Tpastorini-
Just so you know, the Ampere Time batteries do not appear to have low and high temp cutoff in the BMS (battery monitor system). Charging below freezing will destroy them if you will be experiencing freezing temps. You may want to verify this with the seller if you plan on using them in cold temps.
An Amazon customer review-
Does NOT have low temp cut off - beware!
By
Chris Nowak on January 4, 2021 The bad:
- This does NOT have low temp cut off!! RVers, van dwellers, campers - DO NOT USE THIS BATTERY IN FREEZING TEMPS! Charging LiFePO4 will IMMEDIATELY and IRREPARABLY damage your battery! While they can be discharged to about 0F, charging should never happen under 32F. I drained the battery then "froze" it to 20F and it immediately took 25 amps charge! I contacted AmpereTime and this is the email they sent me back:
"We’re really sorry for the confusion.
The BMS in our battery has low temperature cut-off protection function, but if we set this function on our battery, the battery can neither charge nor discharge under 32F/0C. At the beginning, we had set up the low temperature cut-off function for our battery, but later many customers responded that they needed to be able to discharge under 32F/0C. After careful research, our team has decided to block this function.
Currently our battery can be charged at low temperature, but it is charged with a very small charging current. And we’ve used auto motive grade battery cells which have superior quality. Even if charging in low temperature environment, it will not damage the battery. And as what we’ve listed in the charging temperature, we don’t recommend charging under 32F/0C.
Our marketing team has an error in understanding this, which leads to inaccurate information shown on our product page. We’re very sorry for the misunderstanding and thank you for your info, and we’ve revised the inaccurate info on the product page."
Many other batteries on the market can discharge under 0F and only charge above 32F, so this limitation seems unique to this BMS. It took 25 amps at 20F, that's definitely not "very small charging current". It does look like some of the references to low temp cut off have been removed, but not all, and the responses to questions in the Q&A section from the Ampere Time remain. If you've purchased this battery, you need to make sure you have a kill switch on your chargers (alternator, solar, shore, etc) that you can kill charging if it's going to drop under 32F!
- Battery is glued shut so I can't tell if they're new cells or not. Also means if a cell goes bad or BMS dies the whole thing goes in the trash unless you want to get your sawzall out.
The good:
- Based on the lack of low temp cut off, I decided to return this battery. Customer service was good and they allowed me to return it for free, no hassle