Boonie
Senior Member
The last piece of my solar install is the storage battery. I don't know how to explain my simple understanding, but here goes.
It seems that residential solar systems have been using a different technology in designing their storage batteries than the dual purpose deep cycle batteries we typically use in RVs. We started out needing a single battery that could offer both cold engine starting capacity along with the ability to draw down the battery running appliances/lights (House function). We have moved from a single battery to dual battery set-ups splitting the engine starting function from the house function, but we were still using the deep cycle dual purpose batteries. To gain more storage capacity we started using dual house battery set-ups even going to dual 6-volt golf cart batteries. Since the current draw on an RV solar set-up is closer to our appliance/lights function many RVs are now using the solar designed batteries as their house battery.
If this is true then I do not want a dual purpose deep cycle battery either flooded cell or AGM such as an Optima "color" top. What I am looking at is a VMax SLR125 125 AH. What concerns me is the statement in their literature; "Recommended solar panel 175W-450W (120w may be used if Depth of Discharge does not exceed 50%). Even the VMAX 100 AH; "Recommended solar panel 150w-400w (100w may be used if DoD dose not exceed 50%) Since my initial array will be 120w, I am confused. I do not want to loose the capacity offered by this type of battery or somehow damage it. Is this limitation only on the VMax or is this typical of solar batteries?
So I turn this over to the electrical wizards and solar gods for your insight and recommendations.
PS I have assumed the design standard of a 50% depth of discharge in selecting the 120AH. i.e. 30AH per day, 2 days=60AH/50%=120AH
It seems that residential solar systems have been using a different technology in designing their storage batteries than the dual purpose deep cycle batteries we typically use in RVs. We started out needing a single battery that could offer both cold engine starting capacity along with the ability to draw down the battery running appliances/lights (House function). We have moved from a single battery to dual battery set-ups splitting the engine starting function from the house function, but we were still using the deep cycle dual purpose batteries. To gain more storage capacity we started using dual house battery set-ups even going to dual 6-volt golf cart batteries. Since the current draw on an RV solar set-up is closer to our appliance/lights function many RVs are now using the solar designed batteries as their house battery.
If this is true then I do not want a dual purpose deep cycle battery either flooded cell or AGM such as an Optima "color" top. What I am looking at is a VMax SLR125 125 AH. What concerns me is the statement in their literature; "Recommended solar panel 175W-450W (120w may be used if Depth of Discharge does not exceed 50%). Even the VMAX 100 AH; "Recommended solar panel 150w-400w (100w may be used if DoD dose not exceed 50%) Since my initial array will be 120w, I am confused. I do not want to loose the capacity offered by this type of battery or somehow damage it. Is this limitation only on the VMax or is this typical of solar batteries?
So I turn this over to the electrical wizards and solar gods for your insight and recommendations.
PS I have assumed the design standard of a 50% depth of discharge in selecting the 120AH. i.e. 30AH per day, 2 days=60AH/50%=120AH