Changing to lithium leisure battery

[Bigsidavies]

I have the ctek 250 with a Renogy 100ah LiFePo and a 100w solar panel.
The ctek issue is more of a minor pita rather than a major problem.
eg I’ve just been away to Ripon and put the fridge on in the van in the morning before setting off - LB 100%
By the time we set off the LB was down to about 96%.
Drive to Studley Royal Deer park - no output from CTEK during journey. Leave parked in sun - no output from solar via CTEK.
Park up for night in Ripon and LB down to 90% and by following lunchtime it’s about 82%.
Drive to Harrogate and CTEK kicks in and gets LB to 90% by time of arrival and carries on charging via solar while we are in Harrogate.
So basically the CTEK doesn’t kick in until the LiFePo is about 85%, so you can get to site having us a full day driving and already have a depleted LB when you park up which is annoying. So if you are having a week on a site off grid then your solar will have to have enough juice to cover your daily useage and a little extra if you want to push the battery back to 100%

 

[roadtripper]

Going to lithium will give you more usable capacity

Investing in solar will give you more off grid charging

The gold standard would be to do both - reasoning being that more capacity allows you to accept more charge on a "good" day and cover you for the next "bad" day

As @Oceanis says above think about what you want to do and look at your power budget:

• For a couple of nights you may find that a high capacity lithium system allows you to just run on the stored charge so long as you make sure the battery is topped off on a decent drive/EHU at home.
• If you want longer term than that then you may want to look at solar - but only if solar will keep up with your power use. If you want to capture the most then a roof fitted panel (with no shading) will collect all day, but is limited in size. You can increase the size with additional fold out panels but you might only be comfortable with leaving those out when you are near the van.

With specific regard to @Dellmassive experience with the CTEK chargers I believe he has stated its mostly a preference. You might not choose that charger if fitting new but if you have one in place I don't think it would be worth the effort to throw it away (or eBay it) and fit something else.

 

[Dellmassive]

So it will charge the battery whilst it has a load on it. (12v lights ,fridge is on )

Yes. The charger will adjust from bulk,absorb,float charge stages automatically as your loads increase and decrease.

Provided your charger is strong enough to counter your loads..... say 15A - 25A for example.

If you loads on full are 5A, then I would fit a 10A charger, leaving 5A to charge the battery.

If your loads were 10A then I'd fit a 15A or 20A charger, etc.

 

[Eggster79]

Thanks so much everyone for your help with this it’s much aporeciated.

Couple more questions and i promise i’ll stop

If I stick with the ctek charger with lithium and I turn up somewhere and the battery is not fully charged, due to having the fridge on or something during the drive, can i still use the battery or does it need topping up via solar panel or a hook up?

I forgot what question 2 was…

 

[Salty Spuds]

Thanks so much everyone for your help with this it’s much aporeciated.

Couple more questions and i promise i’ll stop

If I stick with the ctek charger with lithium and I turn up somewhere and the battery is not fully charged, due to having the fridge on or something during the drive, can i still use the battery or does it need topping up via solar panel or a hook up?

I forgot what question 2 was…

Why wouldn't the battery be fully charged after a long(ish) run? The charger should easily cope with running the fridge & charging the battery at the same time whilst the engine is running. If, however the battery isn't at 100%, it'll be fine to run the loads until the battery is empty & shuts down or you get more juice into it by whatever means.

 

[Eggster79]

Why wouldn't the battery be fully charged after a long(ish) run? The charger should easily cope with running the fridge & charging the battery at the same time whilst the engine is running. If, however the battery isn't at 100%, it'll be fine to run the loads until the battery is empty & shuts down or you get more juice into it by whatever means.

Something to do with the ctek D2505SE charge profile that when the battery is fully charged it starts to discharge to the float stage while driving.

See the post above or link below, i’m still struggling to get my head round it but i assume it is ctek’s way of dealing with lithium batteries when lithium batteries don’t need it.

Or something

[Guide] DC-DC Charger (for leisure battery) -- How I Done It --

Thanks Lee. Or should I say Mr. Renogy! Been looking at your threads so will work out how to do it all now. Thanks bud.

www.t6forum.com

 

[Pete C]

Thanks so much everyone for your help with this it’s much aporeciated.

Couple more questions and i promise i’ll stop

If I stick with the ctek charger with lithium and I turn up somewhere and the battery is not fully charged, due to having the fridge on or something during the drive, can i still use the battery or does it need topping up via solar panel or a hook up?

I forgot what question 2 was…

The answer is yes. Just use things as you want and let the hook-up or solar do their thing.
You need to keep an eye on the battery level in case your power demands are high, but that is always the case.
There is no reason why you can’t use solar and hookup together.

Pete

 

[CJW]

Don’t know if this helps, but our system is 110ah AGM with 2x100W solar panels and a Renogy DC50S.

We run a compressor fridge, two phones, one camera, one small sound system, our lad’s handheld games console, 21 led light bulbs etc off it.

Battery level never drops below 85% of usable charge at night, and is fully charged before we wake up in the summer.

Am going to get round to adding a PC ventilation fan at some point and am confident it will hardly dent available power.

I have the wiring in for hookup but it’s just not necessary for us so never got a mains charger.

 

[roadtripper]

Something to do with the ctek D2505SE charge profile that when the battery is fully charged it starts to discharge to the float stage while driving.

See the post above or link below, i’m still struggling to get my head round it but i assume it is ctek’s way of dealing with lithium batteries when lithium batteries don’t need it.

