Sprinter battery bank

[billg27]

I also have a 3 stage battery charger plugged into my battery bank that runs automatically anytime that my generator is running. It also has a desulfurization function. Not sure if that's automatic or if that needs to be done manually. Will need to read the owners manual.

And Turtle, when your saying completely discharging a battery, is that a specific voltage level? When I park, battery is usually around 12.8-13 volts. (After battery's are separated and not being charged). But by morning I'm sitting at about 11.4-11.6 volts. I'm running a refrigerator 24/7 plus Espar, TV, LED interior lights and a powered roof vent.

 

[Turtle]

And Turtle, when your saying completely discharging a battery, is that a specific voltage level?

I dunno. Depends on what I said exactly, and in what context. But I probably meant discharging it until it's dead and nothing that's connected to it works.

When I park, battery is usually around 12.8-13 volts. (After battery's are separated and not being charged).

Before measuring the no load voltage is after at least an hour, 12 is better, 24 is best. But after an hour is generally good enough, as most of the surface charge will have dissipated.

But by morning I'm sitting at about 11.4-11.6 volts. I'm running a refrigerator 24/7 plus Espar, TV, LED interior lights and a powered roof vent.

You need a bigger battery bank. Or a newer one. If your current one is old (more than 3 months) don't add to the current bank, replace it with all new batteries, and enough of them to satisfy your amp hour needs for 24 hours without dropping below 50% DoD. Basically, figure out how many amp hours you use in a 24 hour period. If you power the roof vent for 12 hours a day and it uses one amp per hour, that's 12 amp hours over 24 hours. The Espar uses about an amp per hour. If you run the lights for 8 hours and they use 1/2 an amp, that's 4 amp hours over 24.

The fridge will be tricky. You'll need a Kill-a-Watt meter or a battery monitor to tell just how many Watts that thing uses over 24 hours. And it may take you several days to nail it down with a good average.

Whatever your 24 hour requirements are, take that figure and double it, and that's the minimum size your house bank needs to be. The reason it needs to be double the size of your requirements is, the more often you drop below 50% DoD, the shorter the lifespan of the batteries.

24 hours is totally arbitrary, BTW. If can be whatever you want. 24, 48, It's whatever time frame you want to use your batteries without fully recharging them.


This is a table that shows the no-load voltage state of a wet cell battery
(at least one hour with no loads and no charging current applied).

Below is the table for AGM batteries.

Regardless of the type of battery you have, 11.4V-11.6V ain't good.

 

[brokcanadian]

That's it, I'm going to stop wasting my time on Google. Just ask Turtle it's quicker

 

[Moot]

The ProMariner is a smart charger. It has settings for different type batteries. Mine is programmed for AGM batteries so I just let it do its thing.

 

[brokcanadian]

Ok it's becoming clearer now. Finest 85.00 walmart amp I could get Power Acoustik REP4-1400, really is 640w RMS, says 140w max draw (?) I intended this for the sub only or maybe sub and 6x9's, truth be told cheap Pioneer 6x9's and decent 160 watt deck were almost good enough...looking for a bit of youth when I lived in a basement and shook the sidewalk outside getting funny looks from passerby (with a little less deafness). My hunch is, ok with stock alternator but 150 amp taking off original 90 might be safer...battery bank will have to stay as is for now, thanks for posting all of yours, I can dream, but the short runs in current van won't pay enough

Edit: amp has 2 25 amp fuses (per channel?), Class A/B and D, little of everything

Further edit, using your formulas, assuming 640w is correct (300w per channel rough by fuses) I get 90 amp load at .5 efficient...this may be a more efficient amp not being a truly class A...but regardless I need the 150a Alt. Thanks Turtle, I've done lots of mechanical work but never truly absorbed this stuff!

 

[brokcanadian]

One last question...I've seen a few places saying max draw of 140 watt, are audio watts somehow different?

 

[tknight]

Audio outputs are ac not dc so there is some difference don't believe in those watts output ratings they are usually @10-20%distortion if yA want real power get a nice qsc 3406 amplifier it's true power and will blow your windows out faster than opening your door to the wind!

 

[brokcanadian]

I know your side job for me, 4 kids and a wife mean walmart

 

[tknight]

I own a 76,000 watt stero system and don't have but a Sony amazing-fm cd in the truck with stock speakers! I'mike the plumber with a leaky sink at home!
Actually driving is a side job ......


This is a typical show

 

[brokcanadian]

It clicked before I was done calculating how many alternators for 76000 watts in a straight truck

 

[Turtle]

Power Acoustik REP4-1400, really is 640w RMS, says 140w max draw (?)

Depends on how you hook it up. 2 Ohms or 4 Ohms. Bridged at 4 Ohms it's 320 Watts x 2, so 640 Watts RMS.

The 1400 Watts thing is the PMPO - "peak music power output" and is more or less meaningless. An amp can't maintain this for much more than a split second and then only under lab conditions. From that point on, the marketing folks take over and splash this useless number all over the place. RMS is the only number worth looking at.

It's a Class A/B Full Range & Class D Monoblock Amp, so efficiency is good, with .55 or .60 for the A/B and .8 for the subs.

