Broadway Battery Issues

We have a 2014 ek and when we replaced our leisure battery we dropped In a fogstar drift 105ah.
Contrary to what others will tell you this is a drop in replacement with no adverse problems with the alternator on these models. The maximum charging current we've seen has been 10A which the wiring and alternator will cope with quite easily.
The fogstar will give you twice the useful output that lead acid will and for a lot less weight.
To make the most of the battery I replaced the solar with a 100w panel and replaced the solar controller with a decent mppt Victron 75/15 controller which quite neatly sits where the old controller sat inside the 328 box. While you're doing it I would suggest fitting a vanbitz battery master which will keep your engine fully charged throughput the year.

Peter Brown wrote:For the benefit of other owners I feel that I must post.

The dual channel solar controller that is integral to the EC328 is of very good quality and charges both vehicle and leisure batteries perfectly adequately from an 80w solar panel - a battery master is superfluous and would confuse the system.

Installing a lithium leisure battery (fogstar) in a standard split charge system that is configured to charge lead Acid batteries means that the new lithium leisure battery will never be properly charged and will not last as long as predicted.

If you want the different performance  of lithium, which some do, spend the £5000+ necessary  to upgrade effectively.

Unfortunately I'm going to have to disagree with virtually everything you've said.
The pwm controller is out of date compared with the Victron mppt chargers which will extract approximately 20% more energy on the grey cloudy days we tend to get in this country.
I suggested replacing the out of date controller with the Victron so there would be no confusion with the system.
Fogstar suggests bulk charging their Drift range between 14.2 and 14.4v and a float charge of 13.5v and 13.8v ( technically lithium doesn't float charge) which are what the 328 panel charges at and with the app that comes with the victron has a lithium profile to suit. These values can also be changed in the app. The values in the proceeding sentence ensure the fogstar charges efficiently and correctly.
Installing the lithium battery, Victron controller and the battery master will cost approximately £500 and take about 1 to 1.5 hours labour.
I've carried out the above and for the money and bang for buck I can say I couldn't be more pleased.
The last point I would make is that the OP suggested that they were replacing their battery anyway and the thought that the existing controller wasn't working,  what I've suggested above would only cost them £250 more than they might have to spend d anyway.

In my experience it's actually quite hard to make meaningful direct comparisons when changing the solar controller in an EC328!

You might, for example, have had the original (EPIPDB-COM) PWM controller at its default setting, which would have meant it was distributing 50:50 to the two batteries. That's quite hard to compare with, for example, a single-channel MPPT controller plus Battery Master - you would expect the behaviour to be quite different. IIRC I had my EPIPDB-COM controller set at 90:10 in favour of the leisure battery.

I think I got pretty close to a directly comparable setup by using the 2-channel Votronic MPP250, which in some respects is like a Votronic + Battery Master. Like yours, I mounted it in the EC328 where the original PWM controller was.

Everything else - wiring, 100W solar panel and lead/acid battery - all stayed exactly the same. And I have to admit that - 6 years on from making the change - I don't notice a huge improvement in performance, compared with the EPIPDB-COM controller. Low-light performance is definitely better, but the overall gain does not seem (to me) greater than a few percent in typical UK conditions. The conclusion I reached is the same as Peter's - the original PWM controller is very good, considering the design is well over a decade old!

Of course, when you throw a LiFePo battery into the mix it changes things again. It's something I've contemplated over and over, but - as Aethelric said above - whether it's worthwhile depends on how you use power, and I'm not a heavy user (not a TV watcher while I'm away), so I don't think I'll ever be able to justify the cost in the current van. The situation may be different when I change to a newer van...