Changing batteries on a Hymer

[Jack]

New to this van, therefore, little knowledge with regards the Eloktroblock 101 but have read how 'surfisticated' they are. I am thinking about changing the gel 80 amp hr one for two 110 amp hr lead acid ones. Have been thinking about fitting solar panels but think this option is the first one to try. Is there anything to be concerned about in under taking this option?

Many thanks,

[StuartO]

Yes, don't just disconnect at the terminals! Get a copy of the instructions from Schaudt, who are very helpful.

 

As I recall you should connect the MH to the mains, so that the vehicle's 12v system stays energised and then switch the batteries off at the Electroblok, using the big black switch on the panel. Then disconnect and swap over your batteries, then switch them back on at the Electroblok panel.

 

Doing it this way ensures you can't short anything and also preserves the Electroblok's display panel settings, which would otherwise be lost.

 

Don't abandon your Exide G80 lightly. Mine are still going strong nine years after installation. I have two but I doubt I really ever needed two.

[Robbo]

The batteries on my 2002 Hymer 544 were under the front seats, 2 x Gel 80 AH. They were still going strong when I sold it 10 years later.

 

If your current single battery is located under the front drivers or passengers seat, consider how you will maintain them if you go for a flooded type battery. Do you want to remove the seat every time you top them up. That's why Hymer supply Gel as original equipment.

 

Also, if you go for flooded batteries you will need to vent them if located in the habitation area.

[Derek Uzzell]

It may be worth referring back to the October 2014 discussion where Jack first inquired about his 2007 Hymer B544 SL’s leisure battery.

 

https://www.outandaboutlive.co.uk/forums/Motorhomes/Hints-and-Tips/Hymer-Battery/36228/

 

Not too many batteries nowadays can be topped up, though Banner’s popular “Energy Bull” range that’s aimed at the ‘leisure battery’ market can be. If a battery cannot be topped up (eg. if it’s a Varta Silver Dynamic or Bosch S5 that have been recommended in other forum threads) it won’t matter much that, once installed, access is difficult, as the battery effectively becomes ‘disposable’. As maintenance won’t be possible, the battery can be expected to remain in place until it becomes apparent that it’s on the way out - then it gets replaced.

 

As has been advised before, if a battery (even a ‘maintenance free’ battery) can accept a vent-tube it would be sensible to fit one, and this should definitely be done if the battery is installed in a motorhome’s living area.

[Jack]

Thanks for all the help. The siting of second battery not a problem (out side locker) . But once again having second thoughts about whether to change, it seems, although the gel battery could be eight years old it appears to be functioning well enough at the moment. What has brought it to a head now is that we are off to Europe next month for 3/4 weeks and we tend to use Aires and the battery is untested in such circumstances.

On balance 'leave alone if it's not broken' springs to mind!

To read the info from my previous post was also very helpful....I had tried to find it but without success so thank you Derek.

[Derek Uzzell]

Jack - 2015-08-24 10:06 PM

 

...although the gel battery could be eight years old it appears to be functioning well enough at the moment. What has brought it to a head now is that we are off to Europe next month for 3/4 weeks and we tend to use Aires and the battery is untested in such circumstances...

 

My 2005-built Hobby had an 80Ah Exide gel battery as original equipment

 

In March 2012, immediately before travelling to France for a couple of weeks where we would be staying on aires for some of the time, the now-7-years-old battery showed signs of being less able to hold charge than previously.

 

I ignored this Gypsy’s Warning and, when I switched on the heater on the first (cold) morning abroad, the battery died. Apparently this sort of behavour is not unusual with gel batteries - they can work OK for a long period and then their performance can suddenly fall off a cliff.

 

The result of this battery failure meant that I required a replacement battery fast and, because it needed to go under a cab seat and I suspected that no vent-tube had been allowed for there, I opted for an AGM type. This was an expensive choice and one I might well not have made if time had not been an issue.

 

What I’m getting at is that you would be wise to be as certain as you can be before heading abroad that your 8-year-old battery will be able to meet your requirements. What you don’t want to happen is to have your battery fail while abroad (as happened with me) and then need to have fitted a battery of a make/type that you wouldn’t have picked if you hadn’t been under pressure.

 

“If it ain’t broke, don’t fix it” is fine as long as you can be pretty sure your gel battery probably ain’t going to break while you are abroad, but “A stitch in time saves nine” is also a good proverb.

