arthur49 Posted October 15, 2011 Share Posted October 15, 2011 Clive recommends 2 x 6v batteries connected in series as being superior to two 12v connected in parallel and I aim to do this. Has anyone actually done it as venting of gasses seems to be a stumbling block. There is no facility to attach a vent tube meaning, presumably, batteries need to be installed in a box/cupboard, and that is vented? Does the box/cupboard need to be airtight apart from a vent at bottom? Charger is 25A three stage so should be perfectly capable of charging 2 x 6v connected in series? Incidentally, I trust Clive's expertise totally, but why are these batteries a better option? Arthur Link to comment Share on other sites More sharing options...
Mel B Posted October 15, 2011 Share Posted October 15, 2011 This is Clive's website, not sure if there's anything on there that might help, but worth a look: http://www.motts.org/MOTORHOMES.htm Link to comment Share on other sites More sharing options...
Mel B Posted October 15, 2011 Share Posted October 15, 2011 These threads might help too: http://www.outandaboutlive.co.uk/forums/forums/thread-view.asp?tid=17401&posts=8 http://www.outandaboutlive.co.uk/forums/forums/thread-view.asp?tid=21756&posts=21 http://www.outandaboutlive.co.uk/forums/forums/thread-view.asp?tid=22208&posts=14 Link to comment Share on other sites More sharing options...
Brambles Posted October 16, 2011 Share Posted October 16, 2011 Just glancing very quickly through the other threads I noticed shorted cells comes up a lot. This used to be a very common problem with Antimony lead batteries but with Calcium batteries, which most deep discharge batteries are now, shorted cells is a much lesser occurance. Basically because the lead which is shed forms crystals which are not conducting in a calcium battery. Shorts can still happen but is usually because of the plates buckling or swelling too much..By the time this happens the battery is worn out anyway. Main thing is shorts are very much less common, and more likely to go high resistance. Reason for mentioning is because this is one factor used as an argument against batteries in parallel and to favour being in series. Other thing to note is if you buy say two 210 Ah 6volt batteries then you still only have 210 Ah at 12 volts. Two 105 Ah batteries in Parallel, then you can add the Ah rating together to give you 220ah. So looking at prices of Trojan batteries, this is quite an expensive option. The other factor you have to look at, and I have not for a while, is the charge voltage and characteristics of the Trojan batteries selected and if suitable for alternator charging and what the water consumption is like as you may end up having to top up a lot. I agree though Trojan batteries are good batteries. Remember Trojan batteries like all batteries can be murdered just the same as others and if you are paying more for better batteries and you inadvertently abuse them then you are worse of than if you bought cheaper batteries. Also be aware the standard (most) Trojan batteries have a high self discharge rate, 4% a week, which means you can not leave stored sitting idle with out some form of trickle charging. Fine if you have solar panels or hook up when storing van. I am not deliberately trying to be negative, but you need to compare all the characteristics of a battery agianst your intended application which is invariably different for diffrent types of motorhomers and how they use there Motorhomes. Not an easy task. Remember golf buggies have a heavy load for a few hours and then are put back on charge. Motorhomes might go days running the batteries down and then charged over a longer period. Now to move on to specific questions asked. Has anyone actually done it as venting of gasses seems to be a stumbling block. There is no facility to attach a vent tube meaning, presumably, batteries need to be installed in a box/cupboard, and that is vented? If the Trojan batteries have caps, the you need to replace with caps which have tubes attachments, these are linked and vented via a common tube to outside the van. Or mount in externally vented battery box. Does the box/cupboard need to be airtight apart from a vent at bottom? You will need two vents one at top as well so air can flow through the box just like your gas locker, or see answer above for vent tubes. Charger is 25A three stage so should be perfectly capable of charging 2 x 6v connected in series? This should be fine for charging. However Trojan recommend frequent equalisation charges. This is common on these types of heavy duty batteries. Most on board chargers do not carry out an equalisation charge cycle. Food for thought, but I also respect Clive's knowkedge immensly but has this been thought through using latest technology batteries such as Gel and AGM designed specifically for Motorhome and leisure use. I would love to have a couple of Trojan batteries, but I also know if I abuse then I have thrown away a lot of money and topping up batteries with water is something I am prepared to do once a year but not prepared to check more often such as every 5 to 10 cycles. I also want to know if I disconnect my leisure battrey, as I have for the next three months, my batteries will not self discharge and sulphate (age). Maybe I hae changed my mind and would nt love to have a couple of Trojan batteries afterall. However Trojan do make some nice AGM and Gel batteries as well, but not cheap. Link to comment Share on other sites More sharing options...
arthur49 Posted October 16, 2011 Author Share Posted October 16, 2011 Thank you Mel and Brambles........ Apart from being Clive's recommendation of 6v batteries in series, in order for me to achieve 220Ah capacity, the only option is/was 6v batteries. One or two 12v Banner or Varta batteries to achieve 220Ah will not fit the space available (I don't want to put batteries in separate places) I think I might 'downsize' my aspirations and go for a single 12v Banner or Varta at 180Ah as I know that will fit................just! By the way Brambles I was put off Gel and AGM batteries by one of your earlier posts on a different thread. Are you saying there are good AGM batteries available and if so can you point me in right direction?? Incidentally 2 x Trojan T105 delivered to Perth = £260 (Batterymegastore). One Banner Energy Bull delivered to Perth = £262 (Tayna)................ so there is nothing in it re price. Arthur Link to comment Share on other sites More sharing options...
Brambles Posted October 16, 2011 Share Posted October 16, 2011 Arthur, Generally flooded works out the best option as value for money. However for some people AGM or Gel is better as they may for exampel be fitted where it is a pig to access them to check levels and top up. So AGM and Gel are very much fit and forget along with many sealed flooded. Choice all depends on your useage profile. Varta have changed their offerings and now have two liesure batteries series. The Professional flooded and professional AGM. The AGM is a very good battery. The original Hobby batteries are still available under the Bosch brand (or were last time I looked). One advantage of AGM or Gel is they can cope with deeper discharges better but when the use up electrolyte then thats it, the battery needs retiring. Banner have the equivalent to the Bosch ( old Varta) and seems a very popular battery. AGM and Gel also usually have a lower capacity for a given size if comparing to premium flooded, but this can be traded off by the fact you can discharge deeper and get a better life, but you pay a higher proce fro this...all swings and roundabouts. The 1st option should always be flooded for Ah and cycles for your money. Link to comment Share on other sites More sharing options...
Brambles Posted October 16, 2011 Share Posted October 16, 2011 Just had a look and see Varta stil do an equivalent to the Banner 230Ah but is more expensive. Link to comment Share on other sites More sharing options...
arthur49 Posted October 16, 2011 Author Share Posted October 16, 2011 Many thanks Brambles. I value your input and knowledge. Will deliberate for a few days before taking the plunge Arthur Link to comment Share on other sites More sharing options...
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