Lead is dead

[SaylorMade]

You can now get a 100AH LFP battery for 229 USD
And the quality is good too

I even think that Will mentions some of the forum members in the introduction of this tear-down video

https://www.youtube.com/watch?v=2kooJS3wZaA

[CaptTom]

I found lots of these on Amazon, many for for less than that, when I looked yesterday.

One thing I'm curious about; most of these list "BMS" as a feature. Although I admittedly haven't done much research yet, I thought I read somewhere that you don't need/want an internal BMS in each individual battery in your bank. Anyway, it certainly does seem that the cost of LFP these days means replacing my aging FLA bank just became a lot more complicated.

[sailorboy1]

Originally Posted by SaylorMade

You can now get a 100AH LFP battery for 229 USD

Well that isn't a good deal. I got 200ah for $300 1.5 years ago and they are less now.

[SaylorMade]

Originally Posted by CaptTom

I found lots of these on Amazon, many for for less than that, when I looked yesterday.

One thing I'm curious about; most of these list "BMS" as a feature. Although I admittedly haven't done much research yet, I thought I read somewhere that you don't need/want an internal BMS in each individual battery in your bank. Anyway, it certainly does seem that the cost of LFP these days means replacing my aging FLA bank just became a lot more complicated.

There has to be a BMS to control the flow of power, monitoring and balance the cells. There is nothing that prevents you from putting more of these batteries in parallel to create a bank.

What do you find complicated?

[Statistical]

Originally Posted by CaptTom

I found lots of these on Amazon, many for for less than that, when I looked yesterday.

One thing I'm curious about; most of these list "BMS" as a feature. Although I admittedly haven't done much research yet, I thought I read somewhere that you don't need/want an internal BMS in each individual battery in your bank. Anyway, it certainly does seem that the cost of LFP these days means replacing my aging FLA bank just became a lot more complicated.

Drop in replacements are always going to have one internal BMS per battery. That is what makes them (kinda) drop in replacements.

If you want a larger more complex system then yeah you likely are better off using raw cells and a better "external" BMS maybe even one with safety contactors. However now design, and implementation is not just drop in replacement. You are it is the right way to do it for large complex systems but some people are just looking to replace 200 or 300 Ah of lead house bank.

[CaptTom]

Originally Posted by Statistical

...some people are just looking to replace 200 or 300 Ah of lead house bank.

Yeah, that would be me. I guess I got caught up in the weeds, reading about more complex systems and how drop-ins aren't good in that scenario.

OK, drop-ins are OK for my 2-300 AH house bank. Great!

Now it's just a matter of seeing if my inverter/charger and my external alternator regulator have any settings which would be OK for LFPs.

[Mike OReilly]

Originally Posted by CaptTom

Now it's just a matter of seeing if my inverter/charger and my external alternator regulator have any settings which would be OK for LFPs.

This is my issue with making the shift; it’s not just about the batteries, it’s about the whole charging system. In my case, my old alternator certainly has no lithium profile. Nor does my shore-power AC charger. My solar controller is good, but I’m not sure about my wind controller.

I could keep a starter batter, connected to the older chargers, and then DC-DC charge the lithium bank. More complications, and more cost…

I think lithium looks great, and likely will make the switch, but it’s not as simple as dropping in the new batteries.

[emilecantin]

Originally Posted by Mike OReilly

This is my issue with making the shift; it’s not just about the batteries, it’s about the whole charging system. In my case, my old alternator certainly has no lithium profile. Nor does my shore-power AC charger. My solar controller is good, but I’m not sure about my wind controller.

I could keep a starter batter, connected to the older chargers, and then DC-DC charge the lithium bank. More complications, and more cost…

I think lithium looks great, and likely will make the switch, but it’s not as simple as dropping in the new batteries.

Yeah, "drop-in" really is a misnomer. The setup you describe is the one I've had on my boat for about a year cruising the Bahamas and the US East Coast, and it worked very well. I basically just replaced the 1-2-Both switch with a Orion DC-DC in my electrical setup, and now my radio doesn't reboot when I start the engine.


I've always seen this as a temporary setup, and now I'm about to go with a "proper" one. The "drop-in" battery I initially got (because of budget) died this winter, and to their credit, the manufacturer gave me a full refund. I'm now getting a Victron battery with external BMS, which will let me connect the alternator to it, and a new shore power charger. I'll then be able to switch the Orion to charge the start battery instead.