Or something

[Guide] DC-DC Charger (for leisure battery) -- How I Done It --

Thanks Lee. Or should I say Mr. Renogy! Been looking at your threads so will work out how to do it all now. Thanks bud.

www.t6forum.com

The CTEK has a lithium charge profile with a final float stage at a lower voltage to some others. What this means is that rather than hold the battery right at 100% it will let it drop back a bit and then kick in again, if you're unlucky you might end up parking up with 95% or 90% charge.

But, importantly, if you are lithium based you will still have much more usable charge than an equivalent lead acid system.

Why is CTEK doing this a bit differently? It's not clear but if you look around it's a known thing that holding many types of lithium battery to 100% all the time is bad for lifetime. Ideally they should be stored at around a third charge and you'll find modern laptops, phones and EVs tend to try and charge to about 80% unless you ask for full charge. CTEKs main history is in long term battery maintenance so my suspicion is they are using a strategy that is a balance of good available charge and better lifetime.

If you use your van as a daily drive and only need the full capacity a few times a year that may actually be an advantage. Does it make enough of a difference to worry about? Personally I don't think so, I'd just take note of it and use the higher capacity per volume of LiFePo to fit a bit bigger battery. For me the gentler charge rate and the not holding to 100% I'd see as an advantage and it's nice to have options in the charger marketplace. Would be better if CTEK was a little more clear about their choices and why they might be a good thing though...

 

[Eggster79]

Thanks again for this info. I just spoke to a conversion company that said lifepo4 batteries last as long as agm they just have more charging cycles.

 

[Bigsidavies]

Why wouldn't the battery be fully charged after a long(ish) run? The charger should easily cope with running the fridge & charging the battery at the same time whilst the engine is running. If, however the battery isn't at 100%, it'll be fine to run the loads until the battery is empty & shuts down or you get more juice into it by whatever means.

Read my previous comment/example of the shortcoming of the ctek.

 

[Bigsidavies]

Thanks so much everyone for your help with this it’s much aporeciated.

Couple more questions and i promise i’ll stop

If I stick with the ctek charger with lithium and I turn up somewhere and the battery is not fully charged, due to having the fridge on or something during the drive, can i still use the battery or does it need topping up via solar panel or a hook up?

I forgot what question 2 was…

Yeah, stick with the CTEK and the Lithium. It’s not an issue. It just bugs me sometimes. You can discharge your LiFePo to 20% with no effect on number of charge cycles, which is better than the depth of discharge for AGM. It has many more charge cycles than an AGM. And most importantly you can discharge it 100% and not kill it. Do it enough times and you reduce it’s maximum number of charge cycles but do that to an AGM a couple of times and it’s toast.

 

[Salty Spuds]

Read my previous comment/example of the shortcoming of the ctek.

Ahh right, hadn’t noticed that. Very strange.

 

[Eggster79]

I’ve gone for a Fogstar 105ah lithium battery so fingers crossed all will go well

 

[slybacon67]

Hi i am looking to switch from a 105ah lead acid to a Lithium leisure battery. I’m looking at the ones linked below and wondered if anyone has any experience of using one to help me decided.

I’m also thinking about getting a 150w solar panel or if i got a 230ah lithium would that negate the need for solar?

Any help would be much appreciated.

Xplorer Polarmax 100AH Low Temperature Lithium Battery with Bluetooth - Alpha Batteries



Lithium Leisure Battery - Fogstar Drift 12v 105Ah



Roamer 100SMART3 - 12V 105Ah LiFePO4 Lithium Leisure Batter

Hi i am looking to switch from a 105ah lead acid to a Lithium leisure battery. I’m looking at the ones linked below and wondered if anyone has any experience of using one to help me decided.

I’m also thinking about getting a 150w solar panel or if i got a 230ah lithium would that negate the need for solar?

Any help would be much appreciated.

Xplorer Polarmax 100AH Low Temperature Lithium Battery with Bluetooth - Alpha Batteries



Lithium Leisure Battery - Fogstar Drift 12v 105Ah



Roamer 100SMART3 - 12V 105Ah LiFePO4 Lithium Leisure Battery

does the fogstar fit under the drivers seat or do you lay it on its side , how does the renogy compare to these options ,its a little bit more expensive but i think its exactly the same size as my efb battery i have just now that is on its way out.

 

[roadtripper]

LiFePo isn't a "wet" chemistry so they should be fine on their side (but always double check the vendor's advice)

 

[Bigsidavies]

does the fogstar fit under the drivers seat or do you lay it on its side , how does the renogy compare to these options ,its a little bit more expensive but i think its exactly the same size as my efb battery i have just now that is on its way out.

The 100ah Renogy lays on its side too.

 

[Drive Wayne]

If you havent chosen solar yet I would really advise it if you have the need for a CPAP machine as your earlier post says, could be kind of important to keep the battery topped up to keep someone healthier at night. Those CPAP machines take some power!

 

[Strettyp]

I've been flipping between solar or not and have decided that I want to upgrade the leisure battery from the factory fitted jobbie under the passenger seat, and swap the charger so it can be charged while I'm driving, then add an inverter

Ideally I'd like the biggest capacity battery that will fit under the passenger seat base - anyone got any specific battery make/model recommendations that they've used ?

 

[Drive Wayne]

Roamer 230Ah Seatbase 3, designed to go under the front seat even a swiveller. £1125 at the moment. I'm much better at spending other folks money than my own. Great company to deal with, help at the end of a phone, great App to monitor. I would still have solar too though to top it up.