Looking after a L36-EFB

[Stuwsmith]

I've trawled through a lot of the old posts on batteries and solar regulators and picked up a fair bit of information but am still a bit confused as to the best way to charge and look after batteries.

I bought a Yuasa L36-EFB from Tayna last week. Excellent service and arrived next day. Voltage was 12.62v so put it on charge with a CTEK 3.6A charger. It took well over 12 hours for the voltage to rise to 14.4v and switch to standby mode.  After resting for 12 hours battery voltage was still at 13.09v so I surmise the battery is now fully charged and looking good.

I have a Victron 75/15 solar regulator also recently purchased replacing a PWM regulator that has seen good service this past 16 years in my VW Bilbos Nektar. The Victron has the facility to make "user defined" settings, so my questions are.

Is the default 14.4v absorption charge setting the best?

Is the 13.80v float charge too high or should it be nearer 13.4v as read in previous threads?

In default the automatic equalisation is turned off. Should it be turned on? If so, what should the equalisation voltage be?

50% DoD seems to be the rule. Is this the same for a EFB?

What is the voltage of 50% DoD when full charge is 13v?

Although the Yuasa site gives general advice on battery maintenance I cant find any information on correct charging which surprises me a little.

I've learnt from earlier threads that it is probably best to turn off solar charging if the battery is full and no load is being imposed on it and I have altered the wiring to enable me to do this.

I've spent my working life in telecoms and qualified in electrical engineering but must admit working out how to get the best out of an expensive leisure battery is doin me 'ead in!

[spirou]

Much depends also on how you use your MH. If it's parked for long periods then drop the victron down to 13.2-4 for float. I have mine set a few tenths higher as the van is used almost weekly and "storage" mode isn't as much a concern as getting it properly charged when out.

 

Note that even though you have many custom settings available, the victrons still have a brain of their own and will adjust as necessary. There is already a storage mode built in. Also, if you set a certain absorbtion period it is considered as max time. More often than not, if it has been sitting for a while I see a pattern of slowly degrading minimum voltage with sometimes only 1 min in absorbtion then it "wakes" up after about a week and charges a bit more to refresh the battery. Usually does up to 30 min in absorbtion on those days.

 

You could argue that the bulk phase could also be completely omitted in such use but I hardly ever see more than about an amp going in until it reaches set voltage. That takes about two hours or so after sunrise, then a very short stay in absorbtion and the rest of the day it's in float. All voltages temperature compensated of course.

 

Sorry, can't help you with specific resting, 50% DoD, equalizing or absorbtion voltages in your case as I've never looked at Yuasa technical manuals. I would guess equalization with a maintenance free, sealed battery is not the best idea.

 

PS somewhat contrary to most general advice I don't consider 50% DoD as some kind of point of no return. Yes, cycle life drops with deeper discharges but you could easily argue any % DoD is the limit. Obviously you want to keep discharges shallow as often as possible, but going beyond 50% occasionally won't suddenly kill the battery. I keep a daily log and in past 2 years ours has gone bellow 50% 5 times and 5 more occasions were just above that. Most of the time we keep it between 20 and 30% DoD. If the few times we broke the 50 "rule" shortens the battery life by 100 cycles (guessing) out of rated 800 (@75%DoD) I won' be losing sleep over it.

 

[aandncaravan]

I have to admit I don't know the fully charged resting voltage of a Yuasa L36-EFB, I have asked and waiting for the reply, so will chase that up.

I suspect it will be about 12.8v?

50% DOD is roughly about 0.5v less than the fully charged resting voltage so about 12.3v?

 

Will find out and update here.

Don't forget that a new battery can take several cycles to reach full efficiency, typically 10 - 20 charge/discharges.

 

 

Yes 14.4v will give the best compromise between fast charging without overcharging with the resultant internal corrosion. Using a 13.2v float charge rate will protect the battery but may also reduce the efficiency of the system enormously, so not sure that is the best option?

 

Before I answer in more detail about the Float rate can I explain how Motorhome chargers work, because they don't operate as people think?

