Jump to content

Battery advice


Tea Cup

Recommended Posts

I have 2 x 110 Platinum Batteries which at just 2.5 years old look like they are at the end of life. This surprises me because I thought they were highly rated.

 

They are charged by a Durite split charger on the move, and also by 2 solar panels totalling 190 watts when on site. On a recent sunny day these panels were charging at over 20 volts/5 amps.

 

The batteries are not holding the charge overnight, but appear to be otherwise healthy. If I recharge them with a mains smart charger it quickly indicates that the batteries are fully charged. This confuses me. Why do they not retain charge?

 

Could the solar panels have contributed to this apparent early demise in some way? The batteries  have incidentally worked day and night running a 70 litre fridge, for this period of time, even in winter, with no probs so far. The fridge is presently cutting out (at a guess) about 11.5 volts, so this shouldn't have flattened the batteries over this long period of operation.

 

I am reassessing which make battery to replace them with, since I'm not keen to replace them with the same make. I have read threads on this forum but ended up being just as confused.

 

I read somewhere on the dis-information highway that the 110 amp battery sold by Halfords for £89 is in fact a rebranded Bosch L4, but having checked out the online pictures they do not look alike.

 

I was thinking of just one Banner Bull 135 amp to save weight and cost, but wonder if that would be big enough.

 

We tend to stay mostly on campsites with leccy, but often stop on aires or CCC rally sites without leccy, sometimes up to 15 days.

 

This is for a smaller campervan (Vivaro LWB high top). Available space is flexible, but I do need some sort of safe system of clamping, since I am not too happy with the present system of just being restrained by wooden battens - they are in the boot but would easily break out into the main cabin in the event of a cataclismic event. Advice on this would be helpful, as would advice on which battery to go for.

Link to comment
Share on other sites

Charles - 2015-07-29 10:25 PMYour charger has probably boiled the batteries dry if it's been charging them at 20 volts. Is this a typo or something?
Well, perhaps badly worded, it's going thru a 12v PCM regulator, the 20 volt measurement was direct from the panels before the regulator, as was the 5 amp reading. I've no reason to think that there is any problem with that, though I am just about to change it for an MPPT. Sorry.

 

Link to comment
Share on other sites

I have just spoken to the supplier who states that although the batteries are covered by warranty, failing after 2 years is basically fair wear and tear. Since they were running continually feeding the fridge, that would be 730 cycles plus, which is beyond their spec.

 

The thing is, I did this 'cos I thought that batteries liked to be worked and if continually charged by solar, not just stored for the winter months, they would be kept optimally and last longer.

 

I do not understand the world of batteries. And I still don't understand how they can show fully charged, and yet run out of power overnight. Aah well, another £200 plus gone.

 

Link to comment
Share on other sites

Why were you keeping the fridge running permanently? I assume it must be a compressor fridge, but it is still likely to draw more power from the batteries over 24 hours, especially in winter, than the solar is putting back. At times over the winter months there will have been a progressive loss of battery charge that, depending on the weather, may well have run it flat.

 

Don't forget solar produces much less power at any time of day in winter than in summer, plus the days are shorter, plus possibility snow on the panel, or heavy cloud, at which times it will produce virtually nothing. Even in summer flat mounted panels in UK will only get near their full power output for a relatively short period around mid-day. They will produce some power at other times, but the actual outputs will vary greatly between morning and evening, as the sun's angle to the panel varies, and will be reduced by cloud and/or shade.

 

Before you replace the batteries with new ones, I think you may need to look again at what your solar panels are producing in real world conditions over a 24 hour period, and at how well the controller matches their output to the battery state. I also think it would be better for the battery if you turn off the fridge when it is not in use. You should expect to get several years more use from your batteries than you did, so something needs to be changed or you risk merely repeating the experience whatever batteries you get.

 

Regarding the measured state of charge, did you possibly measure the battery state with the solar connected, possibly at about mid day? If so, might you have been measuring the solar panel output, rather than the battery charge state? Might that explain why they seemed to discharge by morning, as the solar output would then have been much lower?

 

A battery that registers 12V is flat, so the 11.5V cut out at the fridge would have taken yours well into the injury zone. A fully charged battery, left with all loads and inputs disconnected for about 4 hours, should show 12.8V or better. At 12.55V it is about 25% discharged, at 12.3V 50% discharged, at 12.2V 75% discharged, and at 12.0V or less, it is "flat". But, for these readings to be meaningful, the battery must be left to stand, disconnected, as above.

Link to comment
Share on other sites

Yes, I've taken the lesson that running the fridge all the time damages the batteries. The thing is, being a campervan it is used all year, and it's handy to have the fridge running when you go out say for the shopping or for a day trip with your milk and food in the fridge, etc. You get used to the access, it's also useful as an extra space when the house kitchen fridge is full.

