Inverter choice

[caribnsol]

I've got a question....I got a good deal yesterday on an inverter, it's a Xantrex Prowatt 1000 ($100 on clearance). The main use I want it for is the admiral wants her T.V. It is modified sine, but the book says it is ok for television (haven't tried it yet). A friend told me not to buy from the boat stores, can get a higher capacity for cheaper at one of the big box stores (Best Buy etc). My battery house bank is (2) 75a/h deep cycle batteries, charged by (2) solar panels and a rutland windgenerator. Works good. With the addtion of the inverter, I am thinking of increasing to (4) batteries.

My question is is there any reason not to get one from the big box stores vice the marine store ? Is an inverter one of those things that should be "marine" use ? I've read as many threads as I could find, but this question wasn't discussed.

thanks
Bill

[GordMay]

$100 is a very good price for a new Prowatt 1000.

[caribnsol]

I thought so also, I wasn't planning on buying yesterday, just starting to do some research and came across it.

[Pblais]

I would say at $100 you are getting a decent price. Checking around they seem to be selling for more than twice that. I doubt any other alternative is going to be much cheaper and probably much less durable.

As far as batteries go with your current setup if you ran a toaster you could run it for about 20 minutes before your battery bank is depleted to about half capacity. That is always the best low end target to discharge deep cycle batteries so you get the longest lifetime. When you take them lower the lifespan decreases faster. The down side with inverters is they take 10 times the DC amps to make AC amps. You also need more starting amps than the amps to run anything.

For TV's, the plasma TV's are the killer consumers of amps. We run a small 15 inch LCD (has speakers too) with a 12 volt CD/DVD player and it runs fine on a 300 watt inverter. Do the math on the power before you get too far into this. Inverters are great but when you start running AC appliances the battery bank account can be wiped really easy.

If you are going to add 2 more batteries it is best to start with 4 new ones and not just add two more. Battery Outlet in Chesapeake or Yorktown are probably the best place to buy them too. They have a web site but they carry more batteries in the store than they sell over the Internet.

You might consider switching to 6 volt golf cart batteries divided into two banks. That could triple your capacity. With 4 batteries having two banks minimizes the problems with on bad cell taking out the whole bank. Also it's a good time to evaluate your charging system. Batteries have got a lot more expensive with the price of lead going sky high if you have not priced them lately. Protecting your battery investment is always a good thing.

With more batteries you'll need some switches. A 1/2/both/off switch would be nice to make two banks. The supply lines to a 1000 watt inverter is going to carry a lot of DC amps. Volts X Amps = Watts! Size the DC supply and ground wires properly based on the distance. Once you start running these extra large cables the cost of the installation is going to increase. Don't wimp out on the installation quality. This is not something to screw up or you will be on fire. A 1000 watt AC load is about 100 DC amps!

The electrical section of the forum has an almost unlimited amount of battery / electrical information you can go through. If you are not sure about your installation use this knowledge base and post more questions.

[caribnsol]

thanks Paul, my current batteries are only about 3 months old, so they are still pretty new. My tv is an lcd and on the tag is says 58w, I was assuming that meant 58w per hour ? There was a 250w inverter installed, but I wanted to upgrade, I was going to use the existing cable, but now I will re-think that (small gauge). After reading your post I will put a lot more thought into this. I did read a bunch of inverter posts yesterday when I started this plan, but had not gone very far on my own install plans.

[Pblais]

58 watts AC is 0.48 AC amps or 5.8 DC amps or about the same amount of power as the 12 volt fridge on most boats. Connecting up your 1000 watt inverter is easily going to handle this TV, but the wiring for it is going to be really expensive. You will spend more than $100 in wiring supplies and switches easily. Plan this all out before you buy the inverter. Undersized wires are a time bomb - literally.

[caribnsol]

already got the inverter, sitting in its box all nice and pretty, but I will get the right switches and wiring. I'll post my plan once I know what it is. I converted my a/c last year from european to us, new panel, new wiring, new shore power, all by the book, all good components.

I did not think this out prior to getting the inverter and it is turning out to be a bigger project than I originally thought. First I'll need to diagram out my current set up and figure out how my existing bank is set up before I start adding components.

[GordMay]

The DC Battery Supply cables, to a Prowatt 1000, should be not less than #4 AWG Cu, for very short distances (4 Ft or less of cable*).
Longer runs will require larger cables: #2 AWG to 16' of cable.

* Cable length = both Positive + Negative runs

[caribnsol]

I've got about 3 feet from the panel to where the inverter will be mounted.

... which would probably be 6 or 7 ft. of cable requiring the larger #2 AWG (or #3, if available).

[Sandero]

I installed a Xantrex 1000 watt invert and the distance required very large cables. They were costly but the problem was getting those fat cables into an appropriate connect to secure to the terminal at the back of the Xantrex. ICK.

I had to purchase (online) "adapters" for audo equipment which allowed me to reduce the lug size down which would fit into the Xantrex. I think they are gold plated too abd were about $8 a piece IRRC.

[Pblais]

It sounds like you are well on your way to a good plan. As you can see lots of help is available to make sure you get it right.

[windsweptms]

Panel?, are you sure want to power the inverter from the DC distruibution panel, Most large inverters should be powered directly from a battery bank with circuit protection. Check your install instructions. s/v Windswept

[caribnsol]

the old inverter came off the dc panel, but it was much smaller. I'll check out my books/instruction.

[Sandero]

My inverter cam with a remote on off panel which I mounted at the nav station where I can see whether it is on or off and turn it on and off regardless of how inaccessible it is.

Try to mount it close by the batts and see if you can get a remote. Shorter power cables are cheaper and less power loss.

[caribnsol]

It did come with the remote. Still thinking about battery location. Currently they are split, boats a cat, there is a built in step to get into the aft berth in each hull, the battery boxes are inside the step.