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BadBoy · 05-23-2011, 10:01 PM

I have installed a 1500 watt inverter into my 99 Southwