LiFePo4 Upgrade - without B2B?

[CamperQuests]

Hi Guys,

Just a quick question which seems to have some conflicting information. I've tried YouTube / Google and seem to get 2 different answers.

We have an Auto Trail T670 - It has a Sargent Unit (EC176) and since we bought it, we had Solar Fitted (175W with Victron MPPT 75/15) whilst we had that fitted, we also had a 'Battery Master' fitted (to charge the Engine battery from the Solar)

But now we want to upgrade the 72AH Lead Acid to a LiFePo4 battery, around 100ah-150ah.

I've found lots of conflicting information out there, some say it can be swapped straight out but not charge to 100% (80-85% max), others say we would require a B2B charger to be fitted.

We would be happy if we could upgrade to Lithium even with 80-85% charge achieved, as long as it is safe for the van, as we would still have much more power to go at.

Can anyone advise?

Thanks,


Kyle

 

[rwg]

I have an auto trail built van with the same Ec176 electrical system. You can fit a lithium battery and the mains charger will get it (slowly) to well over 95%.

If you have an older van without stop start and no smart alternator then apparently you can leave the existing split charge circuit active. With a stop start van you should disable the split charge relay, which means no charging when driving. To replace that facility you may want to fit a b2b charger.

You can disable the split charge simply by removing the vehicle battery fuse in the Ec176 box, although this has minor side effects of not being able to see the vehicle battery voltage or run the electrics from the vehicle battery.

Cheers

Robin

 

[CamperQuests]

Hi robin,

thanks for the quick reply. I don't know much about the electronics on these things, hence why I got someone to fit the Solar and MPPT .

The van is a Fiat Ducato 2020 (69), but it doesn't have stop-start. How would I know if it has a smart alternator?

This is all very confusing to me, haha!!

Thanks,

Kyle

 

[rwg]

Simplest way to tell with no equipment is to go for a drive. Put the ventilation fan on full and then see if it slows down significantly under acceleration and speeds up when you take your foot off the accelerator. If it does that then it's the smart alternator reducing its output when you need power to accelerate and increasing it when coasting..

Cheers,

Robin

 

[CamperQuests]

Thanks,

My Mrs seems to have found that it wouldn't have one unless its Automatic which ours isn't. I haven't noticed any sort of change in fan noise whilst driving (Usually I would notice such things and question it - incase it was a fault, haha!)

I'll look into it more.

We do the majority of our nights off-grid / sites without hook-up. Charging from driving / Solar will be the main source of power. Why can't all this be simple?


Thanks,


Kyle

^{_{Subscribers  do not see these advertisements}}

 

[BillyKontiki]

Hi I have a swift Kon-Tiki based on Decato 20 plate it has a smart alternator, I also fitted 2x 100 ah lithium batteries drop in replacements but were slow to charge with inboard charger, so fitted a
B T B 30 ah charger to charge when driving, and a 30 ah plug in charger when on hook up.
Both with lithium settings and Bluetooth the Sargent onboard charger is left off.

 

[Tombola]

Great van

I had the auto trail Imala on the EC176 sargent system, and prior the auto select van... and the charger etc is woeful max 12amp as a charger then less any amps you may use as power.

Get the B2b fitted if you spend nights off the grid, do it independently from the auto trail wiring is easy enough, plenty posts on here how to do it, People will tell you about smart alternators,fridge, and step relays, dont let that worry you too much if it is none smart . Autotrail did request none smart alternators from Fiat for converting (as in my 2019 imala) and an easy way to test if you are worried is get one of these that shows the voltage at any time

Amazon.co.uk : 12v socket adapter usb

any questions just ask

 

[Camdoon]

I have just started at the other end looking at my solar power which could be upped as Lithium appeared to be the way forward and some extra juice in the batteries sounded sensible. The solar is going to cost £500 the batteries an extra £200 (ok far more output) and before this morning was contemplating not using B2B which would cost another £300 or so. Present system does me for 4 days or so and now not sure whether replacing all this kit is vfm. While we are not heavy users and tend to move on from non EHU sites every few days, I think I have just talked myself out of an expensive overkill.

