Cheap group 4D LiFePO drop in replacement batteries

[carlwk3c]

Originally Posted by flightlead404

If I was at home with plenty of time/tools/access I’d
Consider a full up redesign/rebuild but I’m on the hook and trying to spend another 3-4 months cruising. Also this is a boat I will likely sell in a couple years and don’t want to drop too much $ that I’ll likely not recover. Although I also don’t want to do something shabby and nonfunctional. I do care about the quality of my work lol

Hence my interest in simply increasing useable AHr without massive investment

Related equipment includes new Epever 60a mppt solar controller, master volt 12/50-3 charger and a big standard internally regulated 80a alternator

An 80A internally regulated alternator will have a problem charging LIFEPO4 of any size. First, there’s the matter of a proper charge profile. Second, the batteries will take more charge than the alternator can supply without overheating (burning out). Such alternators are designed for charging a start battery for a short time (and lead starter batteries charge acceptance drops rapidly as they charge. Lithium on the other hand will take very high charge currents right up to 95% or more state of charge.)
You really need a bigger alternator to charge a decent sized lithium bank, and it should be externally regulated with a controller that understands the proper charge profile. (That will require at least 2 V belts, or preferably a serpentine belt and the pulleys for it.

[GrowleyMonster]

I gather you are in the US? Your best bang for the buck might well be GC-2 6V golf cart batteries, if they will fit in your battery box. I found my 8Ds had gotten a bit soft, rather prematurely, and I wasn't able to bring them back. I was very familiar with those golf cart batteries, because they were my power source for my previous boat's EP system. I like the form factor and how long they last with only an occasional equalization cycle, and regular electrolyte level checks and refills. I also like the price, still less than $100 each at Sam's. Knock on wood, but I expect to get 8 years out of them. So yeah, I replaced my FLA 8D batteries with the GC-2 golf cart batteries. It was a no brainer, for me.

The golf cart batteries are much more tolerant of deep discharges than the 4D or 8D FLA, or AGM or "maintenance free" batteries. You do have to keep an eye on them, though. And always have distilled water on hand, for topping up.

Properly installed LiFePO4 are okay and getting better, with modern BMS systems. The problem is they just cost so much.

[flightlead404]

Originally Posted by Jweyndling

I have had AMpere Time 200Ah LePOFe batteries running on my boat for a couple of years now and they seem to holding up really well. If they do fail, you can can replace them and still have spent less than buying "brand name" ones like Battle Born.

I have moved my windlass and bow thruster to start batt and both appear to work well. I spent 2 high intensity hours trying to free my 2nd anchor rode from underneath someone else’s anchor chain yesterday using the windlass rope drum in part worked great. Bow thruster I’ve tested but tend to avoid using just because I want to be expert without it lol

I’ve researched and planned which products and how to install a dc-dc charger to avoid alternator trashing bms load dump issues

I know how to reconfigure my solar

The last piece of the puzzle is a new inverter/charger to replace my currently non Li compatible mastervolt and the 600w pure sine inverter. Specifically are there chargers that support mixed chemistry since my start is remaining AGM?

[Pete7]

Originally Posted by flightlead404

The last piece of the puzzle is a new inverter/charger to replace my currently non Li compatible mastervolt and the 600w pure sine inverter. Specifically are there chargers that support mixed chemistry since my start is remaining AGM?

Don't worry about the engine start battery. Assuming you use the boat regularly, that will be enough for the alternator to keep the engine battery charged. So choose an inverter, or inverter/charger with LFP profiles, or one that you can set up your own profile as you can with a Victron MPPT.

Be careful of were you mount the DC>DC charger particularly if its Victron, they get hot, really hot. So under a berth or in a locker kept closed isn't a good idea if you want them to run for long periods of time and last.

[Scubaseas]

Originally Posted by flightlead404

I have moved my windlass and bow thruster to start batt and both appear to work well. I spent 2 high intensity hours trying to free my 2nd anchor rode from underneath someone else’s anchor chain yesterday using the windlass rope drum in part worked great. Bow thruster I’ve tested but tend to avoid using just because I want to be expert without it lol

I’ve researched and planned which products and how to install a dc-dc charger to avoid alternator trashing bms load dump issues

I know how to reconfigure my solar

The last piece of the puzzle is a new inverter/charger to replace my currently non Li compatible mastervolt and the 600w pure sine inverter. Specifically are there chargers that support mixed chemistry since my start is remaining AGM?

Keep the Mastervolt on the start bank & buy a separate LiFePo4 specific charger for the new house bank?

Or check with Mastervolt if they have a solution?

[flightlead404]

Originally Posted by ranger58sb

See you found instructions. I'd guess that's probably the first best thing to try...

-Chris

Turns out my mastervolt charge master refuses to go into equalization mode even though it is documented in the manual. From a few searches it seems this is a common problem. So I have not been able to equalize. Have been in a slip for a week (another issue) so now we’ll charged but no idea how battery is performing

[flightlead404]

Originally Posted by carlwk3c

An 80A internally regulated alternator will have a problem charging LIFEPO4 of any size. First, there’s the matter of a proper charge profile. Second, the batteries will take more charge than the alternator can supply without overheating (burning out). Such alternators are designed for charging a start battery for a short time (and lead starter batteries charge acceptance drops rapidly as they charge. Lithium on the other hand will take very high charge currents right up to 95% or more state of charge.)
You really need a bigger alternator to charge a decent sized lithium bank, and it should be externally regulated with a controller that understands the proper charge profile. (That will require at least 2 V belts, or preferably a serpentine belt and the pulleys for it.

