Berniea Posted May 30, 2019 Share Posted May 30, 2019 I currently have 3 X 165ah Victron AGM batteries, a 2kw Victron Compact inverter & charger combined and 2 X 150w solar panels. Most of the time we use the van with EHU but on the odd occasion we don't, and it's these odd occasions that has prompted this post. During our normal usage of 2 TVs. ( Not at the same time), LED lights, occasional light use of 800w microwave (3 mins at the most), and here's the big one ...... A Tassimo coffee machine, the very best we can hope to get out of the batteries is 2 days If we didn't use the coffee machine, which draws about 160ah while it's running for about 45 seconds, I'm pretty sure we could last many more days without the need for EHU or starting/driving the van engine. When the coffee machine is running the indicated battery voltage drops from 13 volts to 11 volts and then quickly recovers back to 13ish volts. This takes about a minute. My question is - are my batteries on the way out ( they are now almost 6 years old). Could the significant voltage drop be because the jumper cables that link the 3 batteries together are approx 8mm in diameter, whilst the positive and negative cables that connect to the van system appears to be about 13- 15mm. Could the inter battery connecting cables be the cause of the voltage drop and if I were to replace the batteries should I increase the cable diameter of these jumper cables to match that of the positive and negative cables? Link to comment Share on other sites More sharing options...
spirou Posted May 30, 2019 Share Posted May 30, 2019 Ideally you'd have the interconnects in same or larger diameter as that's the main bottleneck in your system under such large loads. Whether that plays a role in amount of voltage drop I'm not sure. However, the drop itself isn't that surprising. Does it drop faster than it used to? Link to comment Share on other sites More sharing options...
Berniea Posted May 30, 2019 Author Share Posted May 30, 2019 Its hard to tell with absolute certainty if its dropping faster than it used to, but I'd hazard a guess that it is. Would you suggest that before I go ahead and replace the batteries, I replace all the connecting cables first? Link to comment Share on other sites More sharing options...
Keithl Posted May 30, 2019 Share Posted May 30, 2019 How do you have the three batteries wired? There is the simple way of positive and negative connections to the first then jump the others in parallel or the 'correct' way as shown in the attached picture. Assuming the joining cables are the same length then this way the 'path' through every battery has exactly the same cable length so each battery is experiencing exactly the same load. Keith. Link to comment Share on other sites More sharing options...
Berniea Posted May 30, 2019 Author Share Posted May 30, 2019 I can confirm that they are wired in exactly the same way as the diagram shows. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted May 31, 2019 Share Posted May 31, 2019 Presumably your TVs, microwave and coffee machine are all ‘domestic’ 240V appliances and, when you use them, it’s the inverter that is supplying them with electrical power. (Inverters can place a heavy load on leisure batteries, but the load will be expressed in Amps not Amp-hours.) A follow-up question to your “..are my batteries on the way out ( they are now almost 6 years old)” is “What happened 6 years ago when the batteries were new?” I doubt that the coffee machine’s 45 seconds of high demand is a killer (unless you drink a helluva lot of coffee!) but if nowadays you are getting 2 days of use off-EHU (How do you know you only get 2 days of use?) but (as spirou touches on) you got a significantly longer period of non-EHU use when the batteries were new, the batteries must be considered prime suspects. You could remove the batteries a test each one’s current capability, but 6 years is a good lifespan for a leisure-battery and (as has been mentioned here before) AGM batteries are perhaps not ideal for motorhome usage. Link to comment Share on other sites More sharing options...
Berniea Posted May 31, 2019 Author Share Posted May 31, 2019 Derek - I've only had the van for 19 months but the van and batteries are almost 6 years old. In the time I've had the batteries are probably losing voltage a bit quicker than they used to, but that comment is without actual evidence. After two days of use without EHU the voltage is generally around the 12.4v mark (from 13v). If not AGM replacements, what other types do you recommend? Link to comment Share on other sites More sharing options...