 

[Kannon Fodda]

If you have a smart alternator B2B charger rather than the relay type system is important. The smart alternator means power can be drawn from batteries as engine slows/stops and only added when moving and if alternator sees the cab battery as charged it would cut off ignoring the leisure still needing juice. Or something like that.

With standard alternator then relay type charging will work, you rely on the BMS in the lithium to protect it. But you won't get a decent charge as voltages may be wrong (lithium generally a higher 13.6V than max 12.7V of lead acid), and may also take forever as the low charger Amperage can't put enough in during your drive time.

If you have solar with good MPPT controller that may be enough to properly top off the lithium.

Mains charger, for now rely on the Sargent. You can supplement later if needed. Even though it's horribly basic flat always on, effectively that's a float charge that if on EHU would eventually get there and the BMS will then protect.

Big advantage of lithium is weight for capacity in similar case size, and ability to deeply discharge whilst quick recharge. proper lithium charging of B2B and mains help with the recharge speeds.

 

[autorouter]

we had Solar Fitted (175W with Victron MPPT 75/15)

You can change the charging profile of the solar controller to lithium. If you have long sunny days without hookup it will be able to fill the lithium battery very well. Lithium batteries, unlike lead-acid types, don't deteriorate if they are not topped up to 100% regularly. They are happy only going to 50% or 80% for months or years.

The only thing you have to watch, not mentioned so far, is that they shouldn't be charged at all when their temperature is zero degrees or below. So if you don't have temperature sensing and automatic cutoff, make sure to wire in a way to cut off charging when it's very cold. A fuse or switch is sufficient. When all else fails, the inbuilt battery BMS will switch off the charging, but I prefer not to rely just on that.

^{_{Subscribers  do not see these advertisements}}

 

[Tude]

Hi Guys,

Just a quick question which seems to have some conflicting information. I've tried YouTube / Google and seem to get 2 different answers.

We have an Auto Trail T670 - It has a Sargent Unit (EC176) and since we bought it, we had Solar Fitted (175W with Victron MPPT 75/15) whilst we had that fitted, we also had a 'Battery Master' fitted (to charge the Engine battery from the Solar)

But now we want to upgrade the 72AH Lead Acid to a LiFePo4 battery, around 100ah-150ah.

I've found lots of conflicting information out there, some say it can be swapped straight out but not charge to 100% (80-85% max), others say we would require a B2B charger to be fitted.

We would be happy if we could upgrade to Lithium even with 80-85% charge achieved, as long as it is safe for the van, as we would still have much more power to go at.

Can anyone advise?

Thanks,


Kyle

Hi
I’ve just had lithium fitted and a b2b which the battery manufacturer advised to have.
The Seargent unit will have a split charging set up which is no good rhino installs did mine and basically they put a relay in that disables the split side. The new lithium is fabulous and the B2B is fabulous everything works

 

[peterc10]

If you are intending to not use EHU your 175W panel may not be able to proved the amount of charge needed by the battery to keep your electrics working, especially when it is cloudy or raining. The charge will also be lower when the sun is lower in autumn, winter and spring. The B2B is one way of increasing that charge.

A B2B produces a lot more charge when your engine is running than the standard split relay charger fitted on your motorhome. That means you can top up more quickly when you are driving around or to your next destination. If you are going to use a B2B you should connect it directly to the engine battery and habitation battery using larger sized cables than your Autotrail will have, so that they will cope with the higher loads from the B2B. You will also need to disconnect the existing split level charger. Others will be able to help you on that!

But in the end the answer will also depend upon when, how and where (sunnier Spain?) you are going to be using your motorhome. And also how much electricity you want to have available for the set up you have got.

