200Ah LiFePo4 Auxiliary System

[SeanC]

So with the cranking battery on the way out and questions about the 80Ah deep cycle battery l started thinking about replacements. Together there was 160Ah. The SC80 works well but I was finding the on occasions some extra capacity would be good. Overcast days when I was planning a lazy day at the camp etc.

First idea was putting another AGM behind the second row seats.

Then I started thinking about lithium. Found Deep Cycle Systems batteries which were rated for cranking and under bonnet use with 3 year replacement warranty, which was difficult to find in other brands. So this plan was to do a straight swap with a 75Ah auxiliary and 100Ah (1000 CCA) cranking LiFePo4 batteries that can be charged directly from the alternator.

But I though why would I pay that sort of money and then put the batteries in the worst place possible for longevity. If you can’t get the increased longevity that removes one of the benefits of of paying extra for lithium.

So I ended going with 2 x 100Ah LiFePo4 behind the second row seats and an Odyssey PC1350 as a cranking battery. With only cranking duty hopefully I should get increased life span.

As I was mixing battery types I needed an ignition switched DC2DC charger. So the SC80 has been retired for the moment.

Time will tell if it will be a good investment.

Heard a lot for and against so I decided to give it a go and find out.

LiFePo4 Auxiliary Set-up - Google Photos (https://photos.app.goo.gl/636nxRpnukj7wxtJ8)

[p38arover]

Would we be frightened by the cost?

[Milton477]

Good system, you won't be sorry.

[SeanC]

Would we be frightened by the cost?
Maybe.
About $3000 all-up including fitting.

[DiscoJeffster]

Maybe.
About $3000 all-up including fitting.

OMFG. And here I am questioning whether I get home brand or original muesli [emoji23]

[SeanC]

OMFG. And here I am questioning whether I get home brand or original muesli [emoji23]

l did a bit of a comparison. 198Ah Yellow Top vs 200Ah LiFePo4 ignoring the cranking battery which can be used for extra capacity I know.

Optima Yellow Tops (Atutomotive Superstore)
2 x 31T 75 Ah 150Ah 54.2Kg $810
1 x D35 48Ah 16.5kg. $325
198Ah 70.7kg $1135


2 x 100Ah LiFePo4 24kg $2200
$2200 + DC2DC $300 = $2500

About twice the cost a third the weight. I’m not expecting on saving money. If I get around breaking even I’ll be happy.

Playing the long game. Might have an answer in 8-10 years. Who knows. So stay tuned.

[Hugh Jars]

I had 300Ah of lithiums in my camper. 2 ½ years on and no noticeable reduction in capacity. They weren’t rated for cranking, but the best option on the list by far.
Never had any problems with them [emoji1303]

[drivesafe]

Hi Sean, I have set up a few D4 Lithium Battery systems now. The first being about 7 years ago.

At that time, neither the customer ( now a good friend ) or I knew much about Lithium batteries but he already had one of my systems, with an Optima Yellowtop as the auxiliary battery.

Thanks to his assistance, we both learnt quite a lot from that first setup and the first thing learnt was that my Sc80 isolators will not work with a Lead Acid - Lithium battery combo.

No isolator will work in this type of setup.

While the initial Lithium setup was done by replacing the Optima with a lithium. This was very quickly reversed and the Optima was reinstalled and the lithium was moved to the cargo area and charged with a Sterling setup.

I had been recommending to my customers to use Sterling charges for a good few years and then started setting up lithium battery charging with Sterling Battery to Battery chargers.

The main advantage, besides their reliability when charging lithium batteries, is their size.

I now set up these systems with 60 amp Sterling BB1260 battery to battery charges.

I'm guessing you are using something like a 20A or 30A DC/DC charger.

This means if your two 100Ah lithiums are low, you will need to drive for around 8 to 10 hours to fully charge them, but the BB1260 will do a full recharge in about 5 hours and this is about what it would take to recharge a setup using those conventional batteries ( Optima batteries ) you mentioned in your comparison above, using direct alternator charging.