 

A Car battery style charger will 'boost' charge at 14.4v and when the current being drawn by the battery drops below a few amps, it switches to 'Float/Trickle' mode.

The problem with this style of operation in a Motorhome/Caravan, is that the chargers can be left active unattended for days, even months, so if the battery gets tired it may continually draw power at the 'Boost' voltage, never dropping down to the Float/Trickle charge rate.

Obviously charging indefinitely at 14.4v is not only damaging to the battery but introduces a gassing risk with potentially serious consequences, even fire or battery explosion if thermal runaway occurs.

 

 

Therefore the best/safest Motorhome/Caravan chargers use a timer mechanism for the 'Boost' voltage and drop down to a 'Float' charge after so many hours, regardless of whether the battery is fully charged or not.

This is done for safety and one of the many reasons why using a Car style charger in a Motorhome/Caravan should be done only with great caution.

 

Typically a 1 hour or 4 hour timer is used, after which it drops to 13.8v float and the rest of the charge is done at 'a trickle'.

 

I have never been a big fan of the Victron and so never bothered to go into the charging profile for the Victron Solar chargers.

 

I suspect it works like most of the others in that it has an x hour 'timer' during which time it charges at 14.4v before dropping down to 13.8v float where the bulk of the charging will take place.

 

If this is true, dropping the float down from to 13.8v to 13.2v will hamper charging significantly.

 

Victron 230v Mains chargers have two Float voltages, the normal short term 13.8v Float and a more protective, long term 'permanent' Float of about 13.2v, but never seen this mentioned on Victron Solar regulators so don't know if it applies to these.

 

 

 

For long term float charging, most manufacturers specify 13.2v, as used in Data Centres for batteries on permanent charge, but whether that is a good idea for you I don't know.

 

In truth I just don't know how they work.

However, I would be pretty certain that it won't do as most assume and charge continually at 14.4v until the battery is 'Full' before dropping to 13.8v.

 

If it was me, I would opt for a 13.8v Float but disable the solar when the vehicle is idle, so it doesn't actually do any 'real' floating.

 

Or, you sound like you are clued up, so you might want to consider setting the Float voltage to 14.0v so that it charges faster 'off the Boost timer' when you are using the van but then you MUST disable Solar when it is true Float mode, or manually switch it to 13.2v when idle.

 

 

To try and explain with more detail, it may help to look at a charger that 'experts' recommend all the time for use in Motorhomes/Caravans.

I use the CTEK unit as an example because they do publish lots of data on how they work, showing just what a risk using them is.

 

If you look at the photo extract below from the manual for a CTEK MXS 10, you will see all the various charge stages.

The very bottom of the chart list 'Limits' and gives the maximum 'Timer' for each stage.

 

On Start up the charger will hold the Soft Start stage for up to 8 hours, then hold the Bulk phase for a max 20 hours followed by an Absorbtion phase of 10 hours. That equates to a potential 38 hours at 14.4v and if the battery isn't perfect, enough time to melt the battery.

 

Worse still, once up to charge the CTEK goes into a Pulse mode where it monitors the battery and if the voltage falls, like when a battery starts to fault, it restarts the whole phase again back to the beginning to have another go at causing chaos.

 

A proper motorhome battery charger won't budge from 13.8v once the Boost timer expires, and does it for a reason.

 

 

EDIT :

Looks like my reply has crossed with Spirou's and he has real world knowledge in setting these up, so better follow his advice and regard mine as 'General' info.

 

However, his advice regarding 50% DOD should be considered not just in pure battery terms, the deeper you discharge a battery the harder a charger, mains and Alternator, has to work to bring the battery bank back up.

The Deeper the discharge the hard the systems have to work and some are really not designed for deeper than 50% DOD.

 

 

 

 

 

[spirou]

Just to clarify regarding charging and absorbtion period behaviour in victron chargers.

 

There are several built in presets you can choose from for various battery types and then there are custom presets. I seem to remember (can't confirm as the MH is currently somewhere in Serbia with another family member) that default absorbtion period for built in presets is 6 hours. Voltages depend on the battery type chosen. In any case, that period is always considered as maximum allowed and is hardly ever seen in MH practice unless you discharge deeply. But if you plan on using a lot of electric gadgets I suggest you draw most of electricity during daytime with excess solar, rather than night.

