer plates means they can't make the huge amps needed for car starting. So keeping your car battery fully charged is essential for getting the best life out of them.

I put even brand new batteries on the bench charger before going into the car, and even when I'm using the car a lot, I still use the bench charger every month or so - it's surprising how much extra a smart charger will put into a "charged" battery. Car charging systems (both alternator and generator) usually only get about 85-90% charge into a battery, because they are constant-voltage systems, so as the battery charge (and voltage) rises towards max, the difference between the battery voltage and the charging voltage diminishes, resulting the the rate of charge reducing to near zero. A smart charger, on the other hand, will boost the charging voltage a little as the battery voltage come up towards max, so it continues to pump that bit extra into the battery.
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herbie1200
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PostPosted: Wed Nov 19, 2014 5:59 am    Post subject: Reply with quote

Aussiebug wrote:
herbie1200 wrote:
Just a little question: the "solid state" voltage regulator is for a standard 14V-30A generator (115mm diameter, the bigger).

Your generator is a smaller "90mm" unit.

You have to check if it has the same electric specification, 14V-30A. I suspect those units have less amperage, so your regulator does not perfectly fit your equipment.


Whilst that is sort of true, in fact so long as the rating of the VR max amps is the smae or HIGHER than the generator output, it should work OK.

As an example, the BUS generator is 38 amps, and if you try to use a bug VR (30amps) on it, it will probably fail if the amperage load exceeds 30 amps to the car and battery. But you can use a bus VR (38 amps) on a bug (30 amps) and it will work OK.\

...


Not 100% agree.

The amps printed on the regulator are not an indication of regulator power, the amps managed are a punctual setting of the regulator.

A simply called regulator is a "3 in 1" functions device:

- 1: to decouple generator from battery when speed is too low
- 2: to regulate voltage from generator
- 3: to protect the generator from an excess of current production

So if you use a 38A regulator with a 30A generator you are not safe because if, for extracurrent or malregulation, more than 30A (and minus than 38A) are requested to the 30A generator, the 38A regulator does not turn off the generator to keep it in safety.

If you look into a bosch regulator, it's easy to notice a coil with a big size copper wire winding, only a few winding, this is exactly the 'ammeter function' tuned to cut off generator when an excess of ampere is requested.
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vdubmyk
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PostPosted: Wed Nov 19, 2014 7:30 am    Post subject: Reply with quote

All are valid points and I'll put the charger on the battery more often. The generator and VR were purchased from the same vendor and they are made to work together. I've ran the car this way for a few years now and had never had an issue so I was curious. Thanks again for the info.
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61SNRF
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PostPosted: Wed Nov 19, 2014 7:41 pm    Post subject: Reply with quote

vdubmyk wrote:
I did notice the battery has a built in indicator light that when new illuminated green. It no longer is lit even when fully charged. I will get the battery load tested to see if it has a bad cell first and go from there. Thanks again.


If your battery has a "green eye" indicator, it's probably the sealed variety that you can't test the individual cell gravity on.

If so, that green eye is there only to tell you that the battery is sufficiently charged for testing, and that is typically 60% or better.

The fact that it no longer lights is a good clue that it's either still run down or so aged that it's not accepting or holding a charge.

Thus, if it's not lit, a load test is not really valid.

The older lead acid battery's get, the slower they like to be charged.
You can try a 3-5 amp Automatic trickle charge on it for 24-48 hours and see if the light lights.
If not, stop wasting power from The Grid on it and just recycle it Wink
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PostPosted: Fri Nov 21, 2014 2:47 am    Post subject: Reply with quote

A common lead+acid battery shall be charged into a running vehicle, because the acid is supposed to be shaked during charging process.

Static batteries, i.e. batteries prone to be charged in a fixed position, have a different design, often they are gel or AGM.
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PostPosted: Fri Nov 21, 2014 10:28 pm    Post subject: Reply with quote

herbie1200 wrote:
A common lead+acid battery shall be charged into a running vehicle, because the acid is supposed to be shaked during charging process.


Errr, where did you get that from Herbie?

A car battery (flooded cell lead acid battery) does not need to be shaken at all for charging. Since all flooded cell lead acid batteries make some hydrogen and oxygen during charging, the bubbles rising to the surface will stir the acid very nicely to keep it circulating against the plates.
Quote:

Static batteries, i.e. batteries prone to be charged in a fixed position, have a different design, often they are gel or AGM.


The real advantage of GEL or AGM (absorbed glass mat) batteries is that the acid is held in a matrix (gel or glass mat) against the plates, so it's not a loose liquid. They also contain systems which re-absorb any gases produced. That means that these batteries do not need topping up, so they are sealed and can be mounted in any orientation. Normally they have fewer and thicker lead-compound plates for the + and - sides, so they can not produce the same starting amps as a same-sized car battery with many thin plates can make, but they can take a deep discharge without much physical damage to the battery. That makes them ideal for golf carts, powered wheel chairs, "house" batteries in caravans and the like, where they might occasionally have to supply power until they are well discharged, before they get a fresh charge.

Flooded cell car batteries don't like being deep-discharged at all - they are really designed to cope with a discharge of around 15% - a hard start or two - and then get a charge from the generator alternator.