[SeanC]

Hi Sean, I have set up a few D4 Lithium Battery systems now. The first being about 7 years ago.

At that time, neither the customer ( now a good friend ) or I knew much about Lithium batteries but he already had one of my systems, with an Optima Yellowtop as the auxiliary battery.

Thanks to his assistance, we both learnt quite a lot from that first setup and the first thing learnt was that my Sc80 isolators will not work with a Lead Acid - Lithium battery combo.

No isolator will work in this type of setup.

While the initial Lithium setup was done by replacing the Optima with a lithium. This was very quickly reversed and the Optima was reinstalled and the lithium was moved to the cargo area and charged with a Sterling setup.

I had been recommending to my customers to use Sterling charges for a good few years and then started setting up lithium battery charging with Sterling Battery to Battery chargers.

The main advantage, besides their reliability when charging lithium batteries, is their size.


I now set up these systems with 60 amp Sterling BB1260 battery to battery charges.

I'm guessing you are using something like a 20A or 30A DC/DC charger.

This means if your two 100Ah lithiums are low, you will need to drive for around 8 to 10 hours to fully charge them, but the BB1260 will do a full recharge in about 5 hours and this is about what it would take to recharge a setup using those conventional batteries ( Optima batteries ) you mentioned in your comparison above, using direct alternator charging.

Hi Tim. The DC2DC charger is a 40 amp.

[p38arover]

That cost is better than I expected.

My starting battery is 18 months old and is noticeably degraded. When I bought it, I didn't realise it should have been an AGM.

Add to that the two 45Ah deep cycle AGM aux batteries that are the same age and are now of reduced capacity that they struggle the supply just a fridge overnight.

Replacing all within 2 years isn't a good deal compared with your system.

[drivesafe]

Hi Tim. The DC2DC charger is a 40 amp.
Hi Sean, I should have looked at your photo.

Those batteries are rebadged OPTIMUM ( not Optima ) lithium batteries and are not bad. DCS have only been selling them for a short while but I see they have dropped their prices.

I did a lot of testing on OPTIMUM batteries and the company I was doing the testing for, helped OPTIMUM set up a better BMS for their batteries.

[drivesafe]

That cost is better than I expected.

My starting battery is 18 months old and is noticeably degraded. When I bought it, I didn't realise it should have been an AGM.

Add to that the two 45Ah deep cycle AGM aux batteries that are the same age and are now of reduced capacity that they struggle the supply just a fridge overnight.

Replacing all within 2 years isn't a good deal compared with your system.
Ron, first off, your batteries should not have died that quickly. How much driving are you doing.

Also, it is morethen likely that you can recover the lost capacity with some sustained overnight charging.

Secondly, if your driving habits are the cause of your battery situation, changing to lithiums is not the answer because they can suffer from the same problems, but they are quicker to fix.

[ndrew]

So I ended going with 2 x 100Ah LiFePo4 behind the second row seats and an Odyssey PC1350 as a cranking battery. With only cranking duty hopefully I should get increased life span.

As I was mixing battery types I needed an ignition switched DC2DC charger. So the SC80 has been retired for the moment.

Time will tell if it will be a good investment.

Heard a lot for and against so I decided to give it a go and find out.

LiFePo4 Auxiliary Set-up - Google Photos (https://photos.app.goo.gl/636nxRpnukj7wxtJ8)

Mate, thanks for sharing that — you’ve done exactly what I’ve been thinking about doing. My Optima Yellow Tops are leaving me a little bit unimpressed right now — not holding voltage and the reseller isn’t interested in backing the product.

Do you have any extra photos that show how the batteries are secured? I’ve got Front Runner drawers in the back of my D3 and there’s options for mounting where the third row seats are (if I remove them permanently, which I think I’ll do anyway), or in the space directly behind the second row. I’m keen to see how I can best secure them back there safely.

