The Turtle Mobile
- Thread starter Turtle59
- Start date
Can anyone help with info???
I am wanting to run some suitable cable from my two starter batteries (because it's 12v) to the back of my Canter to an Anderson Plug so when I tow my Camper Trailer it will charge the battery on the camper.
Here is my problem.
With the Canter having two batteries, do I need to include both batteries, or do I run an isolator switch etc, etc? Can anyone provide a rough mug map or wiring type diagram for me to work from in-order to get my head around this a little better?
Your thoughts and assistance would be greatly appreciated.
I am wanting to run some suitable cable from my two starter batteries (because it's 12v) to the back of my Canter to an Anderson Plug so when I tow my Camper Trailer it will charge the battery on the camper.
Here is my problem.
With the Canter having two batteries, do I need to include both batteries, or do I run an isolator switch etc, etc? Can anyone provide a rough mug map or wiring type diagram for me to work from in-order to get my head around this a little better?
Your thoughts and assistance would be greatly appreciated.
graynomad
Photographer, traveller
So the Canter crank is 24v and the trailer 12v?
If so it's not advisable to tap off one of the crank batteries, they are different beasts to deep cycle. I would either add a second alternator or get a proper A2B or B2B charger such as those made by Sterling.
If the Canter is 12v you can just run a cable but I would at least add an isolator of which there are 100s on the market. The simplest just closes when the ignition is on, the next step up is one that waits a while until the crank battery is at a certain voltage. But once again a proper charger is a better way to go.
Let me know which it is and we can continue.
If so it's not advisable to tap off one of the crank batteries, they are different beasts to deep cycle. I would either add a second alternator or get a proper A2B or B2B charger such as those made by Sterling.
If the Canter is 12v you can just run a cable but I would at least add an isolator of which there are 100s on the market. The simplest just closes when the ignition is on, the next step up is one that waits a while until the crank battery is at a certain voltage. But once again a proper charger is a better way to go.
Let me know which it is and we can continue.
SkiFreak
Crazy Person
To start with, I should say that I am not an auto electrician.
Having said this, I have encountered quite a few auto electricians that definitely do not inspire me with their knowledge of wiring extra low voltage systems. Just saying...
I have seen lots of "kits" for charging camper trailer batteries (on eBay and the likes) that use 50 amp Anderson Plugs and 6B&S cable (13.29 sq/mm), but I suspect that these are not really optimal.
The cable that runs from your alternator to your batteries is a bit over 6B&S, probably 4B&S. The cable run is about 3m from the alternator to the batteries on a Canter. Add to that another 4m to the end of your truck (from the starter batteries) and the distance to your battery in the camper trailer, probably another 3m. So, to get power to your camper trailer battery there probably needs to be a 10m cable run, which is quite a long way.
You do not need to run off both batteries, just one. Think about how the batteries get their charge from the alternator now; there is just one power cable from the alternator, then both batteries are in parallel.
Your biggest problem in such a setup is going to be voltage drop, so decent sized cables should be used to get power to your camper trailer battery.
If I were doing this I would probably use 175 amp Anderson plugs and 2B&S cable (33.61 sq/mm) from the starter batteries to the back of the truck. A bit bulky, I know, but in my opinion it is better to over engineer than to under engineer any electrical circuit. Maybe that's just me...
Another thing I would include is a Voltage Sensitive Relay (VSR). This will ensure that the starter batteries are charged first and that the camper trailer batteries cannot drain the starter batteries. A VSR is an isolator too. Google VSR if you need more info on how they work. I have seen Narva 140 Amp VSRs for $48 on eBay, delivered. And, if you want to be really safe, add a 100 amp MEGA fuse at the starter battery, before the VSR.
Definitely more expensive doing it this way, as copper is not cheap, but it's the way I would do it...
Having said this, I have encountered quite a few auto electricians that definitely do not inspire me with their knowledge of wiring extra low voltage systems. Just saying...
I have seen lots of "kits" for charging camper trailer batteries (on eBay and the likes) that use 50 amp Anderson Plugs and 6B&S cable (13.29 sq/mm), but I suspect that these are not really optimal.
The cable that runs from your alternator to your batteries is a bit over 6B&S, probably 4B&S. The cable run is about 3m from the alternator to the batteries on a Canter. Add to that another 4m to the end of your truck (from the starter batteries) and the distance to your battery in the camper trailer, probably another 3m. So, to get power to your camper trailer battery there probably needs to be a 10m cable run, which is quite a long way.
You do not need to run off both batteries, just one. Think about how the batteries get their charge from the alternator now; there is just one power cable from the alternator, then both batteries are in parallel.
Your biggest problem in such a setup is going to be voltage drop, so decent sized cables should be used to get power to your camper trailer battery.
If I were doing this I would probably use 175 amp Anderson plugs and 2B&S cable (33.61 sq/mm) from the starter batteries to the back of the truck. A bit bulky, I know, but in my opinion it is better to over engineer than to under engineer any electrical circuit. Maybe that's just me...
