Leisure Battery Charging system

jace_da_face

jace_da_face wrote: »

From what I gather 7 or 8 amps is normal

It'll be written in the manual and probably inside on the dataplate.

jace_da_face

Sir Liamalot wrote: »

Hrmm ok well yellow push-ons (the spades are the males) have an apperature of 6mm² so that makes me think your solar flex is standard 4mm² not 12mm².

Yes I would have to concede that is true. My mistake.

Sir Liamalot wrote: »

The available charge will be reduced by load I guarantee you. You'll see it on your meter when you engage the fridge.

Also true. Took her for a spin today. The loading brings the charge voltage down to about 13.9V. The price you pay I guess. I can't find manual for my fridge but others in the RM 4200 series are rated for 120W @ 12V so 10Amp must be correct. This is what I am now seeing. I've only managed to draw 8Amps prior to rewiring.

Sir Liamalot wrote: »

Most VSRs monitor both batteries because you can have chargers on either...it's best to check.

I'll stick a mains charger on the leisure battery and see what happens.

I have re-crimped some of the terminals, heat shrinked, removed the soldering and tidied up with a bit of rudimentary strain relief. Not a military grade job, but will do for now. I'm not opposed to upgrading to thicker cable, better relays with holders, and housing everything in a nice neat panel with terminals blocks and some future stage. But this will suffice for now. I can now run my fridge!

Nice job. :cool:

Housings make things difficult...no convection cooling...I don't think they're really necessary.

Hey nice meter!...I see we shop in the same place for probes.

jace_da_face

jace_da_face

Liam, I am looking at (inexpensive) battery monitors online. Such as this. I'm a bit confused by the wiring diagram and bad English description. It appears to show the shunt wired between the negative terminals of two batteries. I guess I would just be tying one side of the shunt to chassis ground. What you think?

Moreover, is there a such thing as a battery monitor that logs the current in both direction - load current and charge current?

:pac:

Hehehe...how much time and hair have you got? Can you afford to lose 2 days and a coupla fistfuls of hair?

I can't speak for the one you linked too but I have the previous gen and it's in the e-waste.



I'll send it to you for €10 plus postage if you want...I think I even have the Chinglish "manual" for it...not that it'll help at all because it's completely misleading.
If you were to pay yourself for the time it takes to get the one I have vaguely accurate you'd have bought a good one that works outtov the box with a lower quiescent.
PM me address if you're interested.
I have a friend uses the one you linked to he says it works great, I asked if he checked it against a calibrated meter and he said no.

It'll read positive and negative current. So does the one I'm offering.

The shunt wiring is critical to it's operation. The battery you want to monitor ground only goes on one side of the shunt and everything else including chassis grounds go to thuther. The sense wires one either side.

I recommend a TriMetric. I've tried a Victron BMV, ApprenticeVolt BTM, most of the Chinese offerings and for various reasons they're all junk.
If you only need voltage and SOC then SmartGauge is a great choice, You can use a simple ammeter beside as an affordable solution. After that the Blue Sea M2.

I really don't advise getting one with a small display...they're a bit useless in practicality. Think clock not watch.

jace_da_face

So will your gizmo report + Ah and - Ah as two different figures?

Which gizmo, the TriMetric or the e-waste?

Both report positive and negative amps (charge/discharge) or watts.
Both display %SOC but the e-waste one will take you two days to zero out...if you ignore the manual and get ingenuitive.

They can also show discharged amp hours.
Comparing them is like comparing a Fluke 87 with a yellow poundland job though.

jace_da_face

So the e-waste doesn't log Ah?

Link

jace_da_face

Ah sure, pop into an envelope. I’ll send you my address.:cool:

Hopefully I have the right shunt here...[*rummage#]...you'll really hate me if I send you the wrong one. Good luck with it, I nearly hammer calibrated it twice.

Ta-da



All there. Take your pic of shunts. The brassy* one has an M6 hole and a M8 hole the silvery** one has two M8s.

They're both 250A 75mV as is the meter.