I believe all victron chargers/regulators use the same logic (can't confirm) and will decide on their own how long the absorbtion period should be, based on how much charge the battery needs. I've had a feeling for a while that it could be longer, especially for deeper discharges, but there is no way to force it closer towards the maximum. As to why I think it's a bit short... if I use EHU (Schaudt 208S) to top it up on occasion, the resting voltage (panel covered/disconnected) is always higher than with solar charging. We're talking 0.05V range here so not a huge difference but notable.

[aandncaravan]

Spirou, You write "In any case, that period is always considered as maximum allowed and is hardly ever seen in MH practice unless you discharge deeply".

 

That suggests the Victron monitors the charge rate during the timer period and if it drops below a certain level it switches up to Float?

In which case the time it takes to do that will also depend a lot on the power of the installation, if it is only an 80w Solar panel, it could take quite a while for the charge to make an impact on a discharged battery bank, so it could vary a lot with different set-ups and discharges.

Especially so in Winter or those who holiday outside the peak Summer months, those who venture further North, etc..

 

 

The Schaudt charger in the EBL 208 is one of the best installed in any Motorhome and one of our favourites to work on because the quality is high.

 

But it won't like looking after batteries discharged below 50%, especially more than one battery if it's an early version as it was sized for quite a small battery bank of about 80Ah. Even 50% DOD on a big battery bank might be hard work.

 

See attached chart showing the 1 hour bei Blei Saure (Lead Acid) timer and 8 hours for Gel, which charger more slowly/gently, so need longer.

 

If you do ever deep discharge the battery down past 50%, I would suggest you think about using some other charger to take the initial 10 minute load of charging, like the Alternator, etc.

 

 

Sorry Stusmith, but if you were struggling with it doing your 'ead in' you probaly have a bigger headache but this does demonstrate how one Solar installation can be so poorly set-up and another optimised to get literally twice as much power.

[spirou]

I've seen the Schaudt manual before but I think the stated 8h might be approximate. We currently have a 120Ah (C20) gel battery and the absorption phase can go on for longer than 8h, at least I believe it did a few weeks ago when I left it overnight and it was still in absorption when I unplugged in the morning. MH has been in almost continuous use since May so I haven't done any testing recently to give you accurate figures on the gel setting.

 

I do have an excel file handy from some testing a few years ago with a standard lead acid battery (105Ah) where I logged parameters at 5min intervals and the voltage was held at 14.2-3 for just over 2h in one cycle and 1h30 on the second cycle after a shallower discharge. They were ~6A discharges for 23Ah first cycle, 14.5Ah on the second.

 

Also, isn't the EBL208 designed for 60 to 180Ah batteries with an 18A charger? At least in our case it doesn't seem to be struggling and overheating.

 

 

[Stuwsmith]

Thanks for your replies and advice gents.  You're right Alan my 'ead is still hurting a bit but not quite as much!

My use of battery in the camper is almost solely to keep the compressor fridge going. No TV, hardly any lights, we just go to bed and a few seconds of pump use a day.  The fridge draws about 3.6 amps during its on phase. Waeco reckon the average draw over a day is 0.8 amps but I cant really confirm this. If the weather is cool and the van drops to around 10 deg C or less (we have good sleeping bags!) the fridge is switched off at night.  

The new battery, regulator and my modification to the wiring is the result of the hot summer, a hot van which is little used in the main season as we prefer to use it early or late season, a pwm regulator that went through a daily routine of charging at 14.4v with occasional equalization of 15v and a Banner battery that lost too much electrolyte! 

The Victron according to the little manual has a number of different maximum absorption times ranging from 6 hours max to 1 hour max depending on the battery volts measured when the unit "wakes up" in the morning.

I too, have a feeling that whereas my old pwm regulator may have overdone things a bit the Victron might be under doing things which may not be a bad thing for the battery except I may end up with the fridge draining an undercharged battery too much?

