Upgrading 2013 Autocruise Alto to Lithium (LiFePO4)

[JimmE]

I've been meaning to start writing this up for a while. The upgrade is now well underway, so figured it's as good a time as any to get started on the writeup! Hopefully some of this can be helpful to others considering similar, but as usual - this is how I chose to go about it - not necessarily the 'best' or 'right' way to do it, and certainly not the only way! That said, I try to do things to a high standard - albeit also have a tendancy to over-think things sometimes - so hopefully anyone with more knowledge/experience than me won't find anything here too horrifying!

Background
After purchasing our van last year, we've been researching installing an inverter and associated power system sufficient to run a "low power" (900w) hairdryer and a pair of GHD hair straightners - my OH still won't be without these on a trip! Whilst it all works fine on hookup, that has limited our choice of sites on a number of occassions. On other occasions, even at a site with EHU, needing to be on hookup has limited our choice of pitch and meant we've missed out on a few pitches with great views!

We've had the van a little over a year now, and have had about 35 nights away. At present we tend to 'tour' rather than pitching up in one place for a week, so move every couple of nights and use the van to travel out to see places during the day. So, flexibility of site and pitch is useful as we're always looking for sites at short notice, rather than booking pitches weeks/months in advance. Others may have different preferences, and so different requirements.

When researching the upgrade, I saw lots of posts here and elsewhere from other people looking into the same (going back 12+ years) but few end-to-end posts covering the research, purchase and installation with any follow notes on how it worked out, so that's what I'm aiming to do here. As per another thread I posted a couple of months ago, whilst there are other threads detailing B2B installations, battery upgrades etc on lots of different vans, I've seen far fewer detailed posts on installation process in a PVC, as opposed to larger motorhomes.

So, to spec out and price up the kit required, first step was to figure out how much power actually needed to run these two appliances. It is easy to see the rated power of the hairdryer, but not the GHD straighteners. I suspected the straightners would use less power (and would be 'bursty' rather than 'continuous' but also that they appear to have electronics in them rather than being straightforward electric appliances, therefore assume they would prefer/require a pure sine wave inverter, rather than the cheaper modified wave inverters. Going for pure sine wave also means we can use it to run other electronic appliances in the future if needed.


Power requirements
First observation is that our actual power usage in the van appears minimal. We have never yet used the TV, so the main power draw is the compressor fridge. We installed a Victron SmartShunt shortly after buying the van, which has a small solar panel on the roof. Even in November, we didn't see our usage (estimated in the Victron app) drop below 89% any evening, whilst running the Truma gas heater (fan is battery powered!) and lights etc, so our existing 90ah lead battery and the onboard Sargent split-charge system with the small 80w solar panel and PWM controller appear sufficient for most of our requirements, other than the inverter.

So, how much power do we actually need to provide at any one time?

The travel hairdryer is rated at 900w, but I suspected that like a Microwave, this is the 'heating power' rather than the 'total appliance power draw'.

GHD hair straightners - I could not find any reliable information online or on the straighteners themselves to indicate how much power is required.

Therefore, I decided to buy a cheap 'clamp meter' so that I could measure the power draw of both appliances, when running over 240v. This is a meter which allows you to measure the current being drawn without having to connect an ammeter 'inline' with the circuit. I purchased this meter back in October last year, and it cost £30 delivered - I notice the price has since increased!

Current travels in a circuit - put simply in mains electricity you have the live and neutral connector inside a cable and power comes 'out' one cable and 'back' through the other. Therefore simply putting the meter around the appliance cable is no use as the live and neutral current (in opposite directions) cancel each other out, so you need to split the cable and measure just one. I didn't want to split the cable open on the actual appliances so made up a short fly lead with the outer insulation removed for a short section, to allow me to clamp the meter around just the 'live' (brown) wire, with no bare/live copper exposed.

This worked well, and after taking several readings I came up with the following figures:

Hairdryer - fused at 5A. Max current observed - 4.1A. This was fairly constant.
Straighteners - fused at 3A. Max current observed - 3.1A. This was only a peak - generally it was a little lower, plus cuts out almost entirely when up to temp.

Using the formula from Watt's law (P=IV) we can calculate the wattage, and then the number of amps which would need to be drawn to provide that same wattage from a 12v inverter rather than 240v mains.

