Problem with Lithium battery charging

[baroloman]

Noticed that our Lithium leisure battery no longer seems to be charging from either mains power or the engine (well actually it does sometimes with the engine). It does charge fine from the solar panel though. We've had a couple of people look at it but they were baffled. Any ideas? Many thanks.

 

[Admin]

I need to know what type and age of vehicle to have.

Is the vehicle EURO6?
Does the vehicle have AdBlue?

I need to know what battery you have.

What battery do you have (Make, Model, Capacity)?

I need to know about your charging systems.

Do you have a dedicated B2B (battery-to-battery charger) installed?
Did you have your onboard charger upgraded to a lithium compatible charger?
What solar setup do you have?

Could you please specify how you are determining that the battery is not charging?

Is this from the battery's internal meter or from an external shunt?
When the engine is running could you please provide the voltage and state of charge details as reported by the battery?
When on mains hookupcould you please provide the voltage and state of charge details as reported by the battery?

 

[molly 2]

I would go lithiam tomorrow if they really were drop in replacement as advertised,

 

[QFour]

I would go lithiam tomorrow if they really were drop in replacement as advertised,

Mine was. I just took the very heavy 80A battery that came with the New Carthago out and fitted a New Lithium 120A from KS Energy. Did this 4 years ago and still working fine. Its got bluetooth and will not charge below 5 degrees. Also very light.

 

[molly 2]

No charge setting on My old van

 

[merl]

Just hypothesising and I've mentioned this before but I'd strongly suspect that dropping a plain old lifepo4 battery would work OK apart from the alternator charging current which I think will be slow due to the generally higher voltage of lifepo4. The KS batteries are built using different cells and have a lower voltage than the typical prismatic cells and the resulting charge rate will be higher, how high I don't know but at £600 for 125Ah it's a lot of Dosh. For that you could buy 200Ah of batteries AND a B2B and still have change to buy the cable as well.
Horses for courses
.

 

[wildebus]

Just hypothesising and I've mentioned this before but I'd strongly suspect that dropping a plain old lifepo4 battery would work OK apart from the alternator charging current which I think will be slow due to the generally higher voltage of lifepo4. The KS batteries are built using different cells and have a lower voltage than the typical prismatic cells and the resulting charge rate will be higher, how high I don't know but at £600 for 125Ah it's a lot of Dosh. For that you could buy 200Ah of batteries AND a B2B and still have change to buy the cable as well.
Horses for courses
.

I don't worry too much about the charging profile of Lead vs Lithium for "drop in" Lithium Batteries, but the duty cycle of the chargers, especially on older vans which had charging systems that were not designed to be running flat out for hours and hours, which is what happens when you add a Lithium Battery.

 

[rugbyken]

No charge setting on My old van

i wouldn’t have thought your van was that old barry mines 11 years old i altered the charger to gel and it all works maybe not 100% efficiency but near enough for my purpose , the solar connector is set for lithium and recharges it in a matter of hours if the sun is shining

 

[Nabsim]

Gel setting will be close enough for most lifepo4 but as David says you don’t want a charger not up to the job running flat out for hours. That would depend on how big a battery you fitted and how much you need to put back. I wouldn’t worry too much for a single 100Ah lifepo4, would be more concerned about it going on float all the time. I solved that by knocking the breaker off when I was using the Schaudt charger

 

[merl]

Gel setting will be close enough for most lifepo4 but as David says you don’t want a charger not up to the job running flat out for hours. That would depend on how big a battery you fitted and how much you need to put back. I wouldn’t worry too much for a single 100Ah lifepo4, would be more concerned about it going on float all the time. I solved that by knocking the breaker off when I was using the Schaudt charger

