Yet another lithium question

[Martin P]

These are the charging characteristics of the Calira EVS 38/20 as fitted to our motorhome
Now I can see that it is not perfect for charging lithium batteries but will it be ok?.
Bearing in mind that our batteries are mostly charged by solar anyway, even if the Calira mains charging only worked at a lower rate of efficiency that would be acceptable as the solar panels usually have everything fully charged by noon anyway
It actually works as a split charger in reverse as well which is a bonus. I know there is a company that does a lithium "upgrade" but im not that keen on having it buggered around with.
Just wondering if any of the wizards on here know the exact implications rather than relying on guesswork.
Thanks to anyone who could spare the time to advise me on this.

 

[Martin P]

 

[merl]

That's a typical Lead Acid profile, it'll be fine but try and switch it off after the lithium is full IF you can. It's not hugely important but try not to leave the charger sitting on trickle for days on end, like you would with a lead acid battery.
If the charger has a gel setting switch to that too.

 

[Okta]

That's a typical Lead Acid profile, it'll be fine but try and switch it off after the lithium is full IF you can. It's not hugely important but try not to leave the charger sitting on trickle for days on end, like you would with a lead acid battery.
If the charger has a gel setting switch to that too.

Not sure I agree with using the gel setting in this case. The voltage is the same for gel and liquid acid but the absorption phase (called post charging phase on the graph) is much longer on gel. 10 hours instead of 4 , the shorter period would suit lithium better.

 

[Nabsim]

Not sure I agree with using the gel setting in this case. The voltage is the same for gel and liquid acid but the absorption phase (called post charging phase on the graph) is much longer on gel. 10 hours instead of 4 , the shorter period would suit lithium better.

I was advised to use gel when I first fitted mine, when battery is full it will drop back to float anyway. That's when it needs the charger turning off

 

[Okta]

I was advised to use gel when I first fitted mine, when battery is full it will drop back to float anyway. That's when it needs the charger turning off

That does seem to be the normal generic advice and sometimes it is appropriate. I prefer to look at the individual characteristics of the charger and choose the one with the shortest absorption phase, provided the voltage does not exceed the lithium rate. I doubt that battery manufacturers can be that specific so they say use the gel profile because they know it will not have too high a voltage.

 

[Fisherman]

Why not simply buy an appropriate mains charger with the correct charging profile for lithium. Most mains charger today come with this optional profile.
Also you say you will normally be charging with solar, it’s equally important that your solar charger has a lithium setting to achieve the best results.
Another thing is if you don’t have heaters on your batteries beware of charging below 5c, particularly from a low charge, and charging at a fast rate. Victron chargers offer the option of not charging below 5c.
The advantages given by using lithium warrant the additional cost of replacing chargers if required.

 

[Martin P]

Thank you all for your replies.
Please give me a few moments to go through them, I really do appreciate the help

 

[Nabsim]

Admittedly I am only in the UK in Winter (cold weather charging) but over the last 5 years my battery have never been cold enough to worry about any charge from the solar panels (300W flat on roof). You can still charge below 5 degrees C its just a lower rate.

 

[merl]

That does seem to be the normal generic advice and sometimes it is appropriate. I prefer to look at the individual characteristics of the charger and choose the one with the shortest absorption phase, provided the voltage does not exceed the lithium rate. I doubt that battery manufacturers can be that specific so they say use the gel profile because they know it will not have too high a voltage.

I get your point but having worked on quite a few chargers I don't think that kind of subtlety is something you'd get on the vast majority of MH chargers, all I've witnessed is the 'battery type' switch lowering the voltage threshold for bulk and absorption phases by around 0.5 volts.
If a charger was that sophisticated then I'd expect to see another setting for the Ah rating of the battery being charged because absorbtion time is proportional to capacity, again Ah selection is a rare facility on MH chargers.
Below is a chart showing the typical variation in profiles for Flooded, AGM and Gel, as you can see there's no variation in absorbtion time in the chart, only voltage differences. The AGM setting gives the highest charge voltage but the lowest float, probably best if you think you're likely to forget to switch off once the float stage is reached. Otherwise the gel setting would be best because the charge voltage is lowest.

GEL / AGM Battery – How to select power supply

Only charge GEL batteries using a confirmed and reliable, temperature sensing, voltage regulated charger. Never use a constant current charger! At 25°C/77°F keep charging current in the range of 2.…

inglele.wordpress.com

 

[Nabsim]

Well mine was the Schaudt charger fitted in the EBL plus and additional the same. I checked the battery specs of my lifepo4 and the gel setting came within it apart from the fact it could float. As float wasn't adjustable I would just unplug EHU on the rare occasion I go on a site. Strange but even now I have a couple of proper lifepo4 chargers I still only connect to hookup when I want to charge my battery, had 3 days on a site at Loch Lomond a couple months back and only had ehu connected for 2 hours

 

[Martin P]

Ok, thank you.
Well firstly the reason I dont just change the charger is that the Calira charger in my van is an integrated unit that combines the 240v charging and 240v in /out system with built in circuit breaker, for the ring main and Truma heater, the 12v distribution system with built in fuse board , the fridge 12v and 240v system, and the hab battery and starter battery connection and separation system .
To replace would seem to require a fairly substantial re wire.