Hairdryer - 4.1A x 240v = ~980w contstant
Straighteners - 3.1A x 240v = ~750w peak

So clearly the hairdryer has the highest power requirement. Converting that back to 12v, we can see the current requirement:

Hairdryer - 980 / 12 = ~82A
Straightners - 750 / 12 = ~63A

However, inverters are not especially efficient. Whilst I have a tendancy to 'buy once' I had already done some research and seen that 'good quality' inverters were a lot of money - in this case we were looking to do this on as much of a budget as possible, so I was looking at the 'unbranded' imported pure-sine inverters on Amazon. On that basis I decided to assume the worst, and work on a 20% inverter overhead. This is almost certainly OTT but calculating for this should mean no surprises and a bit of a margin - I don't want to be running the inverter (or any component) at 98-100% capacity all the time.

So, adding the 20% overhead shows that we need a ~1200W inverter and that we'll be pulling ~98A from the batteries and through the wiring.

To be continued!

 

[JimmE]

Choosing components
At this point I started digging deeper into what we might buy - both on the Inverter and battery front. The Victron/etc branded inverters were more than we wanted to spend - at least initially - so we looked at the cheaper pure-sine inverters available on Amazon.

The 1000W continuous models are a much more appealing price than the 2000W continuous models, so I had a look for something in between. I've read/seen several people saying that the 'Giandel' inverters are reasonable (and there are a good number of positive Amazon reviews too), but their 2000W model is close to £300, and we need more than 1000W, the next model down. So, after lots more research, settled on a 'Carrybatt' 1500W model for just under £175 back in May. These also have a reasonable number of positive reviews, although I wasn't able to find much else written outside of Amazon on them.

Our leisure battery is a 90Ah Varta LFD90 - which seems to be considered a good quality standard lead acid battery. It's dated 2019 suggesting it was fitted around a year before the van was sold on. However, we're looking at a ~100A discharge rate, which no lead battery is going to provide without being degraded quickly - so I started researching Lithium/LiFePO4 alternatives.

Wow - it's easy to spend a lot of money very quickly! After many hours of digging, I discovered that pretty much the cheapest 100Ah LiFePO4 batteries available (excluding some sellers which appear to come and go quite quickly) seem to be from Ultramax, who sell directly via their UK distributor on eBay. Around £430 at the time, still more than I wanted to spend. Not to mention that the Sargent EC460 power distribution system in our van doesn't have a Lithium charge profile - meaning the split charge / mains charger and our small PWM solar conroller likely all need upgrading!

I started looking into fitting 2 or even 3 AGM/gel/etc batteries - discounted 3 due to the space we had available and even with 2, the price/weight/space quickly adds up. Total cost would have still been £250 or more, so less, but still lots for batteries which wouldn't take an especially large or fast discharge. I also found that manufacturers were inconsistent with reporting the max discharge rate - some batteries were easy to find this info - others not so much.

Whilst I was still debating which way to go, I noticed one day that two separate offers were combining on eBay! The seller of the Ultramax batteries was offering a discount, and eBay themselves were running a promotion weekend with 20% off! This brought the price of the Ultramax down to £313, so I ordered one there and then.

Ultramax advertises a 100A max discharge rate (1C!), though recommends a 50A 'normal' discharge rate. I'm aware that discharging at full rate is not going to be ideal for longevity - and I don't like to run things 'at capacity' if possible. However, we need a proof-of-concept here if we're going to expand the budget to two batteries, so I figured next step was to get the battery and inverter 'in hand', hook up the inverter to the battery on the bench and take some current measurements to see what the real world power draw is. Additionally, the hair dryer is going to run for approx 8mins a day - the rest of the time the power draw will be much slower - remember my earlier comment that we've never seen our existing 90Ah lead battery drop below 85% even in winter!

If it works out, then we have the option to add a second battery in parallel to halve the power draw from each battery. If it doesn't work, I have the option to return or resell the battery (and/or inverter!) without having dismantled anything in the van.

First test
All arrived and assembled on the bench, I plugged in the inverter and hairdryer, switched on, and it worked! Power draw was showing as about 85A running the hairdryer - lower than calculated - which I was hoping to see given that I had 'rounded up' at various stages of the calculation, and added a larger inverter inefficency overhead than I really expected to see. Feeling pleased things were going well, I booked us into a campsite without EHU, charged the battery and built a quick wooden box/stand so that we could take it away that weekend and use it directly in 'standalone mode' (not connected to the rest of the van) for a couple of nights.

