ah draw?

Ooopps My bad! My apologies. Upon review, I seem VICIOUS!

oldspark wrote: What are the different opinions, and from "who" - ie, what background or authority? ... blah blah blah.... So I ask - where do the opinions differ from above? And by whom?

I sound worse than a Danish Ambassador! I did NOT mean to DEMAND a full account.... etc. My intent was twofold: - to show that IMO "we" were saying the same thing (certain currents may be considered a significant drain - ie, 50mA or ~ 2-3 LED strings etc) whilst other are (ie, 0.6A). - if OTHERS were saying different, WHAT were they saying? (And then with what credentials - battery or auto-elec pro's, mechanics, another forum?) Then I/we could sort out the contradictions, and maybe establish what that 6/10Ah per day (or whatever) means.... If you have sorted it all out, that's fine. But please - if you haven't, please continue hereon. And DOUBLE please - if you figured out what that 6/10Ah means? (ie - 0.6A, or 25mA, or ????)    

That drain is equivalent to 11/2 alarms with 2 LEDs! If the vehicle is used every day, it shouldn't be a problem, although of course less is better! Now my question:- What is this? A GPS tracker? Ours draw 3-4milliamps.

My apologies for being away. My PC quit and ended up replacing it. Anyways, I haven't figured out exactly what these numbers mean as of yet. I asked one friend of mine how he perceived 6/10ah. He thought maybe 6 tenths of an amp draw per day...? The truck is a daily driver, and hasn't had any starting problems since the install. The unit is called The Rumbler. It is made by Federal Signal (emergency warning products). The rumbler takes the frequency of the regular siren tone, and emits it in a low frequency so that drivers can "feel" the siren, in the event they're distracted by something else. For example listening to loud music. Thanks for all the replies!!

The way some specify power consumption can be confusing. It annoys me when people refer to a load as Amp-Hour when they mean Amps. (Amp-Hours is used for time-averaged loads.) I too interpret 6/10 AH as being 0.6AH. If it's a specification from the USA, it's likely they don't understand metric and hence can't use write 0.6 - hence they wrote 6/10ths or 3/5ths etc. The question is, over what period are they referring to?    I'd assume a 24 hour period, If it were per hour, why not say 0.6A? 0.6AH over 24 hours is a 25mA load - ie, the equivalent of a DC LED and some light circuitry (pun unintended).

Yes to 24hrs., google SMART split charging systems, there are some especially marine which charge your main battery fully before attempting to charge the secondary.

If you use diode systems to isolate batteries, unless the regulator senses the battery voltage, the battery will undercharge (by the diode's voltage drop unless the regulator's "S" Sense wire is connected to the battery. I find Smart Split-Charge systems dubious. They may have application where the system isn't on long enough to charge both batteries fully (but that will lead to failure anyhow), but the fastest way to charge the system is unhindered current to both batteries - no current limiting. And I question HOW such systems determine and then limit their currents. It seems they don't even have to know what capacity or type (wet or AGM) its 2 batteries are. (LOL?) IMO - more snake oil. I like my 2-battery system as shown below. It's equivalent to common charge (voltage) sensing solenoids but uses the sensor that most vehicles have - namely the charge lamp. It has worked well on Hitachi, Nippon Denso & Bosch alternators (with integral regulators) with 60 Ohm relays. Some vehicles already have an equivalent relay for electric fuel pumps or similar accessory control - in that case you have that relay power your "aux battery" relay. Note though that some fuel-pump etc systems also get power during cranking (in which case the aux relay could be connected with its #86 to the existing relay output, and its ground #85 to the starter-solenoid circuit so it disconnects the aux battery during cranking).

That's an interesting set up. So if I understand right, the charge light is the "sense" sensor? The vehicle I'm trying to have a system set up in is a 95 nissan pickup. Now I'm not 100% sure, but I didn't think that truck had a "sense" wire. My idea with the solenoid would not work? I assumed that once it was shut off, it would cut the 2 batteries in two, and then the main battery would then receive a full charge. With your above setup I could step down in wire size, as I have 4ga from my isolator to my aux batt. Thanks