kevina Posted May 31, 2019 Share Posted May 31, 2019 My theory, as I've noticed similar with my gel batteries. VRLA batteries have thicker plates so the surface charge gets pulled down quicker than it does on regular batteries. It will also take longer for the voltage (measured at the surface) to come back up but recover they will and better than those with thinner plates. My gels are 6 years old and get a continuous drain from (mostly) the truma during 2 month ski trips, about 35Ah per day. On the rare occassion there is no load it takes over 4 hours for the voltage to fully recover. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted June 1, 2019 Share Posted June 1, 2019 Berniea - 2019-05-31 8:36 PM Derek - I've only had the van for 19 months but the van and batteries are almost 6 years old. In the time I've had the batteries are probably losing voltage a bit quicker than they used to, but that comment is without actual evidence. After two days of use without EHU the voltage is generally around the 12.4v mark (from 13v). If not AGM replacements, what other types do you recommend? Presumably this means that, in 2017, you swapped your 2014 Adria Sonic Surpreme for the 2013/2014 Burstner Grand Panorama you were considering buying? https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Burstner-Grand-Panorama/47127/#M532758 This is why I asked “What happened 6 years ago when the batteries were new?” as there was no follow-up to the above thread to indicate whether or not you went ahead with the purchase - though it seemed a fair guess that, given the three huge 165Ah Victron batteries, you had changed to the Burstner. I’m not a battery expert, but the asking-price of a new Victron 165Ah AGM battery is around £400 - so replacing all three of your current batteries on a like-for-like basis would cost around £1200. From what you said in your original posting Most of the time we use the van with EHU but on the odd occasion we don't, and it's these odd occasions that has prompted this post. I immediately wondered why you needed an enormous 495Ah of expensive battery capacity, but it’s now plain that you would have inherited the Victron batteries when you obtained the motorhome 19 months ago. If the present 495Ah-potential battery ‘pack’ is only good 2 days of non-EHU use of the type you’ve described, the batteries’ current condition must be considered suspect. As you’ve only 19 months of battery ‘history’ to draw on, and the motorhome’s previous owner might have used the batteries brutally, it’s not easy to decide how rapidly the batteiries’ performance is degrading. Victron suggest a design life of 7-10 years for their AGM batteries https://www.victronenergy.com/batteries/gel-and-agm-batteries but (motorhome forum) received wisdom seems to be that gel batteries are a better choice for motorhome use than the AGM type. So, if you wanted to continue with the Victron brand, you could pick gel Victrons instead. Personally, I’d be asking myself how much battery capacity I realistically needed for the "odd occasions" that I would not be on EHU and I’d tailor the replacement battery ‘bank’ accordingly. I would have thought 3 x 165Ah batteries is massive overkill for what you do and that 2 x 165Ah would be more than adequate - or perhaps 3 x 90Ah Victron gels at an overall cost of around £670. For a less expensive option you could choose not to go gel or AGM and fit 3 Varta 90Ah LFD90 batteries (about £280) or 3 Halfords 100Ah HLB700 batteries (£315). Link to comment Share on other sites More sharing options...
Berniea Posted June 1, 2019 Author Share Posted June 1, 2019 Good assumption Derek ( about the Burstner) but in the end we didn't go for that particular van, we bought a Niesman and Bischoff Flair on an Iveco chassis instead. We paid a deposit on the Burstner subject to it being able to fit in our driveway but when the dealer brought it to our house, and after much trying, it eventually went through our driveway gates. However, the driver almost burned the clutch out when he tried to get it back out! The front wheels were just sitting in one place, sponning! To their credit ( Chelston Motorhomes), they gave us back our deposit. We then looked at rear wheel drive vans and the N&B Flair fitted the bill. We widened our driveway gate posts, but not the incline that caused the Burstner tag axle so many problems) and the N&B reverses in, and drives out without a problem. So.... Back to the batteries. I'll look into the option of switching to gel batteries from AGM and might even consider going completely gaga, and installing an EZA power pack! Link to comment Share on other sites More sharing options...
Derek Uzzell Posted June 2, 2019 Share Posted June 2, 2019 Before you decide to go down the lithium battery road, you might want to read Allan Evans’s forum comments (example here) https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Lithium-Batteries-The-honest-Truth-/47818/ This link is to the relevant webpage on his website http://www.aandncaravanservices.co.uk/lithium-batteries.php Link to comment Share on other sites More sharing options...
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