Lithium LifePo4 12v Batteries - Time For An Upgrade?

Hi,

One question. Actually I have the default battery coming with the van: AGM battery of 100ah (the battery is only 1 year old).

I have been looking for information, but it is not very clear: some places says if you want an extra battery, you need to discard your current battery. That you need buy two new, as the battery needs to be the same age.

Is it possible to add an extra battery? I was thinking to add a new lithium battery. Is there any throwback for being different battery type, different ages? if there is any problem, can I fit the battery under driver seat (the two batteries at the same time)? as I want to be the passenger underseat to be free as I want to buy a subwoofer in a near future.
 
waneos said:
Hi,

One question. Actually I have the default battery coming with the van: AGM battery of 100ah (the battery is only 1 year old).

I have been looking for information, but it is not very clear: some places says if you want an extra battery, you need to discard your current battery. That you need buy two new, as the battery needs to be the same age.

Is it possible to add an extra battery? I was thinking to add a new lithium battery. Is there any throwback for being different battery type, different ages? if there is any problem, can I fit the battery under driver seat (the two batteries at the same time)? as I want to be the passenger underseat to be free as I want to buy a subwoofer in a near future.
Click to expand...
If you want batteries of different types then you must fit a DC-DC charger.

Your main starter battery must be AGM as that is the only type of battery the van knows how to manage.

You can theoretically add a pair of AGM batteries - the higher end Californias have this by default - but I doubt you would get 2 under the seat bases (the Cali puts one in the rear cupboard base). It is strongly recommended if you do this that both batteries are identical and you start from new. If you don't you can get very high current flows between the batteries as they are at different ages and therefore wear.

If you are adding a new leisure battery to a van that currently only has a main starter battery then with the basic OEM relay charge approach the should ideally be identical and the same age as they effectively form a single bank when the relay engages. Practically if you are fitting one without the existing OEM relay you are most likely going to need a DC-DC charger anyway, in which case you have two independent battery systems and you can do what you want with your leisure battery.

What exactly do you want to do, what type of van do you have and do you have pictures of the current setup?
 
Hi,

I have t6.1 model beach. This model by default (in Spain) comes with starter battery (I am guessing AGM) and then a leisure battery AGM 100ah under driver seat.

I added 220V to the van (to charge the battery).

So my idea was to add a second leisure battery (lithium) under the driver seat to increase the battery capacity (I want at least to be 48h wihtout charging battery/moving the van, using the fridge). I want to keep the passenger seat free, for the subwoofer.
 
You couldn't practically have a system with an AGM leisure battery and a LiFePo leisure battery.

One option to consider is that currently, because your van is stop/start, your batteries are only charging to about 80%, which with an advised regular discharge limit of around 50% for an AGM type isn't giving you much capacity. Changing from the simple relay system to a DC-DC charger should be quite easy for you as everything you need wiring wise is already fitted and would fully charge your AGM.

Personally I would try that first as 100ah of AGM should be capable of the off grid time you want with a bit of care.

Choose a DC-DC that can do LiFePo (most do) and if it doesn't give you what you want then you can change up to a LiFePo battery. That will be a bit more disruptive as you will have to replace the very neat on battery fuse and distribution block but with LiFePo you can safely use all of your battery capacity and physcially you should be able to get a higher capacity in the same space.

You'd only really need to consider going for a multiple LiFePo battery system if you want substantial off grid 220v inverters.
 
roadtripper said:
You couldn't practically have a system with an AGM leisure battery and a LiFePo leisure battery.

One option to consider is that currently, because your van is stop/start, your batteries are only charging to about 80%, which with an advised regular discharge limit of around 50% for an AGM type isn't giving you much capacity. Changing from the simple relay system to a DC-DC charger should be quite easy for you as everything you need wiring wise is already fitted and would fully charge your AGM.

Personally I would try that first as 100ah of AGM should be capable of the off grid time you want with a bit of care.

Choose a DC-DC that can do LiFePo (most do) and if it doesn't give you what you want then you can change up to a LiFePo battery. That will be a bit more disruptive as you will have to replace the very neat on battery fuse and distribution block but with LiFePo you can safely use all of your battery capacity and physcially you should be able to get a higher capacity in the same space.

You'd only really need to consider going for a multiple LiFePo battery system if you want substantial off grid 220v inverters.
Click to expand...
checking the set up. This what I have.

Is this de DC-DC thing that you mentioned?

IMG_20231006_163607.jpg
 
So if you have the factory BCM controlled relay when you are driving the starter and leisure battery will be connected as a single battery bank.

The van will charge this to around 80%. It leaves that 20% so the batteries can accept charge during regenerative braking.

