Lithium batteries - Confused

[colyboy]

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

 

[funflair]

I think that is because some have all the gubbins inside to make them work from a standard charger and others are more like just the cells and you need all the other stuff as an addition, I have a feeling you will find that the later option is the best but at a price.

Martin

 

[pappajohn]

Different charger maybe but I can't see why any wiring should need replacing or adding.... Its the same electric passing through them.

Personally I would leave it a few years to see what happens, they're only just filtering into the motorhome world.... Look what happened to AGM batteries, now out of favour as a useless lifespan but the dogs do-da's when they first came out.

 

[Jim]

I think this depends on your van and its alternator. I notice that some combinations, those with modern "smart alternators", you need to have a B2B charger fitted otherwise you won't be charging them on the road.

 

[hilldweller]

Considering the "newness" and change in lithium I think the big question is "how much do I need lithium".

Basically it all hinges on weight and volume.

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[eddie]

I have just changed motorhomes and fitted two Lithium batteries. I can only sensibly fit two leisure batteries in without major work. I have replaced two lead acid batteries that joint give me about 100 amp usable weighing in at over 60Kg and the lithium replacements are 30Kg and 200 amp usable.

I haven't changed my charging system as my on road charger is rated at 160Ah so will cope with the theoretical 50 amp per Lithium battery charge rate and will not damage my alternator. My on road charger (B2B) is set to 14.4 VDC so again fine for lithium

Most of the European motorhomes that we are installing lithium batteries to require the installation of a B2B type charger to optimise and protect the batteries. Many German motorhomes that have regenerative braking systems (Regen) have already been fitted with B2B type chargers from conversion to resolve the Regen issues

 

[Pausim]

I fitted a Relion battery that contains a Battery Management System (BMS). I installed a Sterling charger which I already owned because it has a specific LiFePO4 profile and a higher charging rate, which Li batteries can cope with. Relion say that existing chargers that are compatible with AGM batteries should be ok. http://www.jenericramblings.com/wp-...harging-Info-and-Troubleshooting-2-2016-1.doc

At the same time I chose to install other equipment, including b2b and mppt, which involved some additional wiring. However, the basic wiring fuses etc remain unchanged, just supplemented for the new kit.

What Li batteries need varies beween manufacturers. I was surprised to find my Victron b2b had 4 different Li profiles with charging voltages ranging from 13.9v (Dometic) to 14.6v (Relion). I guess it depends on how their individual BMSs are designed and what they are disigned to work with. Clearly they are not all the same, though I suspect the basic chemistry of the cells is similar and the differences lie in the BMSs or in not having one at all.

 

[Justamil]

I spoke to a Battery stand at the NEC who was selling Lithium batteries to be direct replacements for Lead-Acid etc. As Funflair said these have the Lithium charger built into the battery and hence are a direct replacement.

The Good news, a 100Ah 12v battery will provide 100% discharge without damage (so the man said), so the battery was capable of 100Ah and not the 50% discharge of 45Ah for each of your existing 90Ah batteries which most people say shouldn't be discharged by more than 50%. The other added benefit was 14Kg weight as opposed to 24Kg (according to the man), so one new Lithium 100Ah battery would be considerably lighter than your existing two 90Ah batteries.

The Bad news, one 100Ah Lithium battery will cost you £1000.

Not for me, unless I knew I would be keeping my Motorhome for 20 years.

 

[Pausim]

Not for me, unless I knew I would be keeping my Motorhome for 20 years.

I am planning on taking my Li with me if I change motorhomes.

 

[eddie]

I am planning on taking my Li with me if I change motorhomes.

I want the power and the convenience

Funny thing is that people pay thousands for a satellite TV system yet suggest Lithium batteries and they look at you as if your mad

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[sallylillian]

I think Lithium battery sales could become the next PPI scandal as unsuspecting purchasers step into the bear trap. Do research, then some more, about the proposal and what you have as a charging infrastructure.

 

[Stretto Boy]

I am planning on taking my Li with me if I change motorhomes.

At that price, I’m planning on taking mine with me when I snuff it.

 

[hilldweller]

I have read many times that if you discharge a lithium battery below a certain minimum they will never recover.

Maybe new ones have improved, maybe not.

Tesla, who are just about the definitive source of lithium knowledge stress being a bit kind to them massively increases their lifespan.

 

[haganap]

as I understand it and maybe @DMS will confirm as I think he now fits them, its a simple replacement of your charging system to like a B2B type charger.

 

[funflair]

I think like everything Lithium batteries will give longer service if they are looked after, most if not all have circuitry in them that will stop them being discharged too far but apparently they don't like being held at full charge either so I think there is a bit to know about looking after them, as Michael says you need to do your research, i'm sure it's learning curve.

