relay or isolator

Problem: I have a 220amp HO Alternator & a different battery in my engine compartment than the battery bank in my vehicle that powers my radio. I personally want them completely separated at all times so my interior oem components do not see a voltage drop (no dimming). (I also dont want them discharging each other when not in use)

Alright I've done alot of research on both but each has it's pro's and cons. Now The Isolators with the separate Diodes and no moving parts is the technology that I need. One that will charge my Main starting battery, and my battery bank in the back. Basically I want my radio pulling from my battery bank and not front AT ALL with car on or off. But with the voltage drop that's not so efficient of an Isolator to use. Is there any other way to make this to happen?

my theory behind this is I want to keep my battery bank separated from my front battery so my light's and other electrical components will not suffer any voltage drop aka dimming since it is not being used for the massive current draws. Does that sound about right? or is it actually more efficient to just use a PAC-250 relay and add my cranker into the mix of powering the system?

Let me know what you think!
thanks!

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Here we go again!
The diode is the only way to do what you want.

With proper distribution and design you should not have the dimming troubles with a relay.
But for reasons unknown, you chose more batteries rather than a suitable alternator (despite your amp apparently producing well over 30% less output on batteries!!!).
FYI - As I wrote, the norseman wrote more batteries for SPLs - the suggestion being a bigger alternator for road use.   Granted, later he did say bigger battery for road use (which is incorrect), but at least he got the SPL right - except when amp output varies with voltage.


Don't forget to increase your alternator voltage if you use the diodes (ensure the S wire if used is on the battery side).
Don't exceed the diode rating (usually >100A is difficult to get, and they're probably gonna be expensive).
And make sure they are well vented - they get hot wasting all that power LOL!

Diodes - the worst choice of them all. Ha!

We meet again... alright alright, I think I'm just going to go with the PAC-250amp relay, because with the isolator I would have to get the Isolator AND a voltage module to charge at 15.3V just to have it set up a certain way, and I dont have certain money... sooo lol I have decided to go with the PAC AS long as The batteries do not discharge eachother when car is off, I'll be fine for now. Thanks again ole spark!!

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As long as you switch off the PAC, the batteries will be isolated (unless its contacts have fused).
I have described in your other thread & elsewhere how to do this automatically for no cost.

That does not mean that the batteries will not flatten - get a dash-voltmeter for that.


The 15.3V voltage module should cost you about 10c, or 20c with "reversible redundancy", but that depends on your alternator type. (If it's a single wire D+ type, it won't work unless you hack internally.)
However I have no idea why you would want 15.3V unless perhaps you are using diodes to all batteries, or you like AGM thermal runaway. But I have little doubt someone has told you that's what you need.

For someone with a limited budget, I reckon you will be spending way more than you have to, or should!


How are the Florida lads going wrt to answering those questions....? Stay with them - that way you'll have consistent advice.

oldspark wrote:

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As long as you switch off the PAC, the batteries will be isolated (unless its contacts have fused).

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Come onnn so when the car is OFF (no key) with a relay all of the batteries (even the engine battery) will be connected in parallel?? Only when the key is in the "on" position they will be isolated?

Just questions #1 and #2 "yes" or "no" I tried to make those questions as simple to answer as possible lol

1.

2.

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No.
No.

oldspark wrote:

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No.
No.

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PERFECT!

So only when the engine is RUNNING will the batteries be connected in parallel and charging from the alternator, correct?

1. (yes or no) lol

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No.


My "ultimate intelligence battery isolator" solution only connects the batteries together when the alternator is charging.

alright what is the name of yours, or a relay that you know works exactly like yours?

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It has no name.
Any relay.
The PAC you have should be ok.

Geez it hard getting spec on the PAC.
It wasn't until I saw the SPR-200 that it was confirmed that the PAC-200 is a mere relay.

The SPR-200 is merely a PAC-200 with a BC-12 voltage sensor.
That shows how - for automatic isolation - you can spend an extra $35-$80 for no reason.
But wait - is the BC-12 adjustable? No - it will not isolate batteries until partially charged. (12.5V?)

What delays does the BC-12 have ? Good question. No info.
But it uses a microprocessor - I suspect one of those quad-analog LM series. What a pity they want to all that expense and didn't add a simple adjustment feature (whether Philips, USB, or line signaling).


BTW - I like the installation instructions.
First for the PAC-200 - does anyone see a (power wiring) problem?
Then for the PAC-200 in the SPR-200 kit.






Sorry rfhvhtoo - I hijacked a bit.
Not that you'd be using a PAC-200 or -400 for your 4kW system - this is more for the amusement of regulars, and as a hint for prospective installers.

