Dual Battery Alternator Voltage Booster

[NP99]

http://www.ebay.com.au/itm/Dual-Battery-Alternator-Voltage-Booster-MK3-Prado-Landcruiser-Hilux-Nissan-/221232574391?pt=AU_Car_Parts_Accessories&hash=item33827d2fb7&_uhb=1

Anyone seen or used these. Alleged replacement for dc to dc charger

[kevin07]

i did ask an auto electrician friend of mine once about these he said they are crap,why i cannot remember

[Cuppa]

As I understand it they are only useful on the latest vehicles which have a lower voltage output alternator. Raising the voltage on older vehicles does not make the alternator into a smart charger like a dc to dc charger, and would likely result in overcharging of batteries I think.
For anyone considering buying one of these the first step would be to check what voltage the alternator was putting out checking this against specifications. IF the output AND specifications had the output at 13.8v or less it may be worth fitting one of these doohickeys.

Before buying it would also make sense to double check what the battery manufacturer recommends as a charging voltage for their batteries.
Cuppa

[desray]

I have one of these fitted on a 04 Prado v6 with dual batteries, works good for me. Alternator output is now 14.2 volts and charges both batteries fine. Fitted it 3 years ago now still works good .

[megatexture]

Yea seen them around for a while now, can't say I've herd anything bad about them nor good either though i would like to give one a go but not at 50$

[BigRAWesty]

I have one of these fitted on a 04 Prado v6 with dual batteries, works good for me. Alternator output is now 14.2 volts and charges both batteries fine. Fitted it 3 years ago now still works good .

Your one of the lucky ones.. Many have fried batteries due to over voltage...

But yea, not needed in patrols yet, as they haven't fitted sensoring alternators.
But as cuppa said, Its a bandaid fix the crappy situation.. DC-DC chargers will do a lot better job, and the New models have the ability to override the computer so they continue charging the second battery.

Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

[Cuppa]

Btw..... in case anyone was wondering why it is that some of the more recent vehicles have lower voltage outputs, it is apparently to make the cars more fuel efficient. With the alternator having to do less work there is less 'drag' on the motor, & this improves the fuel consumption whilst still managing to put sufficient charge into a cranking battery for starting, bearing in mind that cranking batteries are never fully charged, but rather only 'charged enough'. This may work ok for cranking batteries, but is a problem when charging an auxiliary battery. Why? Because we want our auxiliary battery to be 100% charged in order to ensure it runs our fridge/lights etc for as long as possible. With the common voltage sensitive relay type dual battery set ups this never happens (neither battery gets charged beyond around 80%) & with these newer low output alternators things have gone from bad to worse. To get an auxiliary battery to 100% charge without risking overcharging of both batteries there are 3 options. A 'smart' alternator regulator, a smart dc to dc charger, or solar (with a smart regulator).

All these plug in voltage boosters do is help to make a low voltage alternator into something closer to the 'traditional' alternators we all know. Many folk have manage ok with such alternators only charging their batteries to around 80% capacity, but for longer auxiliary battery life, charging batteries that are a different type to the cranker, or simply to be able to get full use of the auxillary's capacity one of the 'smart' charging methods is required, & these plug in voltage boosters are not smart. Hope this explanation helps someone trying to make sense of the various myths that do the rounds.

Cuppa