Martin

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[two]

1. If you want honest information, don’t ask a salesperson.

2. There are several different types of Lithium battery, so don’t expect them all to be the same.

3. You can discharge Lithium batteries to 0%, but maybe only once! Cars will try to stop you going below around 30% SoC.

 

[eddie]

I think Lithium battery sales could become the next PPI scandal as unsuspecting purchasers step into the bear trap. Do research, then some more, about the proposal and what you have as a charging infrastructure.

Which is why we dont trust people that sell them claiming no change necessary

I have no doubt that people will be buying them next year at open air shows from people that own a gazebo and a website, working out of the back of a sign written van and a PO address next year then posting with lots of sad face emojis when they go bang

None of the Lithium Batteries on sale at the NEC were E Marked exceptthe Sterling units

No.one gave a damn when this was pointed out

Such is life

 

[eddie]

3. You can discharge Lithium batteries to 0%, but maybe only once! Cars will try to stop you going below around 30% SoC.

Evidence?

 

[eddie]

evidence not opinion

 

[Louis]

My experience ‘only’, overcharge lithium batteries= they swell up then useless, allow them to completely discharge = same result.

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[hilldweller]

evidence not opinion

A bit flawed. 25A charge/discharge is not a comprehensive representation. Those people, which he quoted, with inverters will be hammering them with near ten times that current. In our MH, our biggest load is 50W to charger an e-bike.

But without doubt lithium looked spectacular.

 

[HandyAndy]

There's more than one type of Lithium battery, that's the main problem.
LifeP04 - Yes you can pretty much straight swap the battery for your lead acid / AGM. The set points won't be perfect but it won't be overly damaging either. (basically because the cell chemistry is based on a nominal 3.2v which is very close to a Lead acid / AGM... (4 x 3.2v = 12.8v)
However if you go for other types of "LiOn" then no, you need specific charger and BMS (battery management system) to control them as they are more prone to damage in a catastrophic fashion) (basically because the cell chemistry is based on a nominal cell voltage of 3.7v which doesn't divide into 12v very well.. 3P (3 parallel) cells = 11.1v where as 4P (4 parallel) cells = 14.8v
Rules of thumb for LifeP04 to get your head round what it can be charged at safely.. if it's a 100AHr then you can charge it with 100 amps or 1C (1 x capacity)
50AHr then charge it with 50 amps etc
Edit to add more rules of thumb..
stay away from charge voltages above 14.4v and never discharge to below 10v and they will be OK.. (those being the absolute limits)
Don't charge it below 0°C
Don't ever allow a charger to do an equalisation charge on it
and don't leave the solar panel trickle charging it when not in use for long periods.

 

[two]

Evidence?

for what, Eddie?

I suppose I should've said "not many times" rather than "only once".
Deep discharges are said to reduce capacity. Another factor, not mentioned yet, is extreme heat or even extreme cold. Probably not the kind of temperatures we get in the UK but high temperatures have been found to be a problem in Australia.

My car's BMS will do its best to keep the batteries above 30% SoC. Below 22% it will shut off A/C and heating. Below 17% it will enter limp mode. Batteries are guaranteed for 8 years, so they want to protect them as much as possible.

 

[simsy56]

My mate said..............'I've got some of them Lithuanian batteries'......... come back Nellie Pledge!

Craig

 

[Minxy]

@Wissel ...

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[HandyAndy]

you can 100% discharge most lithium cells but as with all chemistries you reduce the cycles but it isn't one cycle LOL, closer to 300 from what I've seen so far but keep it above 80% and you increase that massively compared to wet cell technology... closer to 3000 cycles there. and 50% is around 5000 cycles, from what I've been reading.

If Wikipedia is to believed, it's apparently way better than that!!!

• 100% DOD cycle life (number of cycles to 80% of original capacity) = 2,000–7,000
• 10% DOD cycle life (number of cycles to 80% of original capacity) > 10,000

 

[Pausim]

Some of you may find these LiFePO4 performance characteristics of interest. The fifth graph gives cycle life v depth of discharge.
https://www.solar-electric.com/lib/wind-sun/Relion_RB100_Specifications.pdf
Ok, it is part of their sales pitch but I am not going to lose too much sleep over the occassional 100% discharge..

 

[hilldweller]

Some of you may find these LiFePO4 performance characteristics of interest.

One thing immediately stands out. 100A max continuous discharge. Iffy for kettle/microwave/curlers.

 

[Pausim]

One thing immediately stands out. 100A max continuous discharge. Iffy for kettle/microwave/curlers.

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

 

[Tincataylor]

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

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

The Tincas

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