Leisure Batteries (again!)

[ega95jch]

Hi folks

Would any of you who are knowledgeable about these things pleasetake a look at this?:

12V GEL 135 AH LEISURE BATTERY.BOATS/CARAVANS on eBay (end time 17-Jul-10 11:06:42 BST)

It appears to be a Lucas (reputable make?), and I'm considering getting one, as it looks like a very good price for a gel battery. My van originally came with a mega-expensive 130Ah Sonnenschein gel, which I replaced with lower-powered lead acid types over the years. They were always unsatisfactory, and never lasted long - perhaps because of the lower power (around 85Ah), and maybe because I think I may have an ongoing charging issue. The cost of the equivalent 130Ah Sonnenschein is around £320 (ouch!)

Any 'gen' or other wisdom gratefully received.

Cheers
John

 

[Firefox]

The generally accepted view seems to be go for low cost lead acid and not bother with Gel.

Check out this link:

Sterling Power Products: What is the best battery to use for an auxiliary charging system?

It's very detailed but gives lots of information. I'd also be suspicious of any claim that the batteries can be used for starting and also deep cycling as per your ebay advert.

Another thing about those batteries on ebay is the weight. 48 kg! You can get an equivalent capacity lead acid for half that weight. Unless you have a big rig and it doesn't matter, they will eat into your payload.

If you think you may have a charging issue, why not invest in a better charger instead. It will make a big difference to battery life and performance

 

[mildred]

Battery charging / Gel bats

why not invest in a better charger instead. It will make a big difference to battery life and performance

I second this. The work I'm doing ... currently ( ) ... has demonstrated very clearly that charging and maintenance is absolutely the key to good performance from batteries, whether gel or flooded lead acid (or as mentioned in another thread; "wet" ni-cads). The standard automotive alternator system is pretty brutal and is optimised for replacing the power taken to start a vehicle, not the type of load we typically put on "leisure" batteries.

This is what is behind the Sterling philosophy - by battery to battery charging they can control much better the charge characteristics, even at the cost of the inherent inefficiencies, with a better outcome than direct charging from the alternator.

A good thing about some of the solar charge controllers now available, especially the higher current ones - even if you don't need the higher current (another thread somewhere or other!) - is that there is a considered three or four stage charging regime which will benefit the batteries considerably.

Oh yes - and has been said before - the little traffic light battery charge indicators only give you a rough idea of charge, and a misleading one if the battery is in use, or has recently been charged, or there are multiple batteries in the circuit.

You can do it electronically, but it requires a degree of circuit sophistication, better is a hydrometer (which you can't use with a gel) - but there are even pitfalls with that: the specific gravity may indicate 100% State of Charge (SOC) - but 100% of what exactly? Is the bottom inch of the plates so badly sulphated that the area available for chemical reaction is reduced and so your AH rating is diminished?

Unless you're planning to invert your van, or you need the physical handling characteristics of gels, or you can get good condition gels very, very cheaply, flooded lead acid is the battery of choice as a compromise between cost and function.

Mild Red

 

[ega95jch]

Mildred and Firefox

Many thanks for your wisdom on this one. It would appear that a gel confers no real advantage - it's all marketing spin. So that stuff in the advert about gels lasting much longer is all bull****, then? I'd seen the Sterling page before - there's also this one, which you may find interesting:

Battery Tutorial

I charge my battery via the 240v hook up - the battery never seems to get any charge from the alternator, which leads me to believe that there could be a problem with my van's charging system. Further, I think it may overcharge when connected to the mains. Please forgive my lack of electrical knowledge here. When hooked up, the voltage on the LCD panel slowly builds (as one would expect) until 15.1v is reached, when the display starts flashing. I've been told this is too high, and it should cut off at 14.7v. I'm also not convinced that the charger switches off, and may continue charging and making the battery either overheat or gas the electolyte away. Can I test this? The charging device is a proprietary Westfalia one, and costs absolutely silly money to replace.

When the last gel battery I had failed, it used to get horribly hot (I mean really hot). Since I've been using lead acid, they don't heat up, but I seem to be topping up electrolyte lost by gassing constantly.

Firefox - to be fair, I don't think the advert says anything about it being 'dual purpose' - it seems to be being sold as a purely deep cycle battery. However, if Sterling are to be believed, all that stuff about this battery lasting 500 cycles as opposed to 200 for a lead acid is all tosh.

I'm probably going to look at a wet cell battery now. Should I get 130Ah, as per the van's original spec? Would more/less power be an option? I do have a power hungry Eberspaecher, so I guess the more power the better?

Any further musings/wisdom would be much appreciated!

