Upgrading lead acid to lithium battery (2 Viewers)

[jennywren]

Hi all
I think our lead acid batteries have seen their best days (2x 110A Hankooks in parallel, about/at least 5 yrs old) and I am thinking of swapping out for lithium (either 2x100A or 1x 170A or thereabouts). I have already learnt from previous posts and also, done a bit of research. But, still a bit confused as many lithium producers/sellers seem to indicate their product is a direct replacement/drop-in for standard lead acid batteries. I am not convinced it's that simple (but happy to be told otherwise!) so after a little guidance.

I have previously installed (about 3yrs ago) a 115w solar panel (Victron Energy) with a dual 15A MPPT charge controller (PV Logic). There is also a CTEK MXS 25 charger fitted (when on EHU) by previous owner. This charges the leisure batteries, I have never checked if it also charges the engine battery.

I have been looking at the Eco-Worthy (cheap) lithium and the Renogy (possibly better BMS but not sure?) options, also considered the Fogstar. Happy to consider other options but this is not the main reason for my query.

My queries are:
1) I believe I shall need to upgrade the insitu charger to lithium capability. Is this correct or will this charger be suitable. If not, what sort of power output should I be looking at. Any suggestions for make/model.
2) I am limited to maximum 115w solar panel (not really any further space on roof) . Will this dictate maximum size of new battery/s best to install (I was thinking either 2x100A or 1x 170A, depending on physical sizing etc). If, for example, we installed 200Ah lithium (2x100 in parallel), would the solar panel stand a chance of fully charging it anyway (in summer!).
3) We often go for a couple of weeks at a time without EHU and so far, our current LA batteries/solar has coped well. Our van is only 6m and we are not high users of power.
4) I believe we shall need, either, a bluetooth option lithium battery OR a shunt battery monitor as the existing (voltage based) motorhome wall panel display will be of little use for the flatline lithium discharge/accuracy. Is this correct. If so, am I better off with bluetooth or shunt or is it just user preference.
5) The last thing, how can I tell if my current alternator (have not checked this out yet) will be sufficient for the new set-up or am I worrying for nothing here.

Sorry if I'm asking what has been asked before but I have read several threads and advice and there often appears to be some conflict between views on this, even more so, when you read manufacturers recommendations. I'm also hoping that any answers may help others who are considering the same thing.

Cheers and thanks in advance.

 

[BillyKontiki]

I done a drop in replacement a couple of years ago without changing anything,
But things do work better if you add / upgrade some things like solar and chargers there is an add in the classified section page 3 a funsters selling a good lithium set up.good luck.

 

[Abacist]

A 25 amp mains charger will take 8 hours to charge up 200 Amp Hours of Lithium batteries but a bit less if you keep them above 20% - say 6 hours - a 50 amp charger with a lithium setting will do it in half the time.

You ought to consider a B2B charger as well as you are limited on solar. A B2B will charge up the batteries whilst you drive, using the alternator.

Victron is good kit and does a nice 50 amp charger and Stirling do a good high powered B2B.

 

[jennywren]

I done a drop in replacement a couple of years ago without changing anything,
But things do work better if you add / upgrade some things like solar and chargers there is an add in the classified section page 3 a funsters selling a good lithium set up.good luck.

Many thanks, this was pretty much my conclusion but always good to hear that the 'minimum' would potentially work anyway. I will probably change the mains charger and quite possibly add the b2b dc/dc unit. Thanks.

 

[jennywren]

A 25 amp mains charger will take 8 hours to charge up 200 Amp Hours of Lithium batteries but a bit less if you keep them above 20% - say 6 hours - a 50 amp charger with a lithium setting will do it in half the time.

You ought to consider a B2B charger as well as you are limited on solar. A B2B will charge up the batteries whilst you drive, using the alternator.

Victron is good kit and does a nice 50 amp charger and Stirling do a good high powered B2B.

Thanks for advice. I have since found EddieVanbitz 'idiots' guide which has either answered or confirmed my thoughts.

