Water Tank Cooled Batteries - Temperature Sensor Placement?
Having just built water tanks (see photos) to help control the ambient temp surrounding the batteries, I'm at a bit of a loss as to where the temperature sensors should be placed. This is complicated by two types of sensors: a single (normally) battery-side mounted pad sensor for the Xantrex inverter/charger, and two terminal mounted sensors (Morningstar recommended position) for 2 Morningstar MPPT45 controllers.
The batteries are submerged with the tops about an inch above water level. Questions:
1) Can the Xantrex sensor still be mounted on the side of a battery? Is it waterproof? If not, is there any benefit to placing it on top of a battery?
2) If the Xantrex sensor is waterproof and submerged, would it be accurately monitoring the internal temperature of the battery or be (heavily?) influenced by the temperature of the water? I have a feeling (correct me if wrong) that the internal temp of the battery would be greater to some degree that the surrounding water. This may be less of a concern if the sensor pad is surrounded by air (as it normally would be), but given the substantially greater conductivity of heat/cold by water, the sensor could be influenced (most likely cooled) when surrounded by water cooler than the internal temp of the battery.
3) Are the terminal posts still the best place for the Morningstar sensors? Comments in other posts in various forums recommend attaching temperature sensors to "center mass". If the concerns mention about about waterproofness and heat/cold transfer and sensing accuracy in water submersion are not an issue, can these eye terminal type sensors be attached to the side of a battery (and how)?
A bit of background. The batteries are Ritar 200C lead carbon. The tanks have a circulating water system. Cooling the water bath is a work in progress. I am currently using frozen bottles of water. Even with this the bulk/absorption internal temps have reduced from 34-36 C to 29-31 C. I will be trying something related to modifying a minfreezer, dehumidifier or air conditioner to cool the water further. Any ideas or proven solutions welcome. Living in Nicaragua, there is no Amazon, no commercial/retail water chillers, no meaningful Craigslist, no Best Buy (etc) and the closest semblance of a Home Depot is an overnight trip away. Imagination and re-purposing is the norm.
Thanks for looking at the post and any comments/suggestion.
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