*Not brass
**Not silver

jace_da_face

Ok well you spoil me for choice lol. In that case I’ll go for silver. It looks shiny and more futuristic. Brass just reminds me of a 1920s Art Deco telephone exchange. There I’ve said it. Brass is a dull metal!

Dull yes, decent conductor though. I found some BZP hardware that came with the shunt I'll include these too but I'd recommend chucking them for stainless or brass because they're already showing signs of galvanic corrosion and will only cause you problems.

jace_da_face

Battery monitor arrived today in the post Liam. Cheers. I popped it in this afternoon. Will test more extensively at a later stage. All I can say for now is it measures battery voltage accurately. It is indicating there is a charging current of 1Amp when no charge is present. Hopefully just a case of following the calibration procedure. Will investigate.

jace_da_face

Just had a quick glance at the calibration instructions. It mentions a 33V source. Awkward but doable. It then mentions, now get this, that I draw a 200Amp load! Really! Holy xxxx!

Ok, out with the inverter, hair dryer and some serious copper! Actually I couldn't possibly insert my fluke ammeter as suggested with its tiny probe wires. I could just work quickly. The fluke probes won't even get a chance to warm up. Or maybe I could connect the fluke with jump leads. I'm getting scared.

Edit: Scrap that. Fluke 87 only measures up to 20 Amps. Maybe I can borrow a clamp meter

Sir Liamalot

Sir Liamalot wrote: »

I think I even have the Chinglish "manual" for it...not that it'll help at all because it's completely misleading.

Ah yes. This is why I binned it. Took me 2 days to cal it to only be 400mA off and then I pressed the wrong button weeks later and had to start over.

Don't bother with the shorting wires that'll lead you up the garden path. Just use the installation to get your zero (min) and 20A (max.) readings and keep faddling until you get it. Don't bother with a 200A. You can try a larger max load see if it helps but I didn't.

When the calibration menu freezes, hard reset (power-cycle) and start over.

You need a DC clamp meter not a clamp meter.
The Fluke 87 is only rated 20A for 30 seconds after that you'll be wanting a very expensive fuse.

jace_da_face

Yes I had already concluded that I will not be attempting to draw anything near 200A. Besides, I can’t see myself ever drawing more than 10A in normal usage so I have settled on attempting to calibrate for 20. If it is accurate in that range (0 - 20) that’s good enough for me.

I even had to think about how I might draw 20A. I don't have dummy loads lying about, but I do have a hefty and long Belden multicore data cable coiled up. It has a thick aluminum braided screen. A quick end to end resistance check on the screen indicated it might just be in the range I’m looking for. I did test it across a 6 volt battery and it draws 10 Amps - actually 8A but the battery voltage dropped to 5V as it is on the way out. So more by luck than design, I have my dummy load.

jace_da_face

jace_da_face wrote: »

I even had to think about how I might draw 20A. I don't have dummy loads lying about,

Inverter?
Fridge?
230V fridge on inverter + 12Volt fridge = 20A

jace_da_face wrote: »

but I do have a hefty and long Belden multicore data cable coiled up. It has a thick aluminum braided screen. A quick end to end resistance check on the screen indicated it might just be in the range I’m looking for.

Sounds melty. Car headlamps? ..they're supposed to be melty.

jace_da_face

Fridge on inverter and 12 volts - good idea. It’s not too practical for me to run inverter power to fridge. I might just stick with my coiled cable. I did connect it to a 12 volt battery already (not the leisure battery) and it pulls 20 amps. No smoke, no heat, and not much sparking, so it should be fine.

jace_da_face

jace_da_face wrote: »

It’s not too practical for me to run inverter power to fridge.

It'd be more practical to have inverter power feeding your fridge than 12V.

Plug the hook-up lead into the inverter? [After turning off battery charger]

jace_da_face wrote: »

I might just stick with my coiled cable. I did connect it to a 12 volt battery already (not the leisure battery) and it pulls 20 amps. No smoke, no heat, and not much sparking, so it should be fine.

autumnalcore

jace_da_face wrote: »

No smoke, no heat, and not much sparking, so it should be fine.

