Preventing Instant Darkness
In the last article about lithium batteries, I defined load dumps and shared why they matter.
And, further, I wrote, and believe strongly, that we cruisers should not listen to salespeople who downplay this fundamental characteristic of lithium batteries—they will be home safe in their beds when a load dump puts our boat and our crew in jeopardy.
It's Basic Seamanship
As boat owners we should not tolerate a system that will load dump, any more than we would ignore a broken strand in a shroud or a sloppy rudder bearing.
So let's look at some ways to banish load dumps:
#1 Never "Drop In"
If you have not already bought "drop in" lithium batteries, don't.
The problem with "drop in" batteries is that, since the BMS is inside the battery, it has no way to communicate its intentions before load dumping.
This is a fundamental system architecture issue that's not ever going to get fixed properly.
For example, even if "drop in" vendors add something like a buzzer, or a warning over Bluetooth to our phone, prior to shut down, that will not help much. (See Tip 2.)
And for those who say, "but wait, plenty of people have "drop in" batteries on their cruising boat", I say "yes, and plenty of people invested with Bernie Madoff".
Already Have "Drop In" Batteries
That said, I don't think any the less of you if you have already bought "drop in" batteries. I have made far worse mistakes than that.
After all, the very words "drop in" infer something that's very seductive—all of the benefits of lithium with no added expense or modifications to our boat.
Just as the words "guaranteed high returns" are seductive—high investment returns with no risk.
Sadly, neither are true.
Still, all is not lost. If you already have "drop in" lithium batteries, Tips 4, 6 and 7 will help at least mitigate the load dump problem.