 

 

[StuartO]

But you had the warning of impending failure and you ignored it Derek!

 

Exide gel G80s are not your usual run of the mill batteriies and they can last well over ten years in service as a leisure battery, especially if kept well charged and used only lightly for service discharges.

 

I was convinced my pair must be close to death purely because they were eight years old but they passed a bench discharge test with flying colours and they've stayed in service for two years since then.

 

And would Exide G80s fail suddenly and become unusable as a leisure battery? I rather think not, they would gradually show loss of capacity to retain a useful charge rather than suffer shorting of a cell and therefore sudden death, as starter batteries commonly do.

 

And would it cost a fortune to replace a leisure battery abroad with something good enough to get you home if necessary? A cheap starter battery would serve that purpose and they come cheaply enough in supermarkets etc. You could shop around for a permanent replacement when you get home.

 

And you can get lucky; foreign countries are not mercantile deserts and with a strong Pound Sterling at present, things are generally much cheaper abroad at present. I suffered a starter battery failure in France on a day when all the garages were closed for a holiday and managed to buy a very good replacement starter battery at a reasonable price on a Sunday morning from a branch of Auchan. They had quite a selection on display.

 

There is some risk of facing a frustrating delay if you suffer a starter battery failure but much less so with a failing leisure battery surely? I'm still taking my ten year old Exides abroad with no real anxiety about them at all.

[Brian Kirby]

I think all Derek is suggesting is that jack "stress tests" his battery before he leaves, in sufficient time to get it replaced if necessary.

 

He could turn on sufficient lights to give a gentle discharge rate, say about 5A - so 3 x 20W halogen spots, for example - and record battery voltage over time to see how it falls off. He should start with the battery fully charged via the charger for 24 hours, and then allowed to rest for 4 - 6 hours before he takes an initial voltage reading, then turn on the lights, and see what the voltages are as the test progresses. The readings should be taken with a Volt meter, or multimeter, at the actual battery terminals and not by using the on-board control panel indications.

 

He has an 80Ah battery, so it should start at 12.8 Volts or better after resting (100% charge). It should then take 4 hours to fall to 12.55 Volts, (25% discharged), and 8 hours to fall to 12.3 Volts (50% discharged, but note that 75% discharged is only 12.2 Volts, so the margins are fine). If it hits 12.0 Volts at any point stop, because that is basically flat, and re-charging from below that level may cause charger damage. There should be no need to continue beyond 12.3 Volts. These voltages should be measured about one hour after the lights are turned off, to allow the battery to "settle".

 

If the resulting Voltages are about right the battery is in reasonable condition, but I would then re-charge it for a further 24 hours, allow to rest as before, and then turn the heating and water heating on at full blast for a couple of hours, and see how it copes with a higher load, in case it can't sustain a higher discharge rate.

 

If it does all that it should be fine. If not, it is suspect. Whether it is completely shot will depend on the rate of Voltage drop, the levels reached, and at what point in time; but if jack can do these simple tests and post the results, it will be possible to do better than guessing, which is all we can do at present.

[Robbo]

Another option for Jack is to purchase a Varta silver/Bosch S5 and install it in the outside locker, complete with new cables back to the ECB. Disconnect the existing Gel battery.

 

On return from his September trip, he can then decide whether he needs an additional battery. It might be worth checking the routeing of the battery vent tube if installing the additional battery within the living area.

 

PS. Thanks to Brian for his excellent description of testing the battery - I've bookmarked it for future reference.

PPS. Jack, if you want to find your previous posts just press Search, in the Author box type in Jack and in the box below highlight All Posts, bingo !!!

[lennyhb]

I'm another fan of Gel batteries, if keeping the van for a few years well worth the investment as they really do last. Only down side is the charge time is considerably longer, but an 80 A/H Gel is equivalent to a 110A/H wet cell as safe DOD is 80% opposed to 50% on a wet cell.

[Jack]

Once again many thanks for the excellent responses from you all. I will 'test' the battery as suggested and report back, although it may be a day or two before I can tackle it. The amount you can learn from just a simple question!

[Derek Uzzell]

Exide gel batteries used to be prohibitively expensive, but the asking price (at least in the UK) now seems to have reduced considerably. The 80Ah version most commonly fitted to German-built motorhomes has nominal millimetre dimensions of 353(L) x 175(W) x 190(H) and Tayna currently offers it at £159.98 including VAT and delivery charges.