Don't actually know how critical the whole Don't Float thing is either TBF, it's touted around a lot but I've never been able to find any science behind it. I personally think it stems from lifepo4 charging to full and then stopping and not NEEDING a float and this has morphed into DON'T float cos it's not needed and that's morphed into don't float because it damages them.
When you think about it the 'float' current ends up simply keeping up with self discharge so it's tiny and it more or less simply holds the voltage at a slightly higher voltage than the resting voltage, ( depending on whatever voltage is chosen) so hardly 'charging' anyway.
I set my solar at 13.4 float, it keeps up with the starter battery maintainer and the parasitic draw from the system, and the batteries at about 90% or so, seems perfectly sensible and reasonable in my head OR am I floating at 13.4????? Would 13.6 be so bad ????
Without any scientific reasoning peeps (and suppliers and even manufacturers) just follow the line and from there it becomes fact.

 

[Canalsman]

I have a Victron SmartSolar regulator and LiFePO4 battery setup.

Float voltage is set at 13.45 volts.

Having been a lovely sunny day the regulator is in float mode.

The BMS is showing 99% state of charge and it's cycling between standby and charging modes as compensation is made for the various perpetual, rather than parasitic, current draw. (I think perpetual is a better description. Parasitic implies unwanted which isn't the case.)

If float mode was an issue the charging profiles for devices such as the SmartSolar would would make specific allowance in lithium installations. It doesn't do that and the LiFePO4 default mode includes float voltage.

 

[matbic]

I found this a useful webpage when trying to figure out what to do about floating a lithium battery : https://nordkyndesign.com/practical-characteristics-of-lithium-iron-phosphate-battery-cells/

Not sure about other manufacturers but Victron state their batteries must be held at “absorption” (that’s 14.2V for my battery) for at least 2hrs a month I assume this is to allow the battery management system to balance the cells and recalibrate the state of charge.l

The float voltage specified is 13.5V it’s safe to keep them in this for the rest of the time. However, there is a slight advantage of keeping them at less than 100% state of charge over times when you are not using them but lithium batteries last so long anyway it’s more likely the rest of the van falls to bits before the battery!

The main issue with lithium is not to let them go to zero charge at any time so it’s important to fit something to cut the supply when state of charge is near zero.

This is also why I leave my charger on when leaving the van for a while just as a backup in case there is something discharging the battery it’s better not to go to zero than keep batteries at 100% state if charge. I think this is in line with Victrons recommendations.

Hope this is helpful!

 

[Nabsim]

Do Victron say why you shouldn’t run them flat? Only reason I can think is if your charger isn’t capable of bringing them out of sleep when they go flat it won’t hurt them to run flat or 100% as far as I can see. Was a year or two after I got mine that you started to see ‘recommendations’ that they should be kept between 20% and 80% but that is only for long term storage not in use

 

[wildebus]

Generally when a lithium battery is "dead" and at 0% and the BMS disconnected, the cells themeselves are not flat anyway.

I think it is very true that if you follow a regime of not discharging below 20% or so and not charging above 80% - a common mantra in places like Will Prowse's DIY Solar Forum - you wll get a fair bit longer service hours from the battery but there are two flaws with that approach ...
1) You will be getting nowhere close to using the capacity of the lithium batteries; 2) using the batteries to their full capacity, they will likely outlive how long you need them for anyway.
So why compromise your use of the batteries for extra life you will never get to benefit from?

 

[merl]

I found this a useful webpage when trying to figure out what to do about floating a lithium battery : https://nordkyndesign.com/practical-characteristics-of-lithium-iron-phosphate-battery-cells/

Not sure about other manufacturers but Victron state their batteries must be held at “absorption” (that’s 14.2V for my battery) for at least 2hrs a month I assume this is to allow the battery management system to balance the cells and recalibrate the state of charge.l

The float voltage specified is 13.5V it’s safe to keep them in this for the rest of the time. However, there is a slight advantage of keeping them at less than 100% state of charge over times when you are not using them but lithium batteries last so long anyway it’s more likely the rest of the van falls to bits before the battery!

The main issue with lithium is not to let them go to zero charge at any time so it’s important to fit something to cut the supply when state of charge is near zero.

