Thor Forums

[dkoldman]

Originally Posted by Judge

DK..... I mentioned to you about the Renogy Charge Controllers having the option for a battery temperature probe and while your thread is geared to flooded, AGM and Gel batteries, LiFePO4 batteries are also impacted by temperature.

Here is some info that may be useful when you think about battery temperature for your batteries.

The BMS in LiFePO4's help prevent things like charging and discharging at temps that are too high... or too low.

You mentioned watching ambient temperature as it pertains to charging but you also have to remember that charging in and of itself creates heat..... especially when batteries have been deeply discharged.

The reason for the temperature sensor with some charge controllers is that it measures the actual battery temperature as a result both ambient air and the heat being generated by charging.

A good Charger is key to properly charging a battery based on a specific battery-type charging profile to prevent excess heat from being created.

In the case of my BigBattery LiFePO4 batteries, 131F is the upper temp limit. However, they caution that ambient temps over 90F can be bad when you factor in the heat generated from charging. The built-in BMS will stop charging once the internal battery temp hits 131F.

I installed my LiFePO4's inside the coach so if I am running the A/C on warm to hot sunny days, the temps inside should never reach 90F. But if for some reason my coach was sitting out and the A/C was not running, I would likely kill the shore power and turn off my Solar Controller as an additional safety precaution to prevent the batteries from charging if I felt the inside temp could reach 90F.

Duly noted , my batteries cycle quite a bit but have never been below 12.5vdc. I would actually raise that higher (12.6vdc) if my EC-30 AGS would allow a higher Auto Start setting. Contrary to what some Lithium owners goals are; I struggle to use my generator more. I have a target of 100 hours / year to use; but thus far I have only been able to get 75 / hours per year.

The reason why this topic has intrigued me so much, is that I was thing that the Progressive Dymanics 9200 with Inteli Charge Wizard with it's elaborate 4 Stage algorithm what about all anyone would ever need? Just trying to size up if Temperature Compensation will have any relevant impact on batteries that are designed to last 8 - 10 years based on number of cycles?