P = I^2R

20 * 20 * 0.6 = 240w

jace_da_face

autumnalcore wrote: »

P = I^2R

20 * 20 * 0.6 = 240w

Ah yes, but that's 240w spread across 200 feet of cable. I've run tests, I'm not too concerned that my very long resistor will not work. What I am concerned about is the limited time I have to run a high current through my Fluke meter. This is my dilemma really. The Fluke meter has a 100A internal fuse. This is surely what is passing the current. I am guessing that the limit imposed by Fluke for passing 20 amps for a maximum of 30 seconds is a practical guideline based on heat dissipation of the meter. Nonetheless, I wouldn't want to push it. 30 seconds might be long enough to calibrate.



Here is my setup rig. What are we looking at? Basically a long cable used for the load test, complete with crocodile clips and connectors that enable me to connect to battery with Fluke meter inserted for current measurement, and facility to omit Fluke meter, all with rocker switch to make and break the circuit.



Here is the circuit powered and a current reading of 22.43 amps. Not wishing to leave this circuit powered for too long, I switch it off and remove the Fluke so that I can power up again for a longer period of time to see how hot things could get after a few minutes.



So initially temperature read 23.7 degrees and battery voltage 12.62.



And after 5 minutes temperature rises to over 30 degrees at 12.23V. That's warm enough thank you. I shouldn't need to keep it going any longer. I should pointy out this is still not my leisure battery, just a battery for testing my load.

Sir Liamalot wrote: »

It'd be more practical to have inverter power feeding your fridge than 12V.

Yeah well I still might. I might even settle for half the load with just the fridge on 12V should the Fluke let me down during calibrating. Will give this a go over the next day or two. :eek:

jace_da_face

jace_da_face wrote: »

Here is the circuit powered and a current reading of 22.43 amps.

Blimey that's a good meter!
Driving her like a rental.

jace_da_face wrote: »

That's warm enough thank you. I shouldn't need to keep it going any longer.

Get worried around 50°C

jace_da_face wrote: »

Yeah well I still might. I might even settle for half the load with just the fridge on 12V should the Fluke let me down during calibrating. Will give this a go over the next day or two. :eek:

Swap the £10 HRC fuse for fuse wire. Cheaper than hi-tech fuses or new meters.

HRC is for >400V

jace_da_face

Sir Liamalot wrote: »

Swap the £10 HRC fuse for fuse wire. Cheaper than hi-tech fuses or new meters.

Good suggestion, beats the ‘nail for a fuse’ approach. At this stage I sprinkle a little salt on Flukes guidelines for drawing high currents for 30 seconds. I know pulling 23 amps for under a minute at a time and allowing rest periods in between, will be grand.

So went through the calibration process this evening. There were times when I cursed and blinded, convinced the battery monitor is broken. When trying to increment and decrement voltage and current values, and either nothing happens or the parameter appears to change randomly, then it’s e-bin.com right? But I persevered and came to the conclusion that I was not applying an external power supply to the monitor as the instructions suggest. Between disconnecting power from the leisure battery and switching to an external source (different battery) between all the resets and beginning the process all over again, I concluded that I must have forgotten to switch to external power during calibrating at several stages, and I think that does matter.

In the end I was happy. I got to put my dummy load in circuit and I got the monitor to agree with the Fluke. Roughly that is, when pulling 20 odd amps from a battery, it s a moveable feast. The battery voltage continues to drop and therefore the current does too. So I adjust the monitor to match a value that is falling and hope it is within a reasonable range ~ 500mv, across two displays who’s refresh rates are God only knows.

Currently I am now charging the leisure battery to 100% with a Maypole Charger. When that tells me it is 100%, I will then tell the battery monitor it is 100%. I noticed when I connected EHU to start the charging, my Zig unit wouldn’t power on. I have thinking about keeping the Maypole connected when on EHU and scrapping the Zig. This might just make my mind up for me.

jace_da_face

jace_da_face wrote: »

So went through the calibration process this evening. There were times when I cursed and blinded, convinced the battery monitor is broken. When trying to increment and decrement voltage and current values, and either nothing happens or the parameter appears to change randomly, then it’s e-bin.com right? But I persevered....

