Aux Lithium Battery in a old non-smart Alternator vehicle?

rob_macca67

Well-Known Member
Gents...
I'm looking at installing a Lithium Battery into my 2010 Defender (2.4ltr Tdci engine). From my understanding, the Alternator is not a SMART Alternator and mine charges at a voltage of 14.1 to 14.4volts usually.
My question is... Do I really need a DC/DC Charger if I convert to a Lithium or can I simply use a "Ignition Operated" Solenoid to join the 2 batteries together when the engine is running and then automatically separates when the engine is turned off..?
(Note: Main and AUX batteries are installed together under Passengers seat, so distance is not an issue)

Thanks in advance...

Rob
 

CTL

Well-Known Member
You will read lots of “expert” opinion on the ability of the lithium battery’s inbuilt BMS to regulate voltages and allow you to hook up direct to an alternator or parallel two batteries without the need for a specific lithium profile DC-DC charger. Well that is just “expert” BS. The inbuilt BMS is not a charger, it is there to ensure the battery is protected from over charging, excessive discharging and to keep the individual cells balanced (critical).
To get a decent life, and the best use from your lithium, you need a lithium capable DC-DC charger or AC charger. Some will flame me but their “knowledge” will have come from internet success stories that never get followed up with long term user reports or tell you of the failures which have occurred a couple of years down the track. Go to any of the established, long term electronic manufacturers like Victron, Enerdrive, Redarc, etc and compare their expert advise with the “marketers” of cheap lithium batteries and you will soon see what you really need.
 

shanegtr

Well-Known Member
I believe you will need a DC/Dc charger for this, and here's my two main points why. My understanding is lithium charges at a higher voltage so the DC/DC is required for a more effective charge rate. Second is that lithium have a slightly higher at rest voltage as well and maintain that voltage practically all the way to dead flat - this could affect the disconnection of the old style "smart solenoids" as the disconnection voltage may not be reached until the lithium is flat, along with your starting battery
 

rob_macca67

Well-Known Member
I believe you will need a DC/Dc charger for this, and here's my two main points why. My understanding is lithium charges at a higher voltage so the DC/DC is required for a more effective charge rate. Second is that lithium have a slightly higher at rest voltage as well and maintain that voltage practically all the way to dead flat - this could affect the disconnection of the old style "smart solenoids" as the disconnection voltage may not be reached until the lithium is flat, along with your starting battery
Yes, I knew that, that's why I mentioned a isolator that is only activated when the engine is running and disconnects when engine is off... just like a normal relay operates...
 

rob_macca67

Well-Known Member
You will read lots of “expert” opinion on the ability of the lithium battery’s inbuilt BMS to regulate voltages and allow you to hook up direct to an alternator or parallel two batteries without the need for a specific lithium profile DC-DC charger. Well that is just “expert” BS. The inbuilt BMS is not a charger, it is there to ensure the battery is protected from over charging, excessive discharging and to keep the individual cells balanced (critical).
To get a decent life, and the best use from your lithium, you need a lithium capable DC-DC charger or AC charger. Some will flame me but their “knowledge” will have come from internet success stories that never get followed up with long term user reports or tell you of the failures which have occurred a couple of years down the track. Go to any of the established, long term electronic manufacturers like Victron, Enerdrive, Redarc, etc and compare their expert advise with the “marketers” of cheap lithium batteries and you will soon see what you really need.
With the Built-in protection of the BMS, what happens if u completely drain the Lithium? Is there a process to kick the BMS to allow the battery to start receiving charge?
Re: Balanced Cells: - There's some manufacturers that quote in their specs that their Lithium batteries are a balanced cell system where others don't mention it. How does a BMS keep ALL the cells balanced? I knew the BMS is there for protection in regards to Charging and Discharging, but didn't know (or how) it keeps the cells balanced...
 

Batts88

Well-Known Member
As mentioned above get a Lithium charger after researching it for some time I found it's better for the battery I got mine from Road Tech Marine it's a Powertech 20amp charging my 170ah Renogy it works well and they're pretty cheap. I have another Powertech 20amp charging an agm in my wifes car no problems.
 

CTL

Well-Known Member
With the Built-in protection of the BMS, what happens if u completely drain the Lithium? Is there a process to kick the BMS to allow the battery to start receiving charge?
I chose Enerdrive lithium because they have a built-in reset button on their batteries. Otherwise you need to connect another battery above 12.8 volts until your DC-DC or AC charger kicks into charge mode.

