Ok guys, before starting I need to explain something.
When we first started setting up our electrical system here on the homestead I had no money at all. In the last 5 years we've went through many, slow, changes.
We first started with just the batteries that came in the $500 camper trailer I bought. 2 old "deep cycle" rv/marine batteries.
We could barely run anything at all. The water pump would kill them super fast and by end of night the lights were either off or super dim.
At the time I didn't really understand the differences in the different types of lead acid batteries. I knew the differences between different tech. Like lead acid vs lithium for example, just not one lead acid vs another. I assumed, since they were all made from the same tech, I could expect similar results since they are all batteries. Aka, things meant to store electricity.
We learned the hard way here about the differences in lead acid batteries.
Since then I've been through a ton of different solar equipment. Controllers, inverters, you name it. Yet, we finally got the battery bank I wanted, we needed, day one.
It took an excruciatingly long time to reach this point and with a bit more knowhow 5 years ago I could've avoided a very, very, costly mistake.
I'm essentially going to skip this battery and just say that you should never attempt to use car batteries in an off grid energy system. If you're thinking you'll save money or something just eliminate this option from the list of usable batteries. They are not designed for it.
Notice I keep putting "deep cycle" in quotations. That's because there is nothing "deep cycle" about these batteries.
I really don't understand how they got that name but it's really deceiving. These batteries are essentially car batteries. They are not meant to store electricity.
Wait, aren't all batteries meant to store power?
No. Not all batteries are meant to store energy. I know, all batteries have energy stored in them, but they are not all meant to store energy.
Its about their design. Car batteries and rv/marine batteries are designed to start engines. Not to store power.
They have thinner plates and more cells per battery than anything useful in electricity storage.
There's a rating on these types of batteries.
CCA or MCA. Cold cranking amps or marine cranking amps. They are essentially the same. Close enough for this post anyway. Mca is in marine batteries and essentially means the same thing.
Any battery that's measured in CCA or MCA is designed to release a large amount of amps at once for starting engines. They aren't designed to hold onto power to use for things. (Ever notice how fast the car radio kills the battery?)
You'll see some people online showing how to convert cranking amps into Amp hours. Don't listen to these people. They are ill informed. You cannot convert cranking amps into Amp hours because the battery design is totally different. There really isn't any storage in a battery with that rating.
Shit.
They are complete shit.
We have had essentially no money since landing here. We never moved. We actually got stranded here just after purchasing this property. We were literally stuck on the property without money for the last 5 years, attempting to homestead competely from scratch on a vacant lot. Without any of my tools, clothes, dishes, anything. We had nothing.
So the first couple years we just tried to get free to super cheap batteries. Starting with the two that were in the trailer I bought. Then we got a few refurbished ones from intestate.
After about 2 years of suffering through it, I got a little money and decided to get rv/marine batteries. I followed the fake conversion from CCA to Amp hour and spent 850 usd on a new bank. In total by this time we had acquired 20 of these batteries. 11 were the news ones.
According to the math I had an 11kwh battery bank all said and done.
Nope.
It literally does not matter how many of these junk ass batteries you wire together, it won't power shit!
These batteries were total junk!
I never got more than 6 hours of autonomy. Not kidding, not over 6 hours.
Well, we stayed this way for years because I never had enough money that whole time to correct the mistake. It didn't take long to realize what I did wrong but now I was stuck with this bank.
So we've been running the generator every single night (minus a very select few early on) since setting that up around 2.5 years ago.
The refrigerator shut off every night and I had to balance staying up late enough running the generator so that food would stay cold enough to not go bad right away.
Veggies always went bad fast no matter what though. This changed our diet drastically because we couldn't keep much.
These "deep cycle" batteries are such junk that I could have 1500w coming in from my panels, 500 going out, and the system would die because the batteries would drop voltage super fast.
Living for 2 years knowing what you screwed up and how to fix it, yet having no way to, sucks ass!!
Last week we finally did it though. We Finally got batteries that work.
Now look, the truth is that golf cart batteries are the very least you should get. They are not even close to the best.
We went with 6v, 210ah costco batteries.
Notice that these batteries are actually rated by ah (Amp hour). When you see a battery rated in Amp hours, it's made to store energy.
The difference is super obvious when you see the batteries side by side.
Marine batteries are 12v and about 40lb. Golf cart batteries are 6v and about 60lb.
Why is that significant?
6v batteries have 3 cells in them. 12v batteries have 6.
So, if 6 cells (marine) are 40lb and 3 cells is 60lb (golf cart), it's pretty clear that each cell is much heavier. Meaning much more metal in the plates. They are about 20lb per cell in golf cart vs 6.6 ish lb per cell in marine.
This extra metal translates to much more storage.
Our current system is 48v, so we got 8 golf cart batteries and ran them in series to get the 48v bank.
We now have a bank that's actually 10kwh, and it is a serious game changer. A lead acid bank can be discharged half. So that's 5kwh of usable power.
We've finally got 3 days of autonomy in the bank with our current usage. Everything works all night and on cloudy days, fridge, wifi, tv, computer.
Look, if you have very little money and need to set up a storage bank...
DO NOT UNDER ANY CIRCUMSTANCES BUY MARINE BATTERIES!!
You will hate life until you can afford to buy something decent.
Lead acid golf cart batteries are the cheapest battery tech you can buy that will actually work.
The cheapest place I know to find them is costco. They always have them, they are interstate, they are always the cheapest.
We bought the 8 batteries for our bank for 840 usd, after core.
Our setup is finally working right.
Now that I have a working battery bank I'll be tidying up the system so it's not such a mess. Until then, we're super stoked to finally have reliable power!!
by Michael David
Co-founder of #thealliance and loyal since before the egg.
Instagram|Facebook|Discord|Telegram
Supporting:
Personal Projects:
