AGM with Orion Smart TR 12/12 18 charge current and temp compensation

According to the datasheet of the AGM batteries the charging current without temperature compensation must be limited to 0.2C. When charging a 60Ah AGM with the smallest Orion Smart Tr 12/12-18 the chare current will be 18A or even higher at normal temperature. This corresponds with at least 0.3C. The system will be put in a relative small compartment so I expect that during charging the temperature will rise to 30-40 degrees. Because the Orion Smart does not support temperature compensation and adjustable charge current this seems a less optimal combination. Is there a better solution?

My current thougts are to use a MPPT charger and connect a 12-24V DC/DC converter to the PV input. The Smart MPPT has options for temperature compensation with an external sensor and adjustable charge current setting.

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klim8skeptic ♦ commented · Oct 06, 2020 at 09:28 AM

The system will be put in a relative small compartment so I expect that during charging the temperature will rise to 30-40 degrees.

You expect your battery temp to rise by 30-40 degrees? (Celsius?)

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campervan klim8skeptic ♦ commented · Oct 06, 2020 at 11:05 AM

Based on some simple thermal calculations my estimation is that the ambient temperature of the cabinet can be between 30 and 40 degrees Celsius. The battery might become warmer due to internal heat development.

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klim8skeptic ♦ campervan commented · Oct 06, 2020 at 11:51 AM

Ouch. What would the expected ambient temp be?

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campervan klim8skeptic ♦ commented · Oct 06, 2020 at 12:29 PM

Sorry, my answer was not 100% accurate.

Ambient outside the cabinet: 25-30 degrees maximum (only during warm weather).

Inside temperature of the cabinet: 10 degrees higher (35-40 degrees during warm weather) due to dissipation in the DC/DC converter and battery. Dissipation of the Orion is approximately 30W when charging at full current and that's a lot in a small cabinet.

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