Lithium Batteries - Am I missing the point

[Fraggle 22]

We met a bloke at the weekend who was singing the praises of Lithium batteries. We have motorhomed for 5 years and have 2 x 100amp hr lead acid batteries plus 100 watt solar panel. We rarely use EHU and spend most of our time on CS or THS for approx 12 weeks per season. We have never had a problem with power so I'm not sure why I would spend £900 on Lithium. I know they are lighter and more powerful but it would probably be easier to leave the wife at home than change! Any thoughts would be appreciated.

 

[pau1phi11ips]

Only 600w of solar will not cut it, if you eliminate the gas completely. We used to have 600w and added another 230w of solar. We not completely free of gas, but reduced it dramatically. Last fill up was in spring. Next one I expect it in October. We do have diesel heater and run that most of the time. The gas is mainly used for hot water, then a little for cooking and very rare for heating, if we are out of diesel.

Thanks for the heads up.

I'm using the diesel heater to get hot water using a Bobil system so that takes a bit of strain off the electrical requirement. The solar panels will be able to tilt for better yield too but yeah, I'll have to play it by ear to see if they generate enough for my needs. Not got any more room on the roof since I have a vent one the end and a Maxxair fan the other.

 

[two]

I don't understand an aversion to use gas in a motorhome. Gas energy is cheap although not as cheap as (free) solar. The investment to harvest solar energy and store it would buy an awful amount of gas (which works well in all seasons) however. If you charge your batteries with diesel, don't forget to factor the cost of that into the price of your electricity.

 

[pau1phi11ips]

I don't understand an aversion to use gas in a motorhome. Gas energy is cheap although not as cheap as (free) solar. The investment to harvest solar energy and store it would buy an awful amount of gas (which works well in all seasons) however. If you charge your batteries with diesel, don't forget to factor the cost of that into the price of your electricity.

I will hopefully be eliminating gas from my home use too when the boiler dies. Just because it's cheap doesn't mean it's good.

 

[eddie]

My camper runs on gas so Inlove it

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[Captain Birdseye]

It's a rather more complex equation. For example what depth of discharge do you apply to your LA batteries? If greater than 50% you will definitely shorten their lifetime. You only need half the capacity of lithium to replace LA, ie a 100Ah lithium is roughly equivalent to a 200Ah LA as it can be discharged almost fully. So it's 3x cost for a similar usable capacity. Also LA batteries cannot be charged at anywhere near the rate lithium can. This means that there may simply not be enough hours of daylight (or driving) to fully recharge the batteries. The bottom line is it really depends if you are a light user or not. My own van has a single 100A KS Energy lithium, 200W of solar and a victron B2B. We regularly cane the battery with an inverter (120A draw) but the power is restored fully within a few hours or less. That would not happen with LA batteries.
Lithium batteries are game changers, but only if the usage case requires it.

Agree. We don't use as much with our inverter, but otherwise all the same as you describe.

 

[Garry - June]

It's a rather more complex equation. For example what depth of discharge do you apply to your LA batteries? If greater than 50% you will definitely shorten their lifetime. You only need half the capacity of lithium to replace LA, ie a 100Ah lithium is roughly equivalent to a 200Ah LA as it can be discharged almost fully. So it's 3x cost for a similar usable capacity. Also LA batteries cannot be charged at anywhere near the rate lithium can. This means that there may simply not be enough hours of daylight (or driving) to fully recharge the batteries. The bottom line is it really depends if you are a light user or not. My own van has a single 100A KS Energy lithium, 200W of solar and a victron B2B. We regularly cane the battery with an inverter (120A draw) but the power is restored fully within a few hours or less. That would not happen with LA batteries.
Lithium batteries are game changers, but only if the usage case requires it.

again a misleading quote... "discharged almost fully" ....if you discharge Lithiums to below 20% of their capacity very often you will seriously shorten their lifespan...

 

[Jim]

again a misleading quote... "discharged almost fully" ....if you discharge Lithiums to below 20% of their capacity very often you will seriously shorten their lifespan...

You will. But you can.

 

[pau1phi11ips]

It's a rather more complex equation. For example what depth of discharge do you apply to your LA batteries? If greater than 50% you will definitely shorten their lifetime. You only need half the capacity of lithium to replace LA, ie a 100Ah lithium is roughly equivalent to a 200Ah LA as it can be discharged almost fully. So it's 3x cost for a similar usable capacity.

I'm not even sure it's 3x the price of you build it yourself.

My battery cost £0.11 per Wh and should be good for 2,500 cycles. If anyone can point me towards a better value LA then please do.

I'm looking at 1200 Wh LA and they cost ~£140 which is the same price per Wh, weigh more than 3 times as much and have about 10% the cycle time.

 

[pau1phi11ips]

again a misleading quote... "discharged almost fully" ....if you discharge Lithiums to below 20% of their capacity very often you will seriously shorten their lifespan...