It was a lovely trip staying at Acton Field near Swanage over the May bank holiday weekend. On the first morning I wondered off down the field to do the washing up whilst my OH started using the hairdryer. I only got about halfway across the field when I was called back as it had cut out! At this point I started wishing I'd done some more thorough testing on the bench!

I had a multimeter in the van and a quick check of the battery showed only ~10V which didn't seem quite right. Not much we could do at this point so we had a 'bad hair day' and continued our holiday. Later that day tested again and was seeing a higher voltage (12.x) so tested again and it worked fine, but cut out again after about a minute, dropping to 10v.

I spoke to the site, paid the difference and parked the van on an unused hookup pitch for the day, leaving the battery on charge whilst we went out.

This didn't really make much difference - it would run for about 2-3 mins, cut out, and voltage would not come back up until connected to the charger again.

At this point I figured I must have miscalculated, or that the Ultramax battery must not like even the ~85A draw, or that the inverter was faulty and drawing more than it should. Not much I could do until we returned home, though lots more research ensued in the evenings during the rest of the trip!

 

[Hoovie]

I wonder if the 100A discharge rate quoted on your battery is a bit of a peak rate, and the recommended rate of 50A is actually the 'real' rate it can cope with for more than a minute or so?
Lithium Batteries do get voltage sag with load just like Lead Acid, but to a much lesser degree. Down to 10V on a fully charged battery seems more than I would expect though if the BMS could cope.
Out of interest I checked the spec of my Lithiums and they are up to 100A discharge for upto 30 minutes; and an surge of 300A is permitted for no longer than 3 seconds. My previous Lithiums were also 100Ah units but they had a 150A Discharge capability (unusual in a 100Ah unit and one of that batteries key features), so allowable draws are pretty well down to the BMS design rather than the Lithium technology itself.
I would say generally that with Lithiums you need at least a 100Ah battery with a 100A discharge ability (or equivalent if getting bigger modules) for each 1000W of inverter power to be able to run successfully.

 

[JimmE]

I wonder if the 100A discharge rate quoted on your battery is a bit of a peak rate, and the recommended rate of 50A is actually the 'real' rate it can cope with for more than a minute or so?
Lithium Batteries do get voltage sag with load just like Lead Acid, but to a much lesser degree. Down to 10V on a fully charged battery seems more than I would expect though if the BMS could cope.
Out of interest I checked the spec of my Lithiums and they are up to 100A discharge for upto 30 minutes; and an surge of 300A is permitted for no longer than 3 seconds. My previous Lithiums were also 100Ah units but they had a 150A Discharge capability (unusual in a 100Ah unit and one of that batteries key features), so allowable draws are pretty well down to the BMS design rather than the Lithium technology itself.
I would say generally that with Lithiums you need at least a 100Ah battery with a 100A discharge ability (or equivalent if getting bigger modules) for each 1000W of inverter power to be able to run successfully.

For sure, the Ultramax battery is a 'budget' lithium battery, and the datasheet does quote 100A as a peak rate. As I say, my natural tendancy is to 'over-engineer' things so when researching I was quickly tempted to just double up on the battery etc, but it quickly becomes a large amount of money to spend out upfront, putting me off getting started! Hence I decided to approach this as a 'proof of concept' - most likely by the time we're finished I'll add another battery anyway, if only to extend longevity.

With what I've learned in the last few months, yes I think the BMS itself is in many cases the 'limiting' factor beyond the safe charge/discharge limit of cells themselves. I've not currently got any info on the BMS in the Ultramax battery, though I did see another thread here recently with a link to a 'teardown' video supposedly on the same battery, which I'll take a look at at some point.

 

[JimmE]

Bench testing
At this point, I'm 50/50 between there being an issue with my calculations, or there being either a fault or just general lack of capability with either the battery or the inverter, or possibly even the charger. Unfortunatley, I don't have suitable alternatives of any of those components to be able to rule one or the other out quickly by swapping out, so some more detailed testing was needed.

