Lithium batteries - Confused

[haganap]

evidence not opinion

Thanks Eddie, I think that's very informative and I trust Charlie every time.

in essence people will make up their own opinions but I have a bank of Banner Batteries a B2B charger, a Stirling pure sine invertor and the set up has never given me an issue. every 4 years or so I have replaced my batteries, we use the motorhome for over 90 nights a year on a mix of electric hook up and wild camping.

It seems to me that although the lithium perform amazingly, the video basically demonstrates that so do mine so what is the point? and cost wise at 2 x 110 banners every 4 years at about 300 quid I would have to be going for about 10 years to justify the cost. Can't imagine what I am doing next week never mind 10 years down the line.

 

[eddie]

Lithium may not be for everyone but I wouldn’t want to do do my kettle boiling from 1x100ah battery, whatever the type.

Who would, but my two Sterling Lithium units mean that my Victron inverter charger is rarely off

We don't need Lithium, we don't need inverters, we don't need anything, we could have a mattress in the back of a green painted transit and live down a lane for free

I don't need to do that and prefer to have my creature comforts

Everything you need to know about lithium batteries is set out below:-

#1 They are too expensive
#2 See above.......

The Tincas

This is why some people buy cheap vans and some spend hundreds of thousands of pounds on their van. One "could" say "Everything you need to know about lithium batteries is set out below

#1 Not everyone can afford them
#2 See above

 

[eddie]

Thanks Eddie, I think that's very informative and I trust Charlie every time.

in essence people will make up their own opinions but I have a bank of Banner Batteries a B2B charger, a Stirling pure sine invertor and the set up has never given me an issue. every 4 years or so I have replaced my batteries, we use the motorhome for over 90 nights a year on a mix of electric hook up and wild camping.

It seems to me that although the lithium perform amazingly, the video basically demonstrates that so do mine so what is the point? and cost wise at 2 x 110 banners every 4 years at about 300 quid I would have to be going for about 10 years to justify the cost. Can't imagine what I am doing next week never mind 10 years down the line.

I wouldn't disagree, but if you had a critical weight or power issue, it could be a deciding factor.

The only real negative with Lithium is the expense. Some people wouldn't baulk at spending the thick end of £4,000 on a TV set up, or £3 - £4,000 for AC-DC Air conditioning "for the dog" it's down to choice, and not everyone's first criteria when choosing motorhomes or accessories is financial

 

[Gromett]

There is perhaps a little confusion here. There is a difference between cells and batteries technically speaking. A battery is a group of cells hence the name (battery of cells).

The cheapest way to do this is to buy 4 cells and install them with a Battery Management System (BMS). A BMS performs 3 core functions.
1) Overcharge protection
2) Low Voltage cutt off.
3) Cell balancing.

Lithium cells don't like being overcharged or being discharged too far. A BMS will give your cells protection from this.

There is an issue that not all cells are exactly identical due to manufacturing variation so one cell may have a very slightly lower capacity than the other three in the battery.
If this happens then it is possible this cell will be discharged further than the others causing it to be damaged very slightly lowering it's capacity further. Over repeated cycles this would have a cascade effect as it would then charge up to it's 100% capacity quicker than the others and go over voltage causing the charger to cut off sooner meaning the others in the battery didn't get a full charge.

So a BMS will monitor each cell for over voltage and low voltage at the cell level. It will also when charging ensure that all cells reach full charge at the same time. The way this is generally done is that it will charge the battery up to almost 100% then discharge the cell that is the highest through a small resistor until it matches the next highest. It will then start the charge cycle again until repeat until all cells are at 100% and the same voltage.

People like Relion bundle all this together into a package that looks and behaves a lot like a normal 12V battery. This is expensive but is an easy drop in replacement for an existing system where the owner doesn't want to or can't learn about a proper BMS/Cell system.

If you can put a little effort in you can do it much cheaper. For instance for a 100AH system you could buy 4 of these cells for €111 each.
https://www.ev-power.eu/Winston-40Ah-200Ah/WB-LYP100AHA-LiFeYPO4-3-2V-100Ah-TALL.html?

Add in a BMS system like this (60AMP) for €55
https://www.ev-power.eu/Battery-Man...y-Management-Board-4-cells-12V-60A.html?cur=1

If your van charger is not programmable, then you can either get a decent sterling charger or a budget one like this for €116
https://www.ev-power.eu/Chargers-6V...or-LFP-LTO-cells-4-cells-BMS-input.html?cur=1

This works out a roughly half the price, but you have to do the work yourself.

PLEASE NOTE!!! I am not recommending this configuration, I haven't tested it or even investigated it. I was just giving an example for the purpose of explaining.

Finally. When buying ensure you are buying LiFePO4 cells/batteries. These can take extraordinary abuse and do not burst into flame spontaneously. They are not like the 18650 that you see bursting into flames in vaping machines or like the batteries in cell phones. They tend to be the cobalt NMC etc types which are much much higher energy density and more reactive.

 

[Wissel]

I have been researching Lithium batteries and am some what confused.

Spoken to two companies who sell Lithium batteries with different replies.

1. Tells me i can replace my existing batteries with Lithium ones by just swapping them and using the same wiring!

2. Tells me that I will need extra wiring and other bits and pieces which started to increase the cost quite a bit.

I have two 110 panels and two 90 amp batteries,


Colyboy

Quick answers - Depends on the battery, what trickery it has built in, what charge current it uses and what your existing setup is capable of.

Longer answer (with a fair amount of opinion)

Most "off the shelf" 12v LiFePO4 batteries will have 4 cells inside and a management system (BMS). The BMS "can" control lots of different charging/discharging characteristics including max and min voltage, balancing the 4 cells at the same voltage, charging current, temperature sensing and more. The cells are just dumb and greedy, it's the BMS that protects them. I put "can" in brackets because a lot of BMS's don't do enough (IMO) and some are just plain bad.

