Lithium battery or Solar panels ?

[rollingbyte]

Hi!
I am the proud owner of a T6.1 Ocean. The previous owner did not take good care of the 2 AGM batteries and they need to be replaced. Since I got the Van I have never really experienced the full capacity of AGMs, I always struggled to stay more than 24 hours without driving so I do not have a good sense of what you can get with new AGMs.

Since I need to replace batteries anyway, I am debating going with 1x lithium batteries (the 170Ah kit from Saftkiste), or replacing the 2 AGM and installing 300w of solar. Going with 1x lithium should cost €2.5k and solar + AGM replacement should be around €2K

I am using my Cali in France / Switzerland for week-end trips (2-3 days) in the mountain (all seasons including winter skiing), working remotely, vacation (road trips), and twice per year spending one week at a camp site (with hook up).
I want to be able to stay in a location for 3-4 days and have fridge, computer, heater, etc. running. Not having to pay for hook-up when at a campsite might be a plus.

Maybe someday I will have an e-bike, but for now I am fit enough to ride a regular bike
For e-bike charging, If I go with lithium I'll need to install a proper pure sine wave inverter. If I go with AGM + solar I can get an external EcoFlow battery connected to the load outpout of the MPTT in the trunk to take excess solar and that should do it.

My computer setup requires 30W and runs 8 hours so that's ~20Ah
As per my understanding the fridge should use between 15Ah in colder days to 50Ah in hot summer (where solar panels are effective)
The heater should be offset by the fridge not running in winter.
So I am looking at 35Ah to 70Ah / day.

Being an engineer who worked on charging algorithms for lead-acid and lithium batteries, I feel comfortable doing the lithium retrofit and I have watched literally hours of videos / formus about Cali lithium installation.

Both options seem viable to me:
- 1x Lithium retrofit with 170Ah + later install an inverter if I get an e-bike
- Stick with AGM but install 300w of solar and get an external battery with included inverter if I get an e-bike

I don't have experience with either solar nor lithium in a Cali, so I might be missing some key aspects based on my use case which would help me decide...

Thanks a lot!

 

[colintfcolintf]

not sure if this helps. but had 10 days at Le Mans last July, didn't drive about much, but did start the engine a couple of times to give a quick boost, nearer the end of the stay when in a shadier spot , but the original 2017 Leisure batteries and Roger's (Solar Solutions) 300W Solar kit last the 10 days there, with Fridge on etc etc. I also had a Bluetti AC70P (which fits in the kitchen cupboard)for the likes of kettle and 240V charging of things when needed

 

[Ch1pbutty]

300w solar

 

[Wannabecamperman]

Going with 1x lithium should cost €2.5k and solar + AGM replacement should be around €2K

Surely a Charger One and 2Kwh LFP Power Bank would serve you better? At less than half the cost!

 

[dspuk]

Good condition batteries will last 3 days off grid, 4 if frugal. That’s the VW design principle.

150W solar will get you to 5, maybe 6. 300W will effectively, in the right weather, keep you going indefinitely.

The challenge is going to be e-bike batteries - they are a watt hog.

All irrelevant if you use EHU often or between 3 day sites.

Later 6.1’s have a flat sine wave, so depending on the year you will be fine. Rule of thumb is the 150W inverters are not flat, 300W ones are.

 

[temporarysecretary]

I was in your exact position and bought 2 new AGM batteries and 100w solar.

I have left the fridge on 4 for the last year straight and camped single nights up to a week in the UK and continent. When its cold ill put the heating on and when its dark ill use the lights. I havent ran out of juice since installing it. I was fully prepared to add solar panels if required but haven't needed to at all.

For your computer, recently I added a small USB power station to take some of the extra charge the solar is wasting (gets full every day on my south facing driveway) which gives me 288wh of USB DC power. My camping style is off grid with devices and with 2 children = lots of USBs. I was previously charging things off the leisure batteries but it felt harder to organise with cables plugged into the kitchen etc. My main focus was to make my charging more flexible, secondly to see less waste on the victron app and the more overall capacity on the van was a bonus. This is what I have https://www.ankersolix.com/uk/products/c300-dc?variant=49876551237968

Its a bit bigger than a pint glass and sits in the bottom of the wardrobe charging from the load output on the victron. Next to it is a USB jump starter incase anyone ever needs a start on a site. I charge this from time to time from the Anker.



If you are going the ebike route id just spend more on the power station and get an AC device. The new compact Bluetti look fab but are more than I need so I chose simple.

I feel like if you are going to put lithium batteries anywhere in 2026 it needs to be fully portable, its much more versatile and sooner or later you will find a use that a mobile power pack can meet that an inbuilt lithium could not. Also means you can keep the van simple as it was intended.

 

[wildslammer22]

If you’re using 35ah a day in winter and up to 70ah then the most cost effective solution would be new AGM's giving you around 3 days off grid in winter. Add an MPPT and a 200 or 400w solar blanket - a Renogy one will cost significantly less than fixed panels, be much lighter and more versatile in terms of optimising the yield. The 200w packs tiny and can do double duty as a windscreen cover for some shade in Summer. In fine weather should keep you off grid for at least 5-7 days. The blanket can equally be used to directly charge an Ecoflow or similar for when your legs give up and you need an e-bike!

In my case versatility was my primary driver rather than budget (I also have Starlink which is a power hog on work from van days) so went with 200ah of Lithium,100w panel on the roof to keep the fridge running 24/7 and a 200w solar blanket (with additional MPPT) for longer Summer trips. I don’t run anything that requires an inverter and this set up allows me to be totally independent of EHU.

 

[Ch1pbutty]

We had 300w of panels on the roof + 1 leisure battery only (Beach). Fridge permanently on for 4 years even when parked on the drive (great beer fridge!). Never needed EHU even during the winter.

Also had empty roof bars fitted most of the time, so probably only getting power from 200w of panel due to shadow created from the bars.

 

[rollingbyte]

Thank you all for sharing your experience! Very helpful links and resources.

I am surprised to not see more love for Lithium batteries but that indicates that AGMs are more capable that I think.
Thanks @temporarysecretary for sharing your perspective and that Anker portable battery is quite appealing!

Later 6.1’s have a flat sine wave, so depending on the year you will be fine. Rule of thumb is the 150W inverters are not flat, 300W ones are.

Very useful @dspuk ! That info was hard to find, lots of resources are for older variant. My T6.1 is from 2023 with a 300W inverter, so I should be covered.

I am leaning towards new AGMs, 300w solar (fixed on the roof) and an extra portable lithium battery. I like the idea of being able to use it for other things.

Thank you so much!