Mr Meenah Posted April 12, 2019 Share Posted April 12, 2019 Hi everyone. Firstly thanks for the add. I have to admit I've been a bit of a stalker, lurking in the dark recesses of the forum for a while trying to digest the wealth of knowledge and experience contained herein. I went away last year in my work Sprinter with makeshift beds, camping gaz stove etc. and have just paid a deposit on a low mileage '64 plate Sprinter which I'll convert into a motorhome. Over the last few months I've been watching videos, reading reviews and generally trying to design my build. For all my sins the first thing I bought was a Valence 128ah Lifepo4 battery which, after reading some of the posts on here, Im now wondering whether I've done the right thing. However, it's here. I have it, lets go with what I have. I'm after recommendations for a split charger or other device for charging and maintaining it. My idea is to have 12v only in the van apart for a charging port in the rear garage to charge 2 ebikes and shore hookup to keep the battery topped up when at a campsite. I've been told the battery has built in bms but to what extent I do t know. Apparently it doesn't like to be charged at more the 14.6v ( voltage regulator perhaps ) and doesn't like to be taken down below 11.5v. Can anyone help? Link to comment Share on other sites More sharing options...
aandncaravan Posted April 12, 2019 Share Posted April 12, 2019 The charge/discharge rates of up to 100amps and the many unknowns of Lithium mean this is way outside my comfort zone, so I will leave it to others. Link to comment Share on other sites More sharing options...
Mr Meenah Posted April 12, 2019 Author Share Posted April 12, 2019 Only to be used in 12v mode only, for lighting water-pumps etc. Link to comment Share on other sites More sharing options...
Alanb Posted April 14, 2019 Share Posted April 14, 2019 I am afraid that your terminology suggests that you are still lacking in basic understanding of MH systems. There is for instance no such object as a "split charger". You can however have a split charging system, which will have a split charge relay, The relay may be discrete, or contained a 12V distribution board such as the CBE DS300. To accompany the DS300 you will also require a battery charger and a control unit. The above is the integrated approach, but as you have an almost clean slate you could install separate split charge relay, 12V fuseboard, voltmeter, and tank level guage. As regards mains connection, in addition to an IEC 16A socket you will require a 240V distribution board containing a minimum of an Residual Current Device (RCD), and one or more miniature circuit breakers (MCB). Again CBE manufacture a suitable 240V distribution board. May I suggest as further reading "deepredmotorhome.com", "www.tekyinblack.com/motorhome", and "www.manins.net.au/motorhome". I should comment that tekyinblack seem to have installed the 240V distribution board back to front. (It is normal practice to connect the mains to the RCD and not to the MCB as shown on their diagram.) While Peter Manins did not build his own motorhome, he did retrofit a lithium battery together with the associated control circuitry. Alan Link to comment Share on other sites More sharing options...
aandncaravan Posted April 15, 2019 Share Posted April 15, 2019 Please don't use a standard CBE DS300, or similar, system as the charging rates from the Alternator to the Lithium batteries can be far higher than these units can tolerate. Your entire design should cater for the very high 100amps+ the Valence 128Ah can draw. Few motorhome electronic systems will cope with more than about 50 amps. I would suggest your design starts with a split charging capability of at least 200amps to cope with peaks. That means you need to consider the Alternator, most Alternators won't run at more than around 2/3rds capability for long without overheating. Obviously if you want to take advantage of Lithiums faster charge rate, you need a really big Leisure battery mains charger, probably at least 50 - 75 amps? Our 'Add a second battery' web page high lights how some motorhome units won't cope well with a second battery and the associated high Alternator charging that then occurs. Putting a Lithium in a Campervan/motorhome is a bit like loading 6 batteries on the Alternator, so you can see how there might be an issue, see : http://www.aandncaravanservices.co.uk/add-a-second-battery.php Link to comment Share on other sites More sharing options...
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