Boris Posted October 1, 2018 Share Posted October 1, 2018 Following guidance from Allan Evans at nandscaravanservices we are changing our LB from AGM to a Varta LFD on our 2017 Swift Bolero MH. Thanks to Swift having designed the van around the battery dimensions (!) we have gone from a 100Ah to 75Ah (we are not ever likely to be off-grid) and Sargent tell me "no need to adjust anything" Having now read the 'user guide; for the PX300 it refers to a range of 85-220Ah. Does anyone know if it will be OK on 75Ah or should we look for an alternative that will fit the battery box? BTW, superb service from Alpha Batteries - and a decent discount quoted. Barry Link to comment Share on other sites More sharing options...
aandncaravan Posted October 2, 2018 Share Posted October 2, 2018 If you are always on EHU, then even the cheapest Starter battery will do as the battery will never discharge/do any work because the Sargent charger will handle all the demand for 12v power. However, the 75Ah Varta will be fine in your set-up because it isn't a conventional battery. A charger is designed to be as powerful as possible for it's quoted output because everyone wants fast battery charging. But that can mean that it isn't so good at controlling it's charging current at the lower threshold, potentially overcharging a conventional battery when in 'Float'/'Trickle' mode In your case the charger will only be operational when you are 'on site' which will correspond with the power control LCD display being on, TV on standby, maybe also the heating fan on low, etc. In other words the draw on the charger when the van is in use will exceed that of the 'Trickle' current resulting in almost zero power going into the battery. So long as you don't leave it on long term EHU, a smaller battery will be fine. Even then a Varta LFD/Bosch L series are so resistant to 'overcharging' because of their unique technology, their life should still be many years. A Varta LFD75 will behave more like a 90Ah battery in terms of resisting the 'overcharge' that will shorten the life of a conventional battery. Link to comment Share on other sites More sharing options...
Boris Posted October 2, 2018 Author Share Posted October 2, 2018 Many thanks Allan. The only 12v draw is normally the TV, CPAP machine,overnight, pumps, lights and occasional heating boost fan. When out of use at home I have set up a timer so that EHU goes on for a couple of hours each day with contribution from solar when the sun shines. As always, I appreciate your advice. Barry Link to comment Share on other sites More sharing options...
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