The fuse formula is just a general ballpark thing, mainly to let you know if they're lying or not. In your case, if you go with the 2 Ohm bridge at 640 Watts, then it's easy.

Watts / Volts = Amps

It's going to be more than 12 volts. Some vehicles (most cars, really) operate on 14.4 volts, but of course it varies with temperature and other factors, so it could be anywhere from 14.4v down to 13.2. The Sprinter will generally be between 13.2 (when it's really hot) and 14.2 (when it's Canada cold). 13.8 is a good middle of the road average for a Sprinter under most conditions.

Thus, 640W / 13.8V = 46.38A

Add in the 160 Watt Pioneer (11.59A) and you're at 58 amps.

However, possibly the most important thing that a lot of people don't think of is, that is the maximum possible sustained current the amp will draw at full (un-clipped) power. The only signal type that would require that level of power would be full volume sine waves. If you listen to MUSIC at full volume you can cut that calculated current in about half. If you turn it down at all you can probably cut it in half again.

So the in-service current draw of an amp and head unit like that is probably between 15A and 25A or less on average.

I have a monster Pioneer head unit that's 50 Watts x 4, but that's peak, not RMS. They practically hide the RMS power in the fine print. The RMS is actually 14 Watts per channel.

But I'm only powering the 4" dash speakers (which I've replaced twice).

 

[brokcanadian]

I remember putting some thought in at the time, got a JL 10w3v3 4 ohm and planned on running the Pioneer 6x9s (160 w) on another channel with the 4" tweets, think they were kicker...the 10" sub was rated excellent even at lower watts...the Pioneer DEH-X9600BHS head unit is actually 22w per channel RMS but has great bluetooth phone and app control, and HD radio...thanks for more tidbits, I did calculate at 12v; now not bridging gives me 320 watts total on amp? I think I intended to wire 6x9s and 4" speakers in parallel and bridge the sub channel but it's a 4ohm sub...

 

[brokcanadian]

Found the manual online. Bridged, 4 ohm, 320 watts X2. Ow my head hurts
4,3,2 or mono channel operation

 

[Turtle]

The RMS output on that amp is
4 ohms: 120 watts x 4 chan.
2 ohms: 160 watts x 4 chan.
Bridged, 4 ohms: 320 watts x 2 chan.

So not bridged will be the first one, for a total 480 Watts instead of 640 Watts. If the speakers are 2 Ohms, then it's the second one, 160 per, totaling 640 Watts. The 6x9s are 4 Ohm speakers. The subs may be 2 Ohms.

Either way you've really got no amp worries with the alternator, although replacing the 90 with a 150 isn't a bad idea.

 

[brokcanadian]

Sub is 4 ohm. Gonna save this one for a day when I've slept and the manuals are in front of me. Thanks for the tutorial, I can at least ballpark the loads to Alt, wiring a 4 channel amp with 4 speakers at 4 ohm and a single 4 ohm sub escapes me, especially since I had a reason a year ago...maybe it's dual voice coil I dunno

 

[Turtle]

You'll connect both front and rear left speakers (left dash and left 6x9) to one of the front channels (typically channel 1, or A), and both rights to the other front channel (right dash and right 6x9). That will create a 2 ohm stereo operation.
With your amp specs being:

4 ohms: 120 watts x 4 chan
2 ohms: 160 watts x 4 chan
Bridged, 4 ohms: 320 watts x 2 chan

If you connect one 4 ohm speaker to each channel they will each see 120w, but if you connect two 4 ohm speakers to each channel in parallel, resulting in a 2 ohm load each speaker sees 80w.

That will leave the rear two channels to bridge powering the subwoofer. The 2 ohm stereo power will be combined to provide the 320w. The subwoofer needs to be a single voice coil 4 ohm sub, or a dual voice coil 2 ohm sub with the coils wire in series for 4 ohms.

The drawback is you can't fade from your front to rear speakers. They will always play at the same level with the same settings (gain/crossover). You will still be able to balance left/right. tho.

Or, you can wire the dash speakers to the head unit, the rear 6x9s to the amp, and still have the rear channel for the sub.

 

[brokcanadian]

Thanks...the latter sounds like what I was planning, I seem to have no more room in my head for new things anymore

 

[tknight]

If your gonna put in a kicker type system with a large draw please invest in some storage caps for a tighter low end , as it pounds it will start pumping current in and out of the p and make it bark like fresh do do! Worth the money for the caps .

 

[brokcanadian]

Caps are at walmart now thanks for reminding me, although thanks to Turtle I know draws not so large...

 

[brokcanadian]

Just an update, found a supplier here (they do ship to US) so I thought I'd post the link...200 amp is only 20 bucks more ($260 or $240) so I'd go that route if it plugs in to stock wiring (can't find that info yet) lots of power to have stereo, lights, and ac or heat blasting, while charging the battery bank

ALTERNATOR for DODGE & FREIGHTLINER SPRINTER VAN 2.7L Diesel 2005 2006 05 06

Edit: if the plug fits, lots on the Internet explaining how to upgrade the charge and ground cables on high output alternator installations, that should take care of any wiring harness worries