Sorry, but this is misleading too. This is the case for Lithium-ion (used in phones, tool batteries and 1st gen electric cars) but not Lithium Iron Phosphate which is commonly used for leisure batteries (and some of the latest Teslas). You can easily use 90% of the capacity for 2,500 cycles with LiFePO4. If you're only using low C rates this will be more like 4,000 cycles.

Lithium Titanate chemistry gets 20,000 cycles which is kinda insane!

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[Raul]

again a misleading quote... "discharged almost fully" ....if you discharge Lithiums to below 20% of their capacity very often you will seriously shorten their lifespan...

The discharge rate will do more damage than the depth of discharge. You can take them down to 5% SOC but with a rate under 0,2C and no damage. But hit them with 1,2C and they will suffer capacity loss. LiFePo4 is long lived if discharged up to 0,3C. They can do more but at cost of life span.

 

[eddie]

I can't afford a Lear Jet/my wife won't let me buy a Lear Jet

Anyone with a Lear Jet is a twat
Anyone who buys into the Lear Jet marketing blurb is a twat
Anyone who thinks about buying a Lear Jet is a twat
Anyone who believes the hype about Lear Jets is a twat
Anyone who sings the praises of a Lear Jet is stupid/deluded/misguided (or all of them)

Has anyone who has fitted, or had fitted, Lithium batteries regretted it, and gone back to old battery technology?

Just asking?

 

[Raul]

Sorry, but this is misleading too. This is the case for Lithium-ion (used in phones, tool batteries and 1st gen electric cars) but not Lithium Iron Phosphate which is commonly used for leisure batteries (and some of the latest Teslas). You can easily use 90% of the capacity for 2,500 cycles with LiFePO4. If you're only using low C rates this will be more like 4,000 cycles.

Lithium Titanate chemistry gets 20,000 cycles which is kinda insane!

A colleague of mine upgraded from LFP to LTO, for its house. The 40ah ynlong cylindrical. Those things are like super capacitors, 3C and no heat. Of course he keeps them up to 1C most of the time. Downside is cost only, at 50 dollars a piece plus import taxes. My house is on Lead, and 7th year this bank. I will be soon for a upgrade and torn between high end LFP or LTO. Mainly for their insane rate capability. Sometimes in winter we got only a 2hr window for charging. The LTO can swallow massive amounts in short time.

 

[Raul]

The only regret I have going Li is, I haven’t done it sooner.

 

[Mike Rivers]

Surely the whole point is that Lithium batteries can provide the benefits of an EHU for a period of time without actually hooking up. More remote CL’s without EHU can then become a site choice for those who would otherwise avoid. Obviously there are some here who have mastered the art of getting by on standard leisure batteries and credit to them. Personally if I was embarking on a Scandinavian tour for example I would be seriously looking at a Lithium system. Horses for courses as they say. Certainly would welcome feedback from those members who’ve decided to build their own batteries for a fraction of the cost and whether it worked out for them.

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[Teithwr]

Sorry, I can’t see how to delete this partial post.

 

[Cliff Bryant]

again a misleading quote... "discharged almost fully" ....if you discharge Lithiums to below 20% of their capacity very often you will seriously shorten their lifespan.

Notice how I said ALMOST fully. Just as you said "very often". In practice a properly designed BMS will protect against full discharge just as it protects against overcharging. The maximum discharge level is relative and sometimes configurable. One of the big problems of lithium is the inability to charge at or below 0C. Some batteries have heaters built in to manage this problem.

 

[Cliff Bryant]

I'm not even sure it's 3x the price of you build it yourself.

My battery cost £0.11 per Wh and should be good for 2,500 cycles. If anyone can point me towards a better value LA then please do.

I'm looking at 1200 Wh LA and they cost ~£140 which is the same price per Wh, weigh more than 3 times as much and have about 10% the cycle time.

Insurance implications have stopped me building a battery into a motorhome but I'm very interested in reading about homebrew systems. Our next van will certainly have a lithium system and plenty of solar so that off grid touring is viable.

 

[the1andonly]

Has anyone who has fitted, or had fitted, Lithium batteries regretted it, and gone back to old battery technology?

Just asking?

Gaget John

 

[Teithwr]

I’ve just come back from using our 2014 Autocruise Forte for the first time since the pandemic began. 5 nights in a Staffordshire field playing with the Sealed Knot. We have 2 leisure batteries and an inverter which the previous owner fitted. There is a solar panel which I think is 40w. This has done us fine for the 5 years we’ve had it, using the electrics for lighting, some tv etc. This time though when we tried to warm a meal in the 850w microwave, after about 3 minutes the low battery warning went off and the level lights went red. The following day after some daylight the level lights were back to 3 greens. As you’ll have gathered, I have no idea about these matters. Are the batteries, unchanged by us, on the way out. It’s plugged into the mains when standing at home. If they are should we / could we replace them with lithium? Etc?

