What deep cycle battery to charge car "main" battery

[Shnozz]

My Lotus lives in an underground car park with no access to power nor sunlight. In winter months this presents a battery issue.

I bought a Ctek CS Free but its not up to the task, frankly. I can, however, use it as a pass-thru between a second battery and the car battery. The second battery can then be removed periodically to be recharged and then connected back up.

Any recommendations for a deep cycle battery? Was thinking of limiting this to 80A for weight purposes so its not too heavy to lug back and forth when needing a recharge every month or so.

[charltjr]

I’m guessing you’ve already considered it, but curious as to why you’d not use a battery cutoff instead?

[Shnozz]

charltjr said:

I m guessing you ve already considered it, but curious as to why you d not use a battery cutoff instead?

I would like the alarm and immobiliser active, as well as the central locking. I have also found modern cars tend to be more prone to throwing a wobbly when not connected for a while. Add to that the reset of stereo settings and clocks, and the final issue is the negative terminal to which a cut off would be fitted is in the most inaccessible place imaginable on an Exige, sufficiently so I think you would need to unbolt the retaining clamp to be able to reach it. You can just about get a battery clamp on the top of the neg terminal using some body contortion.

[Weekendrebuild]

Definetly purchase a property with a garage this sounds like a pain. Saving that I’d just get a cut off they aren’t that hard to get to an you can get remote ones.

[CABC]

I get the modern cars don't like to be disconnected, but Lotus/Toyota seem resilient in this regard. There is far less ancillary stuff to get "confused" and the core EMU is solid. I still disconnect my Toyota many times a year, no issues. Fancy modern car from last 10 years, nope.

over on SELOC Arno has described a reliable system. uses the DC Optimate charger and leisure battery.