Dual Battery Options and Fitting

[drivesafe]

Thanks look forward to more info. Just been unlucky with agm in the past, was able to return the battery in question fortunately. Seems that wet cell or others maybe more tolerant of different charging parameters, cheaper, can be topped up etc, though yes don't want to vent inside the van, ideally something with vent line you can run outside.

Hi again Heyasam, you can SAFELY use a wet cell battery and do not have to vent it to outside the cab.


Being as you are in NSW, this is legal ( it is actually only illegal in VIC ) so you could save some money.


But as posted earlier in this thread, you can only use up to 60% of a cranking battery if you want to avoid shortening it’s life span. It would also require that the battery must be mounted upright and this may limit the sizes available that will fit under your seat.


Alternatively, you could use an AGM or Lead Crystal battery and because they can be laid on their side, you will be able to fit a bigger battery.


There is also the advantage of not needing as big a battery. By this I mean, for example, if your were considering a 100Ah wet cranking battery, you would only have 60Ah available, while an 80Ah AGM will give you the same available Ah and a 55Ah Lead Crystal battery will also give you 60Ah of usable capacity.


All just food for thought!

[Transporter]

Thanks look forward to more info. Just been unlucky with agm in the past, was able to return the battery in question fortunately. Seems that wet cell or others maybe more tolerant of different charging parameters, cheaper, can be topped up etc, though yes don't want to vent inside the van, ideally something with vent line you can run outside.

Many wet lead acid maintenance free batteries have vent hole where you can attach vinyl tubing to vent out of the cabin. The vapour from the battery could carry particles of acid,some also leak around the posts, so I wouldn’t fit just battery in the cabin. You could get a battery box to minimise the risk, but it will be bulky.

[drivesafe]

Hi again Heyasam, as I have already posted, as you intend to mount the auxiliary battery under the seat, if you desire, you can SAFELY use a wet cell battery and do not have to vent it to outside the cab.


There are plenty of vehicles that do just this with their cranking batteries.


For example, there were over 250,000 VE Commodores with their cranking battery fitted in the boot and the boot is NOT sealed from the cab.


The first of the VE Commodores had a plastic tube to vent the batteries to the outside, but not long after these vehicles were first produced, they did away with the tube and just let the battery vent into the boot.


Then there is the 20+ million VW Beetles that have the cranking battery mounted under the rear seat, no box, no external venting.


If you decide you want to fit a conventional cranking battery under your seat you will be doing exactly what VW ( and other manufacturers ) has done for many MANY decades.


If you were to mount the battery somewhere else in the cab, yes mount it in a plastic box that is securely fixed in place, but as the area under the seat is already used for mounting batteries, just secure the battery properly, regardless of what type of battery you use, JOB DONE.

[heyasam]

Thanks for advice everyone. Only other part for me to figure out eventually is the 240v to 12v smart charger, with an isolator that links batteries both ways and potentially different battery chemistries. I would like to get a pretty hefty charger maybe 20amps or more as I plan to have some heavy 12v consumers, and still want to put some charge in at the same time. I figure it would need to be connected to the starter battery as the starter is likely to be hotter for the temperature sensor compensation. Though I worry with a lot of smart chargers e.g. ctek that don't have a lot of options with their settings, how would they go once two batteries connected, with potentially different internal resistances, different starting temperatures, could you ends up in overcharging situations for example. Would the smart charge be out smarted?

[Transporter]

The Projecta 25A smart charger is a good option and reasonably priced.

[heyasam]

Thanks Transporter, just found and read the manual, looks like a really good charger as long as I can find a good place inside the van to mount it, then get the 240v power into it.

[drivesafe]

Hi Heyasam, because you are going to be powering devices off the batteries as they charge, while it does not matter what brand of charger you get, just make sure the charger can be set to have a MAXIMUM charger voltage of no more than 14.4v at any time during the charge cycle.


First off, by setting the maximum charge voltage to 14.4v ( or less ) you can then have any mix of different battery types and they will all be able to be fully charged, with out the risk of over charging any of them.