So if you camp off grid after a drive your Leisure Battery will be 80%

If you connect to 220v EHU then your Leisure Battery and Starter Battery will be disconnected (engine is off, relay is off). Your Victron Blue Smart will charge and maintain your Leisure Battery to 100%.

However if you then drive your van the relay will turn on and your Leisure Battery (at 100%) will be connected direct to your Starter Battery (at 80%). So the first thing is some reasonably large currents will flow as the batteries equalise charge and end up at about 90%. Then the van will not charge them until they drop below 80%.

This is the downside of the simple factory approach, even if you do charge the Leisure Battery from other sources (EHU, Solar) as soon as you drive that charge will be used.

If instead of the relay you fit a DC-DC charger then you completely separate the 2 batteries. They can be different types, different capacities and different states of charge.

You then have two charges for your leisure battery, one that charges from the 12v available when the van is running, one that charges from 220v when on EHU.

You can then choose to add a third charger from Solar if you like. Though you can also find DC-DC chargers that can also accept solar input.
 
roadtripper said:
So if you have the factory BCM controlled relay when you are driving the starter and leisure battery will be connected as a single battery bank.

The van will charge this to around 80%. It leaves that 20% so the batteries can accept charge during regenerative braking.

So if you camp off grid after a drive your Leisure Battery will be 80%

If you connect to 220v EHU then your Leisure Battery and Starter Battery will be disconnected (engine is off, relay is off). Your Victron Blue Smart will charge and maintain your Leisure Battery to 100%.

However if you then drive your van the relay will turn on and your Leisure Battery (at 100%) will be connected direct to your Starter Battery (at 80%). So the first thing is some reasonably large currents will flow as the batteries equalise charge and end up at about 90%. Then the van will not charge them until they drop below 80%.

This is the downside of the simple factory approach, even if you do charge the Leisure Battery from other sources (EHU, Solar) as soon as you drive that charge will be used.

If instead of the relay you fit a DC-DC charger then you completely separate the 2 batteries. They can be different types, different capacities and different states of charge.

You then have two charges for your leisure battery, one that charges from the 12v available when the van is running, one that charges from 220v when on EHU.

You can then choose to add a third charger from Solar if you like. Though you can also find DC-DC chargers that can also accept solar input.
Click to expand...
thank you so much. its much clear now.

Just one doubt, so in case of adding a new battery, Will I need to buy a charger right? (the same I have now for the current battery.

Any DC-DC recomendation: 12V, EHU and Solar input? in a future I want ro add solar panels as well.
 
Your Victron that charges the Leisure Battery now in EHU should be fine charging a LiFePo if you choose to change the battery type.

Yes you will need to buy a DC-DC.

My advice would be to consider this simple upgrade keeping the existing AGM that @r00ps documented here:

www.t6forum.com

T6.1 factory aux battery split charge relay upgrade & solar panel install.

Hi, I had the factory fitted aux battery ( under a single seat with swivel base ) fitted to my T6.1 with the intention of using it as a camper leisure battery. After getting less than impressive performance and reading about how the split charge relay is a pretty bad charging method I wanted to...
www.t6forum.com www.t6forum.com

The CTEK is a good mid range choice, will be fine for AGM and can do LiFePo in the future if you need it and can take solar.

As much as I'm a fan of LiFePo in your situation I'd probably just change to the CTEK and add some decent Solar.

When the AGM reaches the end of its life, change to a 100ah LiFePo.
 
roadtripper said:
Your Victron that charges the Leisure Battery now in EHU should be fine charging a LiFePo if you choose to change the battery type.

Yes you will need to buy a DC-DC.

My advice would be to consider this simple upgrade keeping the existing AGM that @r00ps documented here:

www.t6forum.com

T6.1 factory aux battery split charge relay upgrade & solar panel install.

Hi, I had the factory fitted aux battery ( under a single seat with swivel base ) fitted to my T6.1 with the intention of using it as a camper leisure battery. After getting less than impressive performance and reading about how the split charge relay is a pretty bad charging method I wanted to...
www.t6forum.com www.t6forum.com

The CTEK is a good mid range choice, will be fine for AGM and can do LiFePo in the future if you need it and can take solar.

As much as I'm a fan of LiFePo in your situation I'd probably just change to the CTEK and add some decent Solar.

When the AGM reaches the end of its life, change to a 100ah LiFePo.
Click to expand...
thanks for all the answer. I wil go for that route :)
 
roadtripper said:
Your Victron that charges the Leisure Battery now in EHU should be fine charging a LiFePo if you choose to change the battery type.

Yes you will need to buy a DC-DC.

My advice would be to consider this simple upgrade keeping the existing AGM that @r00ps documented here:

www.t6forum.com

T6.1 factory aux battery split charge relay upgrade & solar panel install.

