What, pray tell, is an "apu" ??


Thanks.

 

APU = Auxiliary Power Unit. There are may brands . We have a Rig Master that is self contained. It supplies a/c, heat, and a 6000w gen. Runs on diesel. Has a little Perkins motor.

 

Not all APU's are linked to the main engine. TriPak uses the sme coolant as the big motor. Like I said Some are totaly independent

 

You might take a look at: http://www.yandina.com/c160Info.htm

 

Here is a write up I did. I run a solenoid and dual red tops.

 

I've used a solenoid for the past 12 years. No problems.

 

just a suggestion, i run my boat and camper with 2-3 batteries, using a standard electric continuous duty solenoid, your truck will start fine with one optima, wire other circuits like stereo, interior lighting, and any other loads commonly used while truck is off, leaving a dedicated engine start battery for insurance, you can also wire solenoid to cycle during start, using a 100 watt diode, enabling both batteries during start up. if one is dead, the other will back it up, both will charge during run time, when one goes bad, it wont take the other with it.

 

hey-Hey!!!,
The diode will drop ~.7V between the alternator and the aux batteries. This voltage will be less if you get a Schottky type( v. a silicon PN-junction type ) but they need their specs closely inspected since that style tends to leak, and that would drain the battery you're depending on for starting. That will keep them from getting a full charge if there is no way to remove it from the circuit( a shorting relay? ). Schottky type will drop ~.3V and that will impact reaching 100% SoC less than the PN-junction. I'd still want it removed from the circuit to insure a full charge.
cheers,
Douglas

 

hey thanx again everyone for all the info and opinions.
from what i gather, the continuous duty solenoid is probly the logical option for me.
the amp rating on those is refering to rate at which it can charge right? So i have a 120 amp alternator so i would want atleast a 120 amp continuous duty solenoid

 

The setup we have used on multiple vehciles (gassers, but that shouldn't matter) is to put a HD/CD solenoid between them, then have the solenoid wire to both the starter relay (increase CCA) and to an oil psi switch (for charging). When the rig is off the batteries are isolated, and one wont drain the other so you can jump yourself. We also put a "T" spade at the solenoid so you could move a jumper and close the solenoid with out the starter energized or the engine on.

This is something I would like to do to my 05 someday.

http://www.fisheriessupply.com/produ...m=on&km=entire

 

That bit about the starter-solenoid automatically engaging both banks of batteries when starting is the first time I have read it mentioned in all the countless multi-battery articles and threads that I have perused.

I think it is brilliant.


I would want a manual over-ride/kill on that function, though.


There has been a lot of good information given here; let's keep the good ideas coming.

 

This is basically how my system works, there is 3 positions Auto which will connect the 2 batts when the key is turned on. Off which keeps the batts separate, and emergency which will allow the aux batt to energize the solenoid to start the truck if the main is dead.

Here is the diagram for the control switch

 

We had it setup with the slip fit spade connectors, so it was quite easy to either over-ride or kill, just had to pop the hood. A DP/DT switch could do it from the cab, but we never messed with it enough to worry about.

 

They are also used on almost all aircraft to supply power when the main engines are off including on tanks.

I want a gas turbine APU.

Jim

 

You need to use a Sure Power Separator between your batteries, this will give you everything you are asking for,

This is what I am using to isolate my 3 separate banks from my alternator.

They can be configured to parallel all batteries for starting or you can connect them using switches.

All of the axillary batteries will automatically connect into your system only after your main battery has reached 13.2 volts and then when the alternator stops producing power it will automatically disconnect to be totally isolated.

http://www.smithae.com/products/sure...eparators.html

If you look, the electronics package does all of the sensing while a heave duty 200-amp continuous duty solenoid does the switching.



I am not affilliated with this company in any way but I would reccomend them to anyone because I know they work.
Jim