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.

 

[RowleyBirkinQC]

Our main driver to change would be the weight differential, our two current Banner 92Ah batteries have a total weight of circa 50kg, a single Sterling 120 Ah lithium weighs circa 15kg.

 

[pau1phi11ips]

Anyone considering assembling their own battery? I've just ordered 24 x 285Ah cells which with the addition of a BMS per battery will make six 285Ah 12v batteries.

I made my 24V LiFePO4 battery using 280Ah cells. Couldn't be happier with it tbh. Cost £800 for the cells and the BMS from AliExpress delivered to UK. I capacity tested each of the cells before the battery was assembled.

 

[pau1phi11ips]

Our main driver to change would be the weight differential, our two current Banner 92Ah batteries have a total weight of circa 50kg, a single Sterling 120 Ah lithium weighs circa 15kg.

Yeah, there's a pretty big weight difference. My battery would be 560Ah if it was 12V and weighs 45kg.

 

[jongood]

They will be down to about 182ah due to aging.

I think you were in on the thread where I tried to drain my Gels and got pretty much what it says out of them. I don't know for certain but I strongly suspect they're original fit from 2003.

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[tonyidle]

I made my 24V LiFePO4 battery using 280Ah cells. Couldn't be happier with it tbh. Cost £800 for the cells and the BMS from AliExpress delivered to UK. I capacity tested each of the cells before the battery was assembled.

That's really good to know. I got my post wrong - it was only 16 cells I bought . I still need to decide on / source a BMS (or 3).

 

[pau1phi11ips]

That's really good to know. I got my post wrong - it was only 16 cells I bought . I still need to decide on / source a BMS (or 3).

I went with a Daly Smart BMS. All the power kit in my van is Victron and there's a serial driver for the Daly to be able to talk to the Victron Cerbo. It just plugs into one of the USB using the cable that came with the BMS.

GitHub - Louisvdw/dbus-serialbattery: Battery Monitor driver for serial battery in VenusOS GX systems

Battery Monitor driver for serial battery in VenusOS GX systems - Louisvdw/dbus-serialbattery

github.com

 

[Lenny HB]

I think you were in on the thread where I tried to drain my Gels and got pretty much what it says out of them. I don't know for certain but I strongly suspect they're original fit from 2003.

It was after my advice you tested them and decided you didn't need Lithium.
Are you going for the record 20, 25 years.

 

[jongood]

It was after my advice you tested them and decided you didn't need Lithium.
Are you going for the record 20, 25 years.

Yes I really wanted a justification to change them

But even in crappy welsh weather they still recovered quickly.

 

[Peppadog]

I love the new Lithium battery tech, and will fit them when my Banner 110ah batteries are kaput. I hope the prices and tech improve between now and then. Nobody really wants to carry on replacing with heavy old lead acid batteries that can only survive at above 50% charge do they?

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[Murrays]

I went with a Daly Smart BMS. All the power kit in my van is Victron and there's a serial driver for the Daly to be able to talk to the Victron Cerbo. It just plugs into one of the USB using the cable that came with the BMS.

GitHub - Louisvdw/dbus-serialbattery: Battery Monitor driver for serial battery in VenusOS GX systems

Battery Monitor driver for serial battery in VenusOS GX systems - Louisvdw/dbus-serialbattery

github.com

Good choice. The 200A Daly 4S smart BMS is the one I'd go for if I were building my 12V 280Ah EVE pack again now. Back at the end of 2019 that wasn't an option. I was keen to ensure low temperature charge protection was included and found a 120A unit that fitted my needs, though I had to modify it to deal with currents up to 200A. Daly have units up to 500A and do include low temperature charge protection (I believe).

I just stumbled across offgridvan.life that appear to be selling a prebuilt 12V 280Ah EVE / Daly smart BMS pack if anyone is not keen to make their own. Looks well built in a plywood DIY sort of way... depends how much you value a plastic box around your battery. You'll see from the photo in my previous post that that's not something I bothered with, I needed the smallest pack possible which meant it had to be naked. If there's no box though it's safest to put Kapton tape over all of the exposed busbars and terminals though as these cells are very low impedance and are capable of delivering thousands of amps if short circuited by a falling spanner etc.

Steve.

 

[pau1phi11ips]

Looks well built in a plywood DIY sort of way... depends how much you value a plastic box around your battery. You'll see from the photo in my previous post that that's not something I bothered with, I needed the smallest pack possible which meant it had to be naked. If there's no box though it's safest to put Kapton tape over all of the exposed busbars and terminals though as these cells are very low impedance and are capable of delivering thousands of amps if short circuited by a falling spanner etc.

I put 8 280Ah cells in Stanley Fatmax 28" toolbox. They fit like a charm. Just enough extra room for the Daly BMS and a Victron BMV shunt.

 

[Jamesh]

I put 8 280Ah cells in Stanley Fatmax 28" toolbox. They fit like a charm. Just enough extra room for the Daly BMS and a Victron BMV shunt.