 

The solar output was taken on a recent sunny day, but the output is surprisingly good in the winter, though obviously not for as long. As regards the compressor fridge cut out, it's just a guess, I haven't checked the spec. But I do constantly monitor the solar output and charge, as I have a neat little device that does this more or less permanently connected to a cig lighter socket on the leisure circuit, which I can swap it over to the van charging circuit to check the alternator output. It has always shown healthy figures except for the recent two months. It is only a cheap device but I can double check also with a meter, and it does not appear to lie. I'm aware of the difference between input into the regulator, and output to the battery, you can measure both from the regulator connection points, but feel it must be a problem with the batteries since the setup has run very successfully for 2 years unchanged. I've checked all the wiring and connections. I do top up the charge in the winter, though only when I remember, not to a strict regime. Added to which, the alternator will top up when the van is used.

 

It still confuses me why the batteries show a healthy voltage when fully charged; the green light comes on the smart charger and also on the monitoring device, but that charge does not last. All I can think is that the total capacity of the battery has been reduced, and that the output is thus at sufficient voltage for only a short time. I'll just have to accept that fact and shell out.

 

I am just about to change the regulator for an MPPT which I'm assured is up to 30% more efficient.

 

Thanks for your input though, Brian.

 

 

 

Link to comment
Share on other sites

Tea Cup - 2015-07-30 6:27 PM.................... I'm aware of the difference between input into the regulator, and output to the battery, you can measure both from the regulator connection points, ........................

Not sure if we may be at cross purposes, but that was not quite my point. What I was getting at is that with solar panels permanently connected to charge the battery, AFAIK, the only way to measure battery voltage would be with the solar disconnected and the battery allowed to rest with no load for about 4 hours. Otherwise, what you measure is the solar input charging the battery, and not the actual battery state. I wasn't doubting that either the alternator or the solar are providing a charge to the battery, just that you can't establish the health of the battery while they are doing so, or while something is drawing power from it.

 

To test how well it can hold charge it needs to be left isolated for about 24 hours and then the voltage checked again.

 

To test how well it can sustain a load it needs to have a known steady load (lights for example) placed on it, and the voltage measured hourly over several hours. As your batteries are nominally 2 x 110 Ah, you should be able to take about 65Ah from them over 12 hours, say by switching on 60W of lighting (3 x 20W spots, for example) and leaving it on. After 12 hours the voltage should be around 12.55V (25% discharged). But, to measure that properly you'll need to first turn off the lights and leave the battery resting for an hour or so. The hourly check measurements with the lights on will give a guide, but will not be definitive. However, from what you say, I would expect the voltage to fall quite quickly over only a very few hours, so I don't think you'll be able to complete the full 12 hour test. Hope this helps.

Link to comment
Share on other sites

Yes, I think you are right about the confusion on your post on my part. I did disconnect the solar panels by taking out the fuse, before I took a reading, but didn't leave it 4 hours, maybe 2. There was only .1 of a difference between batteries, and they seemed reasonably healthy. I can repeat that with longer rest time. I had been thinking of opening the fridge door and using the fridge as the known drain using the manufacturers quoted power consumption, but I guess that would be an approximate rating anyway.

I'm thinking of just replacing the 2 batteries with just one new one. This would immediately prove the point. We are going back to France via Switzerland and Italy at the end of the next month, so this would be a good road test too. We probably will not be staying too long on aires so that should be sufficient power in the short term, and could top it up with a second on our return if need be. If there's still a problem having installed the new battery that would have time to sort it before we go.

 

What the dealer said about exceeding the cycle life makes some sort of sense. I did enquire of him what the 3-year guarantee does cover, he firmly stated manufacturing faults only. You've got nowhere to go.

 

Link to comment
Share on other sites

A couple of hours should be near enough. The main thing is not to take a reading immediately the battery is disconnected. If you can use lights of known Wattage they are probably a more consistent load than the fridge.

 

I would guess that one battery should be OK during summer, but I somehow doubt you could keep the fridge running during winter however many batteries you fit because, although it is impossible to say without knowing the actual consumption of the fridge over time, I would guess it consumes more than the solar can put back.

 

The fridge will cycle on and off under thermostatic control, but if it takes an average of n Ah over 24 hours, and the solar puts back an average of n-1 Ah in the same period, the battery will gradually lose charge over time. I'm no expert, but what you describe seems consistent with that having happened.

 

I suspect that the batteries have been damaged by being heavily discharged via the permanent attached load, and not being brought back to a full charge sufficiently quickly thereafter. My understanding is that if the charge is allowed to fall much below 60% of their capacity, they need to be brought back up to full charge pretty much immediately: not just charged up a bit and then discharged some more. I think that is probably how the damage has been caused.

 

I've been hoping brambles would come in on this, as he would undoubtedly know, but he hasn't logged on since 26 June, so I guess he must be away. Best I can do, I'm afraid. Hope it helps.

Link to comment
Share on other sites

I really would like to thank you for this help and advice. Even just talking about it with someone helps, because it clarifies your thoughts a little.

 

I now feel fairly certain the batteries are toast, but will check them along the lines you have mentioned. Thanks

 

Link to comment
Share on other sites

What I am about to suggest may sound radical but bear with me.

 

Wait until it gets dark ....... or if you are the impatient type, throw a bit of old carpet over the Solar Panel. Either way, you will have no solar input.

