Dave Posted March 30, 2010 Share Posted March 30, 2010 I`m soon going to be kitting out a "small" living van to go behind the T, I`m planning on having a single 12V, 100 AH leisure battery to feed the trailer as we only need power for the fridge, lights and a couple of low-demand bits. The question is what is the easiest way to charge a 12v battery from a 24v system? Reading on the web if you just take a feed from one battery you get unbalnced charging, the other option is a second alternator giving you a 12v supply when the engine is running. Has anyone tried this? has anyone got a better idea? any info gratefully recieved. Quote Link to comment Share on other sites More sharing options...
HWade Posted March 30, 2010 Share Posted March 30, 2010 Hi why dont you get a small solar panel, and charge unit thay work very well. thats what i had on my living van, mind you i did have 240 volts as well and i also had a trickle charger. You can get the solar panels on ebay. the control units are made by fox. Howard Quote Link to comment Share on other sites More sharing options...
fv1609 Posted March 30, 2010 Share Posted March 30, 2010 has anyone got a better idea? I would run your fridge from gas. A fridge will flatten your battery quite quickly. Even if you have a solid state cooler box it is quite greedy & only really suited when the battery is being charged when you're on a run. Quote Link to comment Share on other sites More sharing options...
Mk3iain Posted March 31, 2010 Share Posted March 31, 2010 (edited) Hi Dave Try a voltage dropper (or a 24v to 12v split charger), available up to 10amp output. These are commonly used on trucks to power accessories etc. Try your local factor / HGV specialist or "CDC Truck" and "HGV Direct" both online. The split charger is expensive but maybe suits your use, a voltage dropper is cheaper and will do the job but beware of overcharging! Cheers Iain Edited March 31, 2010 by Mk3iain Quote Link to comment Share on other sites More sharing options...
Dave Posted March 31, 2010 Author Share Posted March 31, 2010 Hi DaveTry a voltage dropper (or a 24v to 12v split charger), available up to 10amp output. These are commonly used on trucks to power accessories etc. Try your local factor / HGV specialist or "CDC Truck" and "HGV Direct" both online. The split charger is expensive but maybe suits your use, a voltage dropper is cheaper and will do the job but beware of overcharging! Cheers Iain Plenty of food for thought here, i have already plannned on a solar charger Howard, the fridge (yes it is a fridge and not a cool box) will take 12 or 24v , 240 through an adaptor but no gas option. My plan was to have a 12v battery in the back of the T so that when we go off to the arena and the T is running we can have a quick re-charge at the same time. park up, plug in the trailer, job done. Would a voltage dropper give enough oomph to charge a battery rather than powering the accessories through it? The idea of a second alternator seems to be popular with boats i just wondered if anyone had tried it on a truck. Quote Link to comment Share on other sites More sharing options...
Mk3iain Posted March 31, 2010 Share Posted March 31, 2010 Hi Dave There are droppers up to at least 10amps output. They are voltage regulated so will charge a battery ok over time. The thing to watch for is that they will not switch to "trickle" or switch off when the battery is charged so you would need to make sure it is not charging too long. Also a large capacity battery may cause the dropper to operate at "max" for a time and get warm! Not sure if it would need any extra regulating when used as a charger, but in theory should be ok. As a bonus you can use your Sat-nav etc. Iain Quote Link to comment Share on other sites More sharing options...
Dave Posted March 31, 2010 Author Share Posted March 31, 2010 Hi DaveThere are droppers up to at least 10amps output. They are voltage regulated so will charge a battery ok over time. The thing to watch for is that they will not switch to "trickle" or switch off when the battery is charged so you would need to make sure it is not charging too long. Also a large capacity battery may cause the dropper to operate at "max" for a time and get warm! Not sure if it would need any extra regulating when used as a charger, but in theory should be ok. As a bonus you can use your Sat-nav etc. Iain SAT NAV - Don`t let the "originality or nothing" boys hear those words, you`ll be banished for life Quote Link to comment Share on other sites More sharing options...