 

https://www.tayna.co.uk/ES900-Exide-G80-Marine-and-Multifit-Gel-Leisure-Battery-P7693.html

 

At that price - if Jack’s testing suggests that his present DETA DG80 gel battery might be suspect - replacing this on a like-for-like basis with one or two Exide 80Ah equivalents could make financial sense if (as lennyhb says) he plans to keep his Hymer for several years.

 

A relevant Exide technical leaflet can be found here

 

https://www.portablepowertech.com/library/documents/554b7d1963df3-exidebrochure.pdf

 

and there’s a useful article here

 

http://www.batterystuff.com/kb/articles/battery-articles/battery-basics.html

 

There’s also the possibility nowadays of obtaining a similar size (dimensionally) AGM battery at a not-too-bad price

 

http://www.ebay.co.uk/itm/Hankook-95Ah-Marine-Boat-AGM-Battery-/252018449369?pt=LH_DefaultDomain_3&hash=item3aad785bd9

 

Regarding the Exide 80Ah gel battery that had been fitted as original equipment in my 2005 Hobby, this had always been used lightly for ‘leisure’ purposes only and its charge-state was always well maintained.

 

We were due to travel to France on a Sunday morning in March and, after charging the battery on the Friday and voltage-checking it, the reading was slightly lower than I had anticipated. I recharged on the Saturday and the result was similar. I did not have time to carry out the type of testing Brian has described, but decided that the battery should be OK for a couple of weeks of light use and that I would replace it when I returned home.

 

On Sunday morning the Hobby’s control-panel voltage readout for the Exide battery gave no cause for concern, so we drove to Portsmouth (130 miles), hung around for a few hours at the ferry port and the motorhome sat in the ferry’s car deck for 6 hours during the Channel crossing. After arriving at Ouistreham we drove to the aire at Herouvillette where we overnighted. Still no sign of a leisure-battery problem - all the lights (containing LED replacement bulbs) were working OK, water-pump functional, control-panel readout still OK.

 

Monday morning comes and I switch on the Truma C-6002EH heater. The fan starts and then stops with the red fault light glowing balefully. Control-panel readout delivers bad news and a multimeter check confirms this. The battery still had enough life in it to run the lights and the fridge, but nothing else. My wife not amused...

 

I visited a local Citroen garage, explained our predicament and asked if they could source an equivalent gel battery. I had, by now, removed the Exide from beneath the cab seat so that the garage could confirm its critical dimensions before obtaining a replacement. They did some telephoning and quoted a price that seemed VERY reasonable. I asked them to recheck and it transpired that the battery would not have been a gel type and that they could not, in fact, obtain a gel battery in the size I needed. I then asked if they could obtain an AGM battery of the right size and that was possible (though the price was a mite unpleasant). I put the Exide battery back in; we went to lunch; and in the early afternoon returned to the garage where a Banner “Power Bull” 95Ah AGM battery had turned up. I swapped the batteries over, left the dead Exide with the garage and off we went. The exercise from start to finish had wasted most of a day and (obviously) if I had suspected earlier that the Exide battery might fail so catastrophically I would have replaced it at my leisure in the UK. That’s why I suggested Jack be as confident as possible that his DETA DG80 gel battery should be OK for the 3/4 weeks he will be spending abroad.

 

Back in the UK I asked a technician at Battery Megastore at Tewkesbury if my experience was unusual and he immediately inquired if the battery was gel-type. When I confirmed this he told me that ‘sudden death’ was a known (though fairly uncommon) characteristic of the breed and could be caused by vibration producing bubbles within the gel. Small bubbles could be tolerated, but if large (or enough) bubbles formed the battery could suddenly lose its charge. I had no idea whether this explanation was true or not, but ‘bubble formation’ is also mentioned here

 

http://www.kp44.org/LifelineBatteryLetter__JustinGodber.php

 

Some people live to be 100, others snuff it at 50. Batteries are similar and, while lennyhb might say of gel batteries “they really do last”, that certainly doesn’t guarantee that every gel battery used for motorhome leisure purposes will have a long lifespan. StuartO says of Exide gel batteries "they can last well over ten years in service as a leisure battery” and, while that may indeed be the case, like people living to be 100 it’s probably relatively uncommon statistically.

