Step 9: Adding another battery

Picture of Adding another battery
Update 5/9/12:

I know I had mentioned this in my previous post, but now I actually made a move on it. The problem with my system right now is that the battery is too small for the amount of panels I have pumping juice into. By 9:00 AM the next morning, that battery is fully charged. I'd like to run more stuff at night to pull down the battery down more, but I'm limited because of the lack of capacity. Running cell phones and lights at night was enough to drain the battery, but not enough that the panels couldn't recharge it easily the next day.

Note: Even though I could continue to use the system like this, I would be wasting valuable sunlight hours where the battery is full and I have no need for the power. Really counts when I need the power and don't have any, plus I'm kicking myself at night when I have to shut down loads while I sat and watched the power go to waste all day.

The new battery is at 86 a.h. compared to the previous 104 a.h. battery I got earlier. That's a total of 190 amp hours for those of you who can't do math in their heads. BECAUSE a battery should never be discharged below 50%, I basically have 95 amp hours to play with. Still, this is significantly more than the 52 I had before. I still would like to purchase more batteries, so I will still continue searching for good deals.
wolfgang642 years ago
Yes let's please put this one to rest once and for all,in the 1910s to the 30s Battery bodies were made out of hardwood. especially Henry Ford's model Ts and tractors. His thinking, It's on rubber tires so who cares it's insulated anyway. Remember electric start was a bonus because these vehicles all had handcrank starters.
Hey quick question. On step 9, you say you have it wired in a "weird" way, such that both batteries have the same draw. Do you just mean that you wired them in parallel, or the way you wired them in parallel? If the latter, are the cable losses really large enough that it matters which terminals you use to get the + and - lines? I would not expect that to be the case.
MacOSJoey (author)  silentquasar3 years ago
They are technically wired in parallel. I have the + connected to +, and the same for negative on both batteries. However, instead of connecting the rest of the system to just one battery in normal parallel, the positive connects to the positive on one battery, and the negative is connected to the other battery. The cable size doesn't matter as much, but its VITAL that the lengths are the same to reduce one battery being drawn more than the other. Thanks for commenting!