Bigger Varta batteries? LFD 180, 230?

[CubicleDweller]

Hi All,

 

Looking for advice on choice of leisure batteries. I have a very old Hymer motorhome (1994 S580) and I want to upgrade the whole 12v system. (The leisure battery is kaput, and it has two big old 75w solar panels and a couple of basic controllers.) I have a power-hungry compressor fridge that I'd like to keep, and I want to be able to wild-camp for several days at a time. So I'd like at least 300 Ah of battery capacity, preferably more than that.

 

I've read very favourable opinions of the Varta LFD 90, including this:

 

http://www.aandncaravanservices.co.uk/battery-technology.php

 

So, my question: are the LFD180 and LFD 230 batteries just as good? I'm hoping they're the same Powerframe technology, just scaled up.

 

There is a cupboard under the table in the van that we never use as it is hard to get at. I think I can fit two batteries in there, one above the other (mounted in some sort of metal frame that I'll probably need to get fabricated). 2 x LFD 230 would be a tight squeeze, but it will definitely take 2 x LFD 180.

 

If those batteries are not so highly recommended, then I will probably go for a total of 3 x LFD 90; two of them in the cupboard and one in the existing under-floor battery compartment (which is too small to hold either of the larger batteries).

 

Any opinions on the LFD 180 or 230, or other advice on this project will be gratefully received!

 

Thanks,

CW

 

 

 

 

[Alanb]

Mass of filled LFD 230 is 56.75Kg., so two off would have a significant effect on available payload. Perhaps it would also be wise to consider how you would get them into position.

 

Alan

[CubicleDweller]

Alanb - 2018-06-12 10:25 PM

 

Mass of filled LFD 230 is 56.75Kg., so two off would have a significant effect on available payload. Perhaps it would also be wise to consider how you would get them into position.

 

Alan

 

Thanks, Alan - that's a good point about payload. Think I'll have to get my van to a weighbridge to see how much payload I have to play with.

 

Getting two of those beasts into place in the cupboard would be tricky, alright. It could probably be done, but I'm also looking at another option. There is a low-level external locker - like a beeny box - that I don't use. It looks a bit home-made, not original - and it probably wouldn't be strong enough to hold batteries. I'm wondering if I could construct a metal frame within it, hung form the van floor or chassis. The beeny box would just be keeping the rain away from an under-slung battery rack, really. That would make it easier to get the batteries into place, I think - and would also be safer in an accident. (The other cupboard is right behind the driver's seat, and I'm not sure I can secure 100kg of batteries well enough to not come adrift in a collision.)

 

[aandncaravan]

I would suggest that you think about how you charge the batteries first?

 

On a vehicle that age the Alternator is likely to be around 75amps and is going to struggle with two LFD90's let alone anything bigger?

The wiring from the Alternator will be spindly thin, potentially leading to Voltage drop.

Voltage drop may be an issue elsewhere due to corroded connectors, etc.

The wiring and connectors will obviously also impact charging from the Alternator, even if you can harness enough amps with a bigger Alternator. Try and mount the batteries as close to the Alternator as you can.

 

Mr S. who came to see us today had a Bessacarr with the habitation battery mounted at the very rear. We measured 14.4 volts at the Alternator but it had dropped to 13.66 by the time it got to the habitation area battery. Not surprisingly he had an issue with slow habitation battery charging.

 

 

For a battery bank of 300Ah we would suggest a minimum 30 - 40 amp charger. But with a big charger, you need to be especially wary. Something like the Waeco Perfectcharge might look good on paper, but it's charging methodology isn't suited to Motorhomes, it is Car battery based.

 

Let me explain - A car battery charger generally charges batteries at the 'boost' charge rate of 14.4v until the battery reduces the charge it is 'pulling' to only a couple of amps.

The charger is monitoring the current drawn, 'sees' the battery is coming up to full charge so drops down to it's Float/Trickle 13.8v 'slow' charge rate.

 

Imagine what might happen if the battery gets tired and continues to draw a heavy charge? It will never drop down to a trickle rate. It will 'long term' charge at 'high' volts until a disaster occurs, battery explosion or even fire.

In a motorhome that is unattended for days/months, that can obviously be potentially disastrous.

 

For a car battery that is rarely on charge for more than a few hours, it is fine.

 

The best Motorhome chargers use a 'timer' for safety, charging at 14.4v for, say 4 hours, then dropping down to Float/trickle, even if the battery is only part charged.

Hence the need to size the charger for the battery bank size, it needs to be big enough to charge the batteries to near 'full' in the timer interval, otherwise the rest of the charge may be done at a painfully slow 13.8v.

 

 

If you can sort the charging issues, then no reason not to use bigger LFD's, but they are mega awkward to handle.