Cheers,

— Andrew

[SeanC]

Mate, thanks for sharing that — you’ve done exactly what I’ve been thinking about doing. My Optima Yellow Tops are leaving me a little bit unimpressed right now — not holding voltage and the reseller isn’t interested in backing the product.

Do you have any extra photos that show how the batteries are secured? I’ve got Front Runner drawers in the back of my D3 and there’s options for mounting where the third row seats are (if I remove them permanently, which I think I’ll do anyway), or in the space directly behind the second row. I’m keen to see how I can best secure them back there safely.

Cheers,

— AndrewHi Andrew No other photos yet. Will have a look tomorrow. Pretty confined space with the seats back in.The cargo barrier meant that conventional battery boxes were too high. As you can see the foam flooring was pulled forward so they had a solid base under them. The thought was the foam might allow some movement and the mounts might loosen. The mounting bolts go through the floor and then sealed with silicon. It was a tight fit. Another couple of centimetres in width and I wouldn’t have gotten the seats back in. Without a cargo barrier you could most probably use battery boxes.

[drivesafe]

Mate, thanks for sharing that — you’ve done exactly what I’ve been thinking about doing. My Optima Yellow Tops are leaving me a little bit unimpressed right now — not holding voltage.

Andrew
Hi Andrew, what is the voltage of your Yellowtops and how are you charging them.

Yellowtops batteries actually offer better charging results than lithium batteries, because to charge lithium batteries properly, you need some form of charging device.

Because Optimas can be charged direct form your alternator, you can charge them from a low state, with as much as 100 amps in the initial state of the charge.

As I posted above, you need at least a 60 amp DC/DC device for charging lithium batteries before you get anywhere near what your Optimas will charge at, when charging direct from an alternator.

PLEASE NOTE, I do not sell Optima batteries but I will soon be selling lithium batteries, so this has nothing to do with being biased but is to do with which type of batteries perform best in a given type of situation.

Usually the cause of low voltage in an Optima is insufficient charging time. So replacing them with lithium batteries most likely, will not resolve the problem.

So again, how are you charging your Yellowtops and what sort of drive times are you doing?

[Milton477]

Hi Tim. The DC2DC charger is a 40 amp.

Your pic shows a DC2DC+ I have one & this model will do 50A if the cabling is big enough & you change the settings.

[SeanC]

Your pic shows a DC2DC+ I have one & this model will do 50A if the cabling is big enough & you change the settings.

It does say 40+ in the name. Will have to a read through the manual. Thanks for the heads up.

[ndrew]

G'day, Tim.


Hi Andrew, what is the voltage of your Yellowtops and how are you charging them.

I'm having trouble keeping the Yellow Tops above 12.8V for any length of time, with them rapidly dropping to 12.4V or lower with relatively mild use. They're being charged by a Redarc BCDC1225D.



Usually the cause of low voltage in an Optima is insufficient charging time. So replacing them with lithium batteries most likely, will not resolve the problem.

So again, how are you charging your Yellowtops and what sort of drive times are you doing?

I'm not convinced that it's a charging issue. On a 8-hour run to Western New South Wales recently, I immediately checked the voltage once I arrived at my destination and watched it rapidly drop back to 12.8...12.7...12.6 and so on. It's not a linear drop, I have to admit; it seems to drop from 13.1 to 12.8 rapidly and then more slowly from there.

The car also has a 160W solar panel mounted permanently on the roof which runs into the BCDC1225D.

My motivation to changing to lithium is three-fold: one, I'd love a bit more capacity than my two Yellowtops currently provide; two, I'd like something lighter and to free up some space in the engine bay, and; four, I'd like to replace my BCDC1225D with a BMS like the Redarc Manager30.

Cheers,

- Andrew

[drivesafe]

I'm having trouble keeping the Yellow Tops above 12.8V for any length of time, with them rapidly dropping to 12.4V or lower with relatively mild use. They're being charged by a Redarc BCDC1225D.

