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Solar Converters EQ 24/48-10A, DC to DC Up/Down Converter

Solar Converters EQ 24/48-10A, DC to DC Up/Down Converter
Solar Converters EQ 24/48-10A, DC to DC Up/Down Converter
Item code Brand name Model number Amps
SOREQ-24/48-10 Solar Converters EQ 24/48-10 10A
NOTE: This unit should not be used as a step up or step down transformer to power a load directly. For step up applications please use the CV series models (constant voltage regulator units) and for step down applications please use the PPT series (step down transformer series). Using the EQ series in either of these applications can cause damage to the EQ and will void warranty.

Solar Converters Inc.
Battery Equalizer/DC Autotransformer
Model: EQ 24/48-10

Solar Converters Inc.
24/48 V @ 10 Amps
Model: EQ 24/48-10
Product similar to photo.

This unit is an up or down voltage converter whose output is proportional to its input. It functions both ways, producing 24 V @ 10 Amps from a 48 V input or can be connected backwards to produce 48 V @ 5 Amps from a 24 V input. When connected accross a 48 V battery, it functions as a battery equalizer, allowing loads to be taken off of the 24 V battery section of a 48 V battery pack without fear of damage to the battery pack due to voltage mismatch.


  • >95% efficiency, typically 96% over 20% load
  • Bi-directional power flow
  • Weatherproof, NEMA 4 enclosure

Electrical Specifications

  Input low side Input high side
Input Voltage (nominal battery) 24V 48V
Output Voltage 48. 24.0
Output Current 5.0 10.0
  Current limited Current limited
Ripple at load 30 mv rms 30 mv rms
Efficiency >95% >95%

Mechanical Specifications

  • Enclosure: Weatherproof, NEMA 4 enclosure
  • Dimensions: 4.5" X 2.5" X 2" nominal, resembling a junction box with feet
  • Weight: approx. 2 lbs. Temperature Range: -40 deg C to 60 deg C
  • It is recommended, as with all electronics, that the unit not be placed in direct sunshine.
  • Terminations: 6" flying leads
  • Red: High Input +
  • Black common Neg - for input and output voltage
  • White: Low Input +
  • Wire size: red, black, white: Power leads #12 AWG
  • Humidity: N/A weatherproof

Why have a solar converter?


Solar power is proving itself to be a viable means of generating power for the people. Y2K may or may not be the problem many people predict, but it has energized many people to seriously rethink and educate themselves about the alternative energy option.

A common problem with renewable energy systems is the cost effectiveness of the wiring relative to the non-renewable options. Solar power systems tend to have many components as well as energy storage at low voltages. To avoid voltage drops in the wire, and keep the system efficiency high, the system designer ends up wiring with much larger, heavier and more expensive wire than would normally be associated with the power the appropriate Electrical codes would dictate if it was a typical AC powered circuit. At all times the local Electrical codes must be adhered to.

This effect is greatly magnified if there is a great distance between the panels and the battery. This article is aimed at identifying and suggesting a possible solution to this problem.

Why this is interesting:

The effect of cable drop in a low voltage system can be devastating. A 30 amp system which could typically be wired with #10 AWG wire if small distances are involved needs to be greatly upsized in copper and expense in a typical renewable energy system. A typical electrical code wire size for 30 amps is # 10 AWG, such as you would find wired for a 120/208 V AC 30 amp service - typically your clothes dryer at home.

This is best illustrated by example.

Let us look at a 360 Watt - 12 V at 30 amp system with the panels 200 Feet away ( not uncommon) wired with # 10 AWG.

# 10 AWG cable is 1 milliohm resistance per foot (Wire Tables) 400 Feet (there and back ) of it is 0.4 ohm , The voltage drop in this cable is Voltage drop = CurrentI * Resistance = 30 * 0.4 = 12 V. - this would be 12 V in 12 V or 100 % power lost to the wire loss.

Clearly not a very viable system.

In reality the system would balance itself around the losses. At best the most you would get is 12 amps. i.e.: you paid all the cost of a 30 amp system and at best it will put out 12 A or only 40 % of what you paid for. This is a horrendous loss.

