Lithium Porn

[wildebus]

I did a bit of testing a week or so back on a pair of batteries that I will be fitted next week on a Motorhome and thought it might be of interest to the membership....

Batteries in question are the Poweroad Linc Infinity SubZero LiFePO4 Batteries. These are 100Ah rated and have a Bluetooth BMS and Internal Heating Pads, so pretty well specified. (they also have an RS488 Comms Port but don't think there is a device from Poweroad to use that yet, but a possible bit of futureproofing there?)


I wanted to do a capacity test to check what they will deliver. I decided to put a constant load on each battery in turn, run it until the Victron SmartShunt reported the SOC as 20% (so 80Ah taken out the battery) and then see what the "real" capacity was by reading the Batteries own SOC via the BT app (The difference is the extra undeclared capacity that most good Lithium batteries have).

First off is the 'Red' Battery.
A very consistant load of 3.4A (a 40W lightbulb on an 300W Inverter) and test stopped at 20% SOC according to the SmartShunt, and going to the internal Battery Monitor, we have a SOC of 29%. This indicates the 'real' capacity of the battery is about 109Ah (80Ah taken out, 29% of the batteries "100Ah" remaining)

When looking at the graph there is an interesting drop in voltage around the 65% mark and then it levels out. Intriging.


Onto the 'Purple' Battery.
Identical test load and again taken down to around 20%. Here we have an internal Battery Monitor reading of 27% at the SmartShunts 20% level, so very similar.
The graph scales are a little different, so the lines may appear to look a bit different in the drop, but we have an identical voltage drop at around the 65% SOC level. That is good as shows total consistancy between the batteries.


I am saying the batteries true capacity is around the 107-109Ah mark? That is not strictly right as once these batteries have gone though a few charge cycles, the capacity will actually increase by a few Ah, so you expect potentially maybe 115Ah?
I only did a single discharge test on each one to see what to expect on these batteries, but I think they are pretty nice
Here are some of screenshots of the BMS Data and Info available ...



The other aspect of Lithium as well as their discharge ability is the claim they can recharge quickly? So I also put that to the test ...

After taking 80Ah out the battery, I connected a Victron 30A IP22 Smart Charger to it and with the Smart Shunt was able to see how the battery accepted the charge and how long it took.
I have to say that is a very impressive recharge! The limiting factor here will be the charger output of 30A and as can be seen that is a rock solid level line of 30A for 2 Hours 40 minutes, and only then does it tail off in the last 6 minutes of the charge and the voltage goes to the set 14.2V value.


So that is that. I know the SubZero batteries have been mentioned a fair bit on the forums and so I thought it worth sharing some semi real-world info

 

[nabsim]

The 2x 30A Victron chargers I fitted do an amazing job charging mine Dave, almost looking forwards to bad weather to use them more

 

[wildebus]

Decided to open up a Subzero battery and have a peek inside (don't worry, Chris - not one of yours )

The battery packs are on the right hand side under the yellow sheet. The cut-out in the middle is for the battery sensor.
The cables that go to the +ve and -ve terminals are very substantial and securely fitted there.
To the left of the battery pack is the BMS with a very good sized heatsink - you can see why this batteries current carrying rating is what it is
The little PCBs on the top cover on the left are the RS488 connectors. There are two pairs physically fitted, but only one is labelled as such externally and only that one is connected. The other green PCB on the top cover is for the batteries switch/light panel. You can turn the battery on or put it on stand-by with a switch, and there is a bank of LEDs that indicate the charge level, plus a light that comes on when it is connected via bluetooth (this is handy when you have multiples in a bank so you can see which battery you are talking to).
It is really handy to be able to undo the top and access all this stuff in the event of a service - usually with batteries you end up having to destroy the case to get to the internals Even if you would not service it yourself, this makes it much quicker for someone else to look at it and hopefully fix. And much quicker means much cheaper - if it takes time to break into a case, and a new case is needed after any repairs, that expensive battery might not be economically repairable.


I am also repeating the previous test I did on the last two, but this time I think I will run down to full capacity and check the full voltage range you would expect. Last time I drew just over 80Ah out the 100Ah units and was at around the 28% remaining. Let's see what remains when I have taken 100Ah (currently at 66Ah drawn so should hit the 100Ah at around 9:30 this evening (didn't time the start of the test very well, did I ))

 

[davep10000]

Thats really interesting - exactly what I would have done to check the quality of the internals.
Keen to see your latest results.
What form does the subzero capability take?. Is it a heater pad under neath the cells?
The graphs you published are very reassuring, although one of my concerns about buying a lithium is that they meet their full life specs, as I would want at least 6+ years out of one in normal use.
DP.