 

[mitzimad]

we have a 110 amp lithium 180watts of solar neither the van charger or the solar have a lithium setting weve yet to run out of power

 

[Mikeamapola]

I have just started at the other end looking at my solar power which could be upped as Lithium appeared to be the way forward and some extra juice in the batteries sounded sensible. The solar is going to cost £500 the batteries an extra £200 (ok far more output) and before this morning was contemplating not using B2B which would cost another £300 or so. Present system does me for 4 days or so and now not sure whether replacing all this kit is vfm. While we are not heavy users and tend to move on from non EHU sites every few days, I think I have just talked myself out of an expensive overkill.

I’m in the same boat. Have Led lights now which helps. On the odd occasion the electric step has struggled, so ran the engine for a few minutes and all was ok for a few more days. Like you never in one place for more than 4 or 5 days.

 

[Petroleumblownapart]

I have an auto trail built van with the same Ec176 electrical system. You can fit a lithium battery and the mains charger will get it (slowly) to well over 95%.

If you have an older van without stop start and no smart alternator then apparently you can leave the existing split charge circuit active. With a stop start van you should disable the split charge relay, which means no charging when driving. To replace that facility you may want to fit a b2b charger.

You can disable the split charge simply by removing the vehicle battery fuse in the Ec176 box, although this has minor side effects of not being able to see the vehicle battery voltage or run the electrics from the vehicle battery.

Cheers

Robin

Do not charge a Lithium without a B2B. Whilst running the Lead and the Lithium together (hybrid style) will work initially the Lead Acid will always age before the Lithium and then you risk burning out an expensive alternator. It should never be about doing it on the cheap in my experience. There's a reason for everything.
I strongly suggest that everyone considering short cuts watch this video on YT: If the sound doesn't work on this link, just search for ’How to not blow up your alternator charging a Lithium Battery'.... Not all Lithiums have a BMS apparently!

^{_{Subscribers  do not see these advertisements}}

 

[bigtwin]

Whilst running the Lead and the Lithium together (hybrid style) will work initially the Lead Acid will always age before the Lithium and then you risk burning out an expensive alternator.

Interesting video. Why do you believe that, in a hybrid system (lead and LiFePo4 batteries in parallel) the lead will always age before the LiFePo4?
There is no better way of using (not using) a lead acid battery than in parallel with a LiFePo4 battery as the lead remains virtually unused as it sits there on a float charge from the LiFePo4. Any load connected to the bank will, preferentially, be supplied by the LiFePo4 (due to the higher resting voltage/lower internal resistance). The lead just sits there in its happy place.

It should never be about doing it on the cheap in my experience. There's a reason for everything.

There is nothing wrong with solving a problem cheaply; cutting corners is a different matter.

It’s interesting that the video promotes only the expensive ways of current limiting/controlling the alternator temperature. There is no mention of using the very simple, first principles, method of adding a current limiting resistor. Is that because they have a vested interest?

There are many hundreds of narrow boaters who have adopted the lead/LiFePo4 hybrid arrangement who are using the current limiting resistor method for limiting the alternator output (and hence its temperature). In many cases no modifications have been necessary; in other cases they have added current limiting resistance by replacing their alternator cable with a longer one (resistance is a function of cable length).

Those installations have proved both reliable and safe (no electronics to go wrong) as appropriate precautions have been taken (testing and monitoring of alternator current output and temperature and use of appropriately rated cable). It should be noted that the operating environment for a narrowboat alternator is more extreme than that of a MH whereby the engine spends extended periods of time at idle and there is very little throughput of air in the engine bay (i.e. it’s an enclosed space with limited ventilation).

The beauty of the hybrid arrangement is its simplicity, relying on first principles. However, for some reason, there is some resistance in some quarters (vested interests?) to accepting this solution to the problem.

Most problems originate from a lack of understanding of the issues around a problem. Problems can also occur from using a well accepted solution (to a slightly different problem) in the wrong place. Understanding the issues are key and no one solution can fit all scenarios.

