LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[newhaul]

Originally Posted by Oceanride007

To Newhaul. My alternator is a Motorola 55Amp, and burns up belts quickly. The Enerdrive B2B has some pretty nice features but is only available in 2 Models the 30 and 40+ models. The 40+ can do 50Amps if you follow there instructions regarding wiring.

ok well a 55 amp alternator will quickly fry itself even with a 40 amp b2b . You realistically need to be able to derate your alternator by 20% or so at a minimum when charging Lfp. With a 50 amp setting on the b2b you would realistically want a 75 amp minimum alternator .
Right now you are eating your alternator due to the charging g profile of Lfp . It will take everything you want to throw at it right up till it is about 95% charged .

[Oceanride007]

Newhaul
No nothing else charges my LFP other than MPPT driven from 3, 64v+ House Panels. Alternator not used on LFP. Belt wear is a job in hand.

Haven't decided next step yet but I could upgrade to 24V system, as Fridge AP, inverter and Windlass would be happier there. 3 seperate batteries could be a issue, as would have both 12V LFP and 12V LA starting, don't know about 24V to 12V conversion is there a devise that can charge both LFP and LA technology. Amazing how quick this technology is changing.

[witzgall]

If you want the best chance at getting good information from this group, here are my suggestions:

1. Start a new thread, dedicated to your issue
2. Supply as much info about each of the parts used in the system as you can possibly gather.
3. Photos photos photos!!!

Chris

Originally Posted by Convertible13

I’m having a problem with my lithium battery system I can’t figure out. I bought a Morgan 321 with lithium batteries as the main battery source and an AGM battery as a back up a couple years ago.
To engage the lithium batteries, I turn the main battery switch to the lithium bank and push a contacter button to engage the contacter which then completes the circuit and powers everything. My problem is now when I hit the contractor button, it momentarily engages then disengages. If I switch to the AGM, the contacter engages and stays engaged. The AGM doesn’t have a contacter button. The contacter automatically engages when I switch the main battery switch to the AGM. Ive replaced the relay and ECPC 404 intelligent AH meter and checked all fuses I could find.
Any idea what else I could check? I appreciate any help with this and I’ll be the first to admit that I don’t know much about the lithium system I inherited when I bought the boat.

[DeValency]

Basically keep things as simple as possible = reliable!
Seem to me the safest and simple way would be to have a smart b2b charger from the cranking/AGM bank to the LFP bank rated at 30% or less below the alternator output.

The problem I can see here is when the alternator is running on low RPM and hence delivering lower current and getting less fan cooling.

We can add automatic/manual switches, sensors etc but what would be the real safe, simple and reliable solution?

Thoughts?

Originally Posted by Oceanride007

To Newhaul. My alternator is a Motorola 55Amp, and burns up belts quickly. The Enerdrive B2B has some pretty nice features but is only available in 2 Models the 30 and 40+ models. The 40+ can do 50Amps if you follow there instructions regarding wiring.

[mikedefieslife]

Originally Posted by newhaul

ok well a 55 amp alternator will quickly fry itself even with a 40 amp b2b . You realistically need to be able to derate your alternator by 20% or so at a minimum when charging Lfp. With a 50 amp setting on the b2b you would realistically want a 75 amp minimum alternator .
Right now you are eating your alternator due to the charging g profile of Lfp . It will take everything you want to throw at it right up till it is about 95% charged .

It won't. Even before I melted a terminal of my BB1260 (lack of strain relief on the input, increased resistance and heat), I'd frequently been disconnecting it anyway, as it's a poor former. I carefully ran my 80a alternator directly to my LFP bank monitoring voltages.

It's been many months. The alternator works hard for a short while putting out 70amps, then as it heats up reduces the output to 50, then 40-ish amps.

I will admit I'm probably more comfortable doing this since I have a spare, but no signs of the one in use giving up at the moment.

[newhaul]

Originally Posted by mikedefieslife

It won't. Even before I melted a terminal of my BB1260 (lack of strain relief on the input, increased resistance and heat), I'd frequently been disconnecting it anyway, as it's a poor former. I carefully ran my 80a alternator directly to my LFP bank monitoring voltages.

It's been many months. The alternator works hard for a short while putting out 70amps, then as it heats up reduces the output to 50, then 40-ish amps.

I will admit I'm probably more comfortable doing this since I have a spare, but no signs of the one in use giving up at the moment.

stock internal regulated and with a significant drop in power output .
There have been many discussions on here in other Lfp threads concerning alternators .

How big is your Lfp bank and what is your usage profile?

[mikedefieslife]

Originally Posted by newhaul

stock internal regulated and with a significant drop in power output .
There have been many discussions on here in other Lfp threads concerning alternators .

How big is your Lfp bank and what is your usage profile?

In my experience, the internal regulation will just drop the power output to protect the alternator rather then have the alternator overheat.