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[Lenny HB]

Has anyone who has fitted, or had fitted, Lithium batteries regretted it, and gone back to old battery technology?

Gaget John

Perhaps the question should have been " Has any normal person who has fitted, or had fitted, Lithium batteries regretted it, and gone back to old battery technology?"

 

[JJ]

I love the love Funster Folk have for lithium batteries...

When they get their new battery I plan to get their old ones...

JJ

 

[pau1phi11ips]

I love the love Funster Folk have for lithium batteries...

When they get their new battery I plan to get their old ones...

JJ

I'll drop you a line in 35 years when mine only charges to 80% capacity

 

[Clipgate]

Nothing is perfect and care with both lead acid and lithium is required.
This article came from motorcycle application however I believe quite useful.

<Broken link removed>

 

[funflair]

Surely the whole point is that Lithium batteries can provide the benefits of an EHU for a period of time without actually hooking up. More remote CL’s without EHU can then become a site choice for those who would otherwise avoid. Obviously there are some here who have mastered the art of getting by on standard leisure batteries and credit to them. Personally if I was embarking on a Scandinavian tour for example I would be seriously looking at a Lithium system. Horses for courses as they say. Certainly would welcome feedback from those members who’ve decided to build their own batteries for a fraction of the cost and whether it worked out for them.

This in indeed one point of Lithium but I think there are others such as weight power density etc, we have just done 4 nights in Scotland with minimal sun and used the lithium for boiling kettle and cooking as well as the usual coffee machine and hair dryer, we got down to about 40% capacity.

We have just done 5 nights at Chester with some decent sun for the first 3 days but then overcast, we left with about 80% capacity so could have done a lot longer.

We have 480ah storage and 520 watts solar so a good balance between storage and charge capacity I think but a bit more solar would be good for the dull days.

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[pau1phi11ips]

I’ve just come back from using our 2014 Autocruise Forte for the first time since the pandemic began. 5 nights in a Staffordshire field playing with the Sealed Knot. We have 2 leisure batteries and an inverter which the previous owner fitted. There is a solar panel which I think is 40w. This has done us fine for the 5 years we’ve had it, using the electrics for lighting, some tv etc. This time though when we tried to warm a meal in the 850w microwave, after about 3 minutes the low battery warning went off and the level lights went red. The following day after some daylight the level lights were back to 3 greens. As you’ll have gathered, I have no idea about these matters. Are the batteries, unchanged by us, on the way out. It’s plugged into the mains when standing at home. If they are should we / could we replace them with lithium? Etc?

40W or 400W? 40W is pretty small. You can get 300W panels for ~£75 these days.

That 850W for 3 minutes would likely use about 50Wh which should be no hassle at all for 2 leisure batteries. It sounds like they are indeed kaputt.

 

[Teithwr]

40w seems to be what Swift fit, and fitted, as standard for their factory fitted units. Could I swap it over for a 300w unit easily? Would the PSU etc handle that?

 

[Garry - June]

I can't afford a Lear Jet/my wife won't let me buy a Lear Jet

Anyone with a Lear Jet is a twat
Anyone who buys into the Lear Jet marketing blurb is a twat
Anyone who thinks about buying a Lear Jet is a twat
Anyone who believes the hype about Lear Jets is a twat
Anyone who sings the praises of a Lear Jet is stupid/deluded/misguided (or all of them)

Has anyone who has fitted, or had fitted, Lithium batteries regretted it, and gone back to old battery technology?

Just asking?

So the moral of this story is everyone sell their Motorhomes and purchase a Lear jet...cuz they're good...

 

[pau1phi11ips]

40w seems to be what Swift fit, and fitted, as standard for their factory fitted units. Could I swap it over for a 300w unit easily? Would the PSU etc handle that?

You'll need to see what room you have on the roof. You can compare lots of panel sizes here: <Broken link removed>

The solar charge controller will likely need to be upgraded too if it was paired with a 40W panel before.

 

[Teithwr]

The charger, Victron Blue Solar Duo, has 20A output on the spec sheet so should that mean 240W input is OK with 12v?

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[pau1phi11ips]

The charger, Victron Blue Solar Duo, has 20A output on the spec sheet so should that mean 240W input is OK with 12v?

In theory yes, 240W, but that charger is limited to 28V max from the panel on a 12V battery

https://www.victronenergy.com/upload/documents/Manual-BlueSolar-PWM-DUO-12V-24V-20A-LCD-USB-EN-NL-FR-DE-ES-SE-IT-CZ-RU.pdf

This makes the choice of panel quite limiting and the Price per Watt a bit higher. The bigger panels go down to 28 pence per Watt but the smaller ones that would work with your charger are at best 53 pence per Watt. Like this <Broken link removed>