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

[travelnodes]

Hello,

I'm new to this thread and I have an opportunity and an offer some of you may be interested in... I have a friend who purchased a pallet of used LifePo batteries. He foolishly cut off and threw away all of the BMS boards.

But the cells are still useable (i.e. they are holding a charge per my multimeter) I can buy them cheap and in large quantities. But I would offer some in trade to a skilled Electrical DIY person in exchange for a safe, tested and working array for use as house batteries.

In other words, I send you (or deliver to you) a large supply of LifePo cells clusters and you solder on all the BMS boards, etc. and keep some for yourself and give the rest back to me, ready to use.

If anyone is interested please direct message me or post questions here.

Joe

[newhaul]

Originally Posted by john61ct

It is not in any way dumb, fully "staged intelligence"
.

https://www.expeditionportal.com/for...ithium.204421/

john the dumb comment was tongue in cheek due to it not having Bluetooth or some other outside interface to monitor it .
I know it has 100's of times the computing power of the Apollo spacecraft.

[john61ct]

OK. Maybe I'm too nitpicky about precision in language, but I would not want members left with the impression this unit has some "fatal flaw".

We need pioneers to try it out and report back 8-)

[john61ct]

This is wrt the RUIXU seller selling through the Amazon marketplace, contacted through their PM system.

All just FYI, I am not recommending them, nor do I know if there is any relationship with the Ali seller going by the same name, nor do I know which one is the company Newhaul contacted.

They state they do not make any cells, just package and resell.

They claim these are from Sinopoly: https://www.amazon.com/dp/B07QZF73VG

These https://www.amazon.com/RUIXU-Phospha.../dp/B07PBCDVHZ

are sold as "12V drop-in" but no statement as to the maker of the cells.

They can also package in metal https://www.amazon.com/RUIXU-LiFePO4.../dp/B07QCS2WDH


or PVC wrapped, no Amazon listing.

[newhaul]

Originally Posted by john61ct

This is wrt the RUIXU seller selling through the Amazon marketplace, contacted through their PM system.

All just FYI, I am not recommending them, nor do I know if there is any relationship with the Ali seller going by the same name, nor do I know which one is the company Newhaul contacted.

They state they do not make any cells, just package and resell.

They claim these are from Sinopoly: https://www.amazon.com/dp/B07QZF73VG

These https://www.amazon.com/RUIXU-Phospha.../dp/B07PBCDVHZ

are sold as "12V drop-in" but no statement as to the maker of the cells.

They can also package in metal https://www.amazon.com/RUIXU-LiFePO4.../dp/B07QCS2WDH


or PVC wrapped, no Amazon listing.

great research john as I stated I contacted the company directly not through Amazon.
So when are you going to purchase see Thor someone's cells so you can do hands on research like others here have done?

[newhaul]

Well I spoke to renogy and on their bbq chargers for now they are making the 20 and 40 amp versions . If there is enough demand they will be making a 60 amp version.
https://www.renogy.com/renogy-12v-dc...ttery-charger/

[john61ct]

Ha, read that as barbecue chargers
8-)

[newhaul]

Originally Posted by newhaul

Well I spoke to renogy and on their bbq chargers for now they are making the 20 and 40 amp versions . If there is enough demand they will be making a 60 amp version.
https://www.renogy.com/renogy-12v-dc...ttery-charger/

sorry b2b units

[newhaul]

Just came across this chart in an article about battery fires
Explosions threatening lithium-ion's edge in a battery race | MINING.com
It shows that lithium based batteries are coming down in cost significantly.

[dinghysailor]

I am equipping a 10m LOA lightweight trimaran cruising yacht with a 12v 160ah Lithium Iron Phosphate (LFP) battery. I suspect this battery is much higher capacity than necessary for the electrical equipment currently on the boat but it does allow for the possibility to add a fridge and a DC to 240v AC inverter at some later date.