Cheers
John

 

[maingate]

Hi there,

When you are charging via the hook up, put a multimeter across the battery terminals. It should be more accurate than the van voltmeter.

Switch off the 240 volts and let the battery stand for one hour. Write down the voltage. Leave it 24 hours and check the battery voltage again.

If your voltage is not holding steady, you either have a duff battery (batteries) or something is possibly draining them, like an alarm.

Different vans have different electrical systems. For instance, on mine, I leave the fridge door open when not in use. It is possible for the fridge 12 volt light to be on unless I switch it to the off position on the 3 way selector.

Have a good look round the van. Do you have a TV signal booster in a cupboard? That has drained many a battery (including mine)

 

[Firefox]

Last line of advert says:

A Dependable Deep Cycle Power Storage Solution for Standby and Starting Purposes

I think that's misleading.

Possibly if your alternator is not charging at all your split charge relay is not closing. I've just got my system on an on/off switch. Never fails to work as long as I remember to flick the switch but it's part of my routine on long journeys.

I've modified a Zig voltmeter so I can check at any time what the voltages are for car and aux batteries so I know if it's charging properly. I've also got a good digital multimeter I use to cross check the voltages. I've noticed my 240V charger charges to a higher voltage than the alternator. I think more like 14v rather than 13v. The aux batteries also hold a lot more charge and lasts longer after a 240V charge.

My 240V charger is simply an electronic smart charger from Halfords, about a £50 charger. So far it has kept two 110 Ah aux batteries operating nicely for a year. I'm no expert in this but I reckon the 240v chargers original equipment fitted by motorcaravan makers are no better than my charger especially the budget makers. Maybe the classy German makes have better equipment which give charging regimes like the Sterling ones to really top up a battery, but I don't know. They never seem to make a song and dance about what chargers they fit. It's an out of sight item so they can cut corners as charging regimes are not what most buyers know about. The average buyer is more concerned about kitchen equipment, awnings or air conditioning ;-)

 

[maingate]

Just a bit of general info for anyone.

I have a very old 240 volt battery charger. At times it peaks out at nearly 15 volts. This sort of voltage now and again is good for cleaning the plates inside the battery, as they get covered in Sulphides (or is it Sulphates). I would not recommend this high a charge on a regular basis though. Just a burst for an hour or two is sufficient.

 

[mildred]

I charge my battery via the 240v hook up - the battery never seems to get any charge from the alternator, which leads me to believe that there could be a problem with my van's charging system.

That really needs looking at before you invest further in any type of battery - faults could result in you discharging the "leisure" battery when parked up. Even fairly cheap digital test meters have a 10A DC measurement capability - if you take care about how you attach the leads to the existing connectors that would tell you if you have a charging and/or discharge problem.

Further, I think it may overcharge when connected to the mains.[...] When hooked up, the voltage on the LCD panel slowly builds (as one would expect) until 15.1v is reached, [...] I've been told this is too high, and it should cut off at 14.7v.

Here are the charging curves for the 130AH Sonnenschein gel (as originally fitted) per cell

So, for certain types of charging, at freezing point, 15V for the whole battery would be OK. However - for normal conditions, yes, 15V is too much.

However, you say that you have now changed to an "ordinary" lead acid. Whilst flooded lead acids can, in general, take a higher voltage, again 15V is probably too much - without knowing the exact model and spec of what you're using I can't be specific, but around 14.5V would be more typical. Yes, these half volts are critical.

There is a particular case in which you would take them to 15V and even higher, but that would be unlikely to be done in the van - it's really a work-bench procedure.


Very few motorhome chargers are going to have the complexity to recognise from the charging parameters exactly what sort of battery is fitted, and so I think Firefox is on the nail with the suggestion about using a good quality dedicated charger.

I'm also not convinced that the charger switches off, and may continue charging and making the battery either overheat or gas the electolyte away. Can I test this?

Yes - the cheap digital multimeter will do that for you, and as a rough guide the van voltmeter or a traffic light type indicator will at lest tell you if the charger is still charging.

Since I've been using lead acid, they don't heat up, but I seem to be topping up electrolyte lost by gassing constantly.

That's part of the necessary chemical exchange - there are clever "hydrocaps" that return the water to the cells, but the important thing is that you are monitoring the levels and replacing as necessary.

Should I get 130Ah, as per the van's original spec? Would more/less power be an option?

You need to understand how much energy you are taking from your battery and what your arrangements will be for replacing that. There are various on-line calculators that will assist you. If your charging capability is low then, bizarrely, you may be better off with a smaller capacity battery - you might not be able to pull back a big battery to a reasonable state of charge and it will start sulphating, but a small 110AH , regularly cycled to 100% SOC, will give better service. With regular access to a mains hook-up, possibly solar panels and a sorted alternator system I'd say go as big as you can fit.