Ian

 

[rwg]

If the OP's autotrail wiring is anything like mine then his alternator is safe The split charge circuit is fused at 20a and the wiring is long and not particularly heavy duty. At one point I did some calculations and worked out you'd struggle to get to 20a due to the resistance of the wiring unless the lithium battery was very low (under 20%). There have been some posts on the autotrail v line Facebook page about this very modification and those who have done it have not had the 20a fuse go pop on them.

If the whole thing was connected up with short runs of heavy duty cable it might well be a different story...

Cheers,

Robin

 

[cyberyacht]

I've got a pair of KS Energy 120Ah lithiums and haven't, as yet, fitted a B2B. I keep thinking about it but haven't needed one yet.

 

[bigtwin]

If the whole thing was connected up with short runs of heavy duty cable it might well be a different story...

It most certainly would!

The original alternator cable on my narrowboat was 95mm2 and was great for maximising the current to the original lead acid bank (though still massively over specified) so had to be replaced with a smaller cable when I went hybrid.

Ian

 

[DucatoMan2]

I was in a similar position to the OP. Rather than spend a not insignificant amount replacing essentially the whole electrics on the van, which I doubt would add to its valuation, I bought a stand alone solar power station. I'm happy with this, and it does allow angling panels when sun is marginal. I like having a separate system in case of some failure. Of course an integrated system is in some sense 'neater'. Just something you might assess against your needs.

^{_{Subscribers  do not see these advertisements}}

 

[Lenny HB]

If you are going to the expense of fitting Lithium why try to avoid charging it properly.
If you fit it properly with a B2B a decent solar controller with a Lithium profile and then if you use EHU change the mains charger.
One of the biggest advantages of Lithium is their fast charging capabilities seems silly not to make use of it and if treated properly your batteries will last longer.

 

[peterc10]

I installed my Lithium batteries last year and they cost me over a thousand pounds. Prices have come down now, but they are still the most expensive part of my electrical system revamp by a country mile. Given that, I decided it would be foolish not to treat them carefully and to give them what they needed. So I bought a B2B, new solar regulator, and a new mains charger, all with solar profiles, as well as temperature sensors to make sure that they will not be charging when below zero. Daft not to really.

This year I added more solar panels and another solar regulator to make sure we could survive in the winter if need be. And, to take advantage of all the free electricity, I have also added a 2000W pure sine wave inverter, 3 more outlet sockets and a microwave.

No point in spoiling the ship for a haporth of tar as my Dad used to say.

 

[dawsey]

I installed my Lithium batteries last year and they cost me over a thousand pounds. Prices have come down now, but they are still the most expensive part of my electrical system revamp by a country mile. Given that, I decided it would be foolish not to treat them carefully and give them what they needed. So I bought a B2B, new solar regulator, and a new mains charger, all with solar profiles, as well as temperature sensors to make sure that they will not be charging when below zero. Daft not to really.

This year I added more solar panels and another solar regulator to make sure we could survive in the winter if need be. And, to take advantage of all the free electricity, I have also added a 2000W pure sine wave inverter, 3 more outlet sockets and a microwave.

No point in spoiling the ship for a haporth of tar as my Dad used to say.

Completely agree, this is the setup we have and it utterly transforms the way you can use the van.

 

[Richard J]

A distillation of everything I have read;
Generally a smart alternator and start stop go hand in hand. I don’t believe Ducatos have one without the other. If you have a smart alternator then the B2B is required to persuade the alternator to keep providing charge. They also regulate the current draw to the lithium battery at startup so the starter motor gets enough. They should also restrict charging when sub zero temperatures which not all lithium BMSs will do. And I don’t like the idea of unrestricted current flowing to the lithium; it is said that the alternator can handle it but they are apparently expensive to replace in a modern Ducato as they are are hard to get at.