I now have four Winston prismatic cells and a BMS kit from 123Electricc BV. This BMS includes small signal relays that are intended to be connected to high power relays, solid state or electro-mechanical, these shutting off charge current when the battery is full and shutting off discharge current when the battery is depleted. I have yet to select and purchase the high current relays that i will need. The system is intended to be set up and monitored over a Bluetooth link from a smartphone but I am some way from being able to try that out.

The problem I have at the moment is that the main engine on the boat is a 9.9HP outboard motor and in common with other small outboard motors this has only a single pair of high current cables to connect to a battery plus a multicore cable that goes to the ignition switch. This means that the current from the alternator to the battery and the current from the battery to the starter motor both pass through the same cables so unless I start to redesign the outboard electrical system I cannot connect the alternator to the charge side of the LFP system and the starter motor to the discharge side, as I think would be done with a typical yacht diesel engine. A second problem is that if the outboard alternator is used to charge the LFP battery it is likely that the alternator diodes would be damaged when the charge relay in the LFP system opens.

I can think of three options which might overcome these problems:

Option 1: Simply remove the battery charging system from the outboard. The outboard could then be wired to the discharge side of the LFP system to power the starter motor. The disadvantage is the loss of the charging ability of the outboard motor, which is a pity, although it is not a very powerful alternator so perhaps not a huge loss. The alternator is supposed to produce 6amps at full revs, presumably less at the revs it usually runs at, so it will never provide more than a part of the likely charging requirement if we later on equip the boat with a fridge and a 240v inverter.

Option 2: Modify the wiring within the outboard so that the charging current from the outboard regulator goes to the charging side of the LFP system through a separate cable to the main cable that powers the starter motor. I have a wiring diagram for the outboard and I think this should be feasible but I expect it would invalidate any warranty on the outboard and there is some risk of expensive damage if I make a mistake. The current outboard is out of warranty but some day I may need a new one. Something would still need to be done to protect the outboard alternator against damage when the charge relay on the LFP system opens. I asked Sterling Power if their alternator protection device would do this and the technical department said they thought it would but could not be sure since they have not tested it with an outboard alternator. They suggested I might also consider a Sterling Alternator Linearisation device or one of their Battery to Battery chargers for this application, both of those are more expensive than the alternator protection device and they could offer no gaurantee of success.

Option 3: Make the outboard electrically independent of the main LFP system by providing it with its own battery. Perhaps this could be a motorcycle battery which might weigh only a few Kg if it is an AGM lead battery, or a bit less if lithium. (I would like to keep weight to a minimum). Having opted to have a sophisticated high capacity LFP battery system on the boat it does seem a pity to then add a second battery just for the engine, but I realize that is what is done on many yachts. Having two batteries on the boat does allow the option to have interconnecting cables and switches so that one battery can act as a back up for the other, but I dont want to make it all too complicated.

I would be grateful for comments re. the above options, or further options I am not aware of.

[Q Xopa]

Originally Posted by john61ct

OK. Maybe I'm too nitpicky about precision in language, but I would not want members left with the impression this unit has some "fatal flaw".

We need pioneers to try it out and report back 8-)

Yes agreed, good suggestion. We are looking forward to your reports of use.

[Q Xopa]

Originally Posted by newhaul

sorry b2b units

This guy seems to be putting up his money and reporting back-

https://www.youtube.com/watch?v=kF_cVEYxj3E&t=3s

He like the Rich Solar (Renogy clones) version to the Renogy's. They have beefier terminals etc.

But he likes Tracer EPEver's best.

He outlines his reasons. Fully custom settings, although not as easy as Victrons. But cheaper, better terminals and more capacity.

[newhaul]

Originally Posted by dinghysailor

I am equipping a 10m LOA lightweight trimaran cruising yacht with a 12v 160ah Lithium Iron Phosphate (LFP) battery. I suspect this battery is much higher capacity than necessary for the electrical equipment currently on the boat but it does allow for the possibility to add a fridge and a DC to 240v AC inverter at some later date.

I now have four Winston prismatic cells and a BMS kit from 123Electricc BV. This BMS includes small signal relays that are intended to be connected to high power relays, solid state or electro-mechanical, these shutting off charge current when the battery is full and shutting off discharge current when the battery is depleted. I have yet to select and purchase the high current relays that i will need. The system is intended to be set up and monitored over a Bluetooth link from a smartphone but I am some way from being able to try that out.