Solenoid, relay - same thing. (Ambiguities - a solenoid is a coil as in the actuating coil of a relay. But a BIG relay is often called a solenoid.) I bet your Nissan has a charge lamp wire - aka "D+" or "L" from the alternator. Or don't you have a charge lamp? In single-wire alternators (ie, heavy B or B+ cable to battery +12V that all alternators have, plus a single other wire), the charge-Lamp "L" is called D+. In 2- & 3-wire alternators, it is called L. That goes to the dash's charge lamp as shown in the diagram. It might instead go to a relay that controls charge and other lamps, but not on older vehicles. That L/D+ circuit may also be diode-connected to other lamps that are tested upon IGN-on (eg, brake warning light). On older cars, these tested lamps also comes on whenever the alternators stops charging (and the ignition is on - eg, charge failure or engine stall). The above diagram depicts a typical charge-sense relay (solenoid) system except that the after-market "smart" relays/solenoids use a voltage sensor to control the relay (#86) - eg, relay on if the main battery/alternator exceeds (say) 13.5 Volts (and off if below 13.0, and maybe if above 14.5 etc). I had a system like that - a sensor with settable voltage and hysteresis delays - that would control the relay (in its case, a latching 80A relay). But when it failed, I hit on the above idea.... (Alternators don't need water proofing against high-pressure engine cleaners.) It's not quite the same as the voltage sensing method. Instead, it connects the 2nd battery whilst its alternator thinks that it is charging.... ie, its charge lamp is off. It is the same system that is used for many electric fuel pump relays where the fuel pump "shall be off if the engine is NOT running". [ FYI: Hence if you have that fuel pump, consider connecting your relay's #86 to the fuel-pump relay's output so as to not add extra load to the (alternator) voltage-regulators L/D+ output - but other considerations include if the fuel pump is on during cranking or is ECU controlled (in which case it is better to have the new aux-battery relay supply the L/D+ signal to vehicle - ie, intercept the L/D+ with your #86 and relay, and feed its output (#87) to the battery and the original L/D+ wire; with a reverse-biased spike-protection diode across the original L/D+ wire). ] It's a bit like saying that instead of the aftermarket voltage sensors turning on their relays when they think the car is charging, the alternator turns on the relay when it thinks it's charging. Nice, simple, and it merely costs a relay - which you should have anyhow (unless you intend to parallel batteries full-time - but even someone that purports to be Jim McIlvaine, eCare Manager, OPTIMA Batteries, Inc. hasn't come back to me with evidence to support his statment that it is okay to do so on matched Optimas - I recommend avoiding it....). Plus the all-important fuses at each end (which you MUST have anyhow!) - though I use circuit breakers (until I have some sort of blown-fuse alarm system!). It's only if you have a huge solenoid that you might need a extra relay. (Yes: pun - or ambiguity - intended...) IE - if a big relay (or solenoid) has a big-current solenoid (actuating coil) that might damage the regulator's charge-lamp circuit, then use a smaller relay to turn on the big relay. I know that most alternators (Bosch, N-Denso, Hitachi (= Mitsubishi, Nissan etc)) can handle 60-Ohm solenoids - ie, about 200mA. They can certainly sink (ground) higher currents (1 Amp and higher), but supplying +12V current may be limited to less..... And a caution - jusy about every alternator (regulator) with a charge-lamp circuit needs the charge lamp (or other lamp or resistance) to reliably initiate charging. Whether they continue charging if that +12V "trickle" or "tickle" current source (via the charge lamp or other resistance) is removed depends on the alternator/regulator. And many alternators may initiate charging without a charge lamp, but that's not guaranteed (residual or remnant rotor magnetism refers). And some systems (like the Bosch 2-wire S & L alternators) must have an L connected else their regulator will not function. (I mention the this as a general caution, and also because I have seen so much incorrect information on the web etc.) BTW - your "I assumed that once it was shut off, it would cut the 2 batteries in two, and then the main battery would then receive a full charge is half correct.... When off, the batteries are isolated. But your main battery will NOT receive full charge because the system isn't charging.

BTW - your "I assumed that once it was shut off, it would cut the 2 batteries in two, and then the main battery would then receive a full charge is half correct....

When off, the batteries are isolated. But your main battery will NOT receive full charge because the system isn't charging.

What if while the truck was running and the solenoid off?

I like the above idea and think i'm going to venture down that road. i have an optima red top as my starting battery, and a 12v gel cell type battery that was originally used to power cell tower sites when the power went out. i was lucky enough to get one of these batteries. i just need to effectively charge both.

i was just going to put a solenoid inline between the aux battery and the isolator thinking once it was isolated, my starting battery would take a complete charge. and after a few hours of run time on my aux batt- i'd just turn the solenoid on to charge.

thanks again