In order to get more reasonable power output, the only alternative is to increase the wire size, but this costs more money - the question is how much?

Let us assume we can tolerate a .5 V drop in the cable 4 % power loss to the wire.

The cable resistance must be .5 V loss / 30 amps = .016666 Ohms of resistance in the wire. There is 400 ft of this wire so the ohm per foot = .01666 Ohms / 400 Feet = .0000416 Ohms per foot

When we look this up in the wire tables, we find the nearest size available is 4/0 wire at .045 mohms per foot. This wire is approx. 1 in diameter compared to 0.1 in diameter for # 10 AWG.

After checking with the local electrical supply house , they quote $1,117.06 US for the 400 Ft of number 4/0 in suitable PVC Conduit vrs the originally thought of $214.91 US for # 10 AWG. in its suitable PVC conduit -- AND you still need to buy the controller anyway. This is $902 US more expensive just for the wire. I think anyone would rather spend the money on more power.

There is another way

For long distance runs, why not transfer the power at a higher voltage and then convert to 12 V at the battery with a voltage converting Maximum Power Point Tracking controller (MPPT)? We can wire the same panels for 48 V producing the same power but now at 48 V. The same power (360 W) carried at 48 V nominal (actually 65V @ maximum power point) is 5.5 A amps in the same # 10 AWG wire.

The voltage drop in the cable if now wired with # 10 AWG is V = Current * Resistance = 5.5 X .4 = 2.2V.

Thus panels operating at their maximum power point (65 V) will look like 65 - 2.2 = 62.8 V at the receiving end. This would be a viable system as it has the same lower power loss to the wire, actually 3.3 % instead of 4 %. Same power, but lower cost and higher efficiency of power transfer.

As power is Voltage * Current , and if the efficiency is very high, say 95 % typical of Solar Converters Inc. Controllers, what will be the current at 12V ? After some quick math (I will be happy to supply the details if anyone is interested)

There is 328.2 watts delivered to the 12 V battery or 27.4 A @ 12 V

In this case, your 30 amp investment results in 27.4 amps of current, better than the at best 12.5 amps if wired with # 10 AWG or the $1,117.06 US pricetag if wired with 4/0 AWGand still get at best the same current (Actually 15 % less if not MPPT or its equivalent in upsizing the panels) , not to mention the cost of junction boxes, conduit etc. as well as just plain hassle in dealing with 4/0 AWG - and you still need to buy a controller anyway.


There are a large number of panel manufacturers who already make odd voltage panels that already produce high voltages. For example the excellent Cd-Te panels, Amorphous Silicon, and many notable other technologies made by several different manufacturers. These panels are extremely cost effective,

with prices sometimes 50% lower than normal silicon panels. If you use the high voltage anyway, why not from one of these inexpensive panels? Who would not want to save substantial costs in both the wiring and the raw panel and get more power to boot? Note these cost savings are available even if you have a short distance to wire.


The low voltage of renewable energy carries some cost penalties in terms of wiring over long distances. There is a potential triple saving using higher voltage power generation. Get all the power of the panels with a voltage converting MPPT controller, 2) on the panels themselves , and 3) again on the HV power transmission over a long distance. It literally does not get better than this. The savings are great and could easily save a couple thousand if not more in a typical 12 V @ 30 amp installation.

Special Shipping Note:
All Solar Converter Products are behind in production. These items are usually shipped directly from the manufacturer in Canada. They cannot be shipped by any expedited methods such as UPS Blue or Red. They will generally be shipped via Canadian Express Mail which avoids import brokerage fees of $50-$60. Lead time on these products may be up to 4-6 weeks depending on their production. This is true of all Solar Converters products with the exception of the battery desulphator (item code SORBD-2) that we stock in our warehouse. If you want Solar Converters products to be shipped by normal Canadian Post, but would prefer to have the rest of your order to be shipped by a faster method, please write this information in your order's notes during checkout.

Solar Converters Inc.

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