 

[Petroleumblownapart]

A distillation of everything I have read;
Generally a smart alternator and start stop go hand in hand. I don’t believe Ducatos have one without the other. If you have a smart alternator then the B2B is required to persuade the alternator to keep providing charge. They also regulate the current draw to the lithium battery at startup so the starter motor gets enough. They should also restrict charging when sub zero temperatures which not all lithium BMSs will do. And I don’t like the idea of unrestricted current flowing to the lithium; it is said that the alternator can handle it but they are apparently expensive to replace in a modern Ducato as they are are hard to get at.

Spot on. We have 100 AH Lithium on Schaudt with a Battery Master too, smart alternator, B2B, Solar and an Ecoflow from home. Never been below 35% from May to end of September. Use sites for Mains electric heating between October and end of April. On trips we average 50 miles per day and at home it's our daily driver. I once used the Ecoflow to run the MoHo over 2 days and still had spare juice and that was pre solar fitted. With a compressor fridge the solar runs it fine if the sun is out and easily tops up both the Lithium and Engine battery (via the Battery Master).

^{_{Subscribers  do not see these advertisements}}

 

[Hoovie]

Interesting video.

I haven't watched that video for a few years, but from memory, it is a setup that would never apply to a typical Motorhome as there will always be a load on the alternator in the form of the Starter Battery (although it could apply to a narrowboat I believe in some setups?).
For a motorhome audience, that video is misleading and irrelavent.

Why do you believe that, in a hybrid system (lead and LiFePo4 batteries in parallel) the lead will always age before the LiFePo4?
There is no better way of using (not using) a lead acid battery than in parallel with a LiFePo4 battery as the lead remains virtually unused as it sits there on a float charge from the LiFePo4. Any load connected to the bank will, preferentially, be supplied by the LiFePo4 (due to the higher resting voltage/lower internal resistance). The lead just sits there in its happy place.

I like a graph or two
This one taken from my motorhome this month illustrates nicely your comment "There is no better way of using (not using) a lead acid battery than in parallel with a LiFePo4 battery as the lead remains virtually unused"

The green line is the Lithium SOC; the orange line is the Lead SOC. The Lead only really joins the party when the Lithium is getting very low (so in terms of service lifecycles, the Lithium will be using much more of its way greater cycles than the Lead is.
(note, when I say "joins the party", Lead and Lithium are both present and available at all times, but the Lithium is the one doing the work, the Lead is just skiving in the background).

There is nothing wrong with solving a problem cheaply; cutting corners is a different matter.

It’s interesting that the video promotes only the expensive ways of current limiting/controlling the alternator temperature. There is no mention of using the very simple, first principles, method of adding a current limiting resistor. Is that because they have a vested interest?

There are many hundreds of narrow boaters who have adopted the lead/LiFePo4 hybrid arrangement who are using the current limiting resistor method for limiting the alternator output (and hence its temperature). In many cases no modifications have been necessary; in other cases they have added current limiting resistance by replacing their alternator cable with a longer one (resistance is a function of cable length).

Those installations have proved both reliable and safe (no electronics to go wrong) as appropriate precautions have been taken (testing and monitoring of alternator current output and temperature and use of appropriately rated cable). It should be noted that the operating environment for a narrowboat alternator is more extreme than that of a MH whereby the engine spends extended periods of time at idle and there is very little throughput of air in the engine bay (i.e. it’s an enclosed space with limited ventilation).

The beauty of the hybrid arrangement is its simplicity, relying on first principles. However, for some reason, there is some resistance in some quarters (vested interests?) to accepting this solution to the problem.

I think it is a lack of imagination that is the resister to the Hybrid concept rather than vested interests.

Most problems originate from a lack of understanding of the issues around a problem. Problems can also occur from using a well accepted solution (to a slightly different problem) in the wrong place. Understanding the issues are key and no one solution can fit all scenarios.

