New Alternator?

Northern tool has a good price on battery isolators right now. if i didn't have a baby in my arms I'd post a link. =)
 
"Battery isolator: allows an auxiliary battery to be charged by the vehicle's system, yet not participate in engine starting."
That's what I need!... I think... if I go the additional battery route. Wire it in parallel and put a battery isolator on it, it would do away with the need for the second inverter and charger. If I understand correctly my inverter and anything else I did not want to experience the voltage drop would still be able to pull juice from the whole system. Anybody know what size wire would be required to run to the third battery, since it would be just for charging purposes it would not have to be as large as the "cables" that run to the other batteries would it?
 
The yellow top optima are great and are widely available. Also kinetic which you might be able to find locally or order online. Kinetic has a very strong car audio following and those guys beat their batteries down. Both are deep cycle batteries that you can drain dry and still recharge. Normal batteries take damage when you drain them dead. Although some would disagree you can put optima and kinetic inside the cab or in the trunk with out worry since they are sealed batteries. I've had the optima yellow top under my rear seat for months with out a problem. But I had to remove it due to limited space for my subwoofers. I hear sears has good batteries and interstate but for only under the hood placement and I'm not sure about their deep cycle version.
 
Are the Optima batteries all that they are cracked up to be? What about the DieHard Gold Tops? Or even the WallyMart premiums?

What is hot - and what is not?
And why?


I've heard mixed reviews about Optima. some say they are great, and others say they aren't so great.

personally I use duralast but I'm not running anything more than a radar detector and my power inverter, and my cell phone charger or scanner charger at any given time.
 
I'm not a battery expert, but here're some thoughts about what I've read that influenced my setup....

The standard vehicle starting battery is designed to deliver and accept high currents, and to survive in the high temperatures of the engine compartment. It doesn't do that well for supplying a sustained current, and its life suffers if discharged toward exhaustion. The spiral-wound cell batteries for starting (Optima?) have premium design features at a premium price.

Deep-cycle batteries are designed to deliver and accept lower currents, and for less stressful temperatures. In return they provide significantly more total energy capacity and durability when run toward exhaustion.

It's not a good idea IMO to charge a deep-cycle battery directly off the alternator/regulator because the charging current (and voltage) can spike quite high.
 
I'm not a battery expert, but here're some thoughts about what I've read that influenced my setup....

The standard vehicle starting battery is designed to deliver and accept high currents, and to survive in the high temperatures of the engine compartment. It doesn't do that well for supplying a sustained current, and its life suffers if discharged toward exhaustion. The spiral-wound cell batteries for starting (Optima?) have premium design features at a premium price.

Deep-cycle batteries are designed to deliver and accept lower currents, and for less stressful temperatures. In return they provide significantly more total energy capacity and durability when run toward exhaustion.

It's not a good idea IMO to charge a deep-cycle battery directly off the alternator/regulator because the charging current (and voltage) can spike quite high.

I was just thinking about this today... if your alternator is keeping three batteries charged what sort of current would be going to the spare battery, and does it matter what kind, how small the third battery is?

For those with the same problem as I'm having... unless I figure out some reason it wouldn't work because of the questions above, I've decided to get a regular small sealed third battery wire it in parallel, put an isolator on it, then run my inverter off of it. That way when I start my truck the inverter will still be supplied with the full 12.5 volts from this battery, while the other batteries are supplying current to my starter. When my truck is running the extra battery will be charged by the alternator. When my truck is not running, all of my equipment will still be able to pull juice from all three batteries. Theoretically the third battery could be tiny since it would only be supplying current by itself just the short time I'm starting my vehicle. But it must still be able to handle whatever charging current it will be receiving... maybe I could reduce this some how... just thinking.

Josh
 
Far as the quality of optima, the red tops, well for me- stink. I've killed 3 by running them dead and they were permanently damaged and wouldn't hold a charge for long. Yellow tops are made to take a beating but cost a deal more unless your local autozone guys are brainless like they was when I bought mine. My deep cycles have no issues with taking a high current charge. I've been running a optima yellow top off my 250A alternator for over 2 years now.

Joshua all the batteries would get the same amount of current but would in effect be divided by the number of batteries needing charged. But 3 batteries is way overkill and your asking for alternator problems if your running stock.

let's see, on my truck I have:

4-150w floods
6-65w spots
2-85w fogs
1-150w remote control spot w/ camera
yes the silly LED light bar
5 gallon 150PSI viair compressor
3000w RMS amp
1600w RMS amp
300w RMS amp
aftermarket DVD/NAV/TV
CB
Yaesu 8900R ham
1000w inverter
9.5T electric winch
old school scanner
laptop@65w
additional LCD display
camcorder on inverter
headrest monitors
battery chargers for cameras

This is all running off 1 optima yellow top right now and the 250A alternator. I run a very solid electrical distribution system and aside from running a rather small solar panel to trickle charge, my system does fine. I'm pretty sure you don't need 3 or even 2 batteries. Unless of course you plan on using a big microwave in your truck.
 
