You obviously want as many amp hours as you can get, but even more important is the construction. The biggest 8D's will give you 245amp hours. The really big boys are the 4D abd 8D batteries. Once you have one of these, you can also use to more precisely figure out what each of your devices draws.Īt 125 amp hours they sound like group 31 batteries, 24 is the smallest, then 27 then 31. So, when the battery monitor tells you the battery is depleted, it's really only halfway discharged (which is what you should consider empty anyway). One great feature is that you can set it to consider the 50% discharge level to be 'empty' when calculating time remaining and displaying battery status via the LED bar graph. It is literally the closest thing you can buy to a 'fuel gauge' for your batteries.

Multiply amps x time for each, then sum that column for total usage.Īlso, if you don't already have one, consider buying a battery monitor such as the Link 10 (if your batteries will be tied together as one large bank), or the Link 20 (if they'll kept separate, with a switch to use each as needed). enter each device, its amp draw, and estimated time that it will be used. It's fairly easy to create a spreadsheet for creating a 'budget' of projected power usage within a given time period. So, your 125ah batteries are effectively just 62ah (usable) each. However, because it is strongly recommended that you not deeply discharge these batteries, they say you should only discharge them to about 50%. So, theoretically, you could run this light for about 62 hours on one of your batteries. Suppose you have light that draws 2 amps. Very easy, assuming the devices will run off of DC (if you're using an inverter to provide AC, I think it gets a little more complicated).

Is it pretty easy to figure out how many hours a device, such as a laptop, or port.

Lifetime of marine 4d batteries