Regarding the mains charger, I was more concerned about possible damage (to the new batteries) rather than the time to charge it as we rarely use EHU and if we do, then 8hrs/overnight would not be unduly unreasonable for us. It's my understanding that the recent lithiums are pretty robust and adequately protected through there inherent BMS. Is this your understanding? I have read the CTEK (manufacturer of the mains charger) info and they advise a lithium profile charger but is this more because of efficient profiled charging rather than not working at all (or doing damage)?

I now believe, as you suggest, a b2b charger will be needed as this will be our main source of charging. I was researching the sterling chargers. Is there a particular size I should consider and/or is this dependant upon output of alternator or does this (output of alternator) not make any difference. I do not know the alternator output other than the m/h is based on 2010 Ford Transit Euro 4.

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[Abacist]

Go for the highest charging rate you can afford. In your van you will not have a “Smart” alternator so making life easier for you!

 

[Marie-Claire]

We only use about 30ah of power per night if off grid , 2 x 100a lithium each day we are only topping it back up rather than having to put the full 200 back, the solar and Van's charger has always worked ok without any upgrades

 

[jumar]

Look at the overheating problems with some B2B chargers...mine is Victron and it has these issues...

 

[headlight]

jennywren I have recently changed from 2 x 100AH lead acids to 1 x 230AH LifePo4 leisure battery.
I had already fitted 200 watts solar and MPPT, 60 amp Sterling B2B and a shunt.
So all I had to do was swap the batteries and change the charge profiles on the B2B and MPPT to lithium.
My onboard mains charger is a Sargent PX-300 which doesn't have a lithium profile.
This charger won't charge lithium up to 100% but also won't damage lithium so as we only have EHU a couple of nights a year I've left it as my main charge sources are B2B and solar.
The difference going from lead acid to lithium is like night and day.
We are on our 3rd day (2 nights) on a site, Cornish Farm (Vanbitz) Taunton.
We're not on EHU and as the weather has been poor have had very little solar so far.
The battery is on 75% SOC at the moment so even with very minimal solar, it rained all yesterday, we could do 8 nights before needing to re-charge in this weather.

 

[jennywren]

jennywren I have recently changed from 2 x 100AH lead acids to 1 x 230AH LifePo4 leisure battery.
I had already fitted 200 watts solar and MPPT, 60 amp Sterling B2B and a shunt.
So all I had to do was swap the batteries and change the charge profiles on the B2B and MPPT to lithium.
My onboard mains charger is a Sargent PX-300 which doesn't have a lithium profile.
This charger won't charge lithium up to 100% but also won't damage lithium so as we only have EHU a couple of nights a year I've left it as my main charge sources are B2B and solar.
The difference going from lead acid to lithium is like night and day.
We are on our 3rd day (2 nights) on a site, Cornish Farm (Vanbitz) Taunton.
We're not on EHU and as the weather has been poor have had very little solar so far.
The battery is on 75% SOC at the moment so even with very minimal solar, it rained all yesterday, we could do 8 nights before needing to re-charge in this weather.

Hi
Many thanks for your detailed reply. Your situation and usage profile pretty much mirror's ours (your solar ability being a fair chunk greater) so really useful, thanks. Enjoy your stay.

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[hja]

Can’t help with the technical stuff but we replaced our single 95ah la battery with 230 ah lithium. We have 120 w solar panel. In our case battery fitted in same under seat position. We were getting ours installed not doing it ourselves, and a bigger battery was very little more than buying a smaller one. We had a new mppt controller. There seems to be no problem in keeping the battery charged, certainly in the summer. We have once done four nights without moving the van but mostly we are driving the van as well as the solar.

 

[Lenny HB]

Look at the overheating problems with some B2B chargers...mine is Victron and it has these issues...

The new Victron XS is 50 amp and runs cool, a lot cooler than the 30 amp that you have.

 

[Lenny HB]

I have been looking at the Eco-Worthy (cheap) lithium and the Renogy (possibly better BMS but not sure?) options, also considered the Fogstar. Happy to consider other options but this is not the main reason for my query.

The Fogstar has the advantage of a built in heater which makes life easier if you need to charge the battery when it is cold.