Tony B Posted March 31, 2010 Share Posted March 31, 2010 There are split chargers available from In Car enternatment places they ar not cheap. But cheraper than blowing something up or setting fire to things. I have one that wil take anythnig from 6 to 50 volts and tap off at difrent voltages. Maplin's do some very useful kit, including a 24 volt inverter now. The gadget is made by Sure Power Industries, Tualtin, Oregon Multi battery isolator Mod. 2402. give you a place to start at least. http://www.surepower.com/ Quote Link to comment Share on other sites More sharing options...
Dave Posted March 31, 2010 Author Share Posted March 31, 2010 There are split chargers available from In Car enternatment places they ar not cheap. But cheraper than blowing something up or setting fire to things. I have one that wil take anythnig from 6 to 50 volts and tap off at difrent voltages. Maplin's do some very useful kit, including a 24 volt inverter now. The gadget is made by Sure Power Industries, Tualtin, Oregon Multi battery isolator Mod. 2402. give you a place to start at least. http://www.surepower.com/ Thanks Tony, i`ll have a look Quote Link to comment Share on other sites More sharing options...
Tony B Posted March 31, 2010 Share Posted March 31, 2010 Glad to be of help. Quote Link to comment Share on other sites More sharing options...
gritineye Posted March 31, 2010 Share Posted March 31, 2010 Dave, if it helps, I have an all electric fridge in my camper van, it will run for about 3 days and nights on a 115 ah leisure battery in the summer, without running the engine to charge battery. If you are able to put cold stuff from your house fridge in it saves power. A long cable may reduce performance though. Quote Link to comment Share on other sites More sharing options...
Mk3iain Posted March 31, 2010 Share Posted March 31, 2010 Stealth sat-nav and other comforts, cunningly hidden in an ammo box and removed when not required! THEY wont notice,.......will they? Quote Link to comment Share on other sites More sharing options...
Tony B Posted March 31, 2010 Share Posted March 31, 2010 AH but, we will know!:cool2: Quote Link to comment Share on other sites More sharing options...
marmon Posted April 2, 2010 Share Posted April 2, 2010 Some thoughts on your installation as I have a fair bit of experience on yachts with similar set ups, firstly I think you will be quite surprised how quickly a fridge will discharge a single 12v battery even an 8 D size, especially if you are regularly taking out beer... :-D I would have thought it better to run 24v especially as your fridge has this capability so two of the largest 12v you have room for and charged simply through a charge splitter (diodes) so as not to run the risk of discharging the engine battery's. Most new electronic equipment is now rated 10-30V but if you have something that needs 12v just use a 24 to 12 transformer for 3-4 amp loads they are about the size of a pack of ciggies theses days. Likewise if you need 240V it will run more efficiently off a 24V Inverter most of which have built in chargers/load balancers simplifying plugging in. Quote Link to comment Share on other sites More sharing options...
Dave Posted April 5, 2010 Author Share Posted April 5, 2010 Gritineye`s point about cable length is something i thought about early on, however one thing we`re not really short of is space to put the batteries, either on the trailer or on the truck. I`ve just had a look at some charge splitters but what sort of amp rating do i need? overkill is probably the order of the day but as these things seem to go from £200 up what should i really be looking for? As i said in my opening msg i won`t be using loads of high-demand gadgets. Quote Link to comment Share on other sites More sharing options...
marmon Posted April 8, 2010 Share Posted April 8, 2010 Gritineye `s point about cable length is something i thought about early on, however one thing we`re not really short of is space to put the batteries, either on the trailer or on the truck. I` ve just had a look at some charge splitters but what sort of amp rating do i need? overkill is probably the order of the day but as these things seem to go from £200 up what should i really be looking for? As i said in my opening msg i won`t be using loads of high-demand gadgets. Just match to your alternator output. If you have a 65amp then get the closest available splitter higher than that. Quote Link to comment Share on other sites More sharing options...
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