This is also why I leave my charger on when leaving the van for a while just as a backup in case there is something discharging the battery it’s better not to go to zero than keep batteries at 100% state if charge. I think this is in line with Victrons recommendations.

Hope this is helpful!

Not really! Just more confused now than I've ever been!
I've seen more than one scientific doc saying that lifepo4 is incredibly tolerant of charge level/voltage and tests show that no real harm is done until they're taken to over 15v. That's contradictory to what's said in the above article which suggests that lifepo4 is very critical, needs to kept below 14V and even needs a short period of float charge akin to LA BUT must NOT be left on float long term. Never seen the ref to Lifepo4 needing a short float either!!
It also mentions memory effect if not charged and discharged correctly, again that's something I've never seen referenced previously BUT it does seem to be tiny and easily 'wiped out' . I'm gonna have to read through the article again cos my heads hurting!

 

[Nabsim]

If it mentions memory effect it isn’t referring to lifepo4 technology, it’s some other lithium flavour.

Checked my mppt settings today and I have absorption set at 14.2v, I presumably did that for balancing, and float set at 13.5v

 

[wildebus]

These are my batteries .....

Top Right is Starter Battery; Top Left is Starter Battery at the B2B input (different is I am able to see the cable voltage drop when the B2B is running)
The Key ones are really the lower left ones ... Lithium sitting at 13.36V and Lead at 14.19V (still charging). Setup so Lithium and Lead are in parallel in use, but when charging, the Lithium disconnects from the chargers when the voltage hits 14.19V - So no floating charge for Lithium in my configuration
Hab Systems - i.e. the system all the habitation services run off - is regulated down to 12.45V at the point it feeds the Sargent unit to avoid high voltage charging peaks and lets me use 'residential' kit like Amazon Echos, etc without needing a regulated supply for each device

 

[merl]

If it mentions memory effect it isn’t referring to lifepo4 technology, it’s some other lithium flavour.

It does Neil and deffo lifepo4 too. Take a look. He even produces graphs to display the effect and quantify the amount which, TBF isn't huge and easily reversed. Nevertheless it's interesting/surprising because, like you, I've never seen it referenced before.

 

[colinm]

I don't worry too much about the charging profile of Lead vs Lithium for "drop in" Lithium Batteries, but the duty cycle of the chargers, especially on older vans which had charging systems that were not designed to be running flat out for hours and hours, which is what happens when you add a Lithium Battery.

That's interesting, I need to replace the (frankly disappointing) 2x75Ah Varta LA in my van, I've been considering 2x70Ah Banner AGM's as the previous Banner AGM did well for holding charge and longevity. We don't need a big battery bank, and one of the new 'cheap' 100Ah Lithium's would do, but the thought of lots of other expense put me off, but one of these and the Apuljack Lithium upgrade on the EBL99 might be an option for not much more money. Any thoughts on that?

 

[wildebus]

That's interesting, I need to replace the (frankly disappointing) 2x75Ah Varta LA in my van, I've been considering 2x70Ah Banner AGM's as the previous Banner AGM did well for holding charge and longevity. We don't need a big battery bank, and one of the new 'cheap' 100Ah Lithium's would do, but the thought of lots of other expense put me off, but one of these and the Apuljack Lithium upgrade on the EBL99 might be an option for not much more money. Any thoughts on that?

I don't know if I would bother with upgrading the EBL99 with the Apuljack change. Lots of folk seem happy with putting it into GEL mode.

If of interest, have a look at this thread ... https://wildcamping.co.uk/threads/for-sale-100ah-lithium-batteries.98574/
Pair of top quality 100Ah Lithiums and other bits for sale.
I would bundle the pair of batteries together with the Schaudt 25A B2B (perfect partner to the Schaudt EBL giving an improved charge rate and has a Lithium setting) plus a custom factory support that allows you to fit the B2B behind the EBL on a ducato/relay/boxer mount for an all-in price of £460 (plus any shipping costs)