Connecting the alternator to the house battery lets you reap one of the major benefits of lithium, which is quick charging (less time running the engine to charge the batteries, yay!)

[emilecantin]

Originally Posted by CaptTom

Yeah, that would be me. I guess I got caught up in the weeds, reading about more complex systems and how drop-ins aren't good in that scenario.

OK, drop-ins are OK for my 2-300 AH house bank. Great!

Now it's just a matter of seeing if my inverter/charger and my external alternator regulator have any settings which would be OK for LFPs.

As someone who's used drop-ins, I'd urge you to reconsider. You have to be really careful, especially with the alternator, because the BMS can't warn you of an unsafe condition and will just disconnect the battery in case of an anomaly. For example, if your alternator is putting in a bit too much voltage, it could disconnect everything, leaving you without instruments, radio, etc.


External BMSes will usually have 2 different contacts for "stop charging" and "stop discharging", so it can turn off your alternator without disconnecting your instruments.


Now, there's absolutely no reason why "drop-in" batteries can't also have these connections (they have to have this signal somewhere on their PCB, how hard is it to add a 2¢ connector), but manufacturers all insist that Bluetooth connection with their shitty app is sufficient in terms of external communication.


Since I've last shopped for batteries, Victron has dropped the price substantially on theirs, and a SmallBMS can be had for pretty cheap too, so the price of their setup can be cheaper than some "drop-ins".


Re: your alternator, if it's a Balmar it can be programmed for lithium. Newer regulators have a "lithium" profile built-in but you can just program the same settings in an older one (https://balmar.net/2017/10/02/balmar...ium-batteries/). That's what I'll do next week with mine.

[CarlF]

The multiple cells with a single BMS banks are becoming increasingly rare. Even the term “drop in” is rarely used anymore as internal BMS batteries have just about the whole market.

All of these batteries are designed to be used in parallel although some brands limit you to four batteries connected in parallel. But four 300AH batteries gives you 1200AH - enough for most cruising boats .

There’s a pretty good argument that having multiple BMS give you redundancy should one fail. The BMS is probably the most common thing to fail.

The one advantage of single BMS batteries are that they theoretically offer communications to protect the alternator if the BMS shuts down. Much was made of this in the early days of lithium banks but since then several alternatives such as DC-DC chargers offer simpler and less expensive solutions to this issue.

[CaptTom]

Well, lead is alive and well on my boat. I bit the bullet and replaced my 6V FLA golf-cart batteries like-for-like. Took me under an hour, counting picking them up at the store and getting them down to the boat. Assuming they last as long as the old ones did, I'm good for another 10-11 years. I'll upgrade then.

[Fuss]

Originally Posted by CaptTom

Well, lead is alive and well on my boat. I bit the bullet and replaced my 6V FLA golf-cart batteries like-for-like. Took me under an hour, counting picking them up at the store and getting them down to the boat. Assuming they last as long as the old ones did, I'm good for another 10-11 years. I'll upgrade then.

Well, I don’t know trawlers so I can’t comment in this particular case.

BUT, if this was a sailing boat, wow, this would be so sad, a mistake of epic proportions!
And probably even cost more than lithium
It would be made even more clear when they later got a Bluetti 20kw lithium or Anker power station and then starting raving on about what a game changer it was….of course it would be when your house bank is lead….
Everything lithium is a game changer compared to lead.

Wow…11 more years with all the disadvantages… oh well
That’s really what this forum is for isn’t it…

Protects the old tech thinking and shoot down the new innovative improvements.

I’m doing a thread on supercaps soon and it will go the same way.

[sailorboy1]

if ones use is such that golf cart batteries last 10 years there would be no reason to change

well except to your back

[Reeve21]

Lead works for me. My AGM's are going strong at 8 years. Solar keeps them topped off on a mooring, and I use a small panel when hauled for the winter.

If I were living aboard I would consider lithium, but for my relatively light use (weekends and vacations, short season in the northeast USA) I see no compelling reason to change at this time.

[Mike OReilly]

The advantage of lithium is much greater Amp-hrs in the same weight/volume. This comes with a disadvantage of the need to reconfigure, and likely upgrading, one’s charging systems, and basic cost. Aa someone who knows what their electrical needs are, I have no need to greatly expand my Amp-hrs. Lead-acid does just fine, so what is the compelling reason to switch?