Fair play!
No E-bin comes later when you press the wrong button sequence and then have to start all over.

Good meters (>€100) work outtov the box by the way. ..just sayin'



100% charge is what the specific gravity tells you. Not what a meter, and definately not what a charger says.
But you are down to ±10% error margin I'd expect.
FLA have a non linear efficiency, it'll manifest as drift over time.

jace_da_face

A guesstimate of actual charge will suffice if the device can report charge in and out with a reasonable degree of accuracy. If it gives me a good picture of my power useage without EHU then it will serve some purpose.

My next step is to go through all my appliances one by one to see why my parasitic current is so high. I noticed this while installing the monitor. It’s up at about 400mA.

jace_da_face

jace_da_face wrote: »

If it gives me a good picture of my power usage without EHU then it will serve some purpose.fast recharge.

That's it that's what they do best and charger performance info.

Power a laptop from an inverter then power it from a car charger if you wanna see an interesting comparison.

jace_da_face wrote: »

My next step is to go through all my appliances one by one to see why my parasitic current is so high. I noticed this while installing the monitor. It’s up at about 400mA.

Yes that is high. Mine is 70mA. Less is more.
Instrument cluster usually, tank monitors, fixed alarms, radio.

jace_da_face

So now I have a decision to make. As my Zig X-3 mains charger looks to have packed it in, I thought I might replace it with my Maypole smart charger. I had been thinking about this anyway. The alternator or the Zig is never going to give the battery the complete multistage charging the Maypole promises to, even though the solar charging, with the right conditions, should.

This post began with the question of suitability of multiple charging sources. I came across an interesting discussion HERE on another forum. It throws in to debate, the question of whether staged charging should be used at all while on EHU, as the effectiveness of consuming battery power while trying to multistage charge is dubious, and therefore a simple float charger is all that is needed. Interesting debate in that link. Both sides seem convincing.

It seems the smartest way at all might be a single charger which accepts charge from multiple sources but also supplies load current. I had thought about feeding mains supplied DC to the solar charger. Then the Zig would feed the solar charger on EHU , as well as the PV panel anyways, and even the alternator for that matter. But even this arrangement would not be aware of load current.

Does it all really matter at he end of the day? Its only a battery after all. As long as I am not running out of power to run my pumps or lights, or needing to replace my battery every year, it's not life or death. But the question remains. Do I whip out the Zig, put it on the bench and tempt to resuscitate or is it for the bin?

Float charger? Disagree. I use my battery.

Simple solution is a good load compensating charger like a Ctek, ProNautic, Xantrex, MasterVolt, Victron, Sterling. Make sure it has ample capacity to power your shore 12volt loads and have 5% > 15% overhead of your battery capacity rating for battery charging. eg. 200Ah battery, 6A nominal running load = 25A Charger.

Low end generic brand or automotive chargers are going to give you problems.
If it has temperature compensation it's a good sign it's safe to leave on a battery indefinately and that it's a well designed charger.

Make it exclusive to solar charging.

Feeding solars controllers works great, you need a current limited input up to the task that doesn't exceed 50% your charge controllers rating or use MPPT and some passive protection is advised.

Sure a device that take inputs from all sources would be great but nobody makes one that's fit for purpose. Unless you go into >1kVA inverter combi charger changeover jobs with solar inputs land.

Does it matter at the end of the day? Replacing a battery every few years is a very economic way to power a motorhome. Always having a battery one foot in the grave...maybe that's annoying maybe it's not...

I whip out working Zigs. I wouldn't be resurrecting any.

jace_da_face

Sir Liamalot wrote: »

I whip out working Zigs.

Liam, this could be your Boards signature!

jace_da_face

My Zig unit seems to have recovered. I didn’t have to do anything really. I just hooked up to mains so I could plug up my Maypole charger. The Zig was switched off and wasn’t working as far as I was concerned. Before I did any charging I concluded that the presence of the Zig was the reason for my high parasitic current draw. A couple of power cycles of the Zig seemed to kick start it again. Parasitic current now down to 137mA.