I'm pretty sure you don't need 3 or even 2 batteries. Unless of course you plan on using a big microwave in your truck.

I'm open to ideas. I know I don't need 3 batteries but I can't think of another way to keep a constant 12.5 volts to the inverter. My truck came with 2 batteries from the factory just for starting purposes, as do all F-250 powerstrokes I assume. I have considered using a large capacitor with an isolator on it in place of an extra battery (if they make such a thing). That would feed a relatively constant voltage to my inverter for say just a few second while I'm starting my truck. I realize my problem is pretty specific, maybe I just have a super sensitive inverter, cause if the voltage drops much below 12.5, as in anytime there is another load on the system, it shuts down. Theoretically the third battery could be tiny, as in moped tiny. Still figuring on it.....
 
Ok that makes sense since you have a 250. I'd first try running a heavy gauge fused cable for the inverter. Actually I'll point you to a knukonceptz.com their stuff is cheap and quality. Here's some links:

Battery Terminal
Inline Fuse Holder
Heavy Gauge Cable
Distribution Block
Then depending on your inverter terminals you'll need a smaller gauge wire from the distribution block to the inverter. My Duracell 1000w handles the 1/0 gauge which is about as thick as your thumb. Then of course the same gauge wire to ground the inverter. Make that short as possible. I grounded mine to a seat bolt.
 
Ok that makes sense since you have a 250. I'd first try running a heavy gauge fused cable for the inverter. Actually I'll point you to a knukonceptz.com their stuff is cheap and quality.

Thanks for the links, I doubt I could use anything that heavy, my inverter is only a 400w, but I'll check their stuff out, a distribution block of some sort would be handy.
Sorry I didn't make that plain about my truck having two batteries just to handle the load required by the starter as not much else I said made sense without knowing that. Running some heavy gauge wire to the inverter would be the simplest thing to do, but as David Wolfson pointed there is voltage drop at the battery when the starter is pulling. But I know there is some additional voltage loss that occurs just due to having small wire, and then going through all the wiring from the power outlet... so I think I'll try the heavy gauge wire run directly from the inverter to the battery first. If that doesn't work, second option will be insert a small third battery isolated just to run the inverter... I could use the same wire.
 
Joshua, I have been using a Optima yellow top battery, with the standard alternator in my Honda Ridgeline. It runs all my equipment and has not shown any draining issues. I have been very pleased. The battery came out of my Subaru Forrester which had a small alternator. The battery solved the problems with all the equipment drawing down the power. A good choice for what I needed to correct.
 
Joshua, I have been using a Optima yellow top battery, with the standard alternator in my Honda Ridgeline. It runs all my equipment and has not shown any draining issues. I have been very pleased. The battery came out of my Subaru Forrester which had a small alternator. The battery solved the problems with all the equipment drawing down the power. A good choice for what I needed to correct.

Yeah, I know those yellow tops are good, and they have a good price, haha.
I got two mega batteries, so I don't have a problem with my equipment drawing them down.

Here's whats going on in more detail.. for those that are experiencing similar problems. And hey its just good to figure this stuff out so you can trouble shoot....

A charged battery shows a potential of around 12.6 volts. When your car is running your alternator is kicking out over 13 volts, sometimes more. An inverter likes voltage that is greater than 12 volts. When a battery is becoming depleted it starts showing a voltage of less than 12 volts... down to 11 then 10 and I guess it would keep dropping. An inverter (at least mine is according to the specs) is designed to turn itself off when the voltage gets down below 11 volts, in the event you forget and leave it on, so hopefully you still have enough juice to start your car.

Another way a battery will show less voltage is when there is a large load on it... as when your starter is trying to start your car. My truck has a huge starter to turn over the diesel engine, and it draws a lot of amps, especially after it has set without running for an hour or so. When the starter is trying to turn over the engine, the voltage that the inverter sees starts dropping. So when the starter starts stealing all the juice, and the voltage the inverter sees starts going down, the inverter thinks "Oh no, the battery is going dead I better shut down"... so it does. But the battery is not going dead, the starter is just stealing all the juice for a very short time, everything is fine as soon as the truck starts up.... but.... the inverter has already shut down.... That then makes me beat my head against the steering wheel because it has interrupted everything I had hooked to the inverter, namely my laptop, with all my stuff running on it. Those of you with a good battery and smaller cars with smaller engines and smaller starters probably don't have this same problem as your starter doesn't steal near as much juice...

There is some additional voltage loss that comes with using small wire, as in what is used with a standard cigarette plug connector, which is what I'm using now to run my inverter. If I run some large wire from the battery directly to the inverter, it will help... but I'm not sure it will be a big enough help to keep it from shutting down. After reading what others have said (thanks for the suggestions) I have figured out the sure way to fix the problem is to install a small battery that is charged off the vehicle charging system, hook my inverter to it, and put an isolator on it so the starter can not steal any of its juice. Therefor the inverter will always see the full 12.6 volts and be able to draw power from the whole system when I'm sitting with out the truck running. Of course there could still be something I'm missing, but I think that will fix it.
 
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