 

[Martin P]

The solar charge controller does have a setting for Lithium batteries

 

[Martin P]

I currently have 2 x 110 amp lead acid batteries so for similar capacity am thinking I would only be needing around 100 amps of Lithium. If I assumed that my 390 watts of solar would keep this pretty much charged by midday then if I was to spend a couple of days on a campsite on hookup (if it was a campsite with only hookup pitches and plugged in to run fridge and truma heater) would that risk damaging either the lith bat or charger

 

[Nabsim]

There is probably a fuse for the inbuilt charger in the distribution system. I don't know the Calira so can't really help. It was easy on the EBL as there was a kettle type plug going into the unit which was for the charger part. Have a look in your manual and see if there is a fuse or plug you can take out to isolate it. If so you can fit a separate charger direct to the battery if you wish or just isolate the existing one when battery is charged.

Does it say what voltage float is on the inbuilt charger?

 

[merl]

Does it say what voltage float is on the inbuilt charger?

According to the bumf it's 13.8 Neil.

 

[merl]

I currently have 2 x 110 amp lead acid batteries so for similar capacity am thinking I would only be needing around 100 amps of Lithium. If I assumed that my 390 watts of solar would keep this pretty much charged by midday then if I was to spend a couple of days on a campsite on hookup (if it was a campsite with only hookup pitches and plugged in to run fridge and truma heater) would that risk damaging either the lith bat or charger

The charger wouldn't be harmed by leaving that running continuously while on site on EHU.
There will be lots of people and articles that say that it'll be harmful to the battery but I've seen NO science based evidence of that at all. I'd be very interested if anyone could provide any.
If you want to err on the side of caution then find a way to switch off the charger like Neil suggested but TBH electronic theory says you don't need to worry about it.

 

[wildebus]

Ok, thank you.
Well firstly the reason I dont just change the charger is that the Calira charger in my van is an integrated unit that combines the 240v charging and 240v in /out system with built in circuit breaker, for the ring main and Truma heater, the 12v distribution system with built in fuse board , the fridge 12v and 240v system, and the hab battery and starter battery connection and separation system .
To replace would seem to require a fairly substantial re wire.

The setup you have with an all-in-one integrated charger and distribution box is fairly typical in Motorhomes. Makes it convenient and saves space but creates limitations sometimes if you want to upgrade.
The approach I took on my own Motorhome with its Sargent all-in-one charge and 12V DC/240V AC distribution box, and have done with other Motorhomes I have upgraded, is to keep the original box in place for its distribution function but simply bypass/disable the charging features on it and replace with external, better devices.
For example;

On a Sargent system, you can usually just turn off the mains charger using its big red (or green) switch; disabling the split/alternator charging is a bit more complex but very doable.​

On an Schaudt EBL unit, disabling the mains charger is as mentioned just a matter of pulling the mains kettle lead out the unit or you can remove a specific fuse. Alternator charging removal usually easiest by removing starter battery cable into EBL but can vary by EBL model (have to consider how 3-way fridge +12V is provided)​

I don't know how the Caliva is wired up but chances are similar approaches to the above can be done.
If you do get a new mains charger bear in mind the size needed for how you like to camp AND how noisy it is. Some chargers are perfectly efficient but have very noisy fans when operating which makes them no use at all in a Motorhome being actually used when on EHU. As far as size goes, remember the charger will be used to both charge the battery AND to provide the power for all the 12V services. So if you decide a 20A charger is big enough to charge the battery say, but you have lights on, a using USB to charge phones, tablets and a laptop and are watching TV when on EHU, you could easily be drawing say 140W of power, which is around 10A from the DC charger which only leaves 10A for battery charging rather than the 20A you may have planned on.

 

[Martin P]

Ah. So maybe I could simply unplug the Calira 240v inlet plug which I could then directly connect to the ring main and also the Truma boiler and just add another charger.
I would lose the Calira breaker though so would have to add one in.
Any makes of chargers recommended?
A lot of food for thought here, thanks

 

[wildebus]

Ah. So maybe I could simply unplug the Calira 240v inlet plug which I could then directly connect to the ring main and also the Truma boiler and just add another charger.
I would lose the Calira breaker though so would have to add one in.
Any makes of chargers recommended?
A lot of food for thought here, thanks

If your Caliva box has the 240V breakers within it as well (like a Sargent unit does) then removing the plug would lose your general 240V though . If it is like an EBL where the 240V breakers are totally separate, then pulling lead into the Calira should do the trick.
I don't know the Calira, but pulling the lead may mean the control panel says you have no hookup plugged in ever? (I think that is what happens if you pull the lead on an EBL with some of their panels rather than remove the appropriate fuse?).
Personally I like the Victron Chargers as they work very well and are backed with a 5 year warranty. The IP22 range goes upto 30A and have no fan so run very quiet, plus there is a "nighttime" mode that halves the output to run totally silently (some folk have very sensitve hearing!). I think some people on the forum have used the Fogstar chargers to go with their Fogstar batteries but have needed to change the fans due to the noise? I'll go for the simple out the box option myself