12 volt power efficiency.....

**feral** · 30th October 2007, 10:13 AM

Originally Posted by cookiesa

Depending on how mechanical you are it looks to me like time to pull out the alternator and do the bushes and bearings and give it a good clean up.

Or off to an auto electrician (assuming your out of warranty of course) and get your alternator done.

.....IT'S A BRAND NEW 120 AMP LANDROVER SUPPLIED AND FITTED ALTERNATOR.

I must be the most un-luckiest bloke around to score something new that is stuffed.....

Oh, hang on..that's not right.....Ron is

**cookiesa** · 30th October 2007, 10:48 AM

I was under the impression the MM 120amp was only suitable for the V8 engine.... Bugger I just bought the 100amp one..... but only paid $335 so I'm happy!

(Not that the alternator capacity is relevant to this!)

Maybe a long shot but if you are certain it is not the alternator itself, How is the drive belt tension/condition? If it is slipping you may not be getting sufficient speed on the alternator to charge properly. (especially when put under load) This may also mean your "charge" light isn't coming on to indicate there is a problem.

**Frontier1** · 30th October 2007, 04:55 PM

All this with the batteries, dual, ect, has got me wondering.

I have a dual battery setup using the old Jaycar kit that you had to put together and install yourself. Have had it running now for a couple of years and it's been great. I actually had the setup done since I ran my boat winch off the back.

Anyway, I am wondering ( Drivesafe & Harley?), whether the new jaycar product Battery Isolator by Steed ( 70amp ) might also be the way to go. The unit is $99.95 and I figure $32 in cabbles and $7 for clips/plugs.

How would you guys rate this compared to either your own sytems or other ones on the market.

I'm wondering this as I think I might install this in the boat as I have has a dead battery scenario recently due to keeping the accessories on and only having the cranking battery to run the lot off. ( Now have two batteries since I had to buy a new Pro 600 series. )

Cheers,Pete'

**drivesafe** · 30th October 2007, 05:22 PM

Originally Posted by Frontier1

Anyway, I am wondering ( Drivesafe & Harley?), whether the new jaycar product Battery Isolator by Steed ( 70amp ) might also be the way to go. The unit is $99.95 and I figure $32 in cabbles and $7 for clips/plugs.

Cheers,Pete'

Hi Pete, post us a link to the product so we can see what it is.

Cheers.

**Frontier1** · 30th October 2007, 05:36 PM

Knew you were going to ask that!

http://jaycar.com.au/productView.asp...Max=&SUBCATID=

Seems a simple enough setup, even for me!

Cheers, Pete'

**drivesafe** · 30th October 2007, 05:55 PM

Hi Frontier1, that device is an absolute NO NO.

Their a diode isolator type and as such, have loads of drawbacks.

The main draw backs are that the lower the battery, the longer these take to charge the battery compered to ordinary relay type Isolators.

Unless you can trick up your voltage regulator ( not recommended ) you will never fully charge your battery and because of the point, you will most likely shorten the operating life of your battery.

Cheers.

**cookiesa** · 30th October 2007, 05:55 PM

If this is the correct one...

http://www.jaycar.com.au/productView...eMax=&SUBCATID=

Then the way I read it it isn't a true dual battery system in the sense of the way we use them. It draws from whichever battery has the higher voltage. To me it reads it will switch and drain from both however 1 dead battery can't flatten the other. More for protecting a battery in a "bank" than isolating them

**drivesafe** · 30th October 2007, 06:25 PM

Originally Posted by cookiesa

If this is the correct one...

http://www.jaycar.com.au/productView...eMax=&SUBCATID=

Then the way I read it it isn't a true dual battery system in the sense of the way we use them. It draws from whichever battery has the higher voltage. To me it reads it will switch and drain from both however I dead battery can't flatten the other. More for protecting a battery in a "bank" than isolating them

Yep, that one seems a strange device and not that sure where it would be used in an automotive set up.

Out of pure curiosity, has anyone got any suggestions on it’s use, other than the one cookies click to.

**Frontier1** · 30th October 2007, 07:38 PM

Ok, fair enough and I always listen to those that know more. (ya' learn more that way!)

So what is the easiest and cheapest solution for what I want, knowing that I want a fully charged cranking battery and power left over charging my accessory battery?.

Plus that in an emergency I can start my car/boat, what have you, from my 2nd battery <or is it as simple as a set of jumper leads from Bat2 to Batt1>?

Thanks guys and sorry if this is rehashing what has gone before in this thread

Cheers Pete'

**PhilipA** · 30th October 2007, 08:17 PM

I hesitate to chime in BUT.
I have 2 alternators ( both 85 AMP Bosch type)and two batteries, run completely separately.
I have a Jaycar volt meter switched between the two batteries ( which I have checked to be accurate).
Both alternators run at between 14 and 14.5 volts depending on temp, when the batteries are fully charged, usually at the upper end say 14.4.
Recently I noticed that the starting battery alternator voltage would fluctuate down to 13.7 volts. I placed a Megapulse on the battery and the charge level went up to 14+, after afew days.
I recenty boughta Supercharge "All Rounder" to be starting battery.
I noticed some interesting things
1 The charge level is now always 14+ and nearer 14.5.
2 the charge level under high load eg aircon is now 14+ wheras before it was about 13.7. This is strange to me as one would think that once going and charged for a while the battery should have no bearing on the system voltage. ie under a similar load the system level should be the same with an old or new battery.
But it isn't so.
The other thing I notice is that my 95 AH AGM will accept about 80-90% charge in about 90 minutes from say 11 volts. At this level my system voltage is about 13.7 volts. It then will rise slowly over say another 3-4 hours to 14.4 volts. remember this alternator is ONLY charging the battery, so is governed by the battery. ( Well the Engle is taking 1.5 AH or so)
So my conclusion is that you get quite a lot of charge in the first short time but the final top up takes quite a while. This will happen regardless of whether you are using an alternator or smart charger as it is the nature of batteries.
Regards Philip A

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