 

The battery voltage level will stabilise. You could then switch on something like a TV and a few lights to provide a 5 amp (or thereabouts) drain on the batteries. Note the voltage every hour and see where it goes. Post the readings on here but remember to stop the amperage drain and allow the voltage to stabilise again.

 

If your voltage falls away badly in a just few hours, your batteries are toast. :-(

Link to comment
Share on other sites

Tea Cup - 2015-07-31 8:31 PMI really would like to thank you for this help and advice. Even just talking about it with someone helps, because it clarifies your thoughts a little.

 

I now feel fairly certain the batteries are toast, but will check them along the lines you have mentioned. Thanks

Wise words from Brian as usual. The companies who supply these compressor fridge units should explain how to use them, how much power they consume etc. They are not really up to being powered by your "leisure" battery for any great length of time. If I was going to bite any bullet I'd fit a 3 way fridge, 12v 240v and gas. I have run a 12v Waeco freeze in the passed using traction batteries by Trojan totalling 560 amp hr and 500watts of solar power, in Spain and down in the Sahara desert (not flat on the roof) and it took them down. I have removed half my battery power, fitted a Sterling BB121250 battery to battery charger and a sterling 50amp pro charger which fully charges the batteries at 14.8v via the alternator or a Honda EU20i in less than 1 1/2 hours and 400 watts of Solar and haven't had a flat battery in 2 years. no tungsten lights all LED, .Flat screen TV and lap top. The down side is weight and having to top-up the water level every month or so. So Compressor fridges are fine on mains electricity on a camp site but not much good else where. Just an opinion and positive advice. I dare say someone will give my view the thumbs down. Anyway I hope that helps.
Link to comment
Share on other sites

I have had the chance to take out both batteries and have charged one to show a full charge. It has been at rest for over 12 hours and shows 12.66 volts. The other battery also shows 12.66 volts, having been at rest for 24 hours plus, having been charged in place by the solar panel, and having been used to power internal lighting. This doesn't sound too bad, according to a chart I have seen it means that they are at least 90% charged. Are they OK?

 

Link to comment
Share on other sites

I am back from hols now Brian.

 

Teacup, not sure I can add much to what has already be discussed. Maybe just a comment on battery state of charge voltage. Basically the state of charge voltage relates to the %age charge of the remaining capacity of the battery. The easiest way to test capacity is as mentioned to discharge a known amount of amperehours and then measure the voltage drop as a result after a rest period.

 

Cannot really add much more just now as my brain is still back in Austria/Italy at at the top of a the Timmeljoch mountain pass and not caught up with the rest of me yet.

 

 

Link to comment
Share on other sites

Brambles - 2015-08-08 10:16 PM

 

I am back from hols now Brian.

 

Teacup, not sure I can add much to what has already be discussed. Maybe just a comment on battery state of charge voltage. Basically the state of charge voltage relates to the %age charge of the remaining capacity of the battery. The easiest way to test capacity is as mentioned to discharge a known amount of amperehours and then measure the voltage drop as a result after a rest period.

 

Cannot really add much more just now as my brain is still back in Austria/Italy at at the top of a the Timmeljoch mountain pass and not caught up with the rest of me yet.

 

 

Thanks for that.

 

I was beginning to believe that I had imagined trying to help a member but that my valuable comments had somehow become invisible. Have no fear, it will never happen again ....... I will just keep me gob shut. :D

Link to comment
Share on other sites

747 - 2015-08-08 10:52 PM

 

Brambles - 2015-08-08 10:16 PM

 

I am back from hols now Brian.

 

Teacup, not sure I can add much to what has already be discussed. Maybe just a comment on battery state of charge voltage. Basically the state of charge voltage relates to the %age charge of the remaining capacity of the battery. The easiest way to test capacity is as mentioned to discharge a known amount of amperehours and then measure the voltage drop as a result after a rest period.

 

Cannot really add much more just now as my brain is still back in Austria/Italy at at the top of a the Timmeljoch mountain pass and not caught up with the rest of me yet.

 

 

Thanks for that.

 

I was beginning to believe that I had imagined trying to help a member but that my valuable comments had somehow become invisible. Have no fear, it will never happen again ....... I will just keep me gob shut. :D

 

Please don't keep your gob shut as then I can't say things like "as already mentioned" and get out of having to reply fully.

Link to comment
Share on other sites

Just put a new battery in, all is well, fridge not struggling etc. Good info about the state of charge of the remaining battery power, which I think I now understand. I will do the power drop test in the next few days on the old batteries, once I've figured out a method, but it is now mostly out of interest. Off to Italian lakes in 2 weeks, so at least the immediate issue seems to be fixed.

 

In checking the system wiring, I came across a 15 amp fuse to a cig lighter socket in the boot that had not fused, but the plastic grip on top of the fuse was welded to the in-line fuse holder!! I've no idea what could have happened to do that, since I am sure that nothing more than a 4 or 5 amp loading has ever been plugged in to it. Have presently disconnected the socket, but if I reinstate it, I would downrate the fuse to 5 or 10 amp. The cig lighter socket supposedly had a 15 amp rating.

 

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...