DSSR50

user manual v0.1

1DSSR50

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Table of contents
Simplified diagram

3Specifications

4

1. DSSR50

53. Option for diversion

1316

Schematic
Links to HW files

218

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ADC1p

ADC1nPVn

PVp

Battery+ to ADC1 shunt connection
should be max 30cm and no fuse, switch
or breaker is allowed there.
Same as above is required for theconnection between the two shunts.

ADC1n / ADC1p
EXTIO3- / EXTIO3+
EXTIO4- / EXTIO4+
PVp / PVn

3

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Specification
DSSR50Max STC current
RC- remote signal
RC+ remote signal
Max PVA+ and PVB+ input voltage
Max PVA+ or PVB+ input
Max fuse or circuit breaker on Batt+Connectors max torqueBattery supply
Dimensions

4Solar PV charge controller when used with SBMS050A (ideal 60 cell PV panels for 24V battery, 30 to 36 cell panels for 12V)
5V to 30V (12kOhm internal so current 1 to 2.5mA depending on voltage)
Connected to PVA+ and PVB+ trough 10 kOhm so it can supply RC51V (so any 60 or 72 cell PV panel or half cell 120 / 144)
30A but total PVA + PVB should not exceed 50A with short peaks up to 60A
63A
216mm (6AWG) 4Nm(35in-lbf) // 6mm2(10AWG) 3Nm(25in-lbf)
8V to 32V
90 x 50 x 23 mmDSSR50

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1.1 DSSR50
Connecting the remote wires on DSSR50. Typical you will connect EXT IO4 but any EXT IOX can be used as long as is set as type 1 or type 6 forthe case where you are using dual PV array.
Up to 12 of this DSSR50 can be controlled by a single EXT IOX (set as type 1) and in case of dual PV array you can have max 12x DSSR50 (largearray type 6) + 6x DSSR50 (small array type 1).

EXT IO4+EXT IO4Battery negative

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1.2 DSSR50
Below there is a simplified diagram of how DSSR50 works.
Current can flow only from PVA+ / PVB+ to Battery+ and not the other way around and since that is an ideal diode there is almost no voltage
drop on it so no heat. The diode shown in parallel with the switch is the mosfet body diode.
The PVA+/PVB+ to Battery+ path is max 1.6mOhm Voltage drop across with 25A on PVA+ and PVB+ so 50A on Batt+ output will be 80mV anddrop in the form of heat will be 4W (measured with ambient temperature of +25C and the PV AB connector temperature was +65C)
Assuming a 27V battery voltage * 50A = 1350W and at this level 4W will be lost as heat thus transfer efficiency is 99.7%

PVB+
PV AB

Battery+PVA+

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1.4 DSSR50 Mechanical installation.
Size of the DSSR50 v04d is 90x50x23mm.
The metal bracket for installing the DSSR50 on 35mm DIN rail is not included. Just search for “SSR bracket 35mm DIN rail”
You will also need two M4 bolts with the ones in below photo being 30mm long.
Of course you do not need to use DIN rail and bracket and you can just use M4 or #8 screws to install on any flat surface.
Distance between the two mounting screws is 47.5mm

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3.1 Options for diversion heating.
For standard water tanks look for 36V usually 1200W rated heating element they have two 600W heating elements in parallel so idea for twoDSSR20 each with two large 60 cell PV panels.
Another option for open barrel water heater is just a calculated 18AWG wire calculated long enough to have 2Ohm.
A PV panel used as heater is also a very nice solution with the advantage that it always naturally works at max power point unlike restive heating.
I experimented with two 60 cell 240W rated panels bypassing a group of 20 cells so that 40 cells in series are used to heat from two 60 cell PV
panels exposed outside. Multiple diodes in series can also be used in the same way as PV cells are basically large diodes.

Above photos are of the two PV panels I use as heaters sinceNovember 2019 and they work great as expected.
You can see the yellow wire soldered in the PV panel connection
box to disable the middle 20 cells of the panels leaving the ideal
40 cells in series.
Max PV panel temperature here is 50C but the most I see wasabout +55C so very reasonable.
The lower 3 images are of my older experiment with a
200liter (55gallon) plastic barrel filed with water andheated to max 55C using three 18AWG loops of wires
tho the water was circulated trough a long loop heating
my concrete floor that before I installed heating
elements directly in to floor.

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3.2 Options for diversion cooling.
For cooling peltier elements can be used tho I did not had time to experiment with they should work tho it will involved quite a lot of DIY work as
there is nothing quite close to what is needed to do this properly.
The closest thing you will find is in the photo below a set of 6 peltier probably 12706 and you will connect all of them in series so you get 5 to 6Vabove them to work efficient then this will take about 2A meaning that you will need about 4 of this sets for one 60 cell PV panel and 8 of them fortwo 60 cell PV panels.
The small fan will be fairly loud and ineffective so you may want this outside and then have isolated pipes moving the cold liquid inside (I will use
some glycol mix just in case so it will not freeze).
Assuming a max of 500W from the two panels with a COP of 1 attainable you will have 500W of cooling power and on the hot side 1000W of heat
will need to be dissipated tho it will be loud and with this small high speed fans thus a custom solution may be better.

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HW files for DSSR20 and DEXT16 (soon to be available).
HW :12DSSR50

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