Under bonnet auxiliary battery

[Big Jim]

I see that the Ranger has a space specifically for an extra battery under the bonnet. A good place for a second camper battery ? The extra weight is in front of the front axle and q's I have a surplus of unused weight on the axle seems a shame not to use it . Ideas on how to connect ?

[zildjian]

A pity you don't do social media Jim there's a discussion on second batteries taking place right now on FB group page, essentially though a split charger relay directs the alternators output first to replenish the car battery, then diverts surplus current to your campers battery, yours would be slightly different as the 'leisure batteries would be physically some distance apart and there would be potentially a lot of amperage lost.

what you probably need is your under-bonnet second battery to charge as a third option and one you could easily lift out and swap into camper as that one becomes exhausted,
I don't have room on this hilux as you do, so instead I went with a pair of leisure batteries in parallel in camper

[mjb666]

Hi Jim
I was adamant i didn't 'Need' Social Media. Eight months ago i signed up to Faceebook just to see the DCG Sister page and now view both.

It and many other pages are Brilliant Fun to read and a great source of info, as Zildjian has pointed out.

Give it a go for a couple of months, if you don't like it, i would be surprised if you don't, then just delete it.

Mike

[Big Jim]

I joined last night ..... grudgingly! I don't want to get addicted.

[sabconsulting]

The problem with having a second camper battery in the engine bay is that I assume you would be wiring that in parallel with the battery in the camper itself. I wouldn't be keen on wiring two batteries together when so far apart. Even with really thick wire between them you would still get a voltage drop over that length (assuming the wire has to stretch the length of the truck to the 7 pin connector, then all the way forward through the camper to the camper battery). That means that the battery in the camper will tend to get drained more and charged less than its parallel brother which is unlikely to give you good battery life.

I have seen US truck camper owners have 2nd batteries in their trucks - but not for the camper, but instead to run power hungry accessories in the truck such as drinks fridges, stereos, etc.

I fitted that spare space with a pair of air horns - useful in Morocco

Steve.

[Gary W]

I see that the Ranger has a space specifically for an extra battery under the bonnet. A good place for a second camper battery ? The extra weight is in front of the front axle and q's I have a surplus of unused weight on the axle seems a shame not to use it . Ideas on how to connect ?

Generally you should try to reduce the distance between heavy current draw items and the battery. In this case though it won't be your primary house battery, more of a big bonus. You can also minimise the voltage drop to the camper by using the correct wire and connections so there's absolutely no reason why you shouldn't use this space to house an additional battery. You should give some thought how everything is connected and charged though.

First thing to clear up is charging. Split charge and VSR relays are just relays, activation aside they are nothing more or less than simple switches. They are either on or off and all they do is connect both batteries together when the engine is running (alternator charging) then disconnect them again when it isn't. It's an extremely inefficient way to try to charge your house battery(s) and in most of the installations I've come across over the years probably never even gets close to properly charging them. I could bore with why if you're interested but rest assured that if you wire your charging system through a split charge relay then via your towing socket to the 'house' battery, it's almost guaranteed to never get even close to a full charge. If you have a modern Euro5 engine it will be lucky to even get to 80% charge.

Luckily optimising your charging system is simple...

1. If you are using more than one 'house' battery make sure they are identical.

2. The best performance still comes from good old fashioned 'Deep Cycle' flooded lead acid batteries (unless you can stretch to Li-ion). Don't bother with cheap 'Leisure' batteries (there's no such thing in technical terms as a 'Leisure' battery, only in marketing terms) and expensive GEL or AGM are only worth the extra if you're going to use the camper off-road when the durability might be worth the trade off. They do not perform as well as a flooded deep cycle battery.

3. Don't bother with split charge relays, they are a waste of time. They were better than nothing when nothing else existed but now we have a choice. Go finstead or a good battery to battery (DC to DC) charger. The are a lot more money but you will never regret it. They are astonishing devices that work far better than you would ever believe possible. They also install in minutes and you can swap them across to your next truck no problem. If you have a Euro5 truck you have no choice, you must use a DC-DC charger or your battery will not charge.

4. Use the correct wire. This will be more akin to welding wire rather than the spindly stuff people tend to use. I'd be happy to calculate (and supply) the correct wire if you like.

5. Reduce the cable run to the absolute minimum and use an 'Anderson' connector to make the connection between camper and truck. Make the connection as close to the camper battery as possible.

6. Fuse everything correctly at both ends and fit a marine battery selector/isolator switch so you can choose either or both batteries to supply the power to your camper.

Installation of the above is an extremely simple DIY job but will totally transform your camper's power reserves. You simply won't believe how much difference optimising the charging system will make. We use all this stuff all the time so if you need help we can supply of everything you need (with Demountable Group Mates Rates of course!).

Best wishes

Gary

[sabconsulting]

Gary mentioned DC to DC chargers - I can second that. CTEK and Sterling Power do such chargers. I have a CTEK which takes inputs from the truck alternator and from the solar panels. I recommend wiring them as close as possible to the camper battery so they supply the correct voltage to the batteries being charged without a voltage drop in between.

The magic of these DC to DC chargers is that they take the voltage coming into them, which may not be high enough to properly charge the battery, and uses solid-state electronics to transform it up to the voltage the batteries need. They will then modulate that voltage as necessary through multiple stages to give optimal charging and battery maintenance.

Also, Gary isn't exaggerating when he talks about welding cable. If you were expecting the cable to take 10 amps for example then you could buy pretty thin cable that is rated not to melt when 10 amps goes through it. But there will be substantial power loss through that cable - so you need much thicker cable to minimise this power loss.

Steve.

[Mike]

All interestingly how does the fridge supply factor into this ?

[Big Jim]

Thank you all for the detailed replies, I have to work out the best way to achieve the best.
Jim

[saDgit]

Gary mentioned DC to DC chargers - I can second that. CTEK and Sterling Power do such chargers. I have a CTEK which takes inputs from the truck alternator and from the solar panels. I recommend wiring them as close as possible to the camper battery so they supply the correct voltage to the batteries being charged without a voltage drop in between.

The magic of these DC to DC chargers is that they take the voltage coming into them, which may not be high enough to properly charge the battery, and uses solid-state electronics to transform it up to the voltage the batteries need. They will then modulate that voltage as necessary through multiple stages to give optimal charging and battery maintenance.

Steve.

Steve, how have you connected the dc to dc charger in the camper to the truck? Have you done it through the 12S socket? Or have you fitted some other plug and socket elsewhere?