Now that I have the facility to disconnect the solars and to raise the float voltage setting I may follow the suggestion of raising the float to 14volt and using caution in order to try and get maximum charge of battery when the van is being used and reverting it/ turning off the solar when the van is not used and no loads are being taken.

Still not sure about the sulphation setting though especially as the L36 is a maintenance free battery.

What really amazes me is that Yuasa does not seem to give any guidance in terms of charging regimes for its batteries.

[aandncaravan]

"Also, isn't the EBL208 designed for 60 to 180Ah batteries with an 18A charger".

 

Spirou, Yes the 18a versions do have the usual theoretical limit of 10 times their current output converted to Ah, so 18amps x 10 = 180Ah total.

But you can see that on the chart above, if it only charges at 18a max for 1 hour at 14.3v, the very most it can put into a battery before it drops to it's 'trickle' level is 18amps.

 

On a battery bank of 180Ah discharged to 50% the remainder of the 90Ah drawn will go in at about 13.8v and low amps, potentially meaning 72Ah takes nearly 70 hours or 3 days!!!

 

 

So yes the theory of the 10 times rule does mean it may support 180AH, but the reality is a pretty poor solution. Hence Schaudt saying if you go above 80Ah you add a second charger and they provide an input socket on the front exactly for such an auxilary charger if the battery bank was upgraded.

 

One of the reasons I got so into batteries in the first place was to find an ultra efficient battery that charged more quickly with the lightest load on the charging systems because of these issues.

 

 

The later Schaudt 18amp chargers had a 4 hour timer and the very latest version as used in the EBL 119 has 8 hours, which will charge the imaginary battery bank above in just over 4 hours, not 3 days.

 

Most people are unable to see that how the charger functions, both mains and solar, can have a huge impact and why the best Solar chargers, like our favoured Votronic, can make an enormous difference by just the tiniest parameter being altered.

 

If you throw into the mix a longer charging AGM battery bank that people recommend is discharged to 75% you can see why they never get fully charged and fail earlier than other types.

 

[aandncaravan]

"Now that I have the facility to disconnect the solars and to raise the float voltage setting I may follow the suggestion of raising the float to 14volt and using caution in order to try and get maximum charge of battery when the van is being used and reverting it/ turning off the solar when the van is not used and no loads are being taken".

 

 

 

Stusmith, I agree.

Given your really heavy use of 12v with that fridge, I would be tempted to effectively use the 'Float' setting as the main charging program and set it even higher than 14v, maybe 14.4v?

 

I don't know the Victron, but if it is "being clever' and dropping down to the 13.8v Float early, then a 14.4v 'artiificial boost' using the Float setting voltage should give you absolute max capability.

 

Your plan to not actually use the Float to maintain the batteries would make that practical.

 

If you are happy to manually switch the Fridge on/off, I would also suggest you don't wire the Fridge from the Victron 'Load' circuitry as this may impact efficiency slightly?

 

 

Idea?

Can you set up the Victron to manually configure the AGM profile to be as per above but leave the Wet setting as is but with a 13.2v Float, giving you the easy ability to switch between the two when you want? Just use the tailored AGM setting when in the van and switch back to 'Wet' acid the rest of the time?

 

 

 

I think you have chosen the best battery for the task you have, it's extra 14Ah over the Varta LFD90 will make quite a difference to eventual battery life. It's twice the battery your old Banner Energy Bull was, literally.

I will chase the fully charged resting voltage and 50% DOD voltage figures and get back here.

 

 

[spirou]

I seem to have missed the panel size comment above. We have a 120W panel and at most times of the year will make up the missing Ah within the time the regulator is still in bulk phase. You can probably tell we don't use much electricity. In the summer it's inevitably in the single digits of Ah.

 

Obviously this doesn't hold up on overcast winter days deep in alpine valleys or up north in Scandinavia where driving for several hours or EHU are/were inevitable after a few days, especially with fresh snow on the panel. On those long freezing days we're at around 15-20Ah in deficit overnight if memory serves correctly. I can't recall what the deepest discharge ever was.