 

This 2010 discussion relates to a DETA DG80 gel battery like Jack’s that, after 4.5 years was no longer able to power a water-pump/heater and no longer able to hold its charge.

 

https://www.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/new-battery-needed/20610/

[StuartO]

Thank you Derek, very useful. I remember a MH salesman whom I had known and trusted for years (I know, but he was very good) saying that in his experience (a lot with Hymers) gel batteries were impossible to predict in terms of lifespan and could fail at five or last over ten.

 

It sounds like the first sign of trouble once they are getting towards ten years old should tell you to replace them.

 

Mine are behaving at present but I think I will need to check them out again - and Brian's stress test sounds easy enough to do, even while on site here in France - just unhook and do it. I'll have to disconnect the solar panels of course.

[Jack]

My apologies for needing to come back so quickly. I am have some difficulty in understanding the sequence of undertaking the 'Stress Test' which Brian offered. The switching of the lights off and on during the test is confusing me (not difficult as some would say) This is what I have done so far but I'm sure I should be tackling it differently.

1) Battery fully charged 13.40

2) Battery left for 4 hours 13.37

3) Lights on (showing 5.4 amp on panel) and left on

4) One hour later 12.72

5) Two hours later 12.64

6) Three hours later 12.57

8) Four Hours later 12.50

 

My query is the comment:- These voltages should be measured about one hour after the lights are turned off. So it seems to me that I'm not doing this test correctly.

Any help would be appreciated, thanks.

[Brian Kirby]

Jack - 2015-08-27 5:08 PM........................My query is the comment:- These voltages should be measured about one hour after the lights are turned off. So it seems to me that I'm not doing this test correctly.

Any help would be appreciated, thanks.

Apologies, my fault and was unclear. What I meant was that after 4 hours, by which time you should have taken a little over 20Ah (so about 25% of its capacity) from the battery, it would be worth just turning off the lights to allow the battery to settle a bit before taking the multimeter reading. Hence leaving it to stand for about 1 hour. With the load disconnected it is likely the voltage would rise a bit. In fact, from what you have posted, if the Voltage is 12.5 after a sustained 5A load over 4 hours, I'd think the battery is doing well. If you haven't yet re-connected the charger, check the Voltage again, and then put the lights back on for another 4 hours. That should take it down about 50%, to give a Voltage in the region of 12.3. Keep an hourly eye on it as you have been doing while the lights are on, just in case. If it finishes in the right ball park after that, I don't think you have a problem. However, don't leave it in that state, put the charger back on for 24 hours to bring it back to full charge again.

 

I'm no expert: the test was suggested to me by Brambles (who is) about 5 years ago - and proved a suspect battery was well and truly shot as the voltages fell like a brick. It started at 12.91V off load, fell to 12.52 as soon as a 6A load was applied, and 1 hour 45 minutes later it was down to 11.86V! Test terminated: battery dead! Excellent Exide gel battery, but some twit had cracked its case installing it! Identical new battery installed, and was still going strong 5 years later, when we sold the van.

[Jack]

Thanks again Brian, it is clear now, seems by default I was on the right track!

[Derek Uzzell]

The 13.40 and 13.37 figures quoted for the battery’s voltage prior to testing seem suspiciously high.

 

If allowed to rest for, say, 12 hours after charging has ceased, and with any surface charge removed, the voltage of a fully-charged good-condition 12-volt gel battery should be about 12.9V. Much higher than that suggests that either insufficient time has been allowed after charging has stopped before taking the voltage reading, or the surface charge is still present, or that whatever instrument (multimeter, control-panel gauge, etc.) has been used to measure the voltage is over-reading.

 

To quote from the battery-testing advice on a link I provided earlier

 

“...you must first fully charge the battery and then remove the surface charge. If the battery has been sitting at least several hours (I prefer at least 12 hours) you may begin testing. To remove surface charge the battery must be discharged for several minutes. Using a headlight (high beam) will do the trick. After turning off the light you are ready to test the battery...”

 

If a battery’s fully-charged voltage cannot be accurately established prior to testing, it won’t be possible to trust the test results.

 

 

[Brian Kirby]

Derek Uzzell - 2015-08-28 9:07 AM

 

The 13.40 and 13.37 figures quoted for the battery’s voltage prior to testing seem suspiciously high.......................

Yes, on reflection, I agree Derek. It might also be helpful if Jack could confirm what he is using to measure the voltages.