That’s the purpose of a limited amperage dc-dc charger. Keeps the load on the alternator low and protects against bms load dump.

[Scubaseas]

Originally Posted by flightlead404

Turns out my mastervolt charge master refuses to go into equalization mode even though it is documented in the manual. From a few searches it seems this is a common problem. So I have not been able to equalize. Have been in a slip for a week (another issue) so now we’ll charged but no idea how battery is performing

20 amp load test would tell you

[flightlead404]

Originally Posted by Scubaseas

20 amp load test would tell you

Good point

I’ll use my clamp ammeter to determine the amperage for my anchor light, fridge, and freezer and then unplug from the shore power overnight.

I’ve got a few days until my new prop arrives !!!!!!!

[GrowleyMonster]

Originally Posted by flightlead404

Turns out my mastervolt charge master refuses to go into equalization mode even though it is documented in the manual. From a few searches it seems this is a common problem. So I have not been able to equalize. Have been in a slip for a week (another issue) so now we’ll charged but no idea how battery is performing

This is pretty common in "smart" chargers. Some of them will go into a quasi-equalization mode if you unplug, then replug them a time, or two in quick succession. However, I have never seen one that goes up to true equalization voltage. It's the lawyers and insurance companies, I think, telling electrical design engineers how to do their jobs. Read the Titan website for proper equalization data for their batteries, which are fairly representative of most true deep cycles. For specifics for your batts, of course you need to get the dope from the manufacturer, but Titan's guide is a pretty good general outline.

The fact is, though, that an equalization cycle MUST BE CLOSELY MONITORED by a knowledgeable human bean. So, that sort of begs the question of whether or not a purely manual charging method should be used for equalizing, since a smart charger programmed for full equalizing can't be trusted to cook the batteries like that, and most or possibly all are NOT so programmed. My method when I had a 48v, 10.5kwhr bank to manage, was to use a large varactor and a salvaged rectifier from an old arc welding machine. With the appropriate instrumentation, of course. I need to set up my new 12v system on Brute Force for that, actually. I just replaced my old 8D setup with six GC-2 batteries, in a single 3P-2S configuration for 12v and about 645ah or 7.74kwhr. I may also install another pair just for starting the Westerbeast.

[flightlead404]

Originally Posted by Scubaseas

Keep the Mastervolt on the start bank & buy a separate LiFePo4 specific charger for the new house bank?

Or check with Mastervolt if they have a solution?

I’ve been looking at the Sterling BCM1260 mixed chemistry module. As I understand it, this would allow me to keep my current Mastervolt 12/50-3 multi output charger, leave one output direct to the start bank (AGM) and run a second output to this module that would convert it to a LiFePO4 profile.

Is this a reasonable approach?

One concern I have is that in the spec sheet it lists a float voltage for their lithium profile. But lithium as not supposed to the floated.

Or could I just use two Victron Orion smart dc-dc chargers? One to charge lithium from the alternator to manage the BMS load dump issue, and the other to charge the lithium from the existing lead acid only mastervolt charger?

[Scubaseas]

Originally Posted by flightlead404

I’ve been looking at the Sterling BCM1260 mixed chemistry module. As I understand it, this would allow me to keep my current Mastervolt 12/50-3 multi output charger, leave one output direct to the start bank (AGM) and run a second output to this module that would convert it to a LiFePO4 profile.

Is this a reasonable approach?

One concern I have is that in the spec sheet it lists a float voltage for their lithium profile. But lithium as not supposed to the floated.

Or could I just use two Victron Orion smart dc-dc chargers? One to charge lithium from the alternator to manage the BMS load dump issue, and the other to charge the lithium from the existing lead acid only mastervolt charger?

Looks like it on the face of it but I'd ask tech support at Sterling first. "float" may not be an exact/correct/accurate term for what it does. But then apparently I have no idea what I am doing so take whatever I say with a grain of salt. There is a float like setting on my Skylla Victron charger. Assuming Victron is an OK product which I think it is apparently "float" is OK but again I would contact Sterling and ask them directly.

One school of thought is everything MUST go through a CAN bus network. Another is to only hire professionals. Whatever they are. Good luck. Both would work IMHO, ie. the BCM1260 OR two dc-dc chargers. But then again...I like the Sterling method though. Redundant is good.

[sailingharry]

Originally Posted by flightlead404

Or could I just use two Victron Orion smart dc-dc chargers? One to charge lithium from the alternator to manage the BMS load dump issue, and the other to charge the lithium from the existing lead acid only mastervolt charger?

It is certainly a reasonable approach. But you could look at it as double the cost needed. Both the alternator and the battery charger are designed to connect to a battery and see 12 volts. There is no reason you couldn't tie them together and use a single Orion. Doubling up the inputs wouldn't even cost you capacity, because you would never use both engine and shore power at the same time.

[flightlead404]

If I only hired professionals I’d never learn anything. Not my style. ��

[flightlead404]

The issue with that is the one from the alternator needs to be low amperage to protect my 80A alternator from overloading when trying to charge a depleted 400 AHr LiFePO4 bank so using the same one would limit the AC-DC charger to charging very slowly