Newbie trying to set up Megawatt for charging

Are you checking battery voltage across the series link or across the posts with the charger and loads on them?

Well I screwed something up or I am missing something. I got the **** thing hooked up, but when I check the voltage with a multi meter on the pos. and neg of the Megawatt I get 2 volts? Seems weird. WIth the the Megawatt on but not hooked up to the batteries, it shows 14.8 volts on my multimeter. I am confused about why I am getting two very different readings. My batteries are 6 volts in series.

When I check the voltage of the batteries, across the positive terminal on one battery and negative terminal on the other battery I get 0.02 volts, but when I check the battery individually out of the camper they show 6.2 volts. ?? I know the Megawatt is working because the fan comes on, and over time I can feel the cables from the Megawatt to the batteries get warm, also my Trimetric inside the camper shows the voltage rising, it started out dead at 10 volts and quickly when to 14.0 volts over an hour or so.

My Megawatt based Hyperwatt 400 has run one week solid (8 days) putting out 56 amps day and night. Extreme modification, two larger fans, caps and rectifiers and larger chokes. Fully recharged a 14 L-16 bank solar home (48-volt) 6 cells at a time. Owner was waiting for an Outback inverter.

https://www.ebay.com/itm/2pcs-Panasonic-HA-680uF-200v-105c-Radial-Electrolytic-Capacitor-25mm-X-40mm/201539338212?hash=item2eecae3fe4:g:Y~cAAOSwh-1W4uMB:rk:3:pf:0

MAJOR Capacitor upgrade


https://www.ebay.com/itm/1PCS-SCHOTTKY-RECTIFIER-DIODE-IR-VISHAY-TO-247-60CPQ150-60CPQ150PBF/362255975000?hash=item5458238258:g:KgsAAOSw~CFY5zFW:rk:1:pf:0

Direct interchange 300% ampere over capacity 150% voltage increase schottky rectifier upgrade.


The two upgrades plus fan ventilation above makes the Megawatt more bulletproof than any converter, inverter, perverter on the market as far as finals power is concerned.

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.

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.

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.

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.

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.

Kudos excellent help!!!