mike48
12th April 2013, 02:57 PM
Kea Conqueror – Raising the Alternator Charge Volts to 14.5
My ex rental 2009 Kea Conqueror is based on a 2008 Toyota VDJ78 Troop Carrier with a 4.5 litre V8 diesel.
When I changed the house battery to a 12 V 120AH AGM type, I wanted to charge the battery as quickly as possible via the alternator, after a night’s use on battery.
I inserted a 1N5404 diode in the alternator sense line, substituting the original fusible link with an ATC type blade fuse holder with the diode soldered across the base.
Toyota call the alternator sense wire “ALT S”.
This gives me high volts with no fuse inserted, and original volts when a blade 10 A fuse is inserted and shorts out the diode.
The diode is polarised so that the cathode or device “bar or ring” is towards the alternator.
I removed the original ALT S fusible link, and added my device between the battery positive and the connection block originally used to connect the fusible link.
The fuse-holder that I used is similar to Jaycar part SZ2045, chosen for robust build.
After installation, I sprayed INOX into my device and on the connectors.
And I have teased out the fuse and diode just for the photos; it is normally lashed back into the cable loom beside the battery out of harm’s way with large twist ties.
When the alternator is charging at 20 amps, my battery wiring (in 13.5 sq mm copper) and ammeter shunt resistance of 0.01 ohm, limit the current and thereby the charge voltage (by introducing calculated these discrete losses) to 14.3 at the battery terminals, rising to 14.5 at 5 amps.
The cable size was deliberately chosen to be not too large, so as to limit the current on high volts charge, and also to keep the volts high at a medium charge of 10 amps, and thus achieve a degree of constant current charging similar to three stage charging characteristic for AGM batteries. I learned this concept from a previous career, and an earlier Kea HiAce installation.
I am aware of the safety, fusible link removal, and battery implications of such a modification.
If you are unsure of these constraints, then don’t attempt this on your vehicle.
Photos give details of diode+fuse device, parts locations and numbers.
Hopefully of use to some,
Cheerio, mike
262815262816262814262817262818
My ex rental 2009 Kea Conqueror is based on a 2008 Toyota VDJ78 Troop Carrier with a 4.5 litre V8 diesel.
When I changed the house battery to a 12 V 120AH AGM type, I wanted to charge the battery as quickly as possible via the alternator, after a night’s use on battery.
I inserted a 1N5404 diode in the alternator sense line, substituting the original fusible link with an ATC type blade fuse holder with the diode soldered across the base.
Toyota call the alternator sense wire “ALT S”.
This gives me high volts with no fuse inserted, and original volts when a blade 10 A fuse is inserted and shorts out the diode.
The diode is polarised so that the cathode or device “bar or ring” is towards the alternator.
I removed the original ALT S fusible link, and added my device between the battery positive and the connection block originally used to connect the fusible link.
The fuse-holder that I used is similar to Jaycar part SZ2045, chosen for robust build.
After installation, I sprayed INOX into my device and on the connectors.
And I have teased out the fuse and diode just for the photos; it is normally lashed back into the cable loom beside the battery out of harm’s way with large twist ties.
When the alternator is charging at 20 amps, my battery wiring (in 13.5 sq mm copper) and ammeter shunt resistance of 0.01 ohm, limit the current and thereby the charge voltage (by introducing calculated these discrete losses) to 14.3 at the battery terminals, rising to 14.5 at 5 amps.
The cable size was deliberately chosen to be not too large, so as to limit the current on high volts charge, and also to keep the volts high at a medium charge of 10 amps, and thus achieve a degree of constant current charging similar to three stage charging characteristic for AGM batteries. I learned this concept from a previous career, and an earlier Kea HiAce installation.
I am aware of the safety, fusible link removal, and battery implications of such a modification.
If you are unsure of these constraints, then don’t attempt this on your vehicle.
Photos give details of diode+fuse device, parts locations and numbers.
Hopefully of use to some,
Cheerio, mike
262815262816262814262817262818