Plus, because you will have devices running off the batteries as you charge them, by setting the voltage to no more than 14.4v, you also remove the risk of the batteries being over charged if any of the devices cycle off and on, which can cause the charger to go from FLOAT mode back to BULK charge mode.


If the charger is set to a voltage high than 14.4v, having the charger continually go back into BULK mode can eventually over charge some batteries.


Whereas switching between FLOAT mode ( usually somewhere between 13.4v to 13.8v ) to a BULK mode no higher than 14.4v, will not effect the batteries, no matter how many times the charger switches voltages.


Last, if you connect the charger to auxiliary battery and use one of my isolators, my isolators have a REVERSE CHARGING function, where if the isolator has turned off, the isolator will allow the auxiliary battery to be nearly fully charged, and then the isolator will turn on to allow the cranking battery to charge.


There are a couple of other isolators that will work this way, but most do not and if the isolator you use does not have REVERSE CHARGING, then you will need to connect your battery charger to your cranking battery if you want both batteries to be charged.

[heyasam]

Thanks drivesafe

[drivesafe]

Hi Heyasam and sorry for the long delay in replying but I am flat out with the usual Easter rush.


Anyway, you mentioned you wanted to get 240vac into your van.


If you are just planning to use an extension cord, and plug it into the charger, so be it. But if you mean you want to set up a permanent 240VAC inlet then this may be the way to go.


Residual Voltage Technology | Generators, Inverters, RVD-SAFE(R) Power Leads, RCD, RVD, Electrical Earth, Earthing, Electrical Safety, Wet Environments


If you get their AC Power-Inlet with the Twin Sockets fitted to the back of it, you do not need an electrician to fit it. But you will need to cut a hole in the side of your van.


Unlike all the other inlets, that simply bolt on to the side of your van and stick out, These have been specifically designed as a recessed application so that the finished install has the Inlet in clear of the body.


They were design to allow inlets to be installed in caravans, where the caravan is built to the maximum legal width.


On these caravans, all other inlets protrude beyond the legal limit and a number of states ( Vic & NSW ) are now clamping down on over width caravans and the two main offenders are the 240VAC inlets and awnings.


While the width is not a problem with your van, these do look much better, but the RVDSAFE AC Power-Inlets also have a number of other unique features.


To bring AC power into any RV, you must protect the incoming AC with an RCD. Which is all good and well except, RCDs do not work in wet situations, which is a common occurrence with RV use.


When an RVD-EMR is added to an RCD, the level of safety increases dramatically, with one of the advantages being that an RVD does trip in wet situations.


I deal with RVDSAFE and Heyasam , if you are interested, I can get these units for you at a bit of a discount.

[Bryn23]

Drivesafe is right about the RVD-EMR.

I looked into this last year, it has many advantages over a normal RCD, well worth the extra coin if bring 230 Volt into the van for a camper.

Im not sure if they still have the videos on their site, but it highlights the benefits over the RCD.

[drivesafe]

Hi Bryn, I hope no one tries this but here the video.

YouTube

[Sunny43.5]

He has bigger ones than me ! I remember some years ago where someone invented a safety cut off system for a drop saw , he placed his arm under the spinning blade and each time it shut off instantly real scary to watch .This is a good system for camping and outdoor use .

[drivesafe]

Here is another video of the RVD at work but this time it is installed in a 12v to 240VAC inverter, something that is also commonplace in RV situations.

YouTube

[TheKiwi]

Sorry to revive an old thread but am hoping someone could share some knowledge.

2016 T6 Multivan tdi340.

Under the front passenger seat is a loom of red wires that just terminate at a dead end. I've peeled the tape off and there is two smaller looms. One has a 5 cables, one has 3 cables.

I haven't got the multi meter on them yet but can any one confirm these go direct to the battery? Has anyone used these to retro fit a second battery?

(Id insert a photo if I could work out how to!)

[drivesafe]

Hi TheKiwi, whereabouts are you in QLD.