The installation as follows (on an RV)
2 x DAH 460W Panel Full Screen 62.4vVoc 9.31AIsc
EasySolar-II 24/3000/70-32 MPPT 250/70 GX
SmartShunt 300A
Victron BatteryProtect 12v24v - 65A
Orion-Tr Smart 24/24-17A 400W NonIso DC-DC charger
Victron Battery Balancer - BBA000100100
The question:
I know I can program my 2nd AC out to activate at a given parameter, such as SOC 95%, Charge condition float etc.
Given that the two panel limit means I can only generate max (in ideal lab conditions!) 860w/16.6amps what steps can I take to prevent/reduce the hwc drawing power from the battery bank (2 x lead carbon 12v 130ah in series) so that I’m only using the excess solar to heat the HWC (25 litre capacity) and NOT drawing power from the batteries? One thought is to replace the 1kw element with a smaller say 500w element but these seem hard to source.
I am intentionally stepping away from a gas/diesel hot water heater so don’t suggest those as alternative solutions!
Many thanks for any assistance the wisdom is able to provide.
With such a small pv array and small battery, you may struggle to achieve what you want.
Easiest solution is simply use ac2 out with assistant to switch it on at say 95% and off at 85%, leaving batterys at at fairly high state of charge.
To fully achieve what you want, would require a controller to vary the power to the heater, possible but dont know of anything off the shelf.
Goes without saying more PV and larger battery would help.
yep, hearing you but roof footprint precludes bigger array, and without a bigger array, increasing battery size significantly would seem counter productive? Could you expand on “To fully achieve what you want, would require a controller to vary the power to the heater”
So having researched some more, it appears that 24v 600w elements are available, so expanding on my original, if I were to use one of these am I still going to be faced with the element demanding 600w regardless of PV power available and if so is there either a hardware or software solution to limit element draw on ac2 to max excess pv power available?
Whichever “element” you use, requires / will use a given wattage.
Your current hardware will provide the required power for element, this power will be provided by the inverter, supplied from pv and or batteries, subject to any control parameters - namely ac2 out ( achievable with current hardware) being on or off and or a power limiting device to control / reduce power to element ( requires hardware device).
You have limited power from pv, which is unable to power load without either drawing power from batteries or the load needs changing - lower wattage element or hardware to limit power.
Even a 500w element would in all likelihood struggle to be poweted from pv without power from batteries.
Yes there are ways to limit power to 24v 600w load, if this is required to be automatic, i would say you’ll need a custom made device that works by either adjusts power supplied from given battery voltage or recieves data from bms or victron equioment.
Why not simple use ac2 out set with on / off assistant to see how it performs.
My understanding of AC2 out is that it will only switch when no or low load on AC1, if my current array will not be sufficient to provide sufficient power to a 500w element then I’m already stonewalled….or am I? If I’ve understood correctly a 24v element would draw dc power direct from the batteries via a suitable supplementary controller (thinking Pundeman Therm boiler) what am I missing. I’m relatively new to solar, having successfully installed a victron system to my home but the RV install is throwing up new challenges!