alternators/batteries my way

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alternators/batteries my way

Postby kfxnando » Fri Jul 16, 2010 3:27 pm

self wrote this article, from experience!! have posted it on various forums, and in some cases it was even deleted deemed as dangerous, well ran such a system in my car that time for years with no problem, and one of those modified alternators still does duty in my Ford, with one major service in 10years, including bearing!!

Well, there are a lot of people with dual battery systems, and there is always a lot of questions and problems around the running of fridges from such a system!! This lead me to write this and then post it on here!!

1st things 1st

My credentials on this topic
Do have a technical back round, and during the years of my last hobby was almost forced to reinvent the wheel when people told me certain things cant be done, like modifying the charge voltage of a alternator, was told it’s a sealed unit and thus the voltage cant be tampered with!!!
Yes the average Jo cant tamper with it!!
Thats when I took my electronics back round and started doing the research

Got the one alternator to over 18V, yep measured with a calibrated meter (all our meters are calibrated at least once a year due to us working to ISO standards at work) so all voltage figures are based on this!!!
With the help of al the above, held various SA records in the car audio competition circles, did what people said was impossible, and learned a lot!!
Did the battery connections and charging system for the holder of the outright SA record vehicle
6 X 15’’ subs in a bullet proof vehicle with 12 amplifiers and 12 SETS of batteries……….
Hope to be able to share some of that knowledge here with regard to extra batteries!!!


So to the 18V charge

Not suggesting that the guys use 18V for their applications
Well, 1st question I hear, what kind of battery would be happy with a 18V charge, well will have to reveal some(not all) of my secrets from those years to explain all!!

AAA
Those days the rules stated that maximum voltage at the amplifiers was 18V, at 1st this confused me, even with my back round, and then it was explained to me by someone who became a very good friend, and when I start digging I normally don’t give up till I fully understand all and become an expert!!

Then together with Sabat batteries (YES they had a finger in the pie ) took things all the way
A battery lead acid or silver calcium or lead calcium can take 2.6V per cell, this will only cause problems when the batteries temperature goes over 45degrees C!!!
And the other battery manufactures confirmed this!!!
At 2.6V per cell, a normal 6 cell battery can take up 15.6 volts of charge, yes deep cycle batteries do like a bit higher voltage (not talking about higher then 15.6, referring to in the 14s Volts will do )

Now to go back to AAA!!
That was obviously not a normal 12V battery from the corner battery centre
We were allowed 18V, so if we took a normal 12 volt battery, and added 2 X 2Volt cells =4volts that would give a total of 8 cells at 2volts each would leave an overnight voltage of over 16V, hence the 18Vcharge
Hope the light bulbs are now glowing
And still have not given the total reason for this so will do it now
Inside the amplifiers are switch mode power supplies, and in the car audio we were always looking for extra power, the higher the sustainable input voltage the more efficient the power supply and the higher the output power and the higher the db of the system, and the more stable the amplifiers became, and the cooler they run!!
Car audio amplifiers are very similar to inverters
My inverter with the 4x4 off does not run my fridge, with the alternator running, it runs the fridge!!!

To put this into a better perspective, to go up 3db one would have to double up on all equipment, amplifiers and speakers, by running the battery setup as described above and going from 12V to 16V one would pick up 1.5db, proven more then once that this works!!! That is 50% improvement in efficiency with out adding extra equipment, except for the batteries!! Witch would actually be more then 50%

Now need to add that I ran more then one alternator, one for the sound system and one for the car, yep two alternators on one motor, you should see what they do in the states!!
However a original alternator can be extensively modified to be more efficient
In my experience, the only alternator worth wile modifying is the bocsh, due to ease of working on and good design lends itself to this sort of modifications
IMO, a Lucas alternator are not subtle for this sort of thing to put it mild!!!
Both coils can be reliably modified, by the right people!!!! This alone will make a noticeable difference to the charge system!!! Including a higher voltage!!!

Now back to physics

Power = VI (voltage X current)

Eg, if a fridge/inverter is 300w = 12 X 25 (know that they don’t draw that much)

Now if you run it off a higher voltage

300w = 14V X 21.4A

300w = 15V X 20A

The more current one draws the more heat is generated, and the more heat generated the more current the appliance will draw, and the least efficient it becomes

So what ideas/suggestions do I have

Well 1st find out what the maximum voltage a camping fridge can handle, although am 99% sure most will survive with over 15Vwould not go over 16V

Inverters will run cooler and be a lot more efficient, and draw a lot less current, hence the batteries would last much longer before needing a recharge!!

Would suggest running an extra battery cell (not a forklift battery cell) and modifying the alternator accordingly , coils and voltage, and no the head light bulbs wont pop!!!

Then the other issue, is the earth cable/s for the whole vehicle/alternator/charge system
Some may not agree, and am not going to get into that whole explanation!!!

However a alternator actually charges via the -ve (do the research, I did!!!)
So with that in mind, I added an extra cables with big lugs onto the casing/mounting of the alternator, the one went to the negative of the star point where all the negatives of all the batteries were connected, and the other to the body!!! Where the old cable went to!!!

For those that have batteries in the back of the vehicle, have a GOOD earth/ground connection in the back with as short/thick cable as possible!!!

All my big lugs and battery terminals were soldered, talking about the BIG lugs, takes a solder bath or a blow torch!!!!

Know that some of the things written above might seem a bit extreme, however thought would do the full story, just like 4x4s, some do it mild and some extreme

The above is my experience with the topic of batteries and alternators, decided to share my experience in the hope of being able to help those who are running multiple batteries and have questions, and those looking for ways of making their systems more efficient

Good luck and hope I was able to help


the only downfall is that brushes in the alternator wear a bit quicker if used under heavier loads constantly, like I did, and they should still be good for around 80000km, that is despite having a smaller pulley the what it had when I got hold of it!!

the other point, is to use only Bosch original regulators as the pirate ones dont like all the modifications and tend to go every 3 moths!! :twisted: :mrgreen:
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kfxnando
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Re: alternators/batteries my way

Postby kfxnando » Mon Apr 09, 2012 5:20 pm

the alternator, has since had the bearings replaced, however after all the years of abuse, it all did very well

and yes the brushes dont last as long with the bigger loads, however still suspect 80 000km +

:mrgreen: :twisted:
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kfxnando
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