Hi, I had the factory fitted aux battery ( under a single seat with swivel base ) fitted to my T6.1 with the intention of using it as a camper leisure battery. After getting less than impressive performance and reading about how the split charge relay is a pretty bad charging method I wanted to...
www.t6forum.com www.t6forum.com

The CTEK is a good mid range choice, will be fine for AGM and can do LiFePo in the future if you need it and can take solar.

As much as I'm a fan of LiFePo in your situation I'd probably just change to the CTEK and add some decent Solar.

When the AGM reaches the end of its life, change to a 100ah LiFePo.
Click to expand...

roadtripper said:
Your Victron that charges the Leisure Battery now in EHU should be fine charging a LiFePo if you choose to change the battery type.

Yes you will need to buy a DC-DC.

My advice would be to consider this simple upgrade keeping the existing AGM that @r00ps documented here:

www.t6forum.com

T6.1 factory aux battery split charge relay upgrade & solar panel install.

Hi, I had the factory fitted aux battery ( under a single seat with swivel base ) fitted to my T6.1 with the intention of using it as a camper leisure battery. After getting less than impressive performance and reading about how the split charge relay is a pretty bad charging method I wanted to...
www.t6forum.com www.t6forum.com

The CTEK is a good mid range choice, will be fine for AGM and can do LiFePo in the future if you need it and can take solar.

As much as I'm a fan of LiFePo in your situation I'd probably just change to the CTEK and add some decent Solar.

When the AGM reaches the end of its life, change to a 100ah LiFePo.
Click to expand...
is the model 250se that you recommend?

I would like to add 240w in solar panels. Will that model support that?
 
From the manual from the UK spec CTEK

Screenshot_20231011-181104-01.jpeg

You should double check that's the same for the model in your market.

So yes 240w is fine so long as the Open Circuit Voltage (OCV) is 23v or less, check that in the specifications of the panels you are considering.
 
roadtripper said:
From the manual from the UK spec CTEK

View attachment 216641

You should double check that's the same for the model in your market.

So yes 240w is fine so long as the Open Circuit Voltage (OCV) is 23v or less, check that in the specifications of the panels you are considering.
Click to expand...
I was thinking of califaktur, as they look sick:

www.califaktur.de

Califaktur solar panel for VW California T5 T6 T6.1 260Wp

Semi-flexible monocrystalline solar panel 260Wp double ETFE Cell efficiency up to 23% Suitable for VW California T5, T6, T6.1 Without drilling and gluing Mounting on VW California original C-rail Track the performance data and battery status live via the app. Victron SmartSolar 75/15 MPPT...
www.califaktur.de www.califaktur.de

Looking at the specs, it says: Open Circuit Voltage Voc: 23.4V

1697058550455.png

Is this ok? or 0.4V makes a difference?
 
waneos said:
any other DC-DC charger that you could recommend?
Click to expand...
This is purely my personal opinion based on experience.
I wouldn’t have a Ctek, they have reliability issues, there’s no Bluetooth comms & the B2B charging profile is “odd”
You already have a Victron mains charger, so stick with Victron.
Combined units I.e. B2B+solar in one box, means that if one part fails, you lose 2 methods of charging…all your eggs in one basket, no redundancy.
I’ve had a Sterling 1230, huge unit no BT, sounds like concord warming up due to the cooling fan.
I’ve had a Ctek, solar side failed, Ctek aftersale support isn’t what it used to be, replaced with a Victron Orion 12/30. The Orion can get hot under heavy usage, especially on Lithium, but this is only for the first 1/2 hour or so. It hasn’t been a problem.
All my kit Is now Victron, it’s been faultless & all runs from the same app.
It’s the way I would do it again.
 
Salty Spuds said:
This is purely my personal opinion based on experience.
I wouldn’t have a Ctek, they have reliability issues, there’s no Bluetooth comms & the B2B charging profile is “odd”
You already have a Victron mains charger, so stick with Victron.
Combined units I.e. B2B+solar in one box, means that if one part fails, you lose 2 methods of charging…all your eggs in one basket, no redundancy.
I’ve had a Sterling 1230, huge unit no BT, sounds like concord warming up due to the cooling fan.
I’ve had a Ctek, solar side failed, Ctek aftersale support isn’t what it used to be, replaced with a Victron Orion 12/30. The Orion can get hot under heavy usage, especially on Lithium, but this is only for the first 1/2 hour or so. It hasn’t been a problem.
All my kit Is now Victron, it’s been faultless & all runs from the same app.
It’s the way I would do it again.
Click to expand...
I have been checking victron and I see many models. isolated, non-isolated etc.. (sorry for my ignorance, I dont have any clue about this but I want to learn).

Having in account my requirements: I have AGM, but I want something that it support Lithium in a future and I want to put the solar panels with open circuit 23.4v (these come with Victron SmartSolar 75/15 MPPT in the pack).

What model should I go?
 
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