Re: Balanced Cells: - There's some manufacturers that quote in their specs that their Lithium batteries are a balanced cell system where others don't mention it. How does a BMS keep ALL the cells balanced? I knew the BMS is there for protection in regards to Charging and Discharging, but didn't know (or how) it keeps the cells balanced...

ALL lithium should have balanced cells.
Active cell balancing utilises capacitive or inductive charge shuttling to transfer charge between battery cells as it is important for longevity and overall capacity that all cell voltages are as close as possible. There will always be very minor differences.
 
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CTL

Well-Known Member
Another tip. One of the best things about lithium is that they will accept bulk charge quickly. Do not restrict your charging by choosing a low amp charger. My 125Ah lithium is charged by a 40 amp DC-DC which is the maximum recommended charger for that battery. Only takes an hour or so of driving to fully charge most days.
 

Albynsw

Well-Known Member
Another tip. One of the best things about lithium is that they will accept bulk charge quickly. Do not restrict your charging by choosing a low amp charger. My 125Ah lithium is charged by a 40 amp DC-DC which is the maximum recommended charger for that battery. Only takes an hour or so of driving to fully charge most days.

I assume it varies between brands but I read an article from an electrical engineer and he said that whilst the lithium are capable of accepting much higher charges it does reduce the batteries life and he recommended that they be charged along similar charging amperages to AGM batteries
 

CTL

Well-Known Member
I assume it varies between brands but I read an article from an electrical engineer and he said that whilst the lithium are capable of accepting much higher charges it does reduce the batteries life and he recommended that they be charged along similar charging amperages to AGM batteries
Did this engineer specialise in lithium technology?
As I said in my first post, take notice of the major players, Victron, Enerdrive and Redarc. There are others but their product is not widely sold in Australia.
An AGM’s recommended charge varies from 10% to 25% of battery capacity depending on manufacturer.
Enerdrive recommends 33% for their lithium batteries.
 

Albynsw

Well-Known Member
Did this engineer specialise in lithium technology?
As I said in my first post, take notice of the major players, Victron, Enerdrive and Redarc. There are others but their product is not widely sold in Australia.
An AGM’s recommended charge varies from 10% to 25% of battery capacity depending on manufacturer.
Enerdrive recommends 33% for their lithium batteries.

I don’t know anything about him but the point he was making is they have a maximum charge rate and a recommended charge rate and not to pick a charger that was closer to the maximum charge rate as it reduces the lifecycle of the battery
I know little about them just repeating what he said
Still thinking I will go AGM again next time as their advantages don’t really fit for my situation
 

CTL

Well-Known Member
Fair enough. Not wanting to pick fault but opinions are like AHs :D
Always look at the manufacturer’s recommendations regarding charging.
As for sticking to AGM’s, I almost did the same on my new ute setup but went out of my comfort zone and fitted lithium. So happy I did, just continues to impress me. Would never go back to AGM.
 

Albynsw

Well-Known Member
Fair enough. Not wanting to pick fault but opinions are like AHs :D
Always look at the manufacturer’s recommendations regarding charging.
As for sticking to AGM’s, I almost did the same on my new ute setup but went out of my comfort zone and fitted lithium. So happy I did, just continues to impress me. Would never go back to AGM.

Yes I guess he was pointing out to read the fine print of the battery manufacturers recommendations to choose the correct charger. I thought it was a point worth noting.
In my case the best place fir my second battery is under the bonnet so the AGM is a better choice. I know there are lithium’s that will go under the bonnet but at the price they want for them and only have a 12month warranty I don’t think it is a good deal for me
 

CTL

Well-Known Member
Yep, agree, don’t put a lithium under the bonnet. The sellers recommending them for under bonnet use are not ones I would give my money to. In your scenario, an AGM will serve you well.
 

Lost1?

Well-Known Member
If you charge a lithium battery at its absolute peak charge rate for longer than the specified period. E.G 100A for 15 minutes or less if that is what the cells in your battery will tolerate, you will cause the battery to degrade. Check the specs of your battery before deciding which system you need. It is possible to run Lithium straight off your alternator. You will only achieve about 95-96% SOC using your alternator.
 