 

[wildebus]

Thats really interesting - exactly what I would have done to check the quality of the internals.
Keen to see your latest results.
What form does the subzero capability take?. Is it a heater pad under neath the cells?
The graphs you published are very reassuring, although one of my concerns about buying a lithium is that they meet their full life specs, as I would want at least 6+ years out of one in normal use.
DP.

I'm not sure precisely where the heater pads are. There is a "normal" Linc Infinity and a "low temp/subzero" Linc Infinity and the difference is the heater, so I am going to assume the cell packs are built the same for economies of scale, and the heater pad on the subzero is either on the sides or underneath (underneath would make sense).
There is a technical document for them at Alpha Batteries here - https://www.alpha-batteries.co.uk/1...um-lifepo4-battery-with-bluetooth-monitoring/ (Alpha are the only approved on-line seller for these Poweroad Batteries I understand).

There is so much talk on Lithium with incredible service life and I can't deny I am slightly dubious on some of them (not this battery particuarly, just Lithium in general) and the BMS I have a nagging doubt of it being the weak link - so to see a battery with what looks like a very robust heatsink on the BMS - and one that is fully servicable as well is a major plus point in my books (maybe other commercial ones have a similar heatsink but who knows without someone like Geeky Philip taking his dremel to one to find out!)

This particular example gave up just under 100Ah before shutting down as one of the cells is slightly down on voltage (I supplied it to a customer in January and it would occasionally error on charging so we swapped it out with another. The battery still worked fine and the customer used it on a weeks tour as soon as travel was permitted in England totally sucessfully, but because it was not 100% perfect, we changed it anyway).
The Subzero is now installed in my Motorhome as the Lithium bit of a Lead/Lithium Hybrid setup, along with a Victron BMV so I can keep an eye on it as it gets used on a daily basis

 

[wildebus]

Batteries going off to the Sunset shortly now installed in their new home ...

Along with a SmartShunt

 

[St3v3]

Nice, but you've got the shunt wires the wrong way around.

 

[St3v3]

Made you look

 

[Canalsman]

Thanks David for the excellent job you have done with my installation.

I'm sure it's going to give many years of reliable service.

May I recommend that if any member needs electrical work carried out that they should contact David for a quote.

 

[wildebus]

This may be of interest to people with Lithium ... some BMS workings....

So take a typical 12V Lithium Battery. It is made up of multiple cells connected in series to make up the 12V. They are nominally 3.2V each, with 4 of them to provide 12.8V (that is the 'standard' 12V battery voltage).
Due to manufacturing variances and tolerances, each cell will be slightly different to another. That is just how it is. When the batteries are put together, previous checks made will have grouped cells together that tested as close to each other as possible, but they are still different.
One of the roles of the batteries BMS - Battery Managment System - is to balance those cells to each other. In use the cells can discharge unevenly, and when charging, they can charge unevenly also. The BMS corrects this over time.

To see this in a live battery, I took some screenshots of a Poweroad Subzero battery BMS display showing the cell voltages over a 24 Hour period. The battery is starting fully charged here.

09:21 yesterday - You can see there is quite a disparity in the voltages between the cells, with a range of 0.27V
19:15 yesterday - The high cells have dropped down as the general voltage as dropped, so the range is now down to 0.18V
09:29 today - The balancing has continued and the difference in the cells is just 0.02V (p.s. that 6.91A is charge IN)


You would see similar patterns on other Lithium batteries if you were able to look at the cell info.

 

[jim and pat dalton]

Wildebus:- Might sound like a dumb question (probably because it is)

We have a solar panel we use to keep our traditional batteries topped up. If we were to fit these batteries would they respond well to being topped up by a constant charge and would the electrical trickery in them manage it.

Or is this a no no?

we fancy running two x 100a/hrs in the moho and also to replace our 6 x 100 a/hrs in the narrowboat (which has 240w solars on roof)

 

[wildebus]

Wildebus:- Might sound like a dumb question (probably because it is)

We have a solar panel we use to keep our traditional batteries topped up. If we were to fit these batteries would they respond well to being topped up by a constant charge and would the electrical trickery in them manage it.

Or is this a no no?

we fancy running two x 100a/hrs in the moho...