I decided at this point to contact the company I bought the battery from, to at least register that there might be a possible issue. Whilst I was out of any 'distance selling regulations' return window, the battery did come with a year guarantee, but I had already had the battery (unused) for a couple of months so wanted to get the issue raised as quickly as possible.

I raised a question via eBay to the seller "Camera Experts" and also via email to Ultramax themselves. It later transpired that both are the same company/group, and my queries ultimatley ended up with the same person, who was quite responsive. They came back the next day to say that they intiially suspected the rate of discharge to be an issue (I quoted my 'calculated' rate of ~98A in my query) and to ask if I had capability to do any more testing.

So, on to some testing. Apologies for the complete chaos in the background of some of the pictures that follow, I was in the middle of a couple of other projects at the same time as doing some of these tests, and in general the garage was a complete mess!

I hooked up the battery with a multimeter to read the voltage, and the clamp meter around the cable to the inverter to read the actual current being drawn.

Starting voltage was 12.75v. On connecting the inverter and load, the current rose to 86.9A and the voltage dropped to 11.8v. Firstly - great to see that my calculations were correct, and my 20% overhead was hugely over-estimated - we were very much below 90A and whilst still more than 'ideal' for a single battery, I felt this was far enough below the 100A spec to at least be justified in raising this as a potential issue with Ultramax.

The voltage drop was more than I expected, but still, the system would run for 30-40 seconds, with the voltage remained stable, until it cut out completely and dropped to ~2v as I'd seen before. By this point, research I'd done into Lithium batteries and BMSs was very much suggesting, as per Hoovie above, that this was likely to be the BMS cutting off the supply - especially seeing the voltage drop so low until put on charge. The process to 'reset' a tripped BMS seems to be to connect to a charger - certainly I would see that after connecting back to the Victron charger for a minute or so, the voltage would come back up to where it started and the battery would work again.

I decided to record a video so that I could see the voltage and current reading at the time the system cut out (and also send this to Ultramax if needed as proof of the issue!)


(Apologies for the format of the video, it seems YouTube now converts all videos less than 1min long to this 'shorts' format, whether you want them to or not....)

Interestingly, this showed that there was no further voltage drop (beyond 11.8v) before the system cut out. The datasheet confirmed that the BMS should only be cutting out (low-voltage protection) when the voltage drops to around 10v, so this seemed like a potential 'fault' to me.

I decided at this point to try a lower load, so a slower discharge, to see if the issue really was related to the rate of discharge. Handily, the hairdryer has a half power setting, so I used this.

This time, it drew only 45A and ran for 2-3 mins before cutting out. However, when I 'restarted' the battery by applying it to the charger, and ran the test again, the voltage this time only dropped (under load) to 12.2v, and whilst running the test (still on half power) the voltage then suddenly increased to 12.7v. This time, it continued to run for some time. I turned the hairdryer to full power (now 89A) and the voltage dropped again to 12.4v (still much higher than the 11.8v from before) and the whole system ran for about 10-15 mins on full power before I switched everything off.

So - finally a 'successful' test but I still couldn't be sure what the cause of the issue was and whether it would happen again.

I was still in contact with Ultramax, and sent them a longer(!) version of the above, and they came back suggesting a slow, full discharge of the battery to 'minimum' voltage (10.5v) followed by a full charge.

I didn't have time to do any further testing before another trip, so I loaded it up into the van (still as a standalone system) and headed off for a week of scuba diving basded out of Penzance! Alas my drysuit leaked, so I had the 'opportunity' to run a small load off the inverter for a few days, running a suit drying fan to get the suit dry again each night! Aside from keeping me comfortable it served the purpose of fully - but slowly - discharging the battery over a few days, until it eventually discharged and cut out at 10.5v as expected.

Ponsandane campsite in Penzance, Cornwall. As there were a group of us staying ahead of an event, they opened a week early for us so we had the site to ourselves most of the week, until the event the following weekend!

Upon returning home I connected it to the Victron charger, and noticed that, as I had observed before (and assumed to be related to the fact that the battery was already effectively "fully" charged), the charger would switch almost immediatley from 'bulk' to 'absorption' phase, yet no charging current would be registered. I tried leaving the battery on charge for a while, after a couple of hours there was no change in the status on the charger and no current was shown as having been transferred to the battery.

