Implementation of dssr50 to dmppt450

[Josh Peterson]

I’m setting up a new system how can I use a standard electric water heater and 36 v heating element with the dmppt450 can I just use the temp sensors from the dmppt? Or should I add a few dssr 50?

[Josh Peterson]

I also have a dmppt 450 and a sbms0 and a sbms120 that I need to be fixed are you able to do that? 

[Dacian Todea (electrodacus)]

Josh,

DMPPT450 seems a bit of an overkill of a single or even two 36V heating elements.  You can use DSSR50 as diversion to heating and connect the original thermostat of the water heater as ON/OFF disconnect by connecting that in series with the low current signal that enables the DSSR50. 

Unfortunately is difficult to ship to US due to tariff requirements.  If I want to ship with CanadaPost (delivered by USPS) I need to pay tariffs in advance and even if is a gift or a repair I still need to provide payment information to a US company called Zonos and they have a phone app only (I never make any payments trough phone as I do not thrust Android security not to mention Zonos security).

I shipped back a repaired SBMS0 recently with UPS where if there is a tariff needed to be paid will be paid by the receiver (as it will be normal) but I do not think it arrived so not sure how that will work out. Is also a bit inconvenient for me to ship with UPS as I need to drive in the city (downtown) and that is about 80km (50 miles) from my location one way about two hours of driving both ways.

I'm waiting to see how that works out then maybe I can offer that shipping option to US for now. Maybe things will improve in the future.

[Josh Peterson]

I will be using 4 1200 watt elements in two water heaters and keeping just 24 panels hooked up on the dmppt 450, will that work? I also have 8 dssr20 with the Rex 16 I could implement

[Dacian Todea (electrodacus)]

Yes 4x 1200W heating elements and 24 panels will work on the DMPPT450.  Just connect a 10K resistor to simulate temperature sensor always showing the same temperature on ET1 and ET2 and connect the thermostat of each of the two corresponding water heater in series with this 10K resistor.

So the ET1 controls TLD2, TLD3 and TLD5 so say connect the first water heater with one heating element to TLD2 and the second heating element to TLD3 then connect the thermostat of that water heater to ET1 in series with a 10kohm resistor. That way as long as water temperature is below the thermostat set-point the water heaters will be enabled and when thermostat opens the circuit the DMPT450 will turn OFF anything connected to TLD2, TLD3 and TLD5.

Same thing for ET2 witch controls TLD1, TLD4 and TLD6 connected to your second water heater.

The DMPPT450 will just work independently without the need for SBMS120 assuming you only need this panels for heating and not need them for battery charging.

Else if you also need battery charging you can use the SBMS0 with the DEXT16 and DSSR20's

[Dacian Todea (electrodacus)]

You can also connect NTC thermistors 10K B3950 instead of 10kOhm resistors. The DMPPT450 without the SBMS120 has a fixed +60C (140F) temperature set for both ET1 and ET2 but not sure where you can glue those thermistors so it can reliably measure water temperature and water will be stratified so will be hotter at the top of the tank. Also not sure if +60C (140F) is what you want for water temperature and that can only be changed as long as it communicates with the SBMS120.