Any chance of a pic?

Sounds like a good set up?

How high is the fatmax toolbox?

Cheers James

 

[CazPaul]

It was after my advice you tested them and decided you didn't need Lithium.
Are you going for the record 20, 25 years.

I am going for it too

 

[pau1phi11ips]

Any chance of a pic?

Sounds like a good set up?

How high is the fatmax toolbox?

Cheers James

Dimensions are 71 x 28.5 x 30.8cm https://amzn.to/3kFJDrB

Here's an older photo. I put perspex in between to the cells to offer a bit more insulation. I've added conduit to the balance wires now it's installed.

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[cmcardle75]

Lots of Lithium batteries say they are drop in replacement, they will work but if you want the best out of them and a long life don't believe it. Fit the correct mains charger/solar regulator & B2B to do the job properly.
Not much point in spending a fortune on the battery then not getting the best out of it.

Some BMSes will basically allow this. Indeed, the BMS on my recently installed 300Ah appears to after some analysis. It appears to cut off all charging when any individual cell voltage exceeds a particular value. This means it takes any bulk current you throw at it and doesn't allow over-voltage or over-timed absorbtion to affect the battery. It seamlessly allows the charger to maintain 14.4V (or whatever the charger thinks appropriate) to the habitation electrics, without allowing the actual cells to be overcharged by an over enthusiastic absorbtion or inappropriate float setting. It doesn't do anything fancy, like allow you to stop charging at 80%, but it is probably not that much worse than many dedicated chargers' LiFePO4 settings.

 

[pau1phi11ips]

Some BMSes will basically allow this. Indeed, the BMS on my recently installed 300Ah appears to after some analysis. It appears to cut off all charging when any individual cell voltage exceeds a particular value. This means it takes any bulk current you throw at it and doesn't allow over-voltage or over-timed absorbtion to affect the battery.

I think the danger here is to the alternator and not the battery. See this video for a demo:

 

[cmcardle75]

I think the danger here is to the alternator and not the battery. See this video for a demo:

Overpowering your alternator is another issue, but should not occur if you either have a B2B charger (of any sort) or enough resistance in the system (i.e. relatively thin or long supply cables), or don't sit about idling. An alternator overload would require a dumb alternator, heavy cabling to a dumb split charge relay, a fairly discharbed LiFePO4, and sitting there idling for a long time. Only some systems would be susceptible to this failure mode, but some defintely will be.

 

[SSILVO]

For those considering making their own batteries, there are loads of vids on youtube on various cells and their output etc. However, there are regulations about moving lithium batteries see link including UK regs. The reason this Could be important for self builds is that the ones supplied for example by Vanbitz are definitely licensed for use on the road (not all are). As we all know Insurance companies love to play a get out of jail card with claims when possible , homemade lithium batteries could just be one.

good luck y'all
https://app.croneri.co.uk/topics/transport-lithium-batteries/indepth

 

[Lenny HB]

Some BMSes will basically allow this. Indeed, the BMS on my recently installed 300Ah appears to after some analysis. It appears to cut off all charging when any individual cell voltage exceeds a particular value. This means it takes any bulk current you throw at it and doesn't allow over-voltage or over-timed absorbtion to affect the battery. It seamlessly allows the charger to maintain 14.4V (or whatever the charger thinks appropriate) to the habitation electrics, without allowing the actual cells to be overcharged by an over enthusiastic absorbtion or inappropriate float setting. It doesn't do anything fancy, like allow you to stop charging at 80%, but it is probably not that much worse than many dedicated chargers' LiFePO4 settings.

The BMS is a safety device to protect the battery its not really intended to control the charging, some work better than others. With the cost of Lithium batteries it s much safer to use chargers that have the correct profiles.

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[cmcardle75]

The BMS is a safety device to protect the battery its not really intended to control the charging, some work better than others. With the cost of Lithium batteries it s much safer to use chargers that have the correct profiles.

Indeed. However, my observations of the BMS on mine lead me to conclude that it wouldn't cook the battery if run on an inappropriate charging profile. My chargers, at it happens, are Lithium compatible, but I was curious to see if the BMS's claims had any merit, or were just marketing nonsense. I was particularly impressed by the seamless transfer between cells disconnected and otherwise. There was no flicker or discontinuity in power, although that might say more for the quality of the Victron chargers as anything else.

 

[jongood]

I am going for it too

You do realise Paul that our battery banks are both going to fail on the next trip now

 

[Murrays]

Dimensions are 71 x 28.5 x 30.8cm https://amzn.to/3kFJDrB

Here's an older photo. I put perspex in between to the cells to offer a bit more insulation. I've added conduit to the balance wires now it's installed.

That's a pretty neat installation, all Victron kit too, looks expensive! Those cells of yours look like CATL rather than EVE though? They are physically very similar, but the terminals are different shape. Given CATL have a 25% global Li-Ion cell market share (2020), you should get good service! I'd have chosen CATL over EVE given the choice.
It must be great to have that much space to work in, my kit is fitted in the dead space at the back of some drawers! Also 24V rather than 12V must be nice.