 

As regards of what you can do with victrons... I've set up 3 custom presets. One for active use with more aggressive charging, one universal and one for storage if I know it won't be used for a while. Just switch between them as you please. Not sure I'd like to fool around with 14.4 setting in float as in... what if you forget and the fridge is off?

 

 

[kevina]

Stuwsmith - 2018-08-26 8:41 PM

 

.......................I bought a Yuasa L36-EFB from Tayna last week. Excellent service and arrived next day. Voltage was 12.62v so put it on charge with a CTEK 3.6A charger. It took well over 12 hours for the voltage to rise to 14.4v and switch to standby mode.  After resting for 12 hours battery voltage was still at 13.09v so I surmise the battery is now fully charged and looking good.............

Interestingly I too bought a Yuasa battery from Tayna last week, only mine was the YBX5020 (silver calcium) for use as a replacement starter battery. Mine arrived reading 12.53v and I put it on to charge with the very same CTEK 3.6A charger. I presume it eventually reached 14.4v overnight but it took a long time to get started and the voltage even seemed to dip a little over the first hour or so. After 24hrs off charge it has settled at 12.89v.

 

My 6 year old Varta silver dynamic starter battery has all but died this summer, dropping to 12.0v from a dedicated charge within 10 days.

[aandncaravan]

Kevina, 12.5v is not far off 40% DOD for a Silver technology battery, is it not likely to have lost quite a bit of life/capacity in being allowed to discharge so low?

 

I would suggest you consider returning it, unless the manufacture date is less than 3 months old.

 

 

Been a few reports of Tayna batteries being delivered already degraded, one Poster on here with ET650's took advice from Exide who advised rejection they were that poor.

 

 

Tayna have a high turnover of Varta LFD90's, every one we have bought has been been above 12.7v, usually nearer 12.8v. But seemingly not so good at less mainstream, possibly because they spend so much time pushing their awful Enduroline range so much?

 

 

The Varta LFD90 Dual purpose battery is much better suited to a motorhome Starter battery than a 'dedicated' starter battery, because motorhome starter batteries often slip to much lower discharge levels when the vehicle is idle and most Starter batteries fail to cope so well with this type of use, preferring to be used each day.

 

The LFD90 usually outperforms a dedicated Fiat Starter battery in terms of CCA 850/1000 from memory, etc. yet also handles deeper discharges when the van isn't used.

 

You might find that Tayna will do a reasonable easy 'swap'?

 

[Stuwsmith]

Alan, after >30 hours "at rest" following a presumed full charge my L36 reads 13.04v.

Good idea about modifying one of the presets. As has been pointed out there are a number of them on the Victron meant for different battery types etc. that can be modified to be used in different situations. One useful facility of Victron is its bluetooth connectivity which enables easy changes to be made.

Another point I am not sure about.  The battery has a label advising removal of transport bung(s) from the vent outlets before use.  On the banner I just used the most convenient one and left the other bunged up.  I dont know if the same applies to Yuasa ones, ie does the vent system act as a single one or is it in two seperate halves that require each to have a vent?

Batteries and their proper maintenance does seem to be a bit of a minefield with so many variables!

[aandncaravan]

Stuwsmith - 2018-08-27 5:36 PM

 

Alan, after >30 hours "at rest" following a presumed full charge my L36 reads 13.04v.

Good idea about modifying one of the presets.

On the Banner I just used the most convenient one and left the other bunged up.  I don't know if the same applies to Yuasa ones, ie does the vent system act as a single one or is it in two seperate halves that require each to have a vent?

 

Batteries and their proper maintenance does seem to be a bit of a minefield with so many variables!

 

 

Yes just unbung one end, central venting is used.

 

You are so right which is why we are campaigning to get ALL relevant battery information ON the battery label in an easy to understand Traffic Light system format.

Everything from resting voltage to a 50% DOD guidance voltage and Fluid Loss rate to Self discharge rate, etc.

See the bottom of this page :

http://www.aandncaravanservices.co.uk/campaign-for-battery-change.php

 

[Stuwsmith]

Just read the lot. Wow, this just confirms my suspicions that all baterries look alike. They are all big black heavy objects of similar dimensions with two lead posts that have a potential difference of 12 volts.  Easy to impersonate and difficult for the average consummer to tell good from bad.  Keep up the good work,  you are right to question the viability of the NCC.

