DIY Alternator (permanent magnetic)

[Jack-Lee]

Hi,

my english still bad, but I try it.

After the battery of my car broke down, i buy a new one.
A LiFePO4 12V/8Ah battery
Safes 13kg! and incrasses the load efficienty from 60% to 90%.

As a result of this, i would reconstruct the alternator.
The old one weighs over 6kg and has an efficienty under 50%
The new one are an modified Brushless Motor with around 900Watts.(about 90% efficenty at generator)

An other coil winding and a "Stern Dreieck Schaltung" i would get a output voltage from 15-55V by an engine speed of 1000-5500U/min

The DIY charge controller should do this:
-controll the chargecurrent about 8Ampere but set the load current on it.
I explain: The controller load the battery with 8A. then i switch the lights on -> they need about 15A. So the controller current raise to 23A. I prevent an overcharge and i get enought Amperes for all consumers.
-overvoltprotection : Output Voltage: 14,5V
-overheatprotection: controller and generator
-undervoltprotection: prevent depth discharge
-autoswitch the "Stern/Dreieck" when the outputvoltage from the generator gains over 55V.
-display load/consumer current/power and batteryvoltage

The generator connect with the cam shaft over a cuppling (maedler.de/Article/60272400). Light and with a 100% efficenty.

I upload pics later

[Cobb]

Ive wondered about doing this. I see PM alternators for wind generators where a alternator was convereted to use magnets vs an electric magnet.

[oil pan 4]

I use FeLiPO4 batteries in my diesel and replaced over 120lb worth of batteries and battery trays with about 20lb of lithium and assorted parts and the standard alternator has worked perfectly.

[Jack-Lee]

Hi,
the new alternator is not ready jet, but i work on it.
The electronic is much simplier as i think.
When the Battery (LiFePo4 12V/8Ah) is full and the Voltage raise over 14,4V, the alternator disconnect from the recifier and runs "free".
Only the "Stern-Dreieck-Schaltung" get it in.

On the Photo you could see the new alternator (in the middle), the old Beltdrive (left) and the cambelt gear-wheel.

The alternator jet get drive with a small toothed belt which runs on plastic gear wheels.
The complete Unit wight under 1kg.

Patrick

[Jack-Lee]

Hi,
i buy a normal Alternator today.. My BL Alternator gets to expensive. I need a 50A Solar-Chargecontroller and a Variomatic -> over 400€ :/
The Alternator is now a Bosch EL 14 40/110A.
But this thing gets modified for a max. efficenty (Schottky-Diodes, low rpm,)

[Jack-Lee]

Hello,
today i messured 3 standard alternators and my DIY alternator.
Driven by my small lathe, i could test as far as 700W Input.

Im happy with my work and suprised that 20 years of technical development nothing change in effictiviness... ALternator 1: BJ:1991, Alternator 2: BJ: 1996, ALternator 3: BJ 2014

Here my results

[elhigh]

Stern Dreieck Schaltung = Star-Delta switch for changing the alternator's voltage output - neat detail.
Verslustleistung = power dissipation (power required to drive the alternator)
Wirkungsgrad = efficiency
Ausgangleistung = power output