Little more on the battery, yeah $140 is about the going rate for a new red top of the cheaper sizes but the 34/78 DT Red is going for $200. The Yellow 34/78 DT(DT=Dual Terminal) get's in the $240 range new. And Joe check the model/size, in my experience with Optimas the 34/78 DT size(the original) is the only one worth bothering with. All the later designs to fit different sizes or save a buck for the single terminal they cut corners on.

If you can be confident the optima is in good shape and a 34/78 DT I think it's worth as much as $100 but that's for you to judge.

PS. I personally prefer older optimas, they just seemed to make them better back in the day. An older optima that hasn't been abused(let drain below 12V) and been in a daily driver is to me worth more then a newer one.

 

Yeah not that I think about it I think I payed a little over $200 after taxes and stuff for mine. I was shocked at the price but willing to fork out the extra money for a better product.

 

I got a guy I found that sells what he calls "refurbished" optimas out of the back of his truck with a 1 year warranty. For all I know they could be just pulse charged cores but at $60 a pop I have bought a total of 7 Red 34/78 DTs off him, 2 have gone bad within a year and he's replaced them. The rest are going strong, strikes me as a deal even if they are just pulse charged cores.

This guy http://seattle.craigslist.org/see/pts/3772436590.html

 

That's not a bad deal.

 

yeah, i've seen that guy around craigslist, but never got around to calling him and making a deal. sounds like he honors his work well enough to offset the imperfect quality, at least for applications where you don't hang your life on the battery.

as for inverters, that would be a 1200w you're looking at. comes out to 10 amps at 120v, so enough to run most drills, sawzall, etc. every tool should be labeled with an amperage rating. it'll probably handle a 4.5" grinder but not a 7".

brute, that 5000w unit is a monster, what would you be doing that has a big enough battery bank to use more than half its capacity?

 

Yeah the thing is big I looked at it in the store. Even more HUGE is that the 5.000w/10,000w rating that comes to as much as 830(@12V) Amps for short bursts and a constant draw as high as 350A(@14V). Powering that would be the real challenge.

Looking to step up to a system where I don't have to realistically worry about power limitations. That can run any single large 110VAC item I have for example my large air compressor, welder, microwave, etc. I could/do have a few little ones in the 1500/3000 - 400W range but unlike DC stuff you can't double up AC inverters to power large items that the 1500/3000 won't. Only shortcoming on this would be that there is no 220 or large high amp(dryer) plug as there would be on a good generator. So for the likely $300 cost plus 2 more alternators and 4 more batteries all installed on the truck, or a diesel generator. The inverter + alternators + batteries have the benefit of better packaging as I can spread them around the truck and supplying for all practical purposes unlimited DC power for the rest of the truck.

 

well, how i see it here, no one item you run on it has the right to exceed 1800w continuous - as thats the rating of the plugs - 15a @ 120v. so a 2000w continuous rig is enough. anything more than that and you're running 2 seperate loads anyway, so having 2 seperate units is fine.
if you're doing something that needs a bigger plug, you really need a 120v generator, which you could get a pretty good one for the price of 2 alternators and 4 batteries as you suggested above.

as you've seen, i have a 2000w rig on my van, and it runs my compressor and stuff with no trouble. but the battery runs down pretty quick under that kind of loads, its a size 4d battery powering it, and only lasts one cycle of the compressor before its hitting the low voltage alarm.

if you really plan to be able to pull 5kw, you may as well do it by buying a generator in that size, it'll be a lot easier and cheaper to set up, and will probably give cleaner power for less fuel.

 

BruteFord
In theory you could piggyback multiple inverters IF and it a BIG IF
they are of the type that allows you to sync the phase of each inverter. We are talking some
very serious money for that. The inverter you want is the type will allow you to feed power back
into the grid. I think you don't want to go that far.

Sean

 

Well all this inverter stuff is no where near a priority, seeing that one at harbor freight just got my wheels turning.

As for sizing, all I really know is that my 1500/3000w one won't get my bigger compressor going. So if I'm going to get a bigger one there really isn't much in between the 1500/3000 one and 5000/10000 one that is really worth it, might as well go all the way.

Did more research and it seems there are better deals on better ones like this one AIMS 5000 Watt Power Inverter | 12 Volt

Shopping around got me to wondering, I know you can take a household 240 plug and split it into 2 legs of 120, can you do the same with a 240 inverter like this, IDK AIMS PWRINV5K24012W 5000W | 12V DC to AC Power Inverter | 240V, Inverter Supply

The whole generator vs alternators/batteries/inverter thing. Yeah a generator would be cheaper, I even found a deal on a used diesel 6500W generator. But the truck could use all that extra stuff anyway to run my 12/24V stuff and have batteries I can drain without the engine running. Also a generator takes up a fixed amount of space and could really only go in the bed, while the other stuff can be placed all over and separate outside of the bed like under the cab and bed.

As for piggybacking or stacking them I came across these 2500 Watt Stackable Power Inverter (Parallel Power Inverter) 12V DC To 240V AC It would be really nice to be able to combine AC power sources but just seems sketchy, risky, and pricey to me.

Anyway, still all talk, not taking the plunge on that stuff yet, too much other stuff to do. Just doing the research now.

 

personally, i didn't like my 1500w unit because its grounded (neutral) wire was 70 volts hot compared to its grounding wire, which raised hell for me when i tried to use it to power the lights in the workshop, making my van 70 volts hot compared to the ground under my feet.
i replaced it with their 2000w model, which has served me well and doesn't have that problem. i thought they also had a 3000w model, but looking at their website now i'm not seeing anything above 1500 except that 5000.
well i just opened the paper ad they mailed me in triplicate, and they still have those sizes listed, and looking up those item numbers, here 3000 Watt Continuous/6000 Watt Peak Power Inverter is the 3000 and here 2000 Watt Continuous/4000 Watt Peak Power Inverter is the 2000 i have. i don't know why they don't show up any other way.

that stackable system looks interesting, but it seems it would require a 120v cord with multiple male plugs to share the load, and that gets a little hazardous in my opinion.

as for being able to split off the two 120v legs from a 240, you should be able to in the same way, as long as they have an appropriate grounded (neutral) wire that relates properly to both plugs, unlike the one i talked about at the start of this post.

personally, if i'm buying it, its either gonna be a well-known name of top quality, or have a store nearby that will respect the warranty. and that has me buying at harbor freight instead of some no-name online.

 

Yes you can split the 240 into 120 if the unit has a true neutral. But like Josh
found out make sure that the neutral is the same as the ground or deadly
things can happen.

Sean
See you all in the May thread