I actually do need the PAC-250 for the 4k system correct? I thought thats how both the isolators and relays were measured, by the amount of current draw to your amps can continuously go through it.

If im wrong. thank g*d...

And the Power for the relay is the accessory wire from the head unit. The same remote wire one that goes to your amps also turns on the relay.

and its fine hijack it all you need, I'll be learning too lol

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Que?
A 250A relay for a 500A load - I don't think so!


And I assumed you were going to charge the 2nd battery even if the amp wasn't in use...

Oh alright I thought you were saying that was PAC-200 was TOO BIG. I was like waitttt a minute. But could I not go off of the fuse ratings of my amplifiers as well?

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And yeah I am going to charge the 2nd battery even when the amp isn't in use. I'm thinking about going with this cheap one and test the waters. Check how hott it is after playing for a while. Only 25$ worth a shot!

https://#/ws/eBayISAPI.dll?ViewItem&item=270534007577&viewitem=&sspagename=STRK:MEWAX:IT#ht_1664wt_1165

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rfhvhtoo wrote:

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I thought you were saying that was PAC-200 was TOO BIG.

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LOL! You crack me up.... Yeah - you have to avoid "too big" relays - they are like batteries that are too big for your electrics and supply too much current.....   


The relay should (or must) exceed the equipment fuses.
But somehow I doubt a 4000W RMS amp will have only 250A of fuse(s)!
(Bullsh amps like those Boss, Evolution, Soundstream OL/EV/XXX-4(KD/000) are not 4k RMS output....)


And for those amps without fuses, your relay should (or must) exceed your battery fuse rating.

rfhvhtoo wrote:

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And yeah I am going to charge the 2nd battery even when the amp isn't in use.

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How?

See I'm catchin on! lol

I will charge all the batteries once a month @ 8amps on the 4 step charger. I called shuriken and they said there is no specific way of charging the batteries, and their battery charger is a 73.5 amp charger. (it claims 1000 watts output at 13.6v so I just did the math)

If I have the batteries hooked up parallel can I can I charge them all at once? With them each being at a different level of charge I would think "no" but you never with technology these days.

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rfhvhtoo wrote:

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See I'm catchin on! lol

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I certainly have yet to see evidence of that. lol!

rfhvhtoo wrote:

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I will charge all the batteries once a month @ 8amps on the 4 step charger.

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Once a month?
Surely you mean after every use? (eg - every day?)

im trying man lol

We'll I dont BURP my radio or anything draining the batteries as much as possible. Like my radio gets about a 30 minute play on the daily basis, simply because law enforcement is fierce. So I play it on the highway on the way to work for about 5 minutes each way Nice and loud, and barely audible outside of the vehicle in the city for about 20 minutes when just driving. I mean if I see a difference in floating within a week then Ill see about charging it more frequently lol

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Well you know how long/much you will use. Allah knows I've asked...
The last I recall was my reply about the battery(s) lasting 20 minutes at most....


But you have my previous replies about sizing and auto-connecting the isolator whenever the alternator is charging.

I might hear back at the first recharge - or whenever the batteries fail - whichever comes first .

So, how are the batteries going? And the system?

As I just updated in rfhvhtoo's charging agm battery, I'm curious to see if the batteries lasted.

And obviously, if they only need recharging once a month, why bother with them at all? (Noting that I still have no info regarding this "100AH per 1kW output" rule. An idiot? Or a battery salesperson?)


Bigger batteries better than a bigger alternator? Choice!
(Except as noted of course. )

This is what I did, added 200 Amp relay and a 3-position rocker switch with a led lights to match the factory look. and see at night.

1st Position. Joins both batteries for starting, and then releases the seconded battery. Your vehicle ( Relay) then switches back to the primary battery after start.

2nd Position. (Middle) starts on main battery, and stays on main battery. (2nd battery remains separate at all times.

3rd Position. Both batteries are joined in parallel. Vehicle starts and runs with both batteries. Good if your main battery dies, just throw the switch and jump start you’re self without getting out of the vehicle. Works good for winches and plows or anything that needs extra power. Just remember to switch it back to position 1 or 2 after you turn off the engine.

This simple switch can be picking up a good electronic store (not radio shack) for about 12 bucks. Wiring is simple, but comes with no instructions. You can refer to some web sites or better yet. Look here at the12 volt for wiring it up.

The Pac Relay is fine. It’s really a White Rogers relay; Stinger is also the same relay. Buy one on any auction for $ $30 bucks or less, Pac is kind of expensive.