At this point I didn't know what to suspect - I was seeing unusual behaviour from the battery and from the charger - but was this due to the battery BMS not "accepting" the charge or a fault with the charger itself?

I verifed that the charger was outputting a suitable voltage, and verified that the fuse in the charger was not blown, and even massively oversized the charging cables with some spare 16mm2 cable (excuse the lack of colour coding!) just to ensure that no-one could blame my test-bench setup, which had previously been using a little bit of spare household 2.5mm2 twin+earth (solid core so wholly unsuitable for installation in a van!) However - no change - still no power being transferred to the (now entirely flat) battery.

I confirmed that the fuse in the charger was not blown (although I would not have expected to be able to measure a charge voltage if it were) and realised that the only way I could test the charger was to try charging another (non-Lithium) battery with it.

I had just recently replaced a small 12v lead acid battery in a UPS at home, so tried charging this. I changed the charger to a standard profile, hooked up the charger, and observed exactly the same behaviour. So, it seems we have a faulty charger!

Contacting the company I bought it from, they asked me to perform various tests (most of which I already had) and then post the charger back to them to test. Unfortunatley I heard nothing for the next two weeks, but impatience had already got the better of me and I decided to purchase another new charger on next day delivery, to test to see if it was the issue or not.

Initially there was no change. Leaving it connected for 90mins, only 0.3A was transferred to the battery. Coupled with some research I had done, this was very much leading me to believe that there was a 'bad' or 'sticky' cell in the battery, which was causing the inconcistent behaviour and bringing the overall voltage of the pack down. I'm not a battery expert but I understand that if the cells are not fully balanced, these types of issue can occur. I got back in contact with Ultramax to update them on the issue, but also decided to try the 'recondition' mode of the Victron charger.

According to the manul this applies a higer voltage than the normal Lithium charging mode. I didn't want to risk invalidating my warranty on the battery, which I expected to need to be replaced at this point. However, on consulting the Ultramax datasheet again, I see that their max charge voltage is within range of the recondition mode on the charger, so decided I was comfortable giving that a go.,

I left it on recondition charge overnight, and came back in the morning to a fully charged battery! I was able to confirm this from the stats in the app, showing a little over 100Ah was transferred.

Since then, each discharge-recharge cycle has worked perfectly on the normal Lithium profile on the charger, and the whole setup with the inverter and hairdryer now work as expected - I ran multiple tests for 10, 15 and 20 mins on full power. Observing the recharge stats also confirmed my calculations matched real-world usage, so we know we should be able to be self-sufficient on this battery for a few days if needed, even discounting any recharge from solar or B2B chargers.

Conclusion
So it seems that there were actually two issues at play here. Firstly the battery itself - I do believe, as above, that one cell in the pack was likely causing the issue.

However, it turned out that despite this I did also have a faulty charger. I actually expected them to come back and say it was working fine at this point (as I'd seen similar behaviour initially with the new charger, prior to trying the recondition cycle). However, when I followed up with the company I purchased it from, they confirmed that they had sent it back to Victron themselves who also tested and confirmed it was faulty. They sent me a replacement under warranty, but as I had already purchased a replacement, I sold the replacement on here and someone got a bargain!

Worth noting that now that the battery was working correctly, the voltage would be >13v (after coming off the charger at 'storage' voltage) before applying any load, would only drop to ~12.5v under 90A of load, and happily run the setup for as long as needed. I did multiple tests of 20 mins, when actual time this will be needed is only 8-10 mins a day, so I'm confident now that the system is capable of delivering the load needed.

So, proof-of-concept successful, now to start installation in the van!

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[autorouter]

I thought one of the main functions of a BMS is to actively balance the cells so that they are all more or less equal. The alternative is 'top-balancing', ie applying a high enough voltage so that all the cells eventually reach their max value - which is exactly what you did. Maybe there's a bad connection inside the battery, to one of the cells. Now that they are all balanced, you might not see any problem again for a long time. Can you get at the BMS readings, maybe with Bluetooth?

 

[JimmE]

The battery I bought doesn’t have a Bluetooth BMS unfortunately. I think that’s one thing which made the troubleshooting more difficult for me at the time - I’m not used to a battery being an ‘active’ component - with no way to monitor it.