 

[Murrays]

Overpowering your alternator is another issue, but should not occur if you either have a B2B charger (of any sort) or enough resistance in the system (i.e. relatively thin or long supply cables), or don't sit about idling. An alternator overload would require a dumb alternator, heavy cabling to a dumb split charge relay, a fairly discharbed LiFePO4, and sitting there idling for a long time. Only some systems would be susceptible to this failure mode, but some defintely will be.

Spot on. I (optimistically) tested my Li-Ion without a B2B initially, using the original hab battery supply. Charging a flat battery (12V) the split charge supply didn't exceed 15A. Hopeless. A 60A Sterling B2B and some 25mm2 cables were quickly on the shopping list to do the job properly.

 

[Rimswell Wanderer]

It's the latest "thing".

Hobbyist love to have the latest thing.

JJ

Absolutely the only drawback is the cost of my Amateur Radio Equipment.

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[pau1phi11ips]

That's a pretty neat installation, all Victron kit too, looks expensive! Those cells of yours look like CATL rather than EVE though? They are physically very similar, but the terminals are different shape. Given CATL have a 25% global Li-Ion cell market share (2020), you should get good service! I'd have chosen CATL over EVE given the choice.
It must be great to have that much space to work in, my kit is fitted in the dead space at the back of some drawers! Also 24V rather than 12V must be nice.

Thanks, it was fun putting it all together. Spent about £2,500 on the electrical but for 7.2kWh of capacity and a 3kW inverter/charger, I don't think that's bad.

There will be 600W of solar on the roof and there's space for a second B2B charger if it turns out 1 isn't enough.
We're not having gas in the van: Induction cooker, toaster, kettle, and the other half's hair dryer is all on the inverter.
Fridge, lights, USB outlets and diesel heater are all 24V. Pretty much zero downside for 24V for me.
The only thing on the 24V-12V converter is the Maxxair fan at the mo.

Love the Victron VRM integration. Can see stats for the electrical system, inside temp, fridge temp, the level of the 3 water tanks (fresh, hot & grey). So good!

 

[Murrays]

Thanks, it was fun putting it all together. Spent about £2,500 on the electrical but for 7.2kWh of capacity and a 3kW inverter/charger, I don't think that's bad.

There will be 600W of solar on the roof and there's space for a second B2B charger if it turns out 1 isn't enough.
We're not having gas in the van: Induction cooker, toaster, kettle, and the other half's hair dryer is all on the inverter.
Fridge, lights, USB outlets and diesel heater are all 24V. Pretty much zero downside for 24V for me.
The only thing on the 24V-12V converter is the Maxxair fan at the mo.

Love the Victron VRM integration. Can see stats for the electrical system, inside temp, fridge temp, the level of the 3 water tanks (fresh, hot & grey). So good!

Yes, the level of integration of the Victron kit is great. I've got a Multiplus II 5000 in my home storage system and it works really well, along with another home made 10kWh 48V Li-Ion pack. Only complaint is the inverter is noisy.
Sounds like you've gone all in on electric, I think I'd have done the same if I'd started from scratch, including the selection of 24V. Nice setup. (I'm jealous...)

 

[Finch]

They're ordered and I'm currently touring. When I have them I'll post about testing, balancing, assembly, and BMS choice. No brackets needed thanks!

I look forward to that too.

 

[sallylillian]

Dimensions are 71 x 28.5 x 30.8cm https://amzn.to/3kFJDrB

Here's an older photo. I put perspex in between to the cells to offer a bit more insulation. I've added conduit to the balance wires now it's installed.

A multi 2, a much more compact unit, wish I could justify swapping but my multi is only 2 years old.

 

[Raul]

Thanks, it was fun putting it all together. Spent about £2,500 on the electrical but for 7.2kWh of capacity and a 3kW inverter/charger, I don't think that's bad.

There will be 600W of solar on the roof and there's space for a second B2B charger if it turns out 1 isn't enough.
We're not having gas in the van: Induction cooker, toaster, kettle, and the other half's hair dryer is all on the inverter.
Fridge, lights, USB outlets and diesel heater are all 24V. Pretty much zero downside for 24V for me.
The only thing on the 24V-12V converter is the Maxxair fan at the mo.

Love the Victron VRM integration. Can see stats for the electrical system, inside temp, fridge temp, the level of the 3 water tanks (fresh, hot & grey). So good!

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.

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[Peppadog]

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.

I bought a cheap Chinese diesel heater but have not yet installed it. 1. The gas only Truma works well. 2. Gas (in my two bottle gaslow set up) is a lot cheaper than diesel.
A lot of what I have read in these latest posts demonstrates that it costs thousands to achieve what some of you guys have now done. I applaud you, but I wonder if you will ever recover the outlay?