Ian

 

[bigtwin]

I like a graph or two
This one taken from my motorhome this month illustrates nicely your comment "There is no better way of using (not using) a lead acid battery than in parallel with a LiFePo4 battery as the lead remains virtually unused"

The green line is the Lithium SOC; the orange line is the Lead SOC. The Lead only really joins the party when the Lithium is getting very low (so in terms of service lifecycles, the Lithium will be using much more of its way greater cycles than the Lead is.
(note, when I say "joins the party", Lead and Lithium are both present and available at all times, but the Lithium is the one doing the work, the Lead is just skiving in the background).

That is a great illustration of what should be an easy concept to understand but one which many are somewhat averse to. Perhaps it is as you say, a lack of imagination.

Ian

 

[bigtwin]

Interesting video.

I haven't watched that video for a few years, but from memory, it is a setup that would never apply to a typical Motorhome as there will always be a load on the alternator in the form of the Starter Battery (although it could apply to a narrowboat I believe in some setups?).
For a motorhome audience, that video is misleading and irrelavent.

I was using the term ‘interesting’ in its loosest sense!

Ian

 

[Billy192]

Hi Guys,

Just a quick question which seems to have some conflicting information. I've tried YouTube / Google and seem to get 2 different answers.

We have an Auto Trail T670 - It has a Sargent Unit (EC176) and since we bought it, we had Solar Fitted (175W with Victron MPPT 75/15) whilst we had that fitted, we also had a 'Battery Master' fitted (to charge the Engine battery from the Solar)

But now we want to upgrade the 72AH Lead Acid to a LiFePo4 battery, around 100ah-150ah.

I've found lots of conflicting information out there, some say it can be swapped straight out but not charge to 100% (80-85% max), others say we would require a B2B charger to be fitted.

We would be happy if we could upgrade to Lithium even with 80-85% charge achieved, as long as it is safe for the van, as we would still have much more power to go at.

Can anyone advise?

Thanks,


Kyle

Hi ,
I had a Autotrail Tribute T620 w

Sargent Unit

Hi Guys,

Just a quick question which seems to have some conflicting information. I've tried YouTube / Google and seem to get 2 different answers.

We have an Auto Trail T670 - It has a Sargent Unit (EC176) and since we bought it, we had Solar Fitted (175W with Victron MPPT 75/15) whilst we had that fitted, we also had a 'Battery Master' fitted (to charge the Engine battery from the Solar)

But now we want to upgrade the 72AH Lead Acid to a LiFePo4 battery, around 100ah-150ah.

I've found lots of conflicting information out there, some say it can be swapped straight out but not charge to 100% (80-85% max), others say we would require a B2B charger to be fitted.

We would be happy if we could upgrade to Lithium even with 80-85% charge achieved, as long as it is safe for the van, as we would still have much more power to go at.

Can anyone advise?

Thanks,


Kyle

Hi,
i had a 2018 Autotrail and swopped out the 90AH lead acid for a 300AH lithium i also had 300w solar. which charged straight to the lithium. in spain it was 100% most of the time. why not have the solar direct to the the lithium? there is a way to use the trickle charger on the sargent to keep the cab batt happy while on hookup. i am not keen on using my alternator to charge a large lithium. IMHO

acid

 

[Petroleumblownapart]

Hi ,
I had a Autotrail Tribute T620 w



Hi,
i had a 2018 Autotrail and swopped out the 90AH lead acid for a 300AH lithium i also had 300w solar. which charged straight to the lithium. in spain it was 100% most of the time. why not have the solar direct to the the lithium? there is a way to use the trickle charger on the sargent to keep the cab batt happy while on hookup. i am not keen on using my alternator to charge a large lithium. IMHO

acid

Deffo a most sensible way. I do the same.. solar to Lithium but I have a batterymaster which automatically tops up the starter battery whenever it can and prevents backfired too.

^{_{Subscribers  do not see these advertisements}}