Ultramax do now offer the same battery with a Bluetooth BMS for only about £20 more… if I’d realised at the time then I think going for that one would have made sense (though I wonder if that’s why they put the offer on the model without!)

Yes, my guess is that the one problematic cell was there from manufacture. Coupled with a faulty charger, it just took this amount of effort to solve.

I could have still returned the battery for a refund/replacement- but it’s been working fine ever since (installed properly into the van this week, still some finalisation to go before we can go away with it yet though!) so I’m not too concerned. It’s in warranty until February so stil some time for any fault to re-materialise.

I was pleased that the company were willing to engage on troubleshooting etc - so whilst it’s a shame I had a fault to begin with, I’m pleased enough with them and the battery that (so far) I’d have no hesitation buying another. We’ll see if I still feel the same next year!

It’s also been valuable (for the long term) to have learned what I did through the process - though I realise others may not have had the time or patience - in other circumstances I might not have had either!

 

[JimmE]

Exisiting power system
Our van, a 2013 Autocruise Alto (later versions known as Swift Select 164) has all its electrical system (12v and 240v) run through a Sargent distribution panel at the bottom of the wardrobe, with a remote control panel above the sliding door.

This appears to have a split charge relay built in - as it charges the leisure battery whilst the engine is running, and has a 'remote' mains charger mounted under the front dinette seat, which is where the single lead acid leisure battery is located.

From some research on both the Sargent website and the Autocruise Technical Manual for our van, I determined that we have a Sargent EC460 system and a PX300 charger.

Whilst the description of the PX300 charger initially sounded good, I realised that there was no option for a Lithium charge profile, so the mains charger would need to be replaced.

We also had an 'EP Solar' 10A PWM solar charge controller which I believe was retrofitted in 2019, again no support for a Lithium battery.

Lastly, the exisitng split charge relay would need to be replaced with a B2B to avoid overloading the alternator. The alternator was actually replaced shortly after I bought the van, under warranty, but I have no paperwork to show what replacement was fitted, so I don't want to risk overloading it as it could be a cheap/unbranded pattern part for all I know.

As we already had a Victron SmartShunt, and I liked the app which gives an easy way to see what is going on, I decided to try to stick mostly to Victron for any other components we upgrade.

This gave me a shopping list:

• Mains Charger - as the goal of this upgrade is to not need EHU, I wasn't too concerned about a high capacity / fast charge from mains - at a minimum you tend to be plugged in overnight so from ~7pm to ~8am still means 12+ hours of charging - so I settled on a Victron BlueSmart IP22 15A charger. (As per earlier posts in this thread, the first one was faulty but replaced by the seller with no problems ever since)
• B2B (DC-DC) charger - as per my first post, we tend to 'tour' and use the van for day trips out, so we frequently do an hour or more of driving, even on days we're not moving between sites - and more when we're moving. Therefore this is a good source of charge for us, so we wanted a good capacity B2B. Victron's largest B2B (AFAIK) is 30A, but given that our daily inverter load is expected to be no more than 15-20A, and the rest of our power usage appears minimal, this means we ought to be able to replenish the majority of our usage with less than an hour of driving, so appears sufficient. Therefore, I bought the Victron Orion-Tr Smart 30A B2B.
• Solar controller - Whilst I may upgrade the solar panel in the future, the controller isn't high on the list of priorities at the moment, I just need something suitable with a Lithium profile. Our panel is only 80w. Therefore I went for the smallest MPPT controller with at least the same charging current as the controller we were replacing, the Victron Phoenix 15A

The B2B was also bought on eBay (from the same Victron dealer as the mains charger) back in February whilst eBay had their promotion codes active, so we only paid £165 rather than the normal £200+. The MPPT was bought more recently with much less discount so cost us £100.

Taking a look through the wiring diagrams in the technical manual, and reading the Sargent datasheets/manuals, (plus taking the distribution panel out to look at the rear of it!) I wasn't able to see any way to deactivate the built-in split charge relay. I was hoping to find a single cable to disconnect (or a physical relay to unplug from a socket) but that seems not to be the case.

Various threads on the forum here and elsehwere discuss similar - in the end I decided that like others, I would likely need to add a relay to disconnect the engine battery from the Sargent system when the engine is running. Various people seem to have had this recommended by Sargent themselves. MHF 'rule 3' asks us not to link to other motorhome forums, but search google for 'disable sargent split charge' and there is a thread on the 'Out and About Live' forum which has a diagram showing you exactly how to connect the relay to achieve this, which helped me realise how this would work.