This is chart of the battery being recharged by Solar. You can see theCurrent into the battery in the bottom graph and the State of Charge in the top graph. As soon as the battery is full, it just no longer takes any charge and the current drops to zero (bit of current noise after that as the battery supplies tiny bits of power and the solar goes up and down but you get the idea )

So answer - assuming your solar controller is a reasonable one - is yes


Your other question ...

... and also to replace our 6 x 100 a/hrs in the narrowboat (which has 240w solars on roof)

This is interesting... being a narrowboat I am assuming weight is not an issue (and if you took out 600Ah of lead battery you might even have to add some more ballast?).
It is off-topic for this thread, but I suggest you have a look at a thread on a sister forum - https://motorhomebuilder.com/threads/turbo-charging-motorhome-electrics.67127/page-3#post-877319 - where I am running a combination of Lithium AND Lead Batteries together
In that thread there is a link to a YouTube video where the poster has added Lithium to his large Lead Acid Battery Bank on his boat and explains very nicely how it is working out for him for the last 18 months.
If watching that makes you think this could be of interest, then I go right into details with lots of data and graphs of how the two work together in a writeup series on my website here - https://wildebus.com/hybrid-battery-bank-introduction/

(PS. None of this is trying to sell you anything - it is just information from myself and Clark (the YouTuber) that is intended to allow people to maybe 'think out the box' and avoid maybe not investing thousands and thousands of pounds where there could be an alternative that maybe works very nearly as well but is a lot more economical.)

 

[jim and pat dalton]

This is chart of the battery being recharged by Solar. You can see theCurrent into the battery in the bottom graph and the State of Charge in the top graph. As soon as the battery is full, it just no longer takes any charge and the current drops to zero (bit of current noise after that as the battery supplies tiny bits of power and the solar goes up and down but you get the idea )
View attachment 59467
So answer - assuming your solar controller is a reasonable one - is yes


Your other question ...

This is interesting... being a narrowboat I am assuming weight is not an issue (and if you took out 600Ah of lead battery you might even have to add some more ballast?).
It is off-topic for this thread, but I suggest you have a look at a thread on a sister forum - https://motorhomebuilder.com/threads/turbo-charging-motorhome-electrics.67127/page-3#post-877319 - where I am running a combination of Lithium AND Lead Batteries together
In that thread there is a link to a YouTube video where the poster has added Lithium to his large Lead Acid Battery Bank on his boat and explains very nicely how it is working out for him for the last 18 months.
If watching that makes you think this could be of interest, then I go right into details with lots of data and graphs of how the two work together in a writeup series on my website here - https://wildebus.com/hybrid-battery-bank-introduction/

(PS. None of this is trying to sell you anything - it is just information from myself and Clark (the YouTuber) that is intended to allow people to maybe 'think out the box' and avoid maybe not investing thousands and thousands of pounds where there could be an alternative that maybe works very nearly as well but is a lot more economical.)

That's fabulous stuff from both your replies, thank you. Btw I did think about the ballast issue but my wife just said "Oh good, I can buy some more books!!"

 

[g8gs]

Decided to open up a Subzero battery and have a peek inside (don't worry, Chris - not one of yours )
View attachment 59177
The battery packs are on the right hand side under the yellow sheet. The cut-out in the middle is for the battery sensor.
The cables that go to the +ve and -ve terminals are very substantial and securely fitted there.
To the left of the battery pack is the BMS with a very good sized heatsink - you can see why this batteries current carrying rating is what it is
The little PCBs on the top cover on the left are the RS488 connectors. There are two pairs physically fitted, but only one is labelled as such externally and only that one is connected. The other green PCB on the top cover is for the batteries switch/light panel. You can turn the battery on or put it on stand-by with a switch, and there is a bank of LEDs that indicate the charge level, plus a light that comes on when it is connected via bluetooth (this is handy when you have multiples in a bank so you can see which battery you are talking to).
It is really handy to be able to undo the top and access all this stuff in the event of a service - usually with batteries you end up having to destroy the case to get to the internals Even if you would not service it yourself, this makes it much quicker for someone else to look at it and hopefully fix. And much quicker means much cheaper - if it takes time to break into a case, and a new case is needed after any repairs, that expensive battery might not be economically repairable.


