Moderator: I was not sure whether to post this here or the equipment forum but the report is geared towards imaging use, so I chose B&II forum. Please move to equipment forum if needed...
Batteries are critical to those of us who seek dark skies where power is not available. I spent a lot of time researching my power requirements and battery technologies and chose this battery...
I paid $369 which I felt was a excellent deal for an 80ah (960watt-hour) lithium battery and it also included a 10amp charger. Unfortunately the price has jumped to $459 today just three weeks after I ordered mine .
This battery weighs only 19.8 lbs has a BMS, two USB side ports, and a carry handle. It is extremely easy to carry around. Yes, it was over twice the price of a good AGM 100ah battery but the light weight and depth of discharge (DOD) capacity are worth it to me. One can discharge a LiFePo battery to 80% and still maintain thousands of cycles of life. So my 80ah battery should easily provide up to 64ah for 5000 cycles. I will likely expire long before this battery does at my current rate of clear nights! AGM batteries should not be taken much below 50% to preserve life. So in one sense, an 80ah LiFePo battery is equivalent to a 128ah AGM which would weigh on the order of 80 lbs and easily cost over $200 which brings the price gap even closer.
Since the laptop runs at 19.5V, other items run at 12V and some items run at 5V, I decided to normalize everything and work in Watts from here on. I estimated my power requirements to be around 41 Watts/hour for my setup which consists of the following powered items:
- Mach1 mount
- ASI174mm mini uncooled guide camera
- ASI1600mm Pro cooled main camera
- ZWO EFW Filter wheel
- Dew Not DN09 heater strip
- Dewbuster control unit
- Moonlite focus motor
- Dell lattitude E6430 laptop (using a PWX voltage converter, display, wireless, and bluetooth all turned off, and with battery removed)
To simulate a road trip to a dark site, I charged the battery fully overnight but then disconnected the charger when I woke up. The battery sat idle all day. I then connected power at 6:45 pm and ran the system until 6:45 am this morning, I measured the no load voltage on the battery in the morning to be 13.08V. The voltage-DOD curves are very flat so it's hard to get a really accurate reading, but I interpolated from some tables and think I had about 35% capacity left. So I used 65% capacity over 12 hours which is well below 80% and easily covers my longest possible night. Working backwards, my system was using (0.65)(960)/12 = 52 Watts/hour. So my initial estimate of 41 Watts/hour was low by 26%. Not sure why that was, but I am good with what I have. I put the battery back on the 10amp charger at 6:45 am and it fully charged somewhere between 4 and 6 hours. I did not check often enough to obtain the exact recharge time.
So in summary, this battery is perfect for my needs. As long as the build quality was good, and only time will tell that, I should be set for life with a single battery that can run the entire rig all night long anywhere I go.
Disclaimer: I am by no means a battery expert. This is only my laymen's opinions and I may have got some of this wrong! Please keep that in mind.