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I'm new to all this and would like some advice.

 

I am converting an ex-builders van into something I can travel in. the first piece of advice is charging my liesure battery. Is it possible to charge it from the van's electrical system (obviously this is only possible when I'm driving) If so how i. e. how do I wire it up? what are the dangers to watch out for? Also how much charge can I expect ot get from a solar panel on the roof of the van?

 

thanks - van_man

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I'm new to all this and would like some advice.

 

I am converting an ex-builders van into something I can travel in. the first piece of advice is charging my liesure battery. Is it possible to charge it from the van's electrical system (obviously this is only possible when I'm driving) If so how i. e. how do I wire it up? what are the dangers to watch out for? Also how much charge can I expect ot get from a solar panel on the roof of the van?

 

thanks - van_man

A solar panel charge will depend on the power of the panel basically. a 100w panel and a solare charge controller should output a constant 8amp charge in good summer sunlight.

To charge the leisure battery properly as you travel the ideal way would be to fit a dc-dc charge controller like the the ctek one. --> https://www. roadpro. co. uk/retail/12v24v-electrical-products/battery-management/ctek-dc---dc-chargers/ctek-d250s-dual-dc-dc-charger-12v-1321. htm

 

Obviously there are other things you can do, such as fuel cells etc, but this is a couple of ideas.

Edited by dreadly

An eye for an eye only ends up making the whole world blind.

Mahatma Gandhi

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On caravans we have 12V chargers that work off EHU (elec hook-up) by plugging into 240V.

If you plan to do this then get a caravan type charger. We also charge the leisure battery from the car battery ONLY when the towcar is being driven. Done through a split charge relay. This is often seen as the grey sockrt on the back of towcars.

 

And Welcome!

Graham

Unless otherwise stated all posts are my personal opinion 

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Question has to be what alternator is fitted? But in general there are a number of ways to charge the second battery.

1) Simple relay there are two basic types those with built in voltage detectors and those which need wiring to the alternator warning light which will depend on alternator fitted. Since under fault conditions high amps could be drawn I would always fit a fuse as well. This is cheapest and for a van where distance between two batteries is short likely the best.

2) The blocking diode again depends on alternator the theory is good but in practice not had much success with these.

3) The DC to DC converter these are really for boats and caravans where the distance between the two batteries is quite a bit they are good but unlikely required in a van and are expensive.

4) The alternator control box these are very complex and basic idea is to kid the alternator into thinking the battery is flat so it gives out far more power and uses a pulse charge system to bulk charge the aux battery as fast as possible without damage so it can recharge it in the short time the engine is running common with narrow boats.

 

Depending on your power requirements first or last likely the best. If for example your an away worker and often spend the night in pub car park and just drive the van 3 miles to work every day and that is only power it gets then number 4 is likely what you require. But if normally used for family holiday and in the main you use sites with hook up then number 1 likely good enough for odd time without hook up.

 

As to solar panels will need to be specials able to flex and really no idea of the outputs again away worker and likely well worth while family holiday not so sure worth the effort.

 

So this is the bees knees set up like this and as you would expect very expensive the other end is this very cheap slightly better is this the 0-727-33 Durite unit is voltage sensitive so does not require extra wires connecting to alternator warning light system. The relay is for two reasons. One so when stopped the main battery is not discharged and two when you crank the engine it will not try and draw starter current from the aux battery. Some of the versions used on boats have an over ride so you can use the aux battery to assist starting but then very heavy cables are required between both batteries. In which case you could use a simple battery isolator and do it manually.

 

Sorry did put in pictures but seems I not allowed.

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A few of these concepts ericmark discusses can be seen visually here: http://www. marcleleisure. co. uk/Sund001/SplitCharge01. htm. The further down the page you go, the more technical the solution but the implementation is simpler.

 

You can buy simple split charge relays (aka voltage sensing relays) from places like RS-Components (http://uk. rs-online. com) or Towsure (http://www. towsure. com/product/SelfSwitching_Combination_Relay) or if you'd prefer one of the all-in modules I've heard that Stirling Power are pretty good, they make split charge diodes (~£50)*, more advanced splitting systems (~£100) and up to advanced battery charging systems (~£280).

 

*0v drop split charge diodes are mentioned but I can't find any example products.

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Sterling do the zero volt drop diodes once van_man replies and we know a little more I will expand Gordon Equipment also do a whole range but think you have to buy through an agent they don't sell to general public. RS are expensive but so are Sterling really designed for boats so very good quality.

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I'm new to all this and would like some advice.

 

I am converting an ex-builders van into something I can travel in. the first piece of advice is charging my liesure battery. Is it possible to charge it from the van's electrical system (obviously this is only possible when I'm driving) If so how i. e. how do I wire it up? what are the dangers to watch out for? Also how much charge can I expect ot get from a solar panel on the roof of the van?

 

thanks - van_man

As other have said i would use a Voltage sensitive relay and use the vehicles alternator as the main charging source. We supply a VSR for £25 can be found here http://www. caravantechnology. com/12V-Voltage-Sensitive-Relay-P125C33. aspx suitable for alternators up to 140A. Just simply connect the device to the positive of the starter battery and the positive of the secondary battery. This will enable the vehicles alternator to charge the secondary battery, However the VSR ensure the starter battery has priority and will only attempt to charge the secondary battery once the starter battery is fully charge. ..

 

The amount of charge will depend on the size of you alternator and the amount of driving you are planning on doing. Many modern vehicles alternator will produce more power when under load even when not driving.

 

If you secondary battery is huge or you want faster charging then add a small solar panel or purchase an mains smart charger.

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Hi CaravanTechnology,

 

thanks for the info. I've check the link out and it seems to be the best solution.

 

Is the distance between batteries an issue?

What happens if I hook up a convetional charger to my leasure battery - do I have todisconnect anything.

If I am stationary for a long period of time and away from a power point, can I use a solar panel without the above (ie disconnection)

 

Sorry about the many questions.

 

Any one else on the forum used or know about this solution?

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The distance between the batteries can be an issue as voltage drop can occur across the cable. but you should be fine in your van. ..

 

If either battery is receiving a charge the VSR will activate. This allows the charging of the second battery from an external battery charger or second charging source so you wont need to disconnect.

 

Yes you can use a solar panel when no mains is available but depending on the size of the panel and what you draw is will determine if it will be efficient or not

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