The Zig hangs on by the skin of its teeth. I don’t reckon I’ll hook the Maypole up as permanent EHU charger + PSU for reasons you mention Liam i.e. not a noteable brand, not load compensating, just a cheap auto charger, fine for intermittent charging.

jace_da_face

jace_da_face wrote: »

My Zig unit seems to have recovered.

Is that good news?

jace_da_face wrote: »

Before I did any charging I concluded that the presence of the Zig was the reason for my high parasitic current draw. A couple of power cycles of the Zig seemed to kick start it again. Parasitic current now down to 137mA.

So removing it will improve battery performance!
:pac: Case closed!

jace_da_face

jace_da_face wrote: »

It seems the smartest way at all might be a single charger which accepts charge from multiple sources but also supplies load current.

Found one from the land of Oz.



Overlanders seem to like them. Can't comment, never tested one, the external temp sensor and a 14.8V set-point speaks volumes to it's credibility though.
The fact it comes with a real monitor is also quite telling. Most of the market offerings would lose sales hand over fist if they did that because you'd see how poor the unit is outtov the gates without having to wait for your third battery replacement for the penny to drop.

CJhaughey

Has anyone ever looked at the CTEK D250SA and SmartPass 120 combo?
They look like they might be a pretty handy solution to many of the problems with onboard battery management.

Ctek, DS250

Hmm interesting..
Ctek make a good product but I don't especially like them. I find them overpriced and conservative.

The Smartpass 120A is a Merlin Smartbank inna fancy wrapper.
The DS250A is an over- cold-rated Sterling B2B 20A with an odd MPPT solar charge controller attached.

It's not going to help with a poor performing mains charger/maintainer/battery boiler.

Having a look at the manual tripped the BS detector a few times.

Ctek, DS250 wrote:

• Power reduction: 30°C 16A, 50°C 13A

That's a 13A continuous unit! After 30mins most electronics' thermal design point is ≥50°C

Ctek wrote:

• SMARTPASS 120 supplies consumers from the alternator instead of from the service battery while the service battery is charging, which permits faster charging.

That's a naturally occuring property of a higher voltage source, in a correctly wired system the alternator powers loads never the battery. It's a fundamental principle of electricity, not something I would be claiming as an inbuilt feature.

Ctek wrote:

TIP 6 Heavy current consumers (more than 80A) must be connected directly to the service or starter battery.

That's an 80A continuous unit with 120A surge and 350A instantaneous.
They're relying on the alternator to throttle before the unit melts...yeah why not..that's perfectly ok...but it's an 80A unit!


Other things to be aware of;

• The Voc of the solar input forces you to fit expensive 12v panels because it can't handle bigger. The whole point of MPPT in my opinion is so you can use half the price domestic panels.
• The smartpass is not a boosting unit. So you'll never get 120A from it, the DS250 is only boosting 20A (derate to 13A after 30 mins) after that you are still relying on the not so useful alternator regulator. As such it will still require compensatory cable routing and gauge and possibly an external alternator regulator to get close.
• The temperature compensation is too conservative. 23 mV/°C from 25°. Standard is 30mV/°C
• 14.7V setpoint conservative & non-programmable. (14.8V + 30mV/°C kicks bottom)
• Absorption timeout 12hours = 95% charged for flooded batts = diminishing returns.
• Engine battery trickle charging feature, could be a double-edged sword. I'd call it a parasitic load, maybe it's useful to some.
• 13A continuous charge + alternator on a 300Ah battery?

No meter...no surprise there. No mains regulation other than to throttle other inputs.


Other than that they are using the wrong symbol for the ground and calling it an earth with an earth symbol depicted. An earth is an earth potential conductor that is staked to the planet earth with an electrode of some kind. A Ground is a reference point in an electrical system that is grounded to a chassis. A negative is an ungrounded or floating 0V potential with reference to the positive.

They can be and often are all connected at the same point but they are not the same thing.




Sure it works, and probably well enough for some, apples to apples though it's an overpriced half-a-solution.
Yer paying premium for the BS marketing.


In terms of versatile, high performing multi-input BMS from the manual alone I'd give it a speculative 6/10 where 0 is a Zig/Calira/blok-thing and 9 is my home-brew system*. :P


* when it's finished

Here ya go CJ.



