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ecomodded 03-29-18 05:50 PM

eSmart3 MPPT max 2000w 12 to 48v output
A tip for our readers wanting a good controller for a sub 2000 watt system. After research via YouTube I thought it wise to buy the eSmart3 40A version of the controller ( $175 delivered ) to future proof the system somewhat.

Photo is from the seller on ebay I purchased from

Advanced MPPT control algorithm, MPPT efficiency ≥99.5%,Machine conversion efficiency up to 98%

DC 12V/24V/36V/48V automatic recognition

Maximum PV input voltage up to DC130V (20A 30A 40A );150V (50A 60A)

3-Stage charge: (constant current, constant voltage, floating charge) to extend the battery life

Discharge mode: ON/OFF mode PV voltage control mode.

4 kinds of batteries (Sealed lead acid,Vented, Gel, NiCd). Other kinds can be defined by user.

CE,ROHS,FCC certifications 2 years warranty


The system

Currently in process of piecing together a small PV system using 100w semi flex panels.

So far just 2x 100w panels and this charge controller so Im still a ways off :)

For now thinking of getting about 150AH in 12v batteries to get the system up and running , then ad panels and batteries as they are acquired.
Suggestions correction tips and advice needed to avoid making dangerous or expensive errors.

So far i have these few things to consider for sizing a battery bank to a array [/B]

1000W of solar panels gives about 70A of charge current into 12V. Lead acid batteries cannot be fast charged

You want the charge current to be 1/10th of the Ah rating of the battery.
Would need a 700Ah battery to handle the current. 20 of the 35Ah batteries.

If the battery is smaller you are wasting the charge current that is available from the solar panels.

You should not move more than 50% of the battery capacity each day.

700Ah in batteries = 350Ah per day in and out , 350Ah * 12V = 4200Wh per day


Using that formula converted from 1000w panels to just 200w in panels , 700AH minus 80% = 140AH averaged out to 150AH battery

The semi flex panels are made up from Sunpower back contact cells

Things I need

Panel disconnect switch
Fuses possibly a breaker switch
Power line from panels to controller / batteries.

Things I don't know I need :)

_________ __________ _________

ecomodded 03-30-18 12:56 PM

When sizing / pricing DC wire today The math indicates at 3% loss 8 Gauge at 33 feet is suitable for 30A @ 48 volts / 1440w. I foresee having 800w to 1200 watts eventually.

To get the ball rolling ordered 100 feet of Marine tinned 8 gauge wire from


Manufactured from individual copper strands tinned to perform in the harshest marine environment.

Ultra-Flexible type 3 stranding resists fatigue from vibration and provides added corrosion protection

Exceeds all UL 1426, us coast guard charter boat (CFR title 46) and ABYC standards

The green was reduced down in price to $87 + tax for 100' so green it will be ( I will color code it ).

One step closer next is disconnects fuses and 2 more 100w panels from there its battery storage. Im thinking of using a old set of batteries salvaged from a golf courses and people who have upgraded their PV system.

*Finding cheap usable batteries is going make this cost effective* Im about $500 deep now and need to spend say $300 more on 2 panels and disconnects etc , then it will be ready for batteries :)

The wire calculator I used >

ecomodded 03-30-18 05:02 PM

AWG vs Gauge

As it turns out 8-gauge and 8 AWG are different diameters. luckily I ended up with thicker 8 gauge.
The differences in diameter are not linear , in this case 8 gauge is nearly as thick as 6 AWG

8 AWG = 3.26 mm
8-gauge = 4.06 mm

6 AWG = 4.11 mm
6-gauge = 4.88

Converted to max current 30' @ 3% loss

8-gauge = 43A
8 AWG = 33A = 25% less current

The wire calculator in the previous post was for solid core wire this time using a marine wire calculator and posted it below.

Using 8 AWG ( not the thicker 8 gauge )

Max current 30' 48v 3% loss = 38A / 1824w

Max distance with 8-gauge 50' length 48v @ 22A 3% loss = 1056w

Technically I could increase the max current / wattage by 25% of those 8 AWG numbers but I won't as I don't need the current but do like the reduced voltage loss the thicker wire provides.

Tinned Copper

Not only does tinning boost copper's properties. Tinned wire lasts longer in operating temperatures of over 100 degrees Celsius! It is that simple.
A 12 gauge tinned copper wire will last up to 10 times long than a comparable 12 gauge bare wire.

Tinned copper makes soldering connections easier. Tin being one of the primary components of solder.
The tinning itself boosts coppers conductivity and makes it more resistant to breakage.

ecomodded 04-01-18 02:12 PM

Im suspicious if the the wire is 8 AWG or 8 gauge it will work either way I'm doubting the ad worded it correctly. Anyhow you can't have a charge controller without batteries , came across the below batteries and may go for a set or 4 720AH for $500. They are the first used battery set I found so far. Will ask Golf courses maintenance workers about the battery situation , might place a ad as well.

Arriving mid April.
C&D Technologies
180AH maintenance free batteries from a 2009 backup power supply. New $500 ea.

Standby use only. Fully recharged, resting @ 12.75 - 12.80 volts ea.

$150.00 ea.
$125.00 ea. 6 or more
3 month money back warranty
22" x 5" x 12"high
131 lbs.

ecomodded 04-01-18 08:56 PM

Panel platform

Rather then mount panels on the ground plan is to mount them on a 2007 17 ft boat trailer set to spin into position via timer and reversing motor.

The trailer will fit eight 100w panels inside the wheel wheels using 10 feet of its length , although I like the sounds of ten panels so will likely have ten in the end.

found a cost effective 1000w inverter on ebay for $167 with free shipping from china

DC voltage range 40 - 61 volt

Over voltage protection

120 volt

92% efficiency

The price of the 93% to 96% models is from 3 to 10x higher then the above inverter


Semi flex panel deal 100w back contact semi flex 18v $130 ca if you search well on ebay.$_59.JPG

creeky 04-16-18 06:26 PM

I like the esmart3. Looks like a good mppt controller. I have ordered some for testing myself. So will get back to you on that. Certainly the price is right. And you can get a wifi module for it.

But can I ask a few questions?

You overpay by 30% on your solar panels. And you skimp on the solar controller and inverter.


You can buy solid, dependable, reliable solar panels for .70-.80/w almost anywhere now. Panels with a 25 year warranty.

And yet you pay 1.15/w for panels with an interesting history of not lasting that long. See the reviews on ebay and amzn.

Your inverter. Well. There are lots of cheap chinese inverters. Some of them are really good. Quick way to tell is to look at idle draw. The regular idle draw. Not the "standby" idle draw.

According to the mfct website No Load Current Draw < 0.8A. For 48v that would be less than 38w. It can't be that high. I would expect something around 9 or 10. The .8 must be for the 12v. In which case it would be around 10w. Bog standard these days really.

THD. is < 3%. That's pretty good.

I would take the money I saved on the solar panels and get better batteries. But you've probably read my lithium post. So ...

Good luck.

ecomodded 05-11-18 02:32 AM

Hey creeky , I choose the more expensive semi flex panels so can bring them on camp trips for a portable power source to charge my ebike.I thought of using the panels at home as well after I got them so picked up a better mppt controller for home use , have the mini mpt-7210A charge controller for travel /camping.

creeky 05-15-18 08:11 AM

Hopefully the panels last. I'm seeing terrible reviews. Maybe you could use better panels at home and do the semi flex for camping only?

I'll probably try some too. It would be nice for camping. Lugging a 40lber around is a pain.

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