The problem I have at the moment is that the main engine on the boat is a 9.9HP outboard motor and in common with other small outboard motors this has only a single pair of high current cables to connect to a battery plus a multicore cable that goes to the ignition switch. This means that the current from the alternator to the battery and the current from the battery to the starter motor both pass through the same cables so unless I start to redesign the outboard electrical system I cannot connect the alternator to the charge side of the LFP system and the starter motor to the discharge side, as I think would be done with a typical yacht diesel engine. A second problem is that if the outboard alternator is used to charge the LFP battery it is likely that the alternator diodes would be damaged when the charge relay in the LFP system opens.

I can think of three options which might overcome these problems:

Option 1: Simply remove the battery charging system from the outboard. The outboard could then be wired to the discharge side of the LFP system to power the starter motor. The disadvantage is the loss of the charging ability of the outboard motor, which is a pity, although it is not a very powerful alternator so perhaps not a huge loss. The alternator is supposed to produce 6amps at full revs, presumably less at the revs it usually runs at, so it will never provide more than a part of the likely charging requirement if we later on equip the boat with a fridge and a 240v inverter.

Option 2: Modify the wiring within the outboard so that the charging current from the outboard regulator goes to the charging side of the LFP system through a separate cable to the main cable that powers the starter motor. I have a wiring diagram for the outboard and I think this should be feasible but I expect it would invalidate any warranty on the outboard and there is some risk of expensive damage if I make a mistake. The current outboard is out of warranty but some day I may need a new one. Something would still need to be done to protect the outboard alternator against damage when the charge relay on the LFP system opens. I asked Sterling Power if their alternator protection device would do this and the technical department said they thought it would but could not be sure since they have not tested it with an outboard alternator. They suggested I might also consider a Sterling Alternator Linearisation device or one of their Battery to Battery chargers for this application, both of those are more expensive than the alternator protection device and they could offer no gaurantee of success.

Option 3: Make the outboard electrically independent of the main LFP system by providing it with its own battery. Perhaps this could be a motorcycle battery which might weigh only a few Kg if it is an AGM lead battery, or a bit less if lithium. (I would like to keep weight to a minimum). Having opted to have a sophisticated high capacity LFP battery system on the boat it does seem a pity to then add a second battery just for the engine, but I realize that is what is done on many yachts. Having two batteries on the boat does allow the option to have interconnecting cables and switches so that one battery can act as a back up for the other, but I dont want to make it all too complicated.

I would be grateful for comments re. the above options, or further options I am not aware of.

you are in luck . The manufacturer of the outboard already figured all of that out. Just hook up the positive and negative wires for the outboard to your battery as normal. It will all work just fine.

As to possible damage if the bms were to disconnect it would not harm the alternator setup on the outboard. .

One word of advice don't expect the outboard to actually provide any useful charging for your house bank. The outboard will put out at best 9 amps.( the biggest optional setup I have seen for a sub 15 hp outboard.)
it is designed primarily to just provide charging to.recharge from starting the motor and running a small fishfinder.

[john61ct]

I would never trust someone trying to monetize their online community "contributions".

Sure stuff like that is cheap, and for some that is important.

Yes a bit of a step up from scraping the bottom of the Ali/eBay/Amazon marketplace cheap-chinese barrels, good enough for most

But don't try to say it's actually good quality like Victron, Outback, Morningstar, Midnight. . .

[newhaul]

Originally Posted by john61ct

I would never trust someone trying to monetize their online community "contributions".

Sure stuff like that is cheap, and for some that is important.

Yes a bit of a step up from scraping the bottom of the Ali/eBay/Amazon marketplace cheap-chinese barrels, good enough for most

But don't try to say it's actually good quality like Victron, Outback, Morningstar, Midnight. . .

you do realise that all of the brands you mentioned are for sale on eBay right?

and your opinion of tracer?