stevec176 Posted January 17, 2021 Share Posted January 17, 2021 I am considering swapping over to a Lithium battery and would like advise please. I currently have 2 x Banner 110 amp batteries and a 100 watt solar panel so my questions are, What size Lithium battery would I need and would I need to make changes to my system. I don't have an Inverter and don't do much camping with using EHU so batteries will mainly be used for TV, lights, charging phones etc. On the back of this months MMM is an advert for Eco Tree Lithium batteries and a 110 amp is £749. Any advice opinions welcome please. My main reason for considering changing batteries is saving weight. Each of my current batteries each weigh 23.4kg and the Lithium is 13.7kg so a total saving of 33kg. Link to comment Share on other sites More sharing options...
spirou Posted January 17, 2021 Share Posted January 17, 2021 stevec176 - 2021-01-17 4:47 PM What size Lithium battery would I need and would I need to make changes to my system. . . . Eco Tree Lithium batteries and a 110 amp is £749. The necessary changes to the system depend on what the current system is. Specifically the EHU charger, solar charge controller and B2B (alternator charging). Before you go any further with this, please take a good look at those as it might be a very expensive and dangerous mistake. Also worth taking a look at your cable sizes. Can't do much with 100A continuous current rating if your tiny cables will melt after a few minutes of passing 50A. Regarding size.... yes, a 110amps seems a good enough fit for relatively light use outside of winter months. Regarding the Eco Tree battery... the price & datasheet do not inspire too much confidence in any superior quality, seems to be aimed at the lower end of the spectrum. The thing that worries me particularly is that it does not mention low temperature charge cut-off. If you think you will never make the mistake of charging when battery temperature goes below 5°C it might be OK, but what happens when you sell the MH to someone down the line and they destroy the battery on the first cold morning? just an opinion... Link to comment Share on other sites More sharing options...
stevec176 Posted January 17, 2021 Author Share Posted January 17, 2021 Thanks Spirou, That all sounds more complicated than I thought, I have no expertise in electrics so might wait until I can actually talk to somebody who knows what they are doing. Link to comment Share on other sites More sharing options...
plwsm2000 Posted January 17, 2021 Share Posted January 17, 2021 I recently swapped 2 gels to a Lithium for the same reason. The gels were 27kg each so 54kg combined. At the same time, we had self levellers fitted (around 45kg) and by losing the jack and ramps, it is about weight neutral. As has been said, you MUST have a B2B with a Lithium profile (same for the solar controller). I fitted a Lifos that has built in freeze protection but you may also need to fit temperature sensors (for the B2B and for the solar) to limit charging at high temperatures. I am sure you have read the sales pitch for Lithiums that they have the same usable capacity as two similar sized Lead acids. It is correct to say you can run Lithiums down to 80-90% but only 50% for Lead-acids (without damage), but you do lose the "emergency reserve" of the lead-acids. This could be handy if you say get stuck somewhere without EHU, or your charger fails at a bad time. With Lithiums, the power just stops dead but the Lead-acids could still be used below the 50% if you had no other option. I still don't regret changing to Lithium though. Link to comment Share on other sites More sharing options...
Hans Posted January 17, 2021 Share Posted January 17, 2021 Sorry Spirou but i have no clue what you are saying about the present cables. And Amps flowing in present cables and a LITHIUM BATTERY. PLEASE EXPLORE FURTHER. Link to comment Share on other sites More sharing options...
spirou Posted January 17, 2021 Share Posted January 17, 2021 A lithium battery is capable of much higher sustained currents than lead. And if whoever built the MH was saving weight everywhere possible, you might have quite thin cables that would not be too happy with potential high currents flowing through them. On our first van most cables were as thin as 4mm2 while 6mm2 was used for charging via alternator (also, no B2B) and 18A mains charger. I'm quite sure it was not a total outlier either. I'd say you're looking at 10 and 16mm2 cables used on the better made MHs. I'd be quite surprised to see 25mm2 or more on a standard MH originally designed for lead batteries. Current rating of a 4mm2 cable (depending on source, method and conditions) is between 35 and 46A. 6mm2 cable is rated between 40 and 59A, 10mm2 @ 54-81A, 16mm2 @ 73-109A, 25mm2 @ 95-180A. In the case of OP, the specified battery is capable of 110A constant discharge current and 54A charge current. Now, look at the cable current numbers above again and imagine this battery in our s**tty first van. *-) I'd be reasonably happy with it in our current van but still might need to upgrade a cable or two, plus the 25A mains charger which would definitely overheat very soon. Not to mention it has no lithium charge setting. A straight drop in replacement (as advertised) these things are most definitely not. Link to comment Share on other sites More sharing options...