271ah FLP bank often taken to 20% SOC. Before that I had a 675ah FLA bank taken to 50% at time, but hooked up to a Sterling Alternator to Battery charger. That was a great piece of kit and always extracted the max from the alternator. Unfortunately it wasn't customisable enough for the LFP bank.

I don't plan to stay with this setup long term. I will either repair the Sterling Battery to Battery charger BB1260 (despite my hate for the thing), or possibly try the Victron Orion smart TR unless I can find an externally regulated alternator that will fit on my yanmar 3GM30.

[DeValency]

Originally Posted by mikedefieslife

In my experience, the internal regulation will just drop the power output to protect the alternator rather then have the alternator overheat.

271ah FLP bank often taken to 20% SOC. Before that I had a 675ah FLA bank taken to 50% at time, but hooked up to a Sterling Alternator to Battery charger. That was a great piece of kit and always extracted the max from the alternator. Unfortunately it wasn't customisable enough for the LFP bank.

I don't plan to stay with this setup long term. I will either repair the Sterling Battery to Battery charger BB1260 (despite my hate for the thing), or possibly try the Victron Orion smart TR unless I can find an externally regulated alternator that will fit on my yanmar 3GM30.

Yes, you can find externally regulated alternator for your Yanmar, add an external (expensive) programmable regulator etc. to lower the actual output from 120A to 70.... and go from there. (minus probably $1,500 in your pocket)

Or, to my opinion, the straightforward, reliable, simple solution will be the Victron Orion. I still try to find any potential issues to tackle with this setup.

[newhaul]

Originally Posted by mikedefieslife

In my experience, the internal regulation will just drop the power output to protect the alternator rather then have the alternator overheat.

271ah FLP bank often taken to 20% SOC. Before that I had a 675ah FLA bank taken to 50% at time, but hooked up to a Sterling Alternator to Battery charger. That was a great piece of kit and always extracted the max from the alternator. Unfortunately it wasn't customisable enough for the LFP bank.

I don't plan to stay with this setup long term. I will either repair the Sterling Battery to Battery charger BB1260 (despite my hate for the thing), or possibly try the Victron Orion smart TR unless I can find an externally regulated alternator that will fit on my yanmar 3GM30.

I'm considering the renogy 60 amp unit myself coupled up to a 95 amp alternator but as of now my solar seems to do just fine

https://www.renogy.com/12v-60a-dc-to...ttery-charger/
250ah Lfp bank 400 watts solar on a programmable PWM controller

[DeValency]

Originally Posted by newhaul

I'm considering the renogy 60 amp unit myself coupled up to a 95 amp alternator but as of now my solar seems to do just fine

250ah Lfp bank 400 watts solar on a programmable PWM controller

Wish I could... During the day, the solar keep me reasonably charged, with auto piloting 100% of the time. But what would you do if you want to add some more juice in the middle of a cruising night to the very important LFP house bank?

[mikedefieslife]

I remember seeing the renogy, but dismissed it for some reason. Will take another look, but there was certainly something I didn't like the look of.

Balmar alternators are available for 3GM30 for around $500 then there is the MC614 for another $300. I am tempted, but since my plan isn't to run the engine for long periods it might be wasted cash at time when cash isn't so forthcoming.

I have 850w of solar, but two panels are out of commission at the moment, and I'm finding the Caribbean is much more cloudy than the Med, so I'm getting a fair bit less useable sunlight.

[newhaul]

Originally Posted by DeValency

Wish I could... During the day, the solar keep me reasonably charged, with auto piloting 100% of the time. But what would you do if you want to add some more juice in the middle of a cruising night to the very important LFP house bank?

that's when I would fire up my yanmar 3700 generator and run my 2 50 amp car chargers for an hour or so would make a couple pots of coffee at the same time .
But not likely to ever need to do that . My usage is under 50ah a day with refer So I have 4 days reserve power.

[CatNewBee]

Use your stock alternators. No reason to drop 1000$ for a replacement before they are dead. You may have wait a long time for this to happen.

[newhaul]

Originally Posted by mikedefieslife

I remember seeing the renogy, but dismissed it for some reason. Will take another look, but there was certainly something I didn't like the look of.

Balmar alternators are available for 3GM30 for around $500 then there is the MC614 for another $300. I am tempted, but since my plan isn't to run the engine for long periods it might be wasted cash at time when cash isn't so forthcoming.

I have 850w of solar, but two panels are out of commission at the moment, and I'm finding the Caribbean is much more cloudy than the Med, so I'm getting a fair bit less useable sunlight.

the renogy you likely don't like is the 50 amp b2b with solar mppt built in it doesn't allow more than 25 amps from either source.
The 60 amp unit is a lot better on paper .

[newhaul]

Originally Posted by CatNewBee

Use your stock alternators. No reason to drop 1000$ for a replacement before they are dead. You may have wait a long time for this to happen.

no reason to drop a grand ( or more ) on an alternator period. ( IMO) better a small 1k generator and a 50 amp car type charger for a bit of boost when you need it .