Newbie trying to set up Megawatt for charging

[DieselBurps]

Trying to figure out what all I need to set up a Megawatt for charging 2 120 amp AGM batteries.

I was looking at the s-400 Megawatt,cuting one end off some cheap 4 gauge jumper cables from amazon.

What else do I need to start charging? Digital volt meter hooked up to Megawatt?

[MEXICOWANDERER]

THREE issues with Megawatt and Meanwell

Do not allow it to sit flat on it's bottom air intake gets blocked.

Use a pair of dykes and cut aluminum edge of fan shroud. Remove.

GOOP a wire fan shroud atop the housing. MUCH HIGHER FAN AIRFLOW. Critical mod.

[2112]

When I was interested in the Megawatt I contacted the designer via the email address on their website. He answered all my questions. He's a real nice guy, even provided me the schematic. I wanted to replace the voltage adjust pot with a digital pot but never followed through with it. I realized it wasn't necessary after I used it a few times.

I mentioned his product gained a following as a battery charger in the RV world. Now I see he updated his website to include this alternative product function. I'm pleased with mine as a 30A set point charger. I bulk and start the absorb with it and change over to a DROK charger once it gets to 3A at 13.6V to finish the absorb and then float. I have a 3 DROK chargers to continuous float my batteries at 13.2V. I power them with an old 19V laptop charger.

[jharrell]

2112 wrote:
My Megawatt S-350-12 goes into constant current mode (CC) at about 32A and the voltage folds back accordingly. No hiccup. I've operated it in this mode for maybe 10 minutes at the most so I do not know how it would hold up long term. I can't speak for the other models

Good to know, do they mention that anywhere in their manual? Their website is pretty bad, hard to believe they don't even link to their manuals for each model.

[2112]

My Megawatt S-350-12 goes into constant current mode (CC) at about 32A and the voltage folds back accordingly. No hiccup. I've operated it in this mode for maybe 10 minutes at the most so I do not know how it would hold up long term. I can't speak for the other models.

Side discussion maybe of interest: I'll put the DROK 1500W Boost Converter to the test this afternoon so I may put the Megawatt in CC at that time. I'm currently slow discharging one of my 29's for the load. I'll have the Megawatt output set to 13.4V and the boost converter output at 14.4V, common ground. This little converter will charge the battery or die trying, all currents adjusted wide open. The boost converter will shut off the output if the Megawatt output drops below 10V. It will start hiccupping at that point.

[jharrell]

Does anyone know what kind of overload protection the Megawatt has? They have no information on their website and the only thing I could find was a review that had a scan of their paper instructions that said hiccup overload protection which would not be very suitable for battery charging.

You really want constant current overload protection to charge a battery. Some Meanwells have it while others don't, a 3 stage battery charger well that's the first stage.

[MEXICOWANDERER]

Kudos excellent help!!!

[2112]

DieselBurps wrote:
I have the first voltage amp meter that is linked, purchased from amazon. Can anyone tell me where to hook up the yellow wire? I know red + and black - go to their respective spots on the megawatt but am unclear what to do with the Yellow wire?

If you are referring to


The yellow wire ties to the shunt negative.

If you are referring to


The yellow wire connects to battery positive

[DieselBurps]

I have the S-350-12. They have 3 terminals per side. I used 6, 3' 10AWG stranded. I crimped 12/10awg fork terminals on each wire for the power supply end and bundled the 3 and crimped a 8awg eyelet on the battery end. Make sure the terminals for the power supply end will fit the power supply terminal strip.

To measure current I bought This. If you don't have a voltmeter you may be better off with This

I adjust my power supply output to 14.5V before I connect it to the battery to allow for line loss. When it gets down to 1A my battery voltage will be ~14.4V.

A timer is a good idea, set it and forget it

I have the first voltage amp meter that is linked, purchased from amazon. Can anyone tell me where to hook up the yellow wire? I know red + and black - go to their respective spots on the megawatt but am unclear what to do with the Yellow wire?

[MEXICOWANDERER]

Reality is mean

No amount of righteous indignation or political finger pointing stands a chance against it.

I in my youthful wisdom and arrogance signed up for UDT tryouts at boot camp.

If I lasted 60 seconds it would be a miracle. One person lined up behind partner. Jump on piggyback. Wade into estuary. Knee deep muck. Fall. Get plastered with evil smelling muck. Put tail between legs. Retreat back to company barracks. Stand and scrub dungarees at concrete clothes washing slab while buck naked. Supposed to build character.

[pnichols]

MEXICOWANDERER wrote:
Worst case scenario manipulation. Virtually worthless

I wonder what the Navy Seals would think of that phrase ... especially the virtually worthless part?

Don't they quote something like "Prepare For the Worst and Hope For the Best"?

It's been my observation that many RV'ers (none who participate in these forums :B ) "Prepare For The Best and Assume That's What Will Happen".

[MEXICOWANDERER]

Or....

Worst case scenario manipulation. Virtually worthless

"What do I do to prevent an asteroid coming through the living room drapes?"

"Help! I've Fallen And Can't Get Up!"

Ring up room service and have them come and set the thermostat.

[GordonThree]

If it's one thing this forum excells at, it's hand wringing.

[landyacht318]

I've been using the meanwell rsp-500-15 for 4+ years now.

The ability to hold absorption voltage as long as is required to reach full charge, is responsibe for the exceptional service I am getting from my current AGM battery.

Fear of overcharging is a bit silly, its kind of like saying:

I hope the next time I drive, that i can remember I am supposed to stop at a stop sign and it would be better if my car braked automatically at red lights and stop signs so I can concentrate on updating my instagram account.

[MEXICOWANDERER]

https://www.ebay.com/itm/Intermatic-FD6HH-6-Hour-Countdown-Decorator-Decora-Style-Timer-Switch-SPST-...

This one even has a HOLD which should only be used when the power supply is set on long term voltage maintenance better known as FLOAT.

It is installed between the wall socket plug and the power supply.

This is a LIFETIME switch. When your children are in a rest home, this switch will still work fine. It is not a chew and spit purchase. It needs a PLASTIC duplex box and two ROMEX wire strain relief clamps from any hardware store.

And ALL of my seven Megawatts have an actual measured and remeasured ADJSUTABLE voltage range between 10.07 volts to 15.47 volts. Is there some Kryptonite battery out there that this will not agree with?

Meanwells are different. choose the dash fifteen model like the 1500 watt model that is the basis of the charger I am building. Because of the micro-soldering needed with the HIROSE connectors I DO NOT recommend this model for folks wishing knob adjustable remote voltage control.

[MEXICOWANDERER]

From a Starbucks in Chula Vista. Spent the afternoon and night being poked and prodded. Temperament of a snapping turtle.

OP I sent you a PM from the nurse's station yesterday. Whoa talk about a nuclear RN when she found out.

Anyway forgetting about a Megawatt charging, boiling pot on the stove or a child in a hot car is unforgivable. Period. I'm in my mid-seventies. Do some of you need a keeper following you around all day? Yeah I'm crabby but what I write is life, like it or not. It's not about the time, it's not about an aged memory it's about laziness or sloppiness in failing to institute help in remembering that something important is happening and that failure is not an option.

Is is too difficult to set a watch? Set an alarm clock? Put the device on a timer?

The skull and crossbones grade warnings I see here are just silly. YES you can hurt batteries. Yes the melted pot can burn down your house. Our manufacturer gave us a mass of gray matter between the ears. Instead of issuing warnings, issue recommendations for EASY TO USE TIMERS.

Now that I have punctured some hides, I'll give thanks that I have a friend who will drive me to my PO box and retrieve the three INTERMATIC 6 hour wind-up spring timers amongst the baggage parcels waiting for me.

Jeezo! Hospitals kill the innocent. Torture. The room lights come on 6 times between ten PM and six AM.