Conrad Posted January 17, 2021 Share Posted January 17, 2021 I can understand the electrical benefits of lithium batteries, but not so sure about weight saving. In the scheme of things 33kg isn't that much, and main cause of the high fuel consumption in our 'vans is because they are shaped like bricks! Air resistance is main problem, not weight, once you are rolling along. Link to comment Share on other sites More sharing options...
stevec176 Posted January 17, 2021 Author Share Posted January 17, 2021 I'm looking at weight because last time my van was weighed it weighed 3540kg and we've now got 2 electric bikes each weighing about 20kg so getting rid of 33kg would be helpful. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted January 18, 2021 Share Posted January 18, 2021 spirou - 2021-01-17 4:29 PM The necessary changes to the system depend on what the current system is. Specifically the EHU charger, solar charge controller and B2B (alternator charging)... Steve’s vehicle is a Rapido 665F Fiat Ducato-based model bought new in 2016 and his first motorhome. Ignoring the solar panel, a 2016 665F’s electrical system will match that of my 2015 Rapido 640F model and comprise the CBE-made equipment shown on this advert https://magnummotorhomes.co.uk/shop/electrical/power-supply-units/cbe-pc180-kit-electrical-control-unit/ The battery-charger is a CB516 model having a 16A output and selection of wet-acid or gel charging settings. https://tinyurl.com/yyys2zc6 In 2016 Rapido’s standard leisure-battery was a Banner “Energy Bull” 95751 100Ah (K20) https://www.bannerbatterien.com/en-gb/Products/Starter-Batteries/Energy-Bull/226-957-51 and there was a Rapido buyer (expensive) option to add a second 95751 battery. The standard CBE electrical system was NOT upgraded when a second battery was specified. Comments by the late-Allan Evans on on lithium batteries for motorhomes/caravans can be found here http://www.aandncaravanservices.co.uk/lithium-batteries.php The Rapido 665F model was quite large (7.39m in length) with an ‘unladen weight in running order’ of 3005kg. The 2016 Rapido brochure indicates that It could be ordered new on the Ducato ‘light’ camping-car chassis (3500kg or 3650kg) or on the ‘heavy’ chassis (4250kg or 4400kg). Steve’s motorhome is on the 3500kg chassis. https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Motorhome-Weight-Limits-what-is-your-opinion-/46483/ As Steve’s motorhome’s weight is now so critical that a saving of 33kg is considered essential, it might be preferable to upgrade the 3500kg chassis-weight to 3650kg or higher than go down the lithium battery route. Around 40kg for a pair of e-bikes mounted on a rear bike-rack will place extra load on the Rapido’s rear axle and rear tyres and fitting a ‘semi-air’ system to the rear suspension (and perhaps higher rated tyres) may be desirable/necessary to counter this. An upgrade to (say) 3800kg via SVTech and fitting a semi-air system might well be no more expensive than ‘going lithium’. Obviously there are driving licence implications in uprating above 3500kg, though Steve does have the requisite C1 entitlement. https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Rapido-Re-Plating/47492/ Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted January 18, 2021 Share Posted January 18, 2021 stevec176 - 2021-01-17 3:47 PM I am considering swapping over to a Lithium battery and would like advise please. I currently have 2 x Banner 110 amp batteries and a 100 watt solar panel ........ I don't have an Inverter and don't do much camping with using EHU so batteries will mainly be used for TV, lights, charging phones etc. ........ My main reason for considering changing batteries is saving weight.. 'Morning (and my apologiies for cropping your post) Possibly a daft question, coming as it does from a relatively experienced MHer.. but do you really 'need' the second battery? We used to pitch off-grid for days at a time, sometimes for up to a week, with just a single battery and with no (proper) solar panel set up (admittedly, with minimal TV use tho'). If it is about weight saving then losing that (possibly surplus to requirements?) second battery would be an option I'd look into? ( that's assuming you aren't also just lugging around loads of "must have" clobber that never gets used, like a lot of us have/do? (lol) ) I don't think I would be going down the route of having swathes of the van electrical system uprated just to accomodate a new battery. :-S Link to comment Share on other sites More sharing options...