All the major features of that Ctek DS250 except better, faster, more powah, higher IP rating and comes with a meter. :cool:
They do electromechanical and solid state combiners too but used Smartbanks and contactors are cheap and cheerful, I don't think it's necessary though if you are using solar with it.

jace_da_face

Sir Liamalot wrote: »

Found one from the land of Oz.

Looks good but look at the price . I would like to see a unit that also distributed all load power. This would cut out the need to to install a shunt. Not a bid deal I suppose.

autumnalcore

Looks like a nice package especially if you get a friensly expat to hike it home for you. Certainly more attractive than the sterling offerings for the money. Submersible spells potted to me though which always makes me hesitate as its basically irreparable if anything fails wonder what the aftersales is like.

Speaking of reparable, the redarc stuff never seems to show up for parts or repair on ebay going by the forums they seem to have a policy of replacing failed units well outside warranty. Which sounds like a major plus to me.

jace_da_face

jace_da_face wrote: »

Looks good but look at the price . I would like to see a unit that also distributed all load power. This would cut out the need to to install a shunt.

Have you seen what they charge for featureless, under-wired battery killing Ziggybloks?

A distro is an entirely different kettle of fish. You couldn't integrate it, everyone will want something different. Just add yer own fuseblock.

Yeah looks intimidating but it's got:
{15A examples the 30A Manager is only £150 extra}
MPPT solar controller: €300
A Battery Monitor (with a cheap a$$ shunt, but low light solar input will never be confused for end of absorption because it's an integrated unit, which is the single greatest nuisance of auto-syncing jobs): €150
A Quality Mains Charger: €200
An intelligent combiner: €150
A boosted battery to battery charger for smart and dumb alternators: €250
Installation cost for all of the above as a modular kit: ~€350
+€500 for all of the above in 30A

Add to this the claim that it charges to 100% I have never seen a mains charger do this which is why I don't run any.

autumnalcore wrote: »

Looks like a nice package especially if you get a friensly expat to hike it home for you. Certainly more attractive than the sterling offerings for the money.

Yurp
Sterling :rolleyes:
Different league.
Redarc are making the best product they can. Sterling are making the cheapest (and charging the most for it).
Ever notice how ProMariner have a much lower failure rate than Sterling?
ProNautic have a 5 year warranty, ProCharge Ultras have a 2 year warranty. Hazard a guess why! It's the same looking exterior, same board layout.
Edit* [5 year warranty on ProCharge Ultra since 2016 (red terminal cover)]

autumnalcore wrote: »

Submersible spells potted to me though which always makes me hesitate as its basically irreparable if anything fails wonder what the aftersales is like.

Indeed, there's a lot to be said for modularity.

autumnalcore wrote: »

Speaking of reparable, the redarc stuff never seems to show up for parts or repair on ebay going by the forums they seem to have a policy of replacing failed units well outside warranty. Which sounds like a major plus to me.

They are contracting them to the military that ranks them beside Merlin & Xantrex for me.

Don't get me wrong I can do better but I can't do cheaper. It's not programmable although I'd not be unhappy with the presets for the first time ever.
It's got the same 12V solar panel only problems as every other offering...if I was flying two solar panels I'd want two solar controllers because shading.
It's a single point of failure to take out the entire charge system.
I'm pulling 40A-50A (after load compensation) off my alternator these days with low SOC, sticking electronics in the middle will only reduce this and make it less reliable.
Seems like 10mm² is the max cable aperture...meh, fix that with a barrier terminal strip.
I don't run teeny little +12v wires to my shunts.

I heart the solar priority assist feature, I was working on this but was advised against it as it may cause MPP Tracking issues.

12 element

Ring RSCDC30 looks a nice alternative to the CTEK. Thinking about using it in my Van Conversion.

http://www.ringautomotive.com/uk/products/Workshop+Tools/Battery+Maintenance+Tools/SmartChargePro/RSCDC30

Looks good for the money. My preferred MPPT solar controllers cost more.

I haven't used ring products but they're a bit like Durite to my mind. Every-expense-spared, Chinese built jobs.

