A quote from a company that sells parts for building a LiFePO4 battery.

“The battery cells we sell will store A LOT of energy (that is the whole point) – more than enough to maim and/or kill you, your friends and family, and burn down your house, RV, boat or whatever, if you do not know what you are doing.”

If you don’t know what you are doing then the choice is simple. Buy your batteries, do not build them.

Why? A car battery is dangerous, but there are only two terminals to worry about. When you build a LiFePO4 battery from cells, the basic 4 cell configuration involves 8 terminals and multiple other live connections on the BMS. You will be moving these around, assembling (and disassembling) them several times. There will be many opportunities to mess things up, get careless, and get hurt, even knowing what you are doing.

So, let’s assume you do know what you are doing or you are willing to spend the time needed to learn. Here are my recommendations.

Build your own LiFePO4 battery if:

You plan to keep the boat for more than 3 years.
AND
You need more than 100Ah of capacity.
AND
You want to save some money. (You can build a battery pack for about half the cost of a top rated, fully assembled, ready-to-drop-in battery.)

I could write forever on this, and many have. I recommend watching Will Prowse on Youtube. He has excellent information and advice on all of this, including how-to videos.

Good luck and be safe!

We’ve left Kingston.
A front delayed our Monday departure, but then cleared out enough for us to leave the next day. Our first venture south of Seattle led us to Blake Island and the park dock on the NE side.
This was a strategic move as much as sightseeing. A strong low was forecast for Thursday, promising gale force winds all day. It didn’t disappoint. I’m glad we were safely on a dock.
It’s now Friday, and after a windless 5 hour trip we are anchored in Quartermaster Harbor on Vashon Island. It’s a large shallow bay with firm mud to sink an anchor into. There are some gusty winds coming tomorrow, but there isn’t enough fetch for uncomfortable waves to develop. If all goes well we’ll be here till next Tuesday when we head for Tacoma’s Dock Street Marina.

Wanderlust; A very strong or irresistible desire to travel.

It’s time to go. I’ve said that many times, and once again the changing season brings dreams of exploration and long summer days. I look forward to thinking of nothing (and everything) while the world moves on, mostly unnoticed. 

It is time to go.

Summer is coming, our fifth on the boat, and in anticipation I’ve been fixing things that I didn’t know were broken and Sarah is eagerly gathering her art supplies.

It’s time to configure for passage mode. It’s time to stock up and fill the tanks. It’s time to attend to all the last minute stuff because we really are down to the last minute. We are feeling a desperate need to get off the dock.

Cold and stormy days can make the ache manageable. But when sunset boasts flamboyant blues and reds, we can’t help but talk of the warm summer nights we know are coming. We dream of them.

For countless generations our ancestors greeted this time of year by packing up all they own to travel far and wide. Every year they moved with the seasons. I’m guessing the genetic memory of those travels is still within many of us.

If you’re out there, bags packed and keys in your hand, you know how we are feeling, you feel it too.

It’s wanderlust, and it’s time to go.

I’ve been waiting, tracking and agonizing over the arrival of the new battery order. Another delivery debacle like the first one could not be tolerated so this time I ordered from California. (Remember that the first order was still waiting to be unloaded from the slow boat from China.) (And is still reported as such.)
On Tuesday, the tracking showed the second order (from California) would be on time. Sure enough, UPS came through. Two boxes were waiting for me at the office! Woot! I was grinning from ear to ear.

Wait, what? Two boxes? It should have been just one, the long lost first order was in two. Oh.

Back at the boat I quickly discovered these were indeed the lost-at-sea batteries, 2 1/2 months after ordering them.

An hour later I get a call from the office. You guessed it, the NEW order of cells had also shown up. (In one box this time.)

What do you do with twice as many LiFePO4 cells as you planned for? Well, you just build a bigger battery of course. 
​

Want to know more? 
Get ready for a lot of posts. Here is what I’ll cover:
Buying vs assembling.
What size BMS did I use.
What cell configuration and why.
Cell balancing.
Charge and discharge rates.
Why not return one of the sets.
What other devices did I need and why.
Best on-line reference.
​Startup report and testing results.
What size inverter do we have and will I upgrade that?
Would I do this again? Recommend it?
Some misconceptions that will confuse you.
Safety.

So here I sit, with a smile on my face, waiting for batteries.
Not the batteries I purchased two months ago, I’m still waiting on those (and may still be waiting by mid June). I'm waiting for the second set I ordered last week. I’m smiling because this second order will arrive in 4 days.

What’s delayed the first order? 
Turns out there is a backlog of large freighters (from China) anchored off of LA waiting for a time slot to unload. This backlog is due to the massive demand for stuff during covid and LA’s limited ability to unload so many of the really big ships.

It seems our first order is sitting on one of those ships.

I’m not happy about this and would love a refund, but after looking over the terms and conditions of the sale from Aliexpress it was clear I had made a big mistake. They have 3 months to deliver. Until that time I can’t stop the order nor even complain. If they don’t deliver by June 16th I can get a refund, but until then my hands are tied.

Why did I order from China? To save money. Batteries ordered from the US are twice as expensive. But it’s past time to get off the dock and start our summer. To do that we need house batteries and we need them now.

The new order has already shipped from California with a guarantee of a maximum 7 day delivery. The tracking shows they will be here Tuesday.
​
I am so ready for them.