smart alternator override

[reciprovac]

Have any of you electronic gurus out there worked out an easy way to make our smart alternators less smart, and more practical, for us simple souls who want to run an Engel from a second battery.
I have in the past run my lights during daytime to assist in getting the alternator to charge more but a complete override is the only way forward without the ridiculous cost of a DC/DC charger.
Any thoughts would be appreciated.
Regards

[boritz]

The Ultragauge fitted to my MY13 NW always reads ~14v (with engine running) so I'm not certain that the alt is regulated by 'smart' logic.

[mr_bosman]

Do you always have the air con auto?

Try turning off all accessories and advise what the ultrguage sttes the batt voltage is?

[NJV6]

Mine is all over the show, sometimes 14.14 and other times 13.7 with the same assessories on, usually just a/c & radio. Sometimes is is 13.4 and with radio anda/c off its down as low as 12.4.

There seems to be no rhyme nor reason as to why it is 14.14 or 13.7 on mine but it is easy to get 13.7 by just running the climate control on (which always is) so will charge your battery.

[boritz]

Interesting thought...

...Try turning off all accessories and advise what the ultrguage st[a]tes the batt voltage is?...

I'll try to take a look over the next few days.

My ~14v comment above was admittedly based on random casual glances and a rounded approximation since I wasn't interested in decimal portions.

Charging the caravan battery, powering Al-Ko ESC & running the 'fridge prompted me to view the Ultragauge reading. Those infrequent checks were enough to indicate the Paj seemed to be doing the job (and the said 12v clients were happy).

[Mike DiD]

Connect the Negative of the Aux Battery to the Negative of the Starter Battery.

That way the Aux Battery Charging current flows through the Smart Alternator Current Sensor which is at the Front of the Starter Battery.

When EITHER Battery is still drawing charging current, the Smart Alternator will keep the voltage high.

[reciprovac]

smart alternator override

Mike , Do you mean that the negative from the Aux battery has to be connected below the currrent sensor ?
It seems to me that is the only way it would work,can you confirm please.

[NFT5]

Not sure if that's what he meant, but connecting the second battery negative to ground is the only way that the return current will be sensed and the alternator automatically adjusts to compensate. Connecting batteries negative to negative will bypass the sensor so the alternator won't know about any additional current draw.

[ticky]

Connecting batteries negative to negative will bypass the sensor so the alternator won't know about any additional current draw.

I really wish I understood this better...

I believe however, that hooking the negative of the Aux battery to the negative of the Crank battery makes that sensor see just one big ass battery and it WILL charge until both the crank and the Aux battery are charged.

Hooking the Aux to a Body Earth is what causes the Aux to fail to charge as I understand it,... but I am no expert

Steve

[reciprovac]

I really wish I understood this better...

I believe however, that hooking the negative of the Aux battery to the negative of the Crank battery makes that sensor see just one big ass battery and it WILL charge until both the crank and the Aux battery are charged.

Hooking the Aux to a Body Earth is what causes the Aux to fail to charge as I understand it,... but I am no expert

Steve

Yes Steve that is what I am querying with Mike, I am thinking that if you connect the aux negative to the main battery negative terminal the return current will have to go through the sensor then to the aux,then as you suggest the Alternator will see the increased flow through the sensor and increase its charge.

[green troll]

I've said it many times. Mine is hooked up aux neg to main neg with no issues 14.2/3/4

[boritz]

...I'll try to take a look [at the Ultragauge volts while all accessories are off] over the next few days...

Fortunately it was cool enough today to turn off climate control etc.

50 Km round-trip to/from work (Paj only of course, no caravan in-tow).

Ultragauge readings (there appear to be 2 battery voltage gauges available):

- 25 Km outbound: UG Battery Voltage gauge always ~14+v

- 25 Km inbound: ECM Battery Voltage gauge always ~14+v

A single newish 4WD cranking battery which replaced the short-lived OEM lawnmower jobbie.

[vladguan]

Yes Steve that is what I am querying with Mike, I am thinking that if you connect the aux negative to the main battery negative terminal the return current will have to go through the sensor then to the aux,then as you suggest the Alternator will see the increased flow through the sensor and increase its charge.

As I previously understood, hook power hungry accessories -ve to ground to be sensed. However, when I did it to my 270W LED light bar, it created a power drain and tripped the ASTC warning lights. Should I need connecting the LED light bar -ve to the battery -ve?

[drgtr]

Can anyone confirm negative auxillary to main negative battery works?

[vladguan]

Can anyone confirm negative auxillary to main negative battery works?

Should connect it to ground. The issue I had was to do with a faulty light bar. If you connect aux negative to main negative, the extra load won't be sensed by the alternator.