help required,ref leisure batteries.

[fesspark]

Hello again, just collected my new m,home and it has a Varta 95ah AGM professional duel purpose leisure battery. I intended to add another battery to the bank giving the solar panal more to charge than the one, On looking for this extra bty; I could not believe the price of £192 .00 inc del;, the vehicle I part exchanged,had 2x 90ah varta batteries only costing £75.00 each, Does that mean that the 95ah will be good enough by itself or do I need to add another? The 2 90ah and my 160 w solar Panel kept the power up for our needs.Any help or your thoughts welcomed, Fesspark

[Bulletguy]

 

This poster knows pretty much all there is to know about batteries......it's his job! Could be worth sending a pm or email if he doesn't post over the next day or so.

 

http://forums.outandaboutlive.co.uk/forums/view-profile.asp?action=view&uid=25298

[Brambles]

Fess park,

an awful lot depends on how much power you actually use and deplete the batteries. AKA depth of discharge.

Varta AGMs are supposed to be good but there are many reports of them not giving the performance they should in Motorhomes. with Solar panels. I suspect this is down to constant charging and topping up the charge from the solar panel.

There is no doubt in my mind 2 x Varta flooded will outperform a single AGM of similar capacity to one flooded. In effect with two Flooded v a single AGM you have immediately almost halved the depth you will discharge and therefore at least quadrupled the life.

 

So to simplify, two Varta flooded is far better than a single AGM. As Van is new is it possible the dealer would change the battery for a Varta LFD 90 Ah at no cost to you and then you can purchase another.

Just a side note, the Motorhome builder will probably not be paying any more for the AGM, or certainly not much v a flooded as he buys so many and battery manufacturing costs would be very little more but that does not help us as retail customers.

 

The next option is as you have asked. Will it give you the performance you need. Well possibly depending on how much power you use. Agm can be safely discharged more than a flooded. So where as you had 90 Ah available before you are more like 70 to 75 Ah now. For most people with out heavy loads and diesel space heaters, very long hours of TV etc, it is sufficient. Use it until it starts to fail. If you only get two years so be it. When it starts to struggle immediately replace with two varta flooded.

 

I certainly would not go out and buy a 2nd AGM to pair up with the one you now have as for similar money you appear to be able to get two flooded.

 

This is my pennies worth for what it is ,

 

Jon.

[Derek Uzzell]

fesspark - 2018-05-22 6:21 PM

 

Hello again, just collected my new m,home...

 

It might be useful if you provided details of your new motorhome (make and model) and added those data to the Location field in your forum Profile.

 

There’s always the chance that another forum member has - or is familiar with - the vehicle you’ve just bought and can comment on its electrical system based on hands-on experience.

[aandncaravan]

Bulletguy, thank you.

 

 

I agree with Brambles.

 

The usual advice is that 'paired' batteries should be the same size, technology and the same age. Ideally bought as a pair from the same batch. If you have owned the motorhome a few months, it is possible the battery may be several more months older again, possibly a year and maybe too old to pair with a new battery?

Therefore, like Brambles, I would suggest you use the existing single battery until it no longer delivers what you want and then go for 2 flooded/wet batteries?

 

 

Generally the usual AGM batteries aimed at Motorhomes are typically double the cost of a quality flooded/Wet battery but don't deliver double the life.

 

A Varta LFD90 wet/flooded battery delivers 200 cyles, but the 'double the cost' Varta AGM delivers only 350 cycles.

As Brambles alludes to above, AGM's in Motorhomes are not delivering the claimed life or performance, so probably less than 300 cycles in real terms.

 

 

If you want to pay £200 a battery and require long life, then the Exide ES900 gel delivers about 600 cycles, but they are slower to charge, not good at powering high current devices and don't like the temperatures of places like Southern Spain. As per most Gel batteries.

If you always holiday in Norway, only camp with one LED light and no TV, they could last for years

:-S

 

 

If you want ultra long life, then Victron Energy make a Gel battery with 1,500 cycles, but it costs nearly £300.

It's BIG sister delivers 2,500 cycles at 50% Depth Of Discharge (DOD) and has a 20 year design life, but you can probably guess they are not cheap.