I am also repeating the previous test I did on the last two, but this time I think I will run down to full capacity and check the full voltage range you would expect. Last time I drew just over 80Ah out the 100Ah units and was at around the 28% remaining. Let's see what remains when I have taken 100Ah (currently at 66Ah drawn so should hit the 100Ah at around 9:30 this evening (didn't time the start of the test very well, did I ))

Hi there and hi All!.. 'am new here. I've literally registered so i may ask you question @wildebus on this battery... I've had both low temp and non low temp and have a query you may be able to help with.. TIA

 

[jagmanx]

As an aside. I report on my pair of 100amp-hour "platinum batteries" lead-acid or similar
I bought from Alpha.
Consultation with Alpha and Calira. (my ECU for the batteries etc) And wary about my Mppt controller ruled out lithium!
These were fitted in Feb 2020 and my vehicle remained in storage until June 2021.
Storage is indoors but a perspex roof allows some solar !

On retrieving the vehicle in June I was disappointed with the voltage(s) displayed.
I know this is a very poor method but it works.
My previous battery would show 14 plus volts on a sunny morning and only dipped to 12.7 or so overnight !

the new pair rarely showed above 13.6 and dipped to 12.5 too often.

Two months on the road and the battery pair now seem to have benefitted from Engine charging and good solar.
The max voltage is typically 14.4 and most of the time is above 13.5
the lowest voltage is now about 12.9
as I type this 12:30 and light cloud......the voltage is 14.1 and I am running a 150watt inverter charging a shaver !

my observations lead me to conclude the batteries have improved with use and limited discharge !

strange but true

 

[wildebus]

As an aside. I report on my pair of 100amp-hour "platinum batteries" lead-acid or similar
I bought from Alpha.
Consultation with Alpha and Calira. (my ECU for the batteries etc) And wary about my Mppt controller ruled out lithium!
These were fitted in Feb 2020 and my vehicle remained in storage until June 2021.
Storage is indoors but a perspex roof allows some solar !

On retrieving the vehicle in June I was disappointed with the voltage(s) displayed.
I know this is a very poor method but it works.
My previous battery would show 14 plus volts on a sunny morning and only dipped to 12.7 or so overnight !

the new pair rarely showed above 13.6 and dipped to 12.5 too often.

Two months on the road and the battery pair now seem to have benefitted from Engine charging and good solar.
The max voltage is typically 14.4 and most of the time is above 13.5
the lowest voltage is now about 12.9
as I type this 12:30 and light cloud......the voltage is 14.1 and I am running a 150watt inverter charging a shaver !

my observations lead me to conclude the batteries have improved with use and limited discharge !

strange but true

On the last point, Batteries (both Lead and Lithium) don't actually reach their full capacity until they go through a few discharge/recharge cycles, so seeing a better result would not be that unusual.
Having said that, we are talking about a few cycles and not a few months

 

[wildebus]

I did a bit of testing a week or so back on a pair of batteries that I will be fitted next week on a Motorhome and thought it might be of interest to the membership....

Batteries in question are the Poweroad Linc Infinity SubZero LiFePO4 Batteries. These are 100Ah rated and have a Bluetooth BMS and Internal Heating Pads, so pretty well specified. (they also have an RS488 Comms Port but don't think there is a device from Poweroad to use that yet, but a possible bit of futureproofing there?)
View attachment 59094

I wanted to do a capacity test to check what they will deliver. I decided to put a constant load on each battery in turn, run it until the Victron SmartShunt reported the SOC as 20% (so 80Ah taken out the battery) and then see what the "real" capacity was by reading the Batteries own SOC via the BT app (The difference is the extra undeclared capacity that most good Lithium batteries have)...

Seeing this thread popping up reminded me of some new info for the two batteries that I talked about and ...
We got the Factory QC info for the two batteries and whilst they were sold as 100Ah units, one was 115.3Ah and the other was 114.8Ah, so a handy bit of extra capacity over the official rating

 

[jagmanx]

On the last point, Batteries (both Lead and Lithium) don't actually reach their full capacity until they go through a few discharge/recharge cycles, so seeing a better result would not be that unusual.
Having said that, we are talking about a few cycles and not a few months

Yes,

Whilst in storage there should have been almost zero usage/discharge just solar topping.
18 months worth and now 2 months of normal usage ! So does that fit with your statement ?
Raining now..just usb charging of phone/tablet.
Voltmeter showing 13.7 and multimeter 13.9
probable voltage 13.8
David may remember we thought the fixed voltmeter under by 0.1V

 

[wildebus]

If you are comparing it to when you first got the batteries and looked the numbers right away, it could do
People say each time you use a battery you take a bit out of it, but I am not convinced. If you treat them right, you will have the same energy a year later or more.

 

[jagmanx]

The batteries were installed by remote control in March 2020 ..we were marooned in Thailand until June 2021.
So no information re their status on delivery.