[kevina]

aandncaravan - 2018-08-27 4:33 PM

 

Kevina, 12.5v is not far off 40% DOD for a Silver technology battery, is it not likely to have lost quite a bit of life/capacity in being allowed to discharge so low?

 

I would suggest you consider returning it, unless the manufacture date is less than 3 months old.

 

.......................

 

I don't know the manufacture date but the recharge date is July 2019.

Copied below is what Yuasa say so I'm ok with it thanks Alan. It's still at 12.89v

 

B -Maintenance of Stock Handling and Recharging of Batteries

 

WET Charged Batteries

1. Batteries should be installed ideally within 15 months after manufacture. The voltage should be (worse case higher than 12.25V) ideally higher than 12.4V at the time of installation.

 

2. Batteries require recharging when the voltage has dropped below 12.4V due to extended warehouse storage. All safety precautions should be undertaken prior to recharging batteries. See charging instruction section in catalogue for further details. If a battery has been recharged, the recharge date on the back label should be updated by 6 months after second recharge date by physically notching the label. (Note a maximum of two recharges are allowed prior to sale, and product should not be sold a maximum of 9 months after the expiry of first recommended recharge date).

 

2.1 A voltage check should be carried out as a matter of course, both to identify older stock and highlight batteries requiring recharge.

 

2.2 Use a digital voltmeter/multimeter with a minimum of 2 figure resolution (eg 12.76V).

 

2.3 Scrap any batteries below 11.0V (these batteries will have developed sulphation that cannot be completed reversed by charging and so will not give the expected performance and life to the customer.

 

source: https://www.yuasa.co.uk/info/technical/need-know-batteries/

[aandncaravan]

KevinA, accepted.

But that is from a manufacturers point of view, to minimise their costs/time, not the ideal.

 

Although Yuasa are one of the best, and full marks for a recharge date on the battery, Exide and Varta recently advised one poster on here to aim for batteries less than 6 months old.

 

All the good advice on the web says that any battery sat in only a semi discharged state, for any length of time will suffer some Sulphation.

 

What concerned me was that Silver technology batteries, like your new one, tend to have higher 13.0v resting voltages and a very low self discharge rate, so any significant voltage drop is likely to have occurred over many months.

 

 

 

[aandncaravan]

Stuwsmith, you might like this enquiry that has just come in today? You are not alone!!

 

 

The electrics on my nearly new (March 2018 after about 5 months in showroom) Globecar are working OK but I want to upgrade my off EHU ability to comfortably cover 2 or 3 days wild.

The main power drain is the Waeco CoolMatic MDC065 compressor Fridge.

I am unclear about what would work well and be cost effective. The existing set-up includes a Schaudt Electoblock 119 on the AGM setting, a Varta Professional Dual Purpose AGM LA95 leisure battery and a starter battery which appears to be different (having visible cell plugs). This is presumably a standard Ducato fitment.

Questions arising include: Another Varta of a different age for £170+? Two new normal gel batteries for about £200? Add solar panel (£500+? fitted) plus LR1218 or LRM1218 (£70 or £170)? Having read much of your technical analysis of batteries ,chargers and regulators

I am not convinced that just handing over to my supplying dealer or local maintenance people (both trustworthy)will get me the best solution for a figure possibly approaching £1000.

Could you offer advice and if appropriate quote for some or all of the work involved?

Regards B.

 

 

 

[Stuwsmith]

Glad to see I'm not the only one!

I'm pretty sure my fridge is an MDC50, the smallest of the range, in which case it will be a little less power hungry than the slightly larger 65.  In my experience I would say solar charging is a must if off grid for two or three days.  Either that or have a very good battery bank and even then be prepared for the possibility that it may be drained beyond the "safe" level.