Another thing I would include is a Voltage Sensitive Relay (VSR). This will ensure that the starter batteries are charged first and that the camper trailer batteries cannot drain the starter batteries. A VSR is an isolator too. Google VSR if you need more info on how they work. I have seen Narva 140 Amp VSRs for $48 on eBay, delivered. And, if you want to be really safe, add a 100 amp MEGA fuse at the starter battery, before the VSR.
Definitely more expensive doing it this way, as copper is not cheap, but it's the way I would do it...
G'day Graynomad
My Canter is 12v and SkiFreak has the good oil. We could be brothers coz we are on the same wave length. This is exactly what I was thinking, just needed some confirmation. Thanks blokes much appreciated.
Thanks SkiFreak
graynomad
Photographer, traveller
Yeah, what Owen said. I wasn't going to type that much before knowing if it was 12 or 24V 
Whatever cable gauge you use there will be a voltage drop, the only question is how much can you tolerate. Once you know the max charge rate in amps you can calculate the drop for a given wire. Tuning that might save a few $100 over 20 meters (10 x 2 unless you use the chassis as a return which IMO is not a good idea)
That said 35mm2 (I think in metric sizes) sounds about right to me, but I've not done the sums. I used 16mm2 for the same job on my Jimny, and the cable run was only about 3M but that was probably overkill.
Whatever cable gauge you use there will be a voltage drop, the only question is how much can you tolerate. Once you know the max charge rate in amps you can calculate the drop for a given wire. Tuning that might save a few $100 over 20 meters (10 x 2 unless you use the chassis as a return which IMO is not a good idea)
That said 35mm2 (I think in metric sizes) sounds about right to me, but I've not done the sums. I used 16mm2 for the same job on my Jimny, and the cable run was only about 3M but that was probably overkill.
gait
Explorer
the general problem is whether the alternator voltage is high enough to reasonably charge the camper batteries during a normal drive time.
The starter batteries don't have to be fully charged to start the vehicle. Also, it doesn't take long to replace energy used if starting easily. A few minutes by most calculations.
Camper battery charging is a subtly different problem.
I see volts at my starter batteries around 13.7 - 13.8v, sometimes higher. For camper/house battery charging I prefer higher, around 14.2v (depends on battery type). It takes longer to charge at lower volts.
Also depends on battery types. For example vehicle are usually wet cells, camper may be AGM.
Thus, A2B located near alternator, B2B located in camper, or inverter charger located in camper (not recommended to have inverter in vehicle and charger in camper).
A cheap trick is to increase alternator volts with diodes (as low value resistors) in the voltage sensing line for the alternator - but then vehicle battery charging is changed.
Other bit to remember is that as battery approaches full the charging current reduces which reduces the cable voltage drop. All a bit of a balancing act. AGMs accept charge better than wet.
I have lots of solar and B2B. B2B failed a couple of months ago. I originally installed with a by-pass switch. I've occasionally needed to run engine while stationary to charge house (short days, low sun angle, and lots of dust in India). With no solar direct from vehicle to house batteries at 13.7v charging house is slow as a wet weekend. Made even worse by having to replace dying AGM house with starter batteries - all that was availabe at the time and location.
First step then is measure volts at vehicle batteries with engine running to see if its even high enough for adequate camper charging in normal driving time.
The starter batteries don't have to be fully charged to start the vehicle. Also, it doesn't take long to replace energy used if starting easily. A few minutes by most calculations.
Camper battery charging is a subtly different problem.
I see volts at my starter batteries around 13.7 - 13.8v, sometimes higher. For camper/house battery charging I prefer higher, around 14.2v (depends on battery type). It takes longer to charge at lower volts.
Also depends on battery types. For example vehicle are usually wet cells, camper may be AGM.
Thus, A2B located near alternator, B2B located in camper, or inverter charger located in camper (not recommended to have inverter in vehicle and charger in camper).
A cheap trick is to increase alternator volts with diodes (as low value resistors) in the voltage sensing line for the alternator - but then vehicle battery charging is changed.
Other bit to remember is that as battery approaches full the charging current reduces which reduces the cable voltage drop. All a bit of a balancing act. AGMs accept charge better than wet.
I have lots of solar and B2B. B2B failed a couple of months ago. I originally installed with a by-pass switch. I've occasionally needed to run engine while stationary to charge house (short days, low sun angle, and lots of dust in India). With no solar direct from vehicle to house batteries at 13.7v charging house is slow as a wet weekend. Made even worse by having to replace dying AGM house with starter batteries - all that was availabe at the time and location.
First step then is measure volts at vehicle batteries with engine running to see if its even high enough for adequate camper charging in normal driving time.
whatcharterboat
Supporting Sponsor, Overland Certified OC0018
Hi Turtle,
Joe's math is good but you need to allow clearance between the body and cab and also some clearance at the rear. Our 60% overhang rule does not run out to the end of the body but rather it runs to the furtherest point fixed to the body.....so this can mean lights, bumper, spare wheels, even an antenna......so don't get caught with nothing spare behind your external body panels. It's not pretty if you get it wrong and some transport inspector picks up on it.
Regards John
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Hi john and others,
Many thanks for the information gentleman.
John, a question if I may, is there a standard measurement between the truck body and the cab? OR, what is a typical measurement for this gap?