Victron Energy have also recently announced a 'Super Cycle' battery that is GUARANTEED to discharge to 100% DOD and still give 300 cycles at that depth of discharge. I think it delivers 1,500 cycles in normal use, the usual 50% DOD.

Don't know the cost but around £350? A bargain next a £2,000 lithium with similar cycle life.

 

 

 

[fesspark]

Hello Derek, another Burstner ,this time the new 680G large lounge no beds only the drop down, Cheers Fesspark

[lennyhb]

Having had AGM's die in 18 months in the last van in the current van I replaced the AGM with 3 x 78a/h Gels.

If you have an Elecktroblock it will only have settings for AGM & Gel. Alan will probably say the LDF90 is OK on the Gel setting but the latest EBL's have an absorption phase of 16 hours probably a tad long for an LDF90 & the AGM setting the volts are a bit high at 14.7 with an absorption time of 4 hours.

Me, I would ditch the AGM and fit Gels.

[aandncaravan]

Lenny, I fully understand why you say that and with another more powerful charger set-up I would probably agree with you, but on this charger the existing 4 hour 'boost' timer isn't adequate when a second battery is added.

 

The Schaudt charger you refer to is only '18a' peak power unit, which it rarely achieves.

Within 20 minutes of starting up, on 2 x LFD90's down at 50% charge, the charge rate will drop to about 12amps as it warms up and the electronics back down the charge to keep it cool.

Within a further 2 hours charge it will be down to about 8 - 10amps and reducing further.

 

So by by the time the old style '4 hour' timer drops down to it's Float 13.7v level, the batteries would have only had about 45amps put into them. The remaining 45 - 55 amps being applied at a painfully low 13.7v with little more than 'trickle' current.

These are not exact scientific figures, but not far off, see note at the bottom.

Therefore this 18amp charger can take a further 48 hours to bring the batteries up to full.

The charge time of 2 days, showing how inadequate the existing '4 hour boost charge' is.

 

However, you can see how a single battery would be pretty much fully charged in 4 hours, which is what it is designed for, demonstrating how the addition of a second battery doesn't lengthen charging time by double as some might think, but by a factor of 10.

 

When Schaudt increased the 'boost' charge timer from 4 hours to 16 hours it helped bring the charging time of two batteries down to about 10 hours. Therefore the new Lead/Gel sixteen hour timer is just about perfect for the Varta LFD90/Bosch L5, as the last few hours current is very low.

 

But in anycase the Powerframe Bosch L/Varta LFD ranges have a better tolerance of higher charge currents/voltages. The Powerframe EFB range is now ratified as a full Stop Start battery to replace AGM's, happily accepting the 14.8v of any AGM it replaces.

 

The Bosch/Varta is a Silver technology battery, it is even higher technology than the Ford Silver batteries that were designed to 'fast' charge at up to 16v in Ford Transits, Mondeo's and other vehicles that had the intelligent Alternator.

 

These Ford Silver batteries have been shown to still have long lives, even at higher charge rates of both Voltage and current.

Conventional batteries have been shown to have very short lives when fitted in these same Ford vehicles, showing how effective the Silver technology is. Add in the low corrosion characteristics of Powerframe and you have one very tolerant battery.

 

You could even use LFD's on the AGM 14.8v, 4 hour 'boost' charge profile, but you can see two AGM batteries would take forever, just as Wet Leads do in the example above. One of the reasons we have said the rushed adaption to provide AGM capability, was ill thought out.

No doubt in my mind this is a contributing factor in AGM battery life, as people are not expecting their AGM's to take to days to charge, thinking an overnight charge is enough, when even two overnights wouldn't be enough.

 

 

All explained in more detail on our 'How a Charger works' webpage -

http://www.aandncaravanservices.co.uk/how-does-a-charger-work.php

 

 

While the Lead gel setting might not appear to be so ideal for conventional batteries, the effects are generally offset because the people fitting these are probably less battery savvy. Therefore more likely to go for 2 x 110Ah batteries which will actually need a long 16 hour boost charge time. Not just because bigger batteries will need 14.4v for longer, but because the batteries are less efficient so draw more amps overall.

 

Note :

While we talk about two Varta LFD's 'needing' 90Ah to recharge in the example above, it isn't that simple because they are not 100% efficient, so more likely to need 100Ah.