Derek Uzzell Posted January 18, 2021 Share Posted January 18, 2021 In a forum thread in late-2019 Steve said ...I have the TV on and lights for 6 - 7 hours without any problems when away during the winter months...” We bought our first motorhome in 1998. It was a 1996-built Herald with a single Varta leisure battery having (if I remember correctly) a 70Ah capacity. In those days it was anathema for me to actually ‘pay’ for motorhome services like a 230V hook-up and we managed with the Varta battery for the 6 years we owned the Herald. But we never had a TV, never stayed in one place for more than a couple of days, regularly drove for sufficiently long distances that the Varta battery got recharged, and did not use the Herald from November through March. Plainly, if Steve is using his motorhome during the winter months, is having a TV and lights on for long periods (and presumably the heating system too) his leisure batteries will become well discharged and, if he’s not relying on regular use of 230V hook-ups or driving a lot, he will need a fairly high battery capability plus the solar panel’s output. The rationale behind replacing the pair of 100Ah Banner wet-acid batteries with a single 110Ah lithium battery is that the lithium battery will save 40kg of much-needed weight and, because it can be discharged more deeply that the Banner batteries, will have in practice an equivalent capacity. However, the electrical system of Steve’s motorhome was not intended to include a lithium battery, so there will be significant costs additional to the £749 mentioned in this thread’s original posting to allow a lithium battery’s potential to be fully (and safely) exploited. Link to comment Share on other sites More sharing options...
stevec176 Posted January 18, 2021 Author Share Posted January 18, 2021 Thank you all for your thoughts and suggestions, especially Derek who never let's us down, I now know a lot more about my electrical system than before. It would be nice if when one bought a new van it actually came with all the relevant literature for all the systems. We try not to carry too much useless junk, don't even have a spare wheel, so there isn't much we can leave behind. Having only a single battery is an option to consider though. Unfortunately it looks as though changing to a Lithium battery just isn't going to be cost effective. I think I'll have to empty the van and only put in the essentials, including the bikes which go inside the van and then get the van weighed again. I don't like the idea of being over weight but at least I do know roughly what my weight is if I do get stopped. Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted January 18, 2021 Share Posted January 18, 2021 Please disregard my earlier post because I totally misread your battery usage! (I read- " ..don't do much camping WITHOUT using EHU.." instead of what was actually typed- " ..don't do much camping with using EHU.." :$ Sorry. Link to comment Share on other sites More sharing options...
Brian Kirby Posted January 18, 2021 Share Posted January 18, 2021 Which seems to me to raise a further question. What is taken from the battery, whatever its chemistry, must be replaced. I know nothing of the charging needs or characteristics of lithium batteries, other than "standard" chargers are not optimal - from which I assume that vehicle alternator outputs are also sub optimal. I just have a slightly uneasy sense that Steve may be looking for the electrical equivalent of perpetual motion. :-) If the van is not driven for a sufficient time to fully replenish the battery charge, and power consumption when stationary consistently exceeds the charge gained while driving, the state of charge, while fluctuating up and down, will be heading inexorably down - until it is in the danger zone. Under those circumstances I think Steve might be wise to do some arithmetic on how much, in Ah, he uses while static, and how much, realistically, he puts back into the battery while driving (bearing in mind his infrequent use of EHU). Having a large capacity battery bank means ample available power for the van, but also imposes the need to drive for much longer periods between stops so as to put back what has been taken out. The available alternatives appear to be to reduce consumption while stationary (which, in winter, with its long dark evenings and low temperatures, is difficult), to drive for longer between stops, or to use EHU more often. Solar is unlikely to provide much more than is consumed during winter daylight hours - and on dull days won't even achieve that - so realistically, the majority of the recharging has to be from the alternator, and that is likely to be compromised by other power demands from recharging the starter battery and powering whatever auxiliary equipment is also in use (e.g. wipers etc.) used in the van, plus the cable sizes between alternator and habitation battery. Keep it simple might be the best approach. Perhaps considering, instead of the lithium battery plus enabling modifications, at least as a paper exercise, the relative costs of uprating the MAM of the van to eliminate the need for the weight saving, and then replacing one or both batteries with lead-acid plus, if necessary, paying more frequently for EHU - the additional cost of which is not that great in the overall scheme of things. Link to comment Share on other sites More sharing options...
