B2B charging

[Alasdair]

Hi,

I am converting a 314 sprinter into a camper van. I want to be able to charge the leisure batteries from solar and the alternator battery and was going to use a renogy, solar and DC to DC charger. I believe my sprinter has a smart alternator, and the renogy charger can work with a smart alternator and has a IGN+ connection although I am not entirely sure what that is connected to. Does any one have any experience installing this or similar setup?

Thanks Al

[mkguitar]

Hi and Welcome,


Do you have a battery isolator in your plans ?


a battery isolator will take input from the alternator, then connect to the chassis battery.


And a 2nd output to the "house battery" is switched so that it is only connected when the alternator is making power ( engine running) using a trigger wire connected to chassis electrics.


Some methods use a solenoid switch - simple and works BUT the voltage can flow both ways




My 2006 van has a Surepower 16023A ( 160 amp, A for alternator) this has the switched 2nd output to house battery.
This uses didoes so that the power can only run FROM alternator to batteries, not backwards- so the batteries are isolated from each other.
a drawback is that diodes waste power- the typical 14.7 volts from the alternator will drop to about 13.4 volts to the batteries




Another device worth looking into is the Victron Argofet 200-2AC which uses FET transistors to switch the power. No voltage drop.


It is generally not considered a requirement to have solar connect to the chassis battery. It can connect to the house battery via your controller. different types of batteries, lead/acid, agm, lithium each have their own requirements for charge regime

[mkguitar]

2.) do you have plans for an AC mains power to DC converter in your van- in case you are at a campground or even parked up at a friend's house ?



Most UK will use a Cform 16 amp blue plug at the source (You can get a 13A to Cform adapter if need be.) and then a socket on the side of the van.



In most of our US vans the aircon and microwave are the things which tend to run off mains power,
a DC converter supplies the rest for the van and recharges house battery.


on my van LP gas is used for the cooker, hot water heater and for the fridge ( 3 way, it'll run from LP gas, AC or DC power). rather than bottle gas we have a tank built in.


I have rented in the UK/ Ireland from Bunkcampers they do some nice durable units if you are looking for ideas

[Alasdair]

Hi,

Thanks for the advice I have seen so many vans here in the uk. We also went to an RV show in your part of the world as my sister was living in PHX, AZ. There were some amazing vans there!

I am planning on having batteries as our main electrical power source although I will be installing a 240v AC hook up point on the rare occasions we stay at a campsite. The batteries are charged via solar, alternator and AC hook up Heating and cooking is done on LPG and we don’t need air con so our electrical energy use is low compared to what you would typically see in the US I would imagine.

Al

[reilym]

You don't need a battery isolator with a DC-DC charger. There is a thread that uses the voltage sensed at the starter battery to trigger the DC-DC charger: above ~13.6 (engine is running), the DC-DC is on and below ~12.8 it shuts off. This way, if the ignition is left on but the engine is not running, the coach batteries don't deplete the starter battery. That older thread is here. I have been very happy with the 295W solar supplemented with the 60 amp Renogy DC-DC charger.