Mex’s remote rectifier charger/genset – my version

[Bend]

Here is the history:

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/26303825/srt/pa/pging/1/page/1

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/28015670.cfm

And, here is my version after a year of planning and coaching from Mex:





Pic is 180 degrees from above.


The first test produced some screwy numbers. After some contemplation, evaluation, trouble shooting and laziness, I removed the automotive ignition capacitor due to a connectivity issue and checked all sub-circuits. Here are the results of yesterday’s test on a marine semi-deep cycle batt at ~80% SOC:

Individual stator to ground voltage at connector in engine compartment: 17.4v ac
Individual stator to ground voltage at the end of the 15 ft, 8ga, 3 wire extension cord to box: 17.1v ac
DC volts after conditioning at the box at engine idle (600 rpm): 14.3
DC volts after conditioning at box at engine 2K rpm: 14.3
Amps at batt within 3 min after start of charging: 26
Amps at batt after 30 min of charging: 21

Other observations/comments:
The heat sink never got above “almost” warm.
Confirmed batt amp absorption amount with a separate plug-in charger, set at 40 amps available, immediately after above test.

Seems like it is working! I have nothing to test max load available but will try soon with a lower SOC batt. Further results to follow.

[MEXICOWANDERER]

The object of using a three phase rectifier placed alongside far away batteries is that such a setup allows the exact same amperage potential as if a user used 3/0 wiring from alternator to batteries.

Who the hell in their right mind wants to recharge (read the prefix RE- again) a bank of batteries with a measly thirty amps? A 3-phase rectifier would allow for example a hairpin 270 amp alternator to charge six or eight 3-cell batteries at 200+ amps. Call it 6-1/2 times as fast during the bulk stage.

Ooooooo but WAIT that's not all (infomercial)!

Relieving the 270 amp alternators internal rectifiers of 90+% of their amperage affords dramatic cooling of the entire alternator system, including a vulnerable voltage regulator.

When I start Quicksilver, the Niehoff is pumping 400 amps. Do I "trust" Niehoff's rectifier bridge? Hahahahahahahahahahahaha. No. That $5,000 alternator is going to be babied.

Do I have massive 4/0 cables running beneath? No. I have 3 four gauge wires.

Oooooo how about the size of the external rectifier heat sink? It's 3X the size of the Niehoff, well away from the Cummins.

For crying out loud, instead of guesswork, refer to ANY data sheet for ANY diode or rectifier and note thermal DERATING of the device. Do you suppose alternator button, dish, or press-in rectifiers are any different? One last step. Find the rating for the "diodes" (rectifiers) in YOUR alternator. Only in your freakin' dreams are those rectifiers going to stay below 220F when the alternator is working hard. Muse the point that the alternator is sucking heated radiator air PLUS radiated heat from the engine THEN adding a gross vf which translates to watts of heat THEN WAIT THERE'S MORE! The poor stator windings run at 300+F degrees - which is well beyond tolerance level for wire insulation.

Now compare this to someone at a REMOTE campsite (save your noise complaints) starting an engine cold WITH HOOD UP and recharging batteries more than FIVE TIMES AS FAST as with the finest 50 amp converter the world has ever seen. 180 minutes versus 36 minutes. Is I getting through to you? The alternator is yawning, rectifiers 150F cooler. Regulator more than 40F cooler. The stator will heat but with hood up, it's temp will be much cooler.

I don't camp in an RV refugee center. So I yanked the genset, and sold it. I it's too hot I climb mountains, laughing about spaced saved, missing weight, depreciating value of equipment, noise, and even fuel. how much generator and chargers ya think are gonna cost to develop 200+ amps of charge? You sure as hell ain't gonna lift it in-and-out.

This scenario is for SOME RV'ers and certainly not for a majority. It would be great for someone who has enough solar power to be able to shut down the engine when amperage decreases to say 30 amps. Obviously this for high usage camping. Some folks can camp using thirty amp hours per day.

Spending four grand for generators and "smart?" chargers for use at a remote campsite is not my bag. To add insult to injury, all that krap has to run for hours on end and in the end fail to complete it's mission. Oooooo then we have to change oil and filters and maintain a frickin' zoo of controls and worry about "They only want three hundred dollars for a new control board".

An optimist says a cup is half full
A pessimist claims a cup is half empty
An engineer proves the cup is twice as big as it needs to be

[pnichols]

Or you can save your time/energy and just go with a ready-made charger from the marine world that will charge a 12V battery from a 12V battery - just hook the battery in the vehicle to the battery(ies) in the RV with one of these in between:

https://www.amazon.com/Battery-Charger-12V-24V-Current-Limiting/dp/B008BL6MO8

[gotsmart]

Bend wrote:
Major parts:

Power posts-

Schottky Diode-

Fans-

Breaker-

Rectifier-

Capacitor, large-

Capacitor, small-

Heatsink-

Plus: ½ in thick poly cutting board, 6x6x4 electrical box, 8ga & 4ga wire, Anderson connectors

[Bend]

tvman44 wrote:
Would love to see a schematic of your set up to see exactly what is going on.

Please forgive the layman's symbology:



"Why only 40 amps?"

I wanted to ensure the batt was self-regulating amps near the same rate the box vs SOC was.

[time2roll]

Got to love Amazon!

Great work. Why only 40 amps?

[Bend]

Major parts:

Power posts-
https://www.amazon.com/gp/product/B000XBEPFC/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Volt meter-
https://www.amazon.com/gp/product/B009XS1ZY0/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Schottky Diode-
https://www.amazon.com/gp/product/B0056RHMCG/ref=oh_aui_detailpage_o07_s01?ie=UTF8&psc=1

Fans-
https://www.amazon.com/gp/product/B00N1Y3R2K/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1

Breaker-
https://www.amazon.com/gp/product/B001PT7XBE/ref=oh_aui_detailpage_o02_s01?ie=UTF8&psc=1

Rectifier-
https://www.amazon.com/gp/product/B00SKJ02MY/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

Capacitor, large-
https://www.amazon.com/gp/product/B00HKJW3IQ/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

Capacitor, small-
https://www.amazon.com/gp/product/B0087ZAY1A/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

Heatsink-
https://www.amazon.com/gp/product/B00OYF9XU0/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

Plus: ½ in thick poly cutting board, 6x6x4 electrical box, 8ga & 4ga wire, Anderson connectors

[tvman44]

Would love to see a schematic of your set up to see exactly what is going on.