spirou Posted January 18, 2021 Share Posted January 18, 2021 Brian, a lithium battery will recharge the same Ah much faster than lead. If supplied by a capable charger/alternator. A lead battery discharged about 30% (reasonable after a winter night) might start of with 20-30A charge current but will quickly drop to half that in a matter of minutes possibly. Either/or because the charger overheats and due to internal resistance. Lithium does not have that problem until nearly full. Which causes problems elsewhere as the alternator/charger/cables get hammered unless properly sized and managed. Fed directly from an alternator (no B2B to moderate) it will burn out said alternator very, very quickly. I would dare suggest that most standard chargers were not designed to run at full power for hours. Because of rising internal resistance they didn't have to. Allan Evans saw plenty of such cases where people simply added a second battery and made their chargers work hard for longer periods. With lithium it's as if you're adding 3 or 4. Link to comment Share on other sites More sharing options...
stevec176 Posted January 18, 2021 Author Share Posted January 18, 2021 One last question, how do I know if I have a smart alternator fitted? I'm assuming I haven't but curious to know how I would know other than possibly looking on the alternator for some kind of reference details. Thanks and definitely given up the idea of a Lithium battery. Link to comment Share on other sites More sharing options...
Brian Kirby Posted January 18, 2021 Share Posted January 18, 2021 spirou - 2021-01-18 12:04 PM Brian, a lithium battery will recharge the same Ah much faster than lead. If supplied by a capable charger/alternator. A lead battery discharged about 30% (reasonable after a winter night) might start of with 20-30A charge current but will quickly drop to half that in a matter of minutes possibly. Either/or because the charger overheats and due to internal resistance. Lithium does not have that problem until nearly full. Which causes problems elsewhere as the alternator/charger/cables get hammered unless properly sized and managed. Fed directly from an alternator (no B2B to moderate) it will burn out said alternator very, very quickly. I would dare suggest that most standard chargers were not designed to run at full power for hours. Because of rising internal resistance they didn't have to. Allan Evans saw plenty of such cases where people simply added a second battery and made their chargers work hard for longer periods. With lithium it's as if you're adding 3 or 4. Thanks Spirou. Link to comment Share on other sites More sharing options...
rayc Posted January 18, 2021 Share Posted January 18, 2021 stevec176 - 2021-01-18 12:13 PM One last question, how do I know if I have a smart alternator fitted? I'm assuming I haven't but curious to know how I would know other than possibly looking on the alternator for some kind of reference details. Thanks and definitely given up the idea of a Lithium battery. I think that the Smart alternator was introduced on the Ducato only on the ecojet 150bhp Euro6b model. "The 150hp motor can also be had in EcoJet trim, with Start&Stop, a smart alternator, electro-hydraulic power steering and an Eco function, to reduce fuel further. " https://www.autoexpress.co.uk/fiat/ducato So if before Euro6d it will not be a Smart alternator unless it is the 150 ecojet model and i don't believe any motorhome manufacturers built on it. Link to comment Share on other sites More sharing options...