In my own system I built the battery, so bought the cells and BMS separately. I went with a BMS that works with relays to keep the cells safe. If the cells go above a set voltage, the BMS cuts all charging. If the voltage drops to a set level, the BMS cuts all draws. IMO this feature is essential.

My BMS also monitors the temperature of each individual cell. In general, LiFePO4 batteries can be damaged if charged at below zero degrees Celsius. Again, I think this feature is essential.

I coupled my battery setup with a very clever charger that has specific programs for different LiFePO4 batteries. Different manufacturers recommend different charging voltages. I use the same profile for charging as Victron recommend (pretty high chance Victron have the same cells inside their LiFePO4 as me) which is 14.2v. Because LiFePO4 doesn't like being full all the time, the profile on my charger charges at 14.2v for about 30 minutes, then drops to 13.6v. This reduces my capacity slightly, but should keep the cells in great condition for a very long time (hope so anyway).

Besides measuring the voltage, my charger also measures the temperature of the battery. If it detects a low temp it reduces the charging current to a safe level until the temp is increased. So with my setup I have a charger and a BMS that each independently monitor voltages (high and low) and temperature. Either can stop damage, so I don't have a single point of failure.

Charge voltage and current is important when looking after LiFePO4. So if a BMS doesn't have wizardry to stabilise these then a charger should. It's not just to protect the battery, LiFePO4 is greedy. My own cells will charge at 3c, which on my 400Ah battery means the cells will try and draw 1200A. If I was using a simple split charge relay I don't think my alternator would last long

My own setup will charge at 60A when driving, 40A on EHU and has 400w of solar attached. All charging methods are regulated and controlled and constantly monitored. My wiring is ample to take the currents required.

So, if the batteries you are looking at have a BMS that controls charge/discharge voltages and current, and your existing wiring can handle that current, and they can protect themselves from high or low voltages, and monitor temps, then I guess they could be simply swapped in. This is what I would want anyway.

^{_{Subscribers  do not see these advertisements}}

 

[Littlewheels]

I’ve upgraded my Solar to 360amp replaced the PRS 240 Regulator with a Victronic 430 Duo and I now wish to replace the 2 x 95amp Exides with LiFePO4 Lithium’s of the same dimension to provide energy with less depletion and a quicker recovery rate.

Not sure which brand or from where I might source them and having read the above posts do I presume all LiFePO4 Batteries contain a BMS within and if so am I OK to simply connect to my new set up.

I also have an Efoy system in operation.

We use the Kettle, Coffee Machine, Hairdrier, Vacumn etc etc.

Guidance appreciated.

 

[two]

evidence not opinion

(I missed that video on my first pass.)

It seems that the comparison may be flawed because the Lithium battery had an integral BMS to protect it from abuse. Use of latching relays may have produced better results for the Lead batteries by also protecting them from damaging discharges.

The tests performed were described as ‘nasty’ and were clearly more harmful to one type than another. I think the 100Ah Lead-Acid battery provided 90Ah on its first cycle, yet we are regularly advised that they are not designed to go below 50% capacity, so it should be no surprise that it expired prematurely. Lithium, however, are (claimed to be) designed to provide 100% of their charge in a cycle. This test has merely demonstrated how much more tolerant Lithium can be of extreme discharges (particularly if a good BMS is in place). It may not have fared so well if left in a discharged state before recharging.

The video raises a few questions:

• What happened to the Lead Crystal battery and should that be considered typical?
• Why was a Gel battery not included for comparison?
• Why were the labels removed from all batteries, except the Lithium?

(I am persuaded that this material is some kind of promotion.)

 

[eddie]

Well he is the MD of the Company making the claims, suggesting the cycles and the percentage of discharge and putting a five year warranty on his batteries.

He has also ensured that his batteries are E Approved for road use as they supply several ambulance authorities with Lithium batteries and they have to be E Approved for road use.

Charles Sterling has a history of challenging battery manufacturers to submit their batteries for testing on Sterling charger and inverter equipment over the last couple of decades.

(I am persuaded to accept that Charles Sterling of Sterling Power Products is an expert in his field and has been for the last 25 - 30 years)

 

[HandyAndy]

I built (or was building) a Headway LiFeP04 battery out of individual cells, the bad ass ones that can do 200Amps EACH (that's the 3.2v cell on it's own can do 200amps) but the downside of the higher discharge was a lower capacity, each cell was only 8 Ah so I designed a 56 Ah battery 28 cells in total (4S 7P = 4 Series, 7 Parallel) capable of producing 1400amps if I had 12v cables that could support it lol... I don't.
Cost me £361.22
Now when I contacted Victron for some "best practice" ideas for the BMS (as nothing is available that's 250amp capable.. they told me there was no need to install one as long as I check them manually occasionally (every couple of months) as they are quite forgiving..
WIN

Quite evil little things

 

[eddie]

Excellent video!

^{_{Subscribers  do not see these advertisements}}

 

[hilldweller]

A downer on lithium - you manage to wreck one and what tears !

 

[sallylillian]

One of the significant benefits of Lithium which gets little if no inclusion in their feature list is its lack of necessity for regular charging to 100%. It is probably one of the key reasons that is driving me to include them in my new Morelo. Lead acid, and I include all versions, wet, gel and AGM require regular charging to 100%, a proper 100% every couple of days or so, which can take up to 24hrs in some cases as the last few amps are trickled in. Using solar as a charging medium say over a week will never get the battery topped off anywhere near 100% on any day and consequently the ongoing capacity of the battery is being depleted by this practice alone. With Lithium, as I understand it, you can charge to any point then resume use, recharge the next day and so on without derogatory effect.