I'm not convinced that it's a charging issue. On a 8-hour run to Western New South Wales recently, I immediately checked the voltage once I arrived at my destination and watched it rapidly drop back to 12.8...12.7...12.6 and so on. It's not a linear drop, I have to admit; it seems to drop from 13.1 to 12.8 rapidly and then more slowly from there.
- Andrew
Hi Andrew and I am not going to get into what charges better, while on the road, but when at home, do you use a battery charger to charge them, at any time, when they seem to be low.

From what you are saying, it just sounds like they are not being charged properly because of drive time.

Your one big drive, regardless of whether they are charged by a DC/DC device or direct from an alternator, if your batteries are in a poor condition, one long drive will not fix the problem, but long charging times at home with a battery charger probably will.

The link below will give you an idea of what to do, to improve the capacity and condition of your yellowtops.

Just scroll down to the post on Long Term Battery maintenance.

On-Line auto electrical info (https://www.aulro.com/afvb/the-verandah/246755-line-auto-electrical-info-8.html)

[SeanC]

Your pic shows a DC2DC+ I have one & this model will do 50A if the cabling is big enough & you change the settings.Thanks. Now set at 50A.

[SeanC]

Mate, thanks for sharing that — you’ve done exactly what I’ve been thinking about doing. My Optima Yellow Tops are leaving me a little bit unimpressed right now — not holding voltage and the reseller isn’t interested in backing the product.

Do you have any extra photos that show how the batteries are secured? I’ve got Front Runner drawers in the back of my D3 and there’s options for mounting where the third row seats are (if I remove them permanently, which I think I’ll do anyway), or in the space directly behind the second row. I’m keen to see how I can best secure them back there safely.

Cheers,

— Andrew
Hi Andrew. Couldn’t get any good photos. Too tight. This is the battery tray used (OEX ACX0663 UNIVERSAL LARGE METAL BATTERY TRAY) if the battery is wider than the tray it won’t fit behind the second row seats. The tray was either screwed or bolted through the floor. Will have a look underneath tomorrow. The battery hold down is PROJECTA BHD18M UNIVERSAL BATTERY HOLD DOWN TRAY CLAMP 160mm to 175mm CLAMPS KIT.

My battery dimensions are Length 328mm, Width 171mm, Height 215mm. Length and height can be larger but not much wiggle room for the width to fit behind the second row seats.

[IvanR]

Drivesafe
"Thanks to his assistance, we both learnt quite a lot from that first setup and the first thing learnt was that my Sc80 isolators will not work with a Lead Acid - Lithium battery combo.

No isolator will work in this type of setup."


Hmmm I have a Sc80 with calcuim batteries in the D3, and are getting a new van which comes with lithium batteries as standard and the latest Redarc all singing all dancing BMS.
At the moment the Anderson plug is wired to the 2nd battery.
Does this mean the Anderson plug needs to be connected to the main battery to bypass the Sc80 ???

Ivan

[drivesafe]

Hmmm I have a Sc80 with calcuim batteries in the D3, and are getting a new van which comes with lithium batteries as standard and the latest Redarc all singing all dancing BMS.
At the moment the Anderson plug is wired to the 2nd battery.
Does this mean the Anderson plug needs to be connected to the main battery to bypass the Sc80 ???
Hi Ivan and no.

Just make sure the control of the DC/DC device is set up properly, and this is something you can change yourself, if need be, once you have the van.

[Milton477]

My van has Lithiums charged via a DC2DC+ which is connected to the Anderson of the SC80 Traxide system. No problems so far.

[RobA]

One key thing you need to understand about LifePO4 is they don't like heat. So an under bonnet setup is not a healthy spot for them. That in our experience is the only drawback as they are definitely the best aux battery we have used. They recover really fast using solar panels and can handle deep discharge cycles without blinking

Rob