I believe we shall need, either, a bluetooth option lithium battery OR a shunt battery monitor as the existing (voltage based) motorhome wall panel display will be of little use for the flatline lithium discharge/accuracy. Is this correct. If so, am I better off with bluetooth or shunt or is it just user preference.

A Shunt is far more accurate and will give you reliable information on your system.

The last thing, how can I tell if my current alternator (have not checked this out yet) will be sufficient for the new set-up or am I worrying for nothing here.

You have a German van so it probably has an uprated alternator that should easily be able to cope with a 50 amp B2B. A B2B as well as increasing the charge rate it will ensure your battery gets the correct charge and will protect your alternator.

The Victron XS 50 amp B2B is programable for an output of between 1 to 50 amps, our own Funsters RogerIvy & nigelivy run Off Grid Solutions they can supply both Victron & Fogstar and give Funsters a discount.

Offgrid Power Solutions

Offgrid Power Solutions We are specialists in LiFePO4 batteries & Victron Energy systems. We’re here to help build the best offgrid electrical systems so you can focus on your adventure without stressing about how much power you have left! Get in touch with us about how we can help

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[jumar]

The new Victron XS is 50 amp and runs cool, a lot cooler than the 30 amp that you have.

Might need to replace mine...thanks Lenny.

 

[headlight]

Hi
Many thanks for your detailed reply. Your situation and usage profile pretty much mirror's ours (your solar ability being a fair chunk greater) so really useful, thanks. Enjoy your stay.

One other thing, if you add a pair of lithiums in parallel you will need to alter how the batteries are wired as with 2 x lithium you need both positives connected to a bus bar and both negatives connected to a bus bar.
All cabling must be identical ie same length, same rating and same terminals and then you take all your positIves and negatives from the bus bars.
You do this as each battery has its own BMS.
It's easier to just use one bigger lithium.
When new your 2 x 110AH lead acid batteries would have given you a usable 110 amps.
A single lithium of the same size ie 220AH will give you 200 amps usable or twice the amount of power.
Also your lead acids would be happy delivering 20AH each so 40AH.
A 230AH Fogstar lithium will deliver 200AH so enabling you to run an inverter capable of powering an air fryer, microwave etc.

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[jennywren]

One other thing, if you add a pair of lithiums in parallel you will need to alter how the batteries are wired as with 2 x lithium you need both positives connected to a bus bar and both negatives connected to a bus bar.
All cabling must be identical ie same length, same rating and same terminals and then you take all your positIves and negatives from the bus bars.
You do this as each battery has its own BMS.
It's easier to just use one bigger lithium.
When new your 2 x 110AH lead acid batteries would have given you a usable 110 amps.
A single lithium of the same size ie 220AH will give you 200 amps usable or twice the amount of power.
Also your lead acids would be happy delivering 20AH each so 40AH.
A 230AH Fogstar lithium will deliver 200AH so enabling you to run an inverter capable of powering an air fryer, microwave etc.

All great info, much appreciated and will certainly bear in mind and adhere to. Really appreciate your help.

 

[jennywren]

The Fogstar has the advantage of a built in heater which makes life easier if you need to charge the battery when it is cold.


A Shunt is far more accurate and will give you reliable information on your system.


You have a German van so it probably has an uprated alternator that should easily be able to cope with a 50 amp B2B. A B2B as well as increasing the charge rate it will ensure your battery gets the correct charge and will protect your alternator.

The Victron XS 50 amp B2B is programable for an output of between 1 to 50 amps, our own Funsters RogerIvy & nigelivy run Off Grid Solutions they can supply both Victron & Fogstar and give Funsters a discount.

Offgrid Power Solutions

Offgrid Power Solutions We are specialists in LiFePO4 batteries & Victron Energy systems. We’re here to help build the best offgrid electrical systems so you can focus on your adventure without stressing about how much power you have left! Get in touch with us about how we can help

offgridpower.solutions

...thanks so much Lenny for taking the time to add your info and advise, will certainly consider Off Grid Solutions and take all this into account. If I go with the 50 amp Victron b2b, just to be on safe side, what is the minimum my alternator needs to output to keep pace. Cheers

 

[Lenny HB]

...thanks so much Lenny for taking the time to add your info and advise, will certainly consider Off Grid Solutions and take all this into account. If I go with the 50 amp Victron b2b, just to be on safe side, what is the minimum my alternator needs to output to keep pace. Cheers

A 50 amp B2B will be fine with a 129 amp alternator but if it's only a 90 I would set the B2B to 30 amps.

