Calculated Industries 8715 AccuMaster BT Digital Battery Load Tester Analyzes 12V 100-2000 CCA Batteries | Voltage, Capacity% Life, Resistance, Cranking Amps | Amp Hours (AH)

This is an easy to use accurate battery tester. I tested 3 car batteries new to 5 years old and it showed they were all good and also showed percentage of capacity left proportional to age difference and use. I tested 6 12 volt sealed L/A batteries from uninterruptible power supplies and it correctly failed them. It correctly failed a battery from my garage door opener that showed proper voltage but would not operate the door. It passed the new replacement. It showed a good battery was replaced at a friends house for her alarm system that I had replaced 2 years prior. She had an error on her system and replaced the battery thinking that would fix it. I normally use a carbon pile load tester for auto battery tests, but this little tester is now my first choice. Small and light, it is easy to carry around when I need to go mobile for testing batteries.

Easy to follow instructions. Heavy duty cables and strong springs in the clamps. Case seems to handle most impacts. Used three times and shows no sign of failure.

inability to store readings after disconnecting from batteries.

Accurate

Unpackged and tried to test my car battery. Hooked it up red to pos, and black to neg. Just like always. NOTHING! didn't power up, so I swapped the leads and presto! fired up. so if yours doesn't work, try this. I believe they were mis wired and got shipped out. The 5yr Chinese slave labor QA employee missed alot of them. Works as described, and I've tested many different types with fairly reliable results. For what it does, it seems abit pricey, but if it lasts and gives accurate readings, then its worth it.

Works fine. Have never had problems with Caculated industries electronic devices.

I'm sort of a battery tester junkie. I have no fewer than seven battery testers. Don't ask me why I collect these testers. It's a sickness.Including this tester, three of the testers in my collection are electronic testers and four are based on simple load testing. My other two electronic testers are much more expensive than this Calculated Industries tester. The readings on my expensive testers agree with each other, but they don't agree those taken by the Calculated Industries. For example, my expensive testers might read 405 CCA for a 550 CCA battery that's in decline due to sulfation, but the cheap Calculated Industries tester might read 435 to 470 CCA for the same battery depending on whether surface charge is present. My expensive testers can detect the presence of surface charge that can give false readings and will instruct the user to turn on the headlights to drain the surface charge away before testing again, but the cheap Calculated Industries machine can not do that, so it can give very inflated readings.All of these electronic battery testers use some kind of correlation formula to DEDUCE the CCA rating based on the result of capacitance testing by injecting high-frequency signals into the battery. These electronic testers, including the expensive ones, work fine on healthy batteries, but their accuracy falls off on dying batteries.The only truly reliable way to test car batteries is with a heavy, carbon pile, load tester, such as this one: https://www.amazon.com/SOLAR-1874-Carbon-Battery-Tester/dp/B014T7HL3I/ref=cm_cr_arp_d_product_sims?ie=UTF8. Batteries are supposed to be load tested at 1/2 the CCA rating of the battery for 15 seconds. Those light load testers that only load up to 100 A or 125 A don't really stress the battery enough to reliably weed out dying batteries. The light load testers work fine for healthy batteries, but not batteries that are near the end of life.I think the Calculated Industries tester is a fun gadget to own, but it's not all that accurate. It will give at best in-the-ballpark figures. As long as you're willing to live with this uncertainty of results, I guess it's an okay tool.

Works great worth it