mikefitz Posted January 18, 2021 Share Posted January 18, 2021 A far better option for anyone considering a 'drop in' lithium battery is, https://www.alpha-batteries.co.uk/victron-energy-100ah-lithium-superpack-battery-bat512110705/ or, https://sterling-power.com/products/lithium-batteries Either of these batteries have a continuous maximum charge capability of 50 amps. A continuous 50 amp discharge for the Victron and 100 amps for the Sterling ( a slightly more expensive Victron is available with a 100 amp capability). The continuous discharge capability is important to anyone using high power inverters. Both have temperature protection to prevent charging below 0 deg C, but discharge is allowed down to -20C. All the lithium batteries sold for the leisure market have a built in management electronic module (BMS), with a solid state 'computer' and solid state switches to prevent over charge and over discharge that could damage the battery. Possible damage could be venting of noxious gases and overheating and fire on connected wiring and units. This BMS is a very necessary but expensive part of the battery. Cost reduction and perhaps reliability of this component that should be considered when factoring in the purchase cost of the battery. A 'cheap' battery may have a low cost BMS module. Some indication of quality of the BMS is related to the continuous current capability of the battery, The Eco Tree battery has a recommended charge and discharge of just over 20 amps, the maximum values will not be continuous rated. It should be noted that the built in BMS protection is just that, protection, The BMS does not control charging, its a fail safe for the battery. Charging current should be limited by the charging sources. Unfortunately most motor home 12v charging systems are poorly designed and rely on the natural 'internal charge control' that lead acid batteries have, together with the current limiting properties of undersized cables. Changing to lithium often requires the battery chargers and associated cables to be up graded, and integrating into the existing 12v control systems can be challenging. A correctly installed quality lithium system is a very useful upgrade, especially if high power inverters are part of the system. However for many motor home users with modest off grid power requirements, traditional lead acid batteries, are still effective. Weight saving of lithium is often offset by the need to have additional or replacement chargers and cables. Cost saving is debatable, lithium batteries suffer from natural aging of the chemistry and the long term reliability of the BMS electronics is a factor, its considered 5 to 10 years is the projected lifetime. With a dual battery lead acid battery pack, reverting to a single battery and working it harder may be a solution to weight saving. Even replacing a single battery every 18 months may be cost effective. Mike Link to comment Share on other sites More sharing options...
silverback Posted January 18, 2021 Share Posted January 18, 2021 stevec176 just to add my two pennath I am not an expert on electrics! but I have done what you are wanting to do, I did it 2 month ago and only had one trip out, I was assured they were a drop in replacement for lead acid, It is paramount that the lithium have a battery management system (BMS) this does everything needed make sure it also incorporates low temp charge cut off at zero degrees, so it will not charge if the internal temp of the battery is at zero. (this is overcome by having them inside) they also have bluetooth nothing has melted, nothing has blown up and I have not changed anything. the normal battery charger for lead acid does its stuff, the alternater split charge relay does its stuff, I am well happy with them, the only thing I find disconserting is the fact that they always stay above 13v until 10% left then they drop off a cliff! and monitoring them in % terms takes some getting used to, because you are looking at % rather than volts, I got them from here https://www.ksenergy.co.uk/ and all the info also is there, don't be put off with all the doom merchants that your wiring is gonna melt it isn't (well it hasn't yet) and there is no need for a B2B I have found out so far, maybe if you want to charge them faster, I am monitoring that part of it. Jonathan Link to comment Share on other sites More sharing options...
