how to not destroy an alternator when charging LI batteries.
Hi all, https://youtu.be/jgoIocPgOug The video offers solutions.
Forum Discussion
Anyone that charges batteries in a cruising sailboat needs to invest in better ventilation. I've been aboard dozens and dozens of sloops schooners and ketches down here that raise temperatures to above 100F in salons, and galleys when charging batteries.
MOST sailboat engines feature a 2 to 1 or higher pulley to pulley ratio between the engine and alternator. Few engines run optimally at dead idle. Speed is carefully adjusted to hit the "sweet spot" which eliminates jungle drums roughness, noise and vibration.
Floor and rug drying 120vac fans can inject enough air into an engine compartment to lower air temperature as much as fifty degrees. Not theoretically. I used to haul mine as part of my tool load.
The main problem with new fashioned alternators is they have internal fans. Adapt a proper external fan and suddenly temperatures drop dramatically.
Remote rectifier bridges not only remove junction and heat sink heat but open up the slip ring end of the alternator to cooling air.
So the test with the Bosch alternator included playing with a stacked deck. The motor they used was a 1720 RPM with very little pulley advantage. See what happens at 3,000 alternator rotor RPM. The new class of rectified WYE stators allows extremely high amperage at extremely low RPM. FAR FAR FAR slower than what an automotive application can operate at. 3.5 to 1 pulley ratio is very common.
But don't get me wrong. Heat is a terrible enemy of any alternator. My Niehoff and my 50SI 24 volt units are fed cooler air. And both have anodized copper fin stacks for external rectification.
Also..........
A single group 31 battery can accept over 100 amps. A series parallel stack of 4 cheap golf car batteries will eat 120+ amps for longer than I care to state.
So the LITHIUM hook in the BALMAR ad is misleading. The entire concept is invalid.
As a designer, meaning rotor, stator and rectifier concepts makes me eligible to judge this stuff.
If a cruising sailboat alternator has to have its charging potential curtailed to prevent burning up, then it's suffering from a FATAL FLAW. Read garbage, quackery and incompetent system design.
MOST sailboat engines feature a 2 to 1 or higher pulley to pulley ratio between the engine and alternator. Few engines run optimally at dead idle. Speed is carefully adjusted to hit the "sweet spot" which eliminates jungle drums roughness, noise and vibration.
Floor and rug drying 120vac fans can inject enough air into an engine compartment to lower air temperature as much as fifty degrees. Not theoretically. I used to haul mine as part of my tool load.
The main problem with new fashioned alternators is they have internal fans. Adapt a proper external fan and suddenly temperatures drop dramatically.
Remote rectifier bridges not only remove junction and heat sink heat but open up the slip ring end of the alternator to cooling air.
So the test with the Bosch alternator included playing with a stacked deck. The motor they used was a 1720 RPM with very little pulley advantage. See what happens at 3,000 alternator rotor RPM. The new class of rectified WYE stators allows extremely high amperage at extremely low RPM. FAR FAR FAR slower than what an automotive application can operate at. 3.5 to 1 pulley ratio is very common.
But don't get me wrong. Heat is a terrible enemy of any alternator. My Niehoff and my 50SI 24 volt units are fed cooler air. And both have anodized copper fin stacks for external rectification.
Also..........
A single group 31 battery can accept over 100 amps. A series parallel stack of 4 cheap golf car batteries will eat 120+ amps for longer than I care to state.
So the LITHIUM hook in the BALMAR ad is misleading. The entire concept is invalid.
As a designer, meaning rotor, stator and rectifier concepts makes me eligible to judge this stuff.
If a cruising sailboat alternator has to have its charging potential curtailed to prevent burning up, then it's suffering from a FATAL FLAW. Read garbage, quackery and incompetent system design.