Generally, they can produce higher amps for the same physical size, so are better suited for car batteries than GEL or AGM batteries (even the low compression VW engine needs around 200amps to get the engine spinning and about 70 amps to keep it spinning until it fires up). They are cheaper to produce too.
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PostPosted: Sat Nov 22, 2014 11:05 am    Post subject: Reply with quote

you may need to give that battery a high amp charge for a while, 10 amps maybe, but make sure the battery don't get hot during this time. The reason is a battery that has been allowed to die, or constantly undercharged (ie a car driven infrequently, short trips) will become sulfated, and that impedes electric flow, the sulfated battery can sometimes be restored with a high amp charge, this can reverse the sulfate reaction. your generator although rated at 30 amps wont supply that full current unless the battery is completely dead, it will supply a small charging current to a sulfated battery, not enough to break up the sulfate. hence put it on a bench charge that will deliver 10 amps or so, regardless of the battery voltage. as pointed out by other poster, the cars regulator prevent full current going to the battery as the battery voltage raises. for a sulfated battery, the voltage is high enough in it to not allow the cars charging system to give 10 amps to it, as the cars charging system automatically reduces the charge current when the battery is close to full charge, this is not enough to restore a sulfated battery, so a bench tester is needed, one that is capable of supplying 10 amps even to a battery that is at 12.5 volts

give that a try is your battery wont come up to full voltage, If the ten amps don't restore your battery to full voltage, then the battery should be replaced. When the battery is fixed, then make sure the charging system on the car is working ok, and if it is not driven a lot, put a battery tender on it once and a while to keep it from dropping to low and having it sulfate again. remember that when the voltage gets low, it will sulfate, so keep it from ever getting that low again and you should be ok.
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PostPosted: Sun Nov 23, 2014 2:17 am    Post subject: Reply with quote

Good post by Bluebus above.

I have owned trucks with huge batteries fitted with electric winches (200amps current draw), and currently have an SUV with a 120amp hour battery and a Honda Jazz with a tiny 30 amp hour battery, so I have plenty of experience with battery chargers - 5 of them at the moment, 2.7amp dumb charger, 4 amp dumb charger, 24v 4 amp dumb charger, old style 10amp "not very smart" 6/12/24v charger and a new 15 amp smart charger, plus assorted plug-pack low amp chargers.

The smartest thing I ever did was to buy the good multistage smart charger to replace the old style "not so smart" charger I had previously.

This new 7 stage charger checks the battery voltage, and if needed, will oscillate the charge voltage up and down to try to overcome any suphating, then goes through several more stages of different boost levels, and eventuallty settles for a 1 amp tickle charge once it has the battery up to par. And it also has settings for gel, AGM and flooded cell (car) batteries as each prefers a slightly different "end" voltage.

My old 10amp "smart" charger would not charge a completely flat battery if it just didn't see enough voltage to recognise it as a battery - it just called "time out" and switched off. I'd have to try my small "dumb" charger for a few hours to see if I could get SOME voltage reading, then switch to the slightly smarter old charger.

This new 15 amp charger is so smart it's quite safe to use on small batteries like that in my battery jump pack which has a 17amp/hour AGM battery in it (motorbike battery size) which is normally charged with a 0.3 amp plug pack charger, because the moment the voltage starts to rise, the smart charger adjusts the max charging rate to suit, and wont overheat the battery. I've watched it working with a voltmeter attached - very interesting.

My 2.7 amp "dumb" charger which I bought for smaller jobs doesn't get used much at all now.

The newer style of smart chargers can usually charge completely flat batteries and hopefully recover them to useful service, although as we have said above, letting a lead acid battery go completely flat WILL shorten it's life. "Completely flat" for a lead acid battery is considered to be anything less than about 10.5v.
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PostPosted: Sun Nov 23, 2014 5:34 am    Post subject: Reply with quote

Thanks for the battery lesson everyone. I have a Schumacher brand charger that does 3 different amp settings. I charged it for 10 hours on the medium setting, I believe it was 6 amp and the battery reads 12.75 on my voltmeter. I like the idea of the smart charger. Any suggestions or recommendations as far as brand or style?
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PostPosted: Sun Nov 23, 2014 11:29 pm    Post subject: Reply with quote

vdubmyk wrote:
Thanks for the battery lesson everyone. I have a Schumacher brand charger that does 3 different amp settings. I charged it for 10 hours on the medium setting, I believe it was 6 amp and the battery reads 12.75 on my voltmeter. I like the idea of the smart charger. Any suggestions or recommendations as far as brand or style?


Not really.

Mine is made for Super Cheap Australia, but the same thing is probably available in many brand names around the world.

It has 7 stages with 7 LEDS following a graphic of what it's doing, so you can see exactly what it does at any one moment (That suits me -= I like to know exactly what it's doing). And most importantly, it says that it will charge up a completely flat battery - that means it won't give up on a sulphated battery and will do it's best to recover it, unlike some earlier "smart" chargers which had to have a minimum voltage left in the battery to work with. That function does work too - I left my AGM caravan "house" battery too long between charges and it had run completely flat (running the clock and LED volt meter in the caravan), so this charger paid for itself in one operation recovering that very expensive high capacity AGM battery.

They come in various capacities, 6, 10, 15 amp and so on. Just about any will suit, since ""smart" means they wont cook a small battery with a continuous high charge rate, so get the highest amp version your pocket allows.
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