Derek Uzzell Posted January 18, 2021 Share Posted January 18, 2021 I notice that, in this November 2020 forum thread you mentioned that you were considering switching to a lithium battery. https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/B2B-have-I-understood-/56838/ I don’t think you’ve ever explained the reason for doing this, but, as you own a 2019 Auto-Trail Frontier Delaware HB (4500kg GVW I believe), it probably was not to gain a few extra kilograms of payload or lose a few kilograms because your Delaware was near overload. A 2016 Rapido’s CBE-equipment-based electrical system is significantly different to your Delaware’s. Consequently, the fact that replacing your motorhome’s original conventional leisure battery(s) with a KS Energy product has not been problematical doesn’t automatically mean this would also be the case for Steve’s motorhome. I’m going to suggest (diplomatically) that your having made just one trip so far since the battey change was made leaves plenty of scope for things to go pear-shaped in the not too distant future. For Rapido’s 2019 model-year, motorhomes in their more expensive ranges had the option of a 90Ah lithium battery instead of the traditional Banner wet-acid products. The lithium battery Rapido offered was a “Super B Epsilon 90” and it’s mentioned in this Practical Boat Owner article (£1860 price quoted). https://www.pbo.co.uk/gear/lithium-batteries-for-boats-reviewed-12-of-the-best-lithium-boat-batteries-tested-62244/2 The models that could have an optional lithium battery were said to be pre-wired for it, with Rapido’s press release confirming that "Les sections de câble sont d’ores et déjà calibrées pour recevoir une batterie lithium Super B”. It’s plain then that Rapido were aware of potential pitfalls just dropping this battery into a motorhome that had been designed for one (possibly two) wet-acid Banner leisure batteries. Link to comment Share on other sites More sharing options...
silverback Posted January 18, 2021 Share Posted January 18, 2021 yes Derek, I changed not because of weight issues but because I had saved dosh with this pesky lockdown! and I worked it out from years of motorhoming that I was changing batteries x 2 every 3 years due to how I use it with a lot of off grid use, so if I got 10 years out of lithium it would be good economics, and I would double my battery capacity from 2 x 92ah to 2 x 100ah lithium, also the AGM that are put in by Autotrail in my opinion are not suitable because of the charging regime, anyway like you say I have only had one outing so not really tested, the specs of the KS lithium are the same as lead acid I rung them up and had a word and he reassured me they were just drop in replacements, I rung Sargent and they said the same and the charger is capable so I can only base my judgement on what I have been told by the experts who deal with all this electric wizardry, They have blue tooth so I can monitor and when on charge by the on board charger it does the lead acid profile and when the lithiums are charged it just gets knocked off by the BMS most I have seen go into them is 8 amps each same is true when I am driving, so I can only conclude that the BMS in each battery does the correct things, I am not sure where all this fear of melting wires and stuff comes from, but I am open minded enough for people to tell me why they think they draw 50amp all the time then when full they keep on getting 50amp and blow up! also reading articles about lithium by Clive mott seem to say they would not be problems, if after lock down I can get out and give these batteries a good testing then I will report back if my van sets on fire or wiring melts, just one more thing I don't use an inverter all my kit is either 12v or gas Jonathan Link to comment Share on other sites More sharing options...
stevec176 Posted January 18, 2021 Author Share Posted January 18, 2021 I contacted KS Energy about their Lithium battery and their reply is, the KS-LT100B will replace your existing batteries, you do not need to change your alternator or existing wiring (unless you wish to increase the available charge current and charge time), whilst the battery charger should be switched to position A. The existing charger is not very efficient. The battery charger/power supply can be upgraded to a Victron Energy IP22 20A which has a dedicated lithium algorithm and will provide a more efficient charge. So it seems a feasible option, something to think about. Link to comment Share on other sites More sharing options...
colin Posted January 18, 2021 Share Posted January 18, 2021 silverback - 2021-01-18 3:15 PM I am not sure where all this fear of melting wires and stuff comes from, but I am open minded enough for people to tell me why they think they draw 50amp all the time then when full they keep on getting 50amp and blow up! Jonathan Link to comment Share on other sites More sharing options...
silverback Posted January 18, 2021 Share Posted January 18, 2021 colin - 2021-01-18 4:40 PM silverback - 2021-01-18 3:15 PM I am not sure where all this fear of melting wires and stuff comes from, but I am open minded enough for people to tell me why they think they draw 50amp all the time then when full they keep on getting 50amp and blow up! Jonathan right so I watched that, and there is no way the battery gets all them amps, as said above it draws 16 amps tops, anyway I will monitor and tell you if my alternator drops in bits, I would also suggest that Mr Sterling is not being totally revealing in the fact that he doesn't say if the battery has a BMS Jonathan Link to comment Share on other sites More sharing options...
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