I've had my van for over 16years and at first used a free standing panel, I forget the rating but fairly small, 20 or 40watts possibly.  This wasn't really enough partly because it could only be used when parked up somewhere where the panel would be secure.  At a later date I fitted a panel to the roof permanently wired in to the single 110amp flooded battery.  Again this was only a small panel, either 40 or 80 watt, I cant remember, as the van has a pop up roof which is heavy enough to lift up without overloading it with solar panels. This addition proved useful as it worked all day. I can also wire the 2 panels in parallel where circumstances permit.

We typically use the van abroad around April time and again in October. We almost always stay off grid.  

Last year we were in Spain in October and November for 7 weeks, all off grid. We stayed 3 nights in Segovia and quite a few others for 2 nights and the others 1 night. when we moved we generally only moved short distances 60-80 miles sometimes less sometimes more.  The fridge never failed during this time. BUT, the weather was ideal, blue skies every day and cool nights, ideal for the solar panels to add some useful charge, and the fairly regular short journeys must have helped too.  However the battery could well have been discharged below its ideal at times and it is this that I am trying to avoid.  Hence buying a decent battery and changing the regulator from pwm to mppt.

I confess keeping the fridge working and the battery charged becomes an obsession, always checking the regulator, making sure the panels are in the best position etc and using candles instead of the lights!!  Still, its interesting, and a challenge!

[aandncaravan]

I have had an email from someone who claims to improve his Compressor Fridge efficiency by placing into the Fridge gaps between the food, 'inflated' Tesco thin wall 'Fruit and veg bags' they save from the shopping.

 

The cold air inside the bags is then prevented from spilling out when the door is opened, resulting in the Fridge staying Cold and the compressor not energising.

Because the loosely tied bags can be inflated or deflated to accommodate the changing Fridge contents, there is very little air to be lost when the door is open. Bags fold flat when not required so no space is lost.

 

He did note that he is a habitual Tea drinker so regularly opens the Fridge to get Milk, so while it works for him, it might not have the same benefit for you.

He also claims it aids in keeping the Fridge cool overnight when, like you, he powers it down.

 

If you need a new obsession.......

 

 

I understand that Solar works for you, but maybe our new enquirer only uses the vehicle to Ski during the Winter months, a time during which he also needs three times as much power for heating, yet will get only about 5Ah a day out of a 100watt panel.

 

So we need to survey when and where they use the vehicle and what electrical items they want to deploy. We can then work out the daily Ah consumption and then find a power source for the daily power drawn.

 

If you are interested in our assessment and solution, I will PM you a copy, if the customer agrees.

 

[Stuwsmith]

Preventing escape of cold air from the fridge is sound logic but could be an obsession too far for me!

Anyway with a small fridge and a wife who insists that anything, once opened has to go in the fridge there isn't much spare space.

I do actually also have a Webasto diesel heater which is quite heavy on the battery particularly in the start up phase. when cold enough to need to use it however it is only on for 30 minutes or so in the morning and sometimes for a similar time in the evening. With a small VW T4 it soon heats the van sufficient for us.  Because of my obsession I have wired this to operate from either leisure or starter battery and have found that using it with the starter battery for the amount we use it has not been any problem.  I also have a NASA BM1 monitor so can keep an eye on the state of both the batteries.

I agree that a lot depends on the usage of vans, we all have different patterns of usage and my requirements would be very different from someone who always used EHU, used microwave ovens, TV etc.

One thing I haven't done but am thinking about is using the load terminals of the regulator.  Doing this would ensure the battery didn't go beyond a set state of discharge and with the Victron this level can be adjusted.  Until I do this I will have keep a manual eye on battery volts and decide whether to keep the fridge going and sacrifice a bit of battery life or not.  Hopefully I can keep the battery volts above that decision level. 

Yes, I would be interested to know your solution to a customers particular use particularly if the customer used his van in a similar way to me.  Any knowledge that would help me to understand battery maintenance and charging would be useful stuff.

[spirou]

Powering the fridge via load output might be an option, charging the batteries not so much as it's a fixed output as far as I remember.

[Stuwsmith]

As I understand it the option to connect all consumer loads, lights,  pumps, fridge etc just provides a safety cutoff ie when the regulator determines that the battery voltage has fallen to a predetermined level it disconnects all consumers until the voltage has risen to higher level.  The charging side of the regulator carries on as normal as far as I am aware.