CTL

Well-Known Member
If you charge a lithium battery at its absolute peak charge rate for longer than the specified period. E.G 100A for 15 minutes or less if that is what the cells in your battery will tolerate, you will cause the battery to degrade.
And that is why a quality DC-DC should be used instead of charging direct from the alternator
 

Bru9

Active Member
With the Built-in protection of the BMS, what happens if u completely drain the Lithium? Is there a process to kick the BMS to allow the battery to start receiving charge?
Re: Balanced Cells: - There's some manufacturers that quote in their specs that their Lithium batteries are a balanced cell system where others don't mention it. How does a BMS keep ALL the cells balanced? I knew the BMS is there for protection in regards to Charging and Discharging, but didn't know (or how) it keeps the cells balanced...
You should never completely drain the lithium unless sheer neglect, they give you a wide obvious warning by the lower knee.
Balancing is sadly one of the most misunderstood things with li-ion batteries it's pretty pathetic. Beware of the google armchair 2week researchers...It usually does so by "top balancing" when the voltage is 14.3ish plus volts. The amount of work it does per cycle is soo small. Lifepo4 take alongvtine to go outta balance, it can usually handle a fair amount of imbalance. If the cells in the upper knee are out by more than say 300mv thats when to worry, 150 is OK for moderate loads, 50mv is for hard cycling that will degrade the cells anyway. Before lifepo4 went mainstream the 'founding fathers' ran many setups with no balancing and got by for years and years. The tragedy of balancing is if you start off with shit your balancing wont do jack. Just like if you use a cheap agm staying above 50% wont do jack. There are diff grades of quality so without knowing talking of balancing is armchair talk. The internal cells drift in an uncontrollable way and can age differently no matter what. The internal balancing has often been described as a sick joke, cost effective all in one solution so the user is forced to keep going into the voltage knees which isnt healthy longterm. The reccomend charge rates are 0.5C partly coz of this, hitting the cells at high c rates with high voltages is bad, better to keep voltages low.
Here's a funny story, some batts have multi cells in parrelle at the node level, and if a cell is bad the other will hide it and no amount of balancing will address this problem.
It takes years to learn how batteries work, half by experiment. Funny how some who were asking for lithium advice recently are now telling you what's what. Good place to read is expedition portal. Aus forums are just sad.

If the alt is really supplying 14v plus make sure you dont burn out the solenoid, bms. The goldilocks voltage of straight alt charging is ~13.8-13.9V at terminals. Other issue is driving around all the time on full battery will have an impact on lifespan at that voltage, how much? Who knows. The cost of a quality solenoid is more than a dc dc. So I went a dc dc charger coz it was part of a portable setup and i wanted to avoid the mess down the line of smart alts. Also charging off alt direct is a bit like running the washing machine and shower at same time. I'm not a fan of joining a lead acid and lifepo4, coz the diff in voltages. A dc dc is just set and forget, but I understand their large size and required ventilation could be a problem.

A voltage of ~13.4v is usually enough to get a lifepo4 99% charged, albeit quite along time.
 

Batts88

Well-Known Member
So beware of the Google armchair researchers which is exactly what I done to come up with the same result as you did so where's the bit to be wary of again.
 

rob_macca67

Well-Known Member
Gents...
I'm looking at installing a Lithium Battery into my 2010 Defender (2.4ltr Tdci engine). From my understanding, the Alternator is not a SMART Alternator and mine charges at a voltage of 14.1 to 14.4volts usually.
My question is... Do I really need a DC/DC Charger if I convert to a Lithium or can I simply use a "Ignition Operated" Solenoid to join the 2 batteries together when the engine is running and then automatically separates when the engine is turned off..?
(Note: Main and AUX batteries are installed together under Passengers seat, so distance is not an issue)

Thanks in advance...

Rob
Well,
After thinking about it and talking to some 12v battery experts who explained to me that u also need to look at what do u run 12v wise & load wise, how long do u plan to keep your vehicle, the cost of converting to a Lithium,etc, etc... So, I decided to stick with running an AGM but I've added a Solar Panel and a MPPT charger. I don't have or run any high current appliances or even a large Inverter so the best cost option was to stay with the setup I'm running...
The battery I ended up using was a "HVT-70ZZD Ultra High Performance Dual Purpose AGM Battery". I will see what sort of lifespan I get out of this battery... hopefully 5yrs or so as the last one I got a bit over 4yrs out of... So paying about a 1/4 of the price of a good Lithium battery I can afford to change is a few times (4x possibly 4yrs of battery life=16yrs) before it is no longer cost-effective... Well that's the way I'm looking at it at this point in time... may change my mind in the future... who knows
 

Albynsw

Well-Known Member
Rob I have had a couple of those SSB batteries and were happy with them. I am going through the battery dilemma myself at the moment and trying to justify a Lithium setup. Basically you are paying a huge premium for a weight saving from what I can see
 
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