 

[nicholsong]

jennywren

You did not state in OP but just for clarification I hope you are looking at LiFePro4 and not Lithium-Ion, which would be a dangerous fire risk in \ MH.

 

[Lenny HB]

jennywren

You did not state in OP but just for clarification I hope you are looking at LiFePro4 and not Lithium-Ion, which would be a dangerous fire risk in \ MH.

A they actually stated 3 makes batteries they looking at all LiFePO4

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[jennywren]

jennywren

You did not state in OP but just for clarification I hope you are looking at LiFePro4 and not Lithium-Ion, which would be a dangerous fire risk in \ MH.

A 50 amp B2B will be fine with a 129 amp alternator but if it's only a 90 I would set the B2B to 30 amps.

OK, thanks Lenny. So, if the alternator capacity is 90 amps, had I just as well go for the 30amp b2b. Albeit, I believe the newer Victron XS is possibly only made at 50amps at present and possibly worth waiting for (and setting it at 30). From some very quick research, maybe not immediately on the shelf yet.

 

[Lenny HB]

OK, thanks Lenny. So, if the alternator capacity is 90 amps, had I just as well go for the 30amp b2b. Albeit, I believe the newer Victron XS is possibly only made at 50amps at present and possibly worth waiting for (and setting it at 30). From some very quick research, maybe not immediately on the shelf yet.

The 50 amp is more efficient and runs a lot cooler I would go for is as it is not much dearer. Also I think your alternator will be OK with the 50 amp

 

[Poutie57]

One other thing, if you add a pair of lithiums in parallel you will need to alter how the batteries are wired as with 2 x lithium you need both positives connected to a bus bar and both negatives connected to a bus bar.
All cabling must be identical ie same length, same rating and same terminals and then you take all your positIves and negatives from the bus bars.
You do this as each battery has its own BMS.

Can someone explain this as I’m just about to parallel 2 lithium battery both the Same make. I thought it was a simple Kobe just the same as lead acid. Now I’m confused why extra bus bars etc

 

[Poutie57]

Sorry meant to say Job not kobe

 

[Lenny HB]

Can someone explain this as I’m just about to parallel 2 lithium battery both the Same make. I thought it was a simple Kobe just the same as lead acid. Now I’m confused why extra bus bars etc

The reason is so that you keep the cables from each battery the same length to the buss bars then take power to the rest of the system from the buss bars. Doing it this it ensures the BMS from both batteries stay in sync.

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[Poutie57]

Sorry for hijacking the thread but Thanks Lenny, I’ve already got all my + & - going through bus bars then - going through a victron shunt could you tell me what type of bus bar I need and where to place it in relationship to the batteries

 

[Lenny HB]

Best to keep the busbars close to the batteries after the fuses and isolating switches.

https://www.amazon.co.uk/dp/B09MRWBM8W/?tag=mhf04-21

 

[treblid]

OK, thanks Lenny. So, if the alternator capacity is 90 amps, had I just as well go for the 30amp b2b. Albeit, I believe the newer Victron XS is possibly only made at 50amps at present and possibly worth waiting for (and setting it at 30). From some very quick research, maybe not immediately on the shelf yet.

The Victron XS has menu settings to reduce the maximum input current and/or the output current. You can, therefore, throttle the charger back if required to suit your alternator and still benefit from the cooler running temperature.

 

[AdrianChen]

The Victron XS has menu settings to reduce the maximum input current and/or the output current. You can, therefore, throttle the charger back if required to suit your alternator and still benefit from the cooler running temperature.

Yes, and it is far far less likely to throttle back to the low-mid 20a range which the old model was likely to do.

 

[Tude]

The 50 amp is more efficient and runs a lot cooler I would go for is as it is not much dearer. Also I think your alternator will be OK with the 50 amp

It’s at least £100 dearer