I had this load connection facility on my old PWM regulator but never used it. It had a fixed low voltage cutoff of 11.4v and reconnected when at 12.6v  From what I have read on this forum this low voltage disconnect figure seems very low and doesn't seem a figure that would protect the battery. Perhaps it is a figure that is intended to protect the consumer units from low voltage?

The Victron regulator has a number of options for load cut off. 2 user defined settings and 2 Conv. Algorithms (whatever that means) with cutoffs of 11.1v and 11.8v.  It also has Batterylife setting whereby the regulator automatically adjusts the cutoff so that the solar can fully charge the battery.  Considering that a 50% discharged battery will have a voltage of around 12.3-4v. These settings seem a bit low to me.

[aandncaravan]

Stuwsmith, I also think the voltages are low, and so do Yuasa on their charts, which you can see above.

 

Part of the problem is that so much information still abounds from the days when batteries had a resting voltage nearer 12.0v when a 1 volt range down to 11v was 'normal'.

Although we are talking many moons ago, and the best modern batteries are now actually 13v, it is hard to shake it out.

 

 

My biggest problem in raising awareness, is Sargent Electronics who talk about 'protecting the battery' at 9.0v!!!!

For example, the Sargent EC500 manual states -

 

"9v cutoff to protect battery from severe damage. You should not rely on this cut off level during normal operation, but manage your power consumption to a discharge level of 10V."

 

 

'Managing' a discharge to a horrifically low 10v is mad, but 'protecting' it at 9.0v?

Pretty much all the ECxxx manuals state similar.

 

Even the industry revered BS EN 50342 battery test document in it's 'super Deep Discharge test' talks of dropping the battery to no greater than 10.8v, and that is 'destruction testing'.

 

It is just too unbelievable to imagine the biggest battery charging company in the UK doesn't have a clue, which makes it hard for anyone to try and address, even the battery manufacturers can't.

Of course the one who suffers with an over discharged battery is the consumer.

 

But that is is someone else's problem now.

 

 

In my experience the Voltage control of Solar regulators is too course. Even when the electronics is accurate, and they are often way out in real operation plus the limits are inappropriate.

They may also draw some of the power in order to operate.

 

 

I would suggest you would manage it much more efficiently manually, if only because you know when it will be better to keep the Fridge cool and the food safe at the expense of a little battery life.

 

 

Most of all don't forget that an appliance that is designed to work on 14v isn't going to be at it's best at even 12.3v, let alone 11.9v.

So go to pains to keep the voltage decent and ignore those who talk about a battery being able to discharge to 80% because although it will, the 11.5v it is using to run anything will be woeful.

 

But then again, maybe Sargents guidance to run everything at 10v works better than the rule book says?

 

 

 

[aandncaravan]

Alpha Batteries will have stocks of Yuasa L36-EFB batteries next week at something like £109 + shipping, or about £119 all in.

They may offer a token discount amount, at Alphas discretion, if you mention us.

 

The discount isn't meant to be a 'real discount', it is just so that they can gauge the amount of support they are receiving from 'The AandNCaravan Battery campaign' to help decide if their new ethical policy is what buyers want.

If it proves to be a good business model than other retailers will hopefully see the light and work change from within the industry.

 

 

Please also remember that we recommend this same battery, and the slightly smaller Varta LFD90 as the best Starter battery options in a Motorhome, NOT a dedicated Starter battery like the Fiat original.

 

 

WHY?

Because unlike a car starter battery, a Motorhome Starter battery lies idle for weeks so can get quite deep discharged, something a Starter battery doesn't like.

The L36-EFB and Varta LFD90 usually exceed the Fiat/Merc/Renault/Pug OEM Starter battery in performance, but also give deeper cycling capability. For Transits the Varta LFD75 is our recommendation, but double check the physical sizes.

 

It also means the batteries can 'back each other up' in an emergency.

 

 

Additionally, these Varta and Yuasa (especially the Silver technology Varta) Dual Purpose Starter/Leisure batteries will also tolerate being left on Solar 'top-up' better than a dedicated Starter battery.