It's controversial, so I won't take a stance - but batteries in parallel can give problems - usually people fit them merely by running a pair of cables to the extra one, and I have seen this illustrated in several magazine articles. This will result in the new battery getting a lower state of charge, and it may mess up your charging to some extent.

Probably, for ideal fitment, one should use "Y" leads, and of course the batteries should be matched in capacity and electrical characteristics.

Those of an experimental frame of mind could try measuring the potential across the extra link cables and working out what's happened to the power ...

Any further musings/wisdom would be much appreciated!

You asked for it!

Mild Red

 

[cipro]

There is lots of debates on batters on this site and on www however to me still all confusing I hope mine dont let me down

It all does my head in charging, regulating, zigy thing 12.v too 15 some thing.

sorry this post no good to you or anyone else but there must be others
that just drive stop drink and sleep and do it again the next day
and cross there fingers everything keeps working

Happy touring

 

[ega95jch]

Firefox, Mildred and Maingate - many thanks, brilliant stuff, please keep it coming! Cipro - hang in there - we might both learn something!

Firefox - I stand corrected on the leisure/starting point on the advert. So, my course of action now is to get a multimeter. Any advice on this, as I haven't a clue! Something cheap and cheerful from Maplins? I'll start off by taking some measurements from the existing battery, which is a Varta 75Ah, kindly given to me about three years ago. I'm pretty sure it's knackered, but it'll be interesting to see.

I'm thinking that because of the current draw from the Eberspaecher heater, the more power the better so I'm thinking of getting a wet cell around 130Ah. Any caveats here? I don't have room for a second battery, otherwise I'd seriously consider that. The existing batter bay, however, is quite wide and deep, but not that high, so I'll have to be careful there.

Because the van was designed around a gel battery, there's no venting, so I've devised my own. I've got a couple of plastic tubes connected to elbow joints which connect to the sides of the battery. These are routed to the outside through the vent in the gas locker. I understand that the battery gas, like LPG, is heavier than air, so presumably the pressure generated while gassing will push the 'exhaust' out of the vehicle quite efficiently? This way I can safely use a standard wet cell battery. As a matter of interest, presumably gel batteries don't gas at all, so don't need venting. However, in the case of a 'sealed' wet cell, how are they vented? Or is there such a low gas output that it doesn't matter?

Sorry if this seems a bit rambling, but picking the brains of you experienced people may benefit not only me, but other members who are not so well up on this stuff!

Cheers
John

 

[maingate]

Hi ega,

When I wanted a bigger battery for my last van, I measured the dimensions of the battery compartment and then googled for leisure batteries.

If you do this, you can find out the dimensions of the batteries and work out the biggest that will fit. Be sure to work out that the + and - posts on the battery will be the correct way round as there is often not enough length on the battery connections to swop them round.

As for sealed wet batteries, I do not know if they `gas` or not.

As for a multimeter, try Maplin. A few places sell them for less than a tenner. Read the instructions first because some of the cheap ones can be useless once you have made a mistake.

 

[ega95jch]

Thanks Maingate, I'm on the case with the multimeter now. Bearing in mind my possible charging issue, I think I'm going to go for a wet cell, and monitor and measure its performance very carefully. I'm tempted by a gel, as they're lower maintenance, but apparently are much more sensitive to any charging deficiencies.

Will report back on this project!

Cheers
John

 

[robjmckinney]

Wet Cell

If you are going for wet cells why not try Ebay, I got a 180 amp for under a £100 new, delivered, very important considering the weight. You can get upto 300 amp ones if you have the room and don't have issues of balancing or lazy battery. They are deep cycle leasure battery, all measurements are given so you can fit the room you got with the largest size!

 

[ega95jch]

That really needs looking at before you invest further in any type of battery - faults could result in you discharging the "leisure" battery when parked up. Even fairly cheap digital test meters have a 10A DC measurement capability - if you take care about how you attach the leads to the existing connectors that would tell you if you have a charging and/or discharge problem.

Right! I've now got a multimeter. As an electrical numpty, I'd really like some advice on how to use it!

Cheers
John

 

[maingate]

Your multimeter has a DC voltage scale . You need to use the one with the number 20 (ie 20 volts max.)

The symbol for DC volts is _____
........

Black lead is negative, red is positive. You can also put the black lead to earth if necessary.

A fully charged battery can be 14 volts. Under 11 volts means it is flat and might not even recover if charged. Check your battery voltages (engine and Habitation). If they are being charged, the voltage will rise.