My final goal with this upgrade, is for the van to appear to remain as standard as possible. So, installing things 'invisibly' where we can, integrating with the existing control panel where possible, rather than bypassing it. Everything 'just works' with the current setup, so I'd like to keep things that way, rather than ending up with a multitude of new switches, controls, etc.

Given that fitting the inverter requires upgrading to the Lithium battery, and fitting the Lithium battery requires installing/upgrading all three chargers, this efffectively means that the majority of the upgrade has to be done in one go, rather than piecemeal as I had hoped!

 

[jumar]

Good Lord...you do explain in great detail... I'm changing to Lithium in a couple of weeks, adding a Victron B2B also...had great advice on Fun on how to do it correctly...That's All Folks.....Good luck on your set up...

 

[Hoovie]

Interesting read. Thanks.

A few comments which may be of interest to people reading this thread and maybe to yourself in some parts ...

Dead Battery and Victron IP22 Mains Charger. Most chargers will not attempt to charge a totally flat battery. The IP22 however WILL do so. I wonder when the battery died and dropped to 2V, how someone is meant to resurrect the battery with a typical charger? An alternative method could maybe be attaching another charged battery in parallel which will apply ~12V to the dead one?
Not something I have needed to do so cannot be sure on this point. I have noticed that with some batteries fitted with bluetooth BMSes that you need to apply either a charge or a load to wake the bluetooth up if left for a while (not really relevant for your current setup. just an aside comment).

Victron 30A B2B. Yup, the 30A Orion Smart-Tr is the largest Smart B2B Victron currently do, but it is ok to run multiple units in parallel if you want greater charging (and your alternator is ok with it).

Changing the Solar Controller is a good idea, but as you I think suspected, you are limited to what is possible if you want to run it through the Sargent unit. The 15A model is the largest you want to go in this situation, and the Victron MPPT SmartSolar is a great choice (the "Phoenix" is an Victron Inverter range by the way).
FYI for anyone thinking of doing this on their Sargent systems, the PDUs from the EC400 onwards have add-on controllers which you can change from PWM to MPPT, but the EC325 and EC328 units have the Solar Controller integrated and you are stuck with what is fitted unless you bypass the Sargent.

The approach I took to disable the Split-Charge system in the Sargent was a bit simpler than adding a relay - I just removed the D+ input going into the unit (well, to be fully accurate, I put a switch on the signal which I leave off, but it means if I had a reason to, I could have it working as factory again). Disabling the D+into my EC325 has two effects ... it disables the Split-Charge and it also stops the Hab Electrics being disabled. That is an extra bonus for me as it is a stupid feature IMO. I also just leave the Mains Charger switch off as well and don't use the Solar Input - this means the Sargent unit is not doing any charging of any kind (but can be reverted back to standard with a flick of a few switches if I wanted a factory setup again).
You need to be careful where/how you disable the D+ as it also controls the Electric Step if fitted and the 12V signal to a 3-way fridge.
I would be wary of trying to use any of the Sargents charging systems on a Lithium install, not necessarily as they may not be lithium compatible, but they are not designed to be working at full throttle for an extended period. Sargent tend to have a recommendation of no more than about 160Ah of battery capacity, plus Lead charges slower AND as it starts to fill the charge current reduces. Lithium will take all you can give it until full and that will probably overheat the charger which is not designed for that level of work and cause premature failure (this is IMO only).
Just to illustrate, a charge graph from tonight for my own Lithiums that needed a charge ....

Soon as I put the charger on it, it goes up to >50A and stays there the entire time until the batteries are full and then drops. If I was charging using the apparent 25A Sargent Charger, that would have been going full pelt for over 5 hours.
This is something that needs to be considered when deciding that as you are hooked up all night, you don't need a powerful mains charger as you have plenty of time to charge. This is perfectly true, but you have to have a charger that is ok with running at whatever that full power it is for extended times without a problem. Something like the Victron IP22 15A unit is fine for that. Other units may not be so choose wisely. (also if the charger IS for overnight charging when camping, get one WITHOUT a fan - fans can be very noisy at 3AM!)

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