I'd be very skeptical about the rating/performance.
I wouldn't fit one without a battery monitor.

Temp. compensation is 10mV too low. 14.8V ceiling means temp comp doesn't work for Calcium/AGM/Lead Crystal unless the manual is mistaken which is not unusual for Ring.

Here's something similar from Projecta.

jace_da_face

So my solar charge controller does in fact keep my split charge circuit closed after engine stops. The charge controller will not close the relay once open. But it does mean my starter and leisure battery will remain connected if the engine stops and there is enough solar charge to exceed the VSR threshold.

This would be bad if:

(A) My 12V fridge was left on and I didn't realise, as my fridge would continue to run on battery power instead of alternator power once parked up.

(B) I didn't want solar charge to be directed to the starter battery. I mean why would I unless my starter battery was flat? It should just go to the leisure battery.

(C) I didn't want the two batteries left in parallel anyway, as they are not designed to be and are not matched.

This is not a major problem as long as I remember to open the split charge circuit once parked up, by knocking of the PV panel for a few moments and allowing the relay to open.

It is a nuisance if I turn off the engine and restart it again without needing to get out and without isolating the leisure battery, as now the leisure battery is supplying some cranking amps.

A longer term solution is to eventually wire up a switched ignition signal to the VSR. An even longer term solution is to invest in a smart battery to battery charger/ MPPT combo similar to CTEK or one of the other ones mentioned in previous threads.

jace_da_face

jace_da_face wrote: »

(A) My 12V fridge was left on and I didn't realise, as my fridge would continue to run on battery power instead of alternator power once parked up.

The fridge will create voltage sag and the VSR will disconnect.

jace_da_face wrote: »

(B) I didn't want solar charge to be directed to the starter battery. I mean why would I unless my starter battery was flat? It should just go to the leisure battery.

If you maintenence charge the starter battery it might last a decade

jace_da_face wrote: »

(C) I didn't want the two batteries left in parallel anyway, as they are not designed to be and are not matched.

They are both lead acid?
Just add water as needed they'll be fine. You can charge them together. The problem is in discharging them together. Having said that the engine battery will pull down available solar charge to service battery

jace_da_face wrote: »

This is not a major problem as long as I remember to open the split charge circuit once parked up, by knocking of the PV panel for a few moments and allowing the relay to open.

I've never been a fan of automatic split charge. My setup has always been manual with a sophisticated intelligent relay for storage only.

jace_da_face wrote: »

It is a nuisance if I turn off the engine and restart it again without needing to get out and without isolating the leisure battery, as now the leisure battery is supplying some cranking amps.

Unlikely because the drop will open the relay and besides you won't pull more than 30A across that relay with that cable.

jace_da_face wrote: »

A longer term solution is to eventually wire up a switched ignition signal to the VSR. An even longer term solution is to invest in a smart battery to battery charger/ MPPT combo similar to CTEK or one of the other ones mentioned in previous threads.

Manual + meters. Works for me.

jace_da_face

All plausible points Liam which had occurred too me too. But, with the engine turned off having just been running, and split charge engaged and remaining engaged as the solar controller tries hard to maintain a charge, the VSR will eventually flip-flop like a mad man. At this point the voltage is oscillating within the low and high voltage set points of the VSR. I think it could potentially stay that way for a long time, until the sun goes in :eek:.

Turn the adjust pot fully clockwise.

jace_da_face

Sir Liamalot wrote: »

Turn the adjust pot fully clockwise.

Arghhh! Have adjusted it several times already. The last adjustment was to stop the fridge cutting out when driving due to the a battery loading voltage being pulled down. Unless there is a pot for lowering the “hysteresis” band, I’ll give it a go. It’s a real compromise.

I’m gonna get me a switched ignition signal. That’s all there is to it!

..or a better fridge.

jace_da_face

Now that is not even funny. My fridge keeps my beers cool! That is no laughing matter.

At this point I should digress and refer people to what is, or was, a very influential experiment. A recording of an important event that took place by a man in his shed. One that would inspire me to be believe what is possible.

This is an old link, but it’s importance should not be forgotten. Link