 

It seems I did not suggest adequate time between turning off the charger and taking the initial voltage reading. 24 hours would be a safer allowance. Apologies Jack, but it seems you need to repeat the test after leaving the charger on 24 hours to get it back to full charge, and then leaving a further 24 hours with no load applied before taking the initial reading and repeating the test.

[StuartO]

When I bench tested my pair of Exide G80s a couple of years ago I charged them fully on the bench (using a CTEK charger, said to be gel capable) and the final open circuit voltage was 13.4 or so on each. I left them over 12 hours and measured again, same result, another 12 hours, same result. I wasn't aware you have to get rid of surface charge by discharging the battery, which still doesn't really sem to make sense. I checked the voltage on two or more multimeters.

 

However after a few hours discharging (using 21w lamp, so probably a bit too too slowly) I got voltages of around 12.5 - I can't remeber exactly. The voltage on both batteries stayed at around 12.5 even after 24 hours discharging, so I decided that was a good sign and aborted the test. I have since learned a bit more and would follow Brian's testing regime next time.

 

Interesting, was it not, that they stayed at 13 point something for so long?

[Derek Uzzell]

StuartO

 

On-line received wisdom appears to be that a 'flooded’ 12V battery tested correctly can be considered fully charged if its measured voltage is at least 12.7V, with gel/AGM batteries showing a slightly higher voltage.

 

https://www.google.co.uk/?gws_rd=ssl#q=gel+battery+fully+charged+voltage

 

This view seems to be supported by Exide’s own advice

 

http://tinyurl.com/mtoeplv

 

Other than suggesting that all the multimeters you used were over-reading, it’s hard to know why your batteries’ measured voltages were so much higher than one might anticipate, even after 12 hours had elapsed after charging had ceased.

[StuartO]

Derek Uzzell - 2015-08-29 7:25 AM

 

...Other than suggesting that all the multimeters you used were over-reading, it’s hard to know why your batteries’ measured voltages were so much higher than one might anticipate, even after 12 hours had elapsed after charging had ceased.

 

Faulty multimeters are the obvious possibility to consider but I was satisfied they were OK. If they were OK then the next most likely explanation is presumably some sort of very persistant surface charge, which I failed to clear. Both batteries eventually showed "normal" voltages after partial discharge. Both batteries have performed normally in the MH ever since.

 

 

[Brambles]

Another one of these quirks with batteries.

The surface charge can be quite high on batteries. In a high CCA stop/start starter battery there is actually enough surface charge to start an engine. Anyway that is not directly relevant to your Gel battery but just to indicate the scale of surface charge that can be achieved.

Modern Batteries have very low self charge rates and this self discharge is what is relied upon when waiting hours for the surface charge to dissipate. In a Gel or AGM battery the self discharge is particularly low and it is quite feasible for the surface charge to remain for quite a few days or longer if there is no external load.

Usually you get away with saying leave the battery for a few hours because the battery being tested is old or suspect, hence why it being tested and will have much higher self discharge, lower surface charge and will dissipate fairly quickly. Ideally we really should apply a load for 5 to 10 minutes, but then we do not get the opportunity to see what the self discharge is like over a day or so.

... innit complicated!!

[Brian Kirby]

So Jon, what sort of load should be applied for those 5 - 10 minutes to remove the surface charge on gel/AGM type batteries? Would it be different for flooded? Silly question, I guess, but how can one tell if it has gone? It's a bit like hunting the Snark! :-D

[Brambles]

Brian Kirby - 2015-08-29 5:47 PM

 

So Jon, what sort of load should be applied for those 5 - 10 minutes to remove the surface charge on gel/AGM type batteries? Would it be different for flooded? Silly question, I guess, but how can one tell if it has gone? It's a bit like hunting the Snark! :-D

You need to remove about 1% of the batteries capacity. So for a 100Ah battery that is 1 Ah, so 1 amp for an hour, 2 amps 30 mins, 4 amps 15 minutes.

A 60 watt headlight bulb will draw 5 amps so ...12 minutes.

a 21 watt lamp is 34 minutes.

 

I have found on worn batteries you can do lot quicker and just watch the voltage as it settles. It will immediately drop when you connect the load, and then slowly drop and settle..then you can disconnect, wait a couple of minutes and measure the voltage again.

[Brambles]

Never answered the whole question. Different for Glass or non drip? I don't actually know. I would think it would be much the same and never really given it much thought.