Bear in mind they are not a 'mainstream' size, so any in stock might have been on the shelf a long time and already be past it.

Varta recommend you only buy matched batteries from the same batch when coupling more than one.

 

 

I assume you are fairly new to this, so forgive me if you are not, but are you aware that in Winter even a 300w Solar set-up won't power a compressor Fridge for long?

In mid winter 300watts will generally harvest about 16Ah a day in the centre of the UK, a bit more in Cornwall and about 30% less in Northern Scotland.

I would guess you will need a minimum of about 40Ah per winters day with Fridge, heating, lights, laptop, etc draw?

 

It is not easy to support a compressor fridge in the UK except during the sunniest and longest days, hence why most motorhomes have a gas Fridge.

 

 

[CubicleDweller]

Thanks, aandncaravan, for that detailed reply.

 

Yes, I'm thinking about how this will be charged, but I was trying to keep the post fairly simple by confining it to batteries. (I tend to write long, detailed posts in forums, only to find that most people lose interest before getting to the end of them! So these days I try to be more brief. :-) )

 

For most of the year the van sits idle in an outdoor storage facility. So the existing solar panels mean that the current small leisure battery is fully charged when we start any trip. Trips are mostly just weekends as I work full-time; so I'm hoping with a higher battery capacity I can get a full weekend away from that initial charge. In that scenario, if doesn't matter if it takes almost a week for solar to recharge the battery fully. (Hmm... it would take longer than a week - but we don't get away every weekend, and hopefully the alternator will typically finish the job once we get moving...)

 

Later I'll be replacing the panels with more modern ones (and more of them) and a good charge controller, and it's then that I would hope to get several days out of the battery between spells of driving or EHU. We're planning to spend September in Spain and France, and so I want to add the extra solar by then - hopefully in Spain it will be enough to let us get by with just the occasional night on EHU; especially since we'll be moving every day or two.

 

You're right that the existing wiring is fairly skinny, and I think there are significant voltage drops everywhere. I'm assuming that the wiring between the panels, controller and batteries will be upgraded as part of this. Perhaps also the wiring from the alternator and the split-charge relay. I know some people upgrade the alternator, too, but I was really hoping not to take on anything in the engine compartment. 8-) Thinking more about the numbers, it might be necessary. I'm keeping the batteries as close as I can to the front of the van to keep the cable run from the alternator as short as possible.

 

Thanks for pointing out that "non-mainstream" batteries are likely to have been sitting around longer with the distributors/retailers. That, combined with the difficulty of handling them, is starting to put me off the bigger batteries.

 

Yes, a 3-way fridge would make this all much simpler. But I'm a member of a couple of Facebook groups for owners of old Hymers and a huge number of postings there start with "Help! My fridge isn't working on gas..." I'm hoping that when I eventually get this all sorted it will be hassle-free in comparison.

 

Thanks again for the reply. I'm getting plenty of food for thought here....

 

 

[Deneb]

aandncaravan - 2018-06-12 11:23 PM

 

II assume you are fairly new to this, so forgive me if you are not, but are you aware that in Winter even a 300w Solar set-up won't power a compressor Fridge for long?

In mid winter 300watts will generally harvest about 16Ah a day in the centre of the UK, a bit more in Cornwall and about 30% less in Northern Scotland.

I would guess you will need a minimum of about 40Ah per winters day with Fridge, heating, lights, laptop, etc draw?

 

It is not easy to support a compressor fridge in the UK except during the sunniest and longest days, hence why most motorhomes have a gas Fridge.

 

Just a quick point re the compressor fridge. We were in the Vosges earlier this year, fairly wintry conditions with roads closed by snow etc.

 

Having recently installed a Victron BMV712 prior to our trip I found that we never exceeded 26Ah a day total consumption including the fridge being "on" continuously. We were easily able to last two days without any serious depletion of the batteries and had a couple of days in which the batteries were fully recharged by the 100Ah solar panel during the day (fridge still running, but no other consumers for several hours as we were out and about). I'd also replaced our Votronic SR solar regulator with a Votronic MPPT version, and have to say the difference in performance has been noticeable despite only having a single 100Ah panel.

 

One thing to bear in mind about a compressor fridge (as with any fridge I suppose) is that its power consumption is related to some extent to the ambient temperature, since it doesn't need as much energy to maintain the same temperature in cold weather as it does in hot weather (as long I suppose as you aren't heating the interior of your van like a furnace). Even in hot weather, we find ours only runs for about a third of the time, e.g. the compressor cuts in for a period of about 10 minutes every half hour maximum.

 

I've been very happy with ours, an Isotherm CR85EL) and the relatively light discharge of our two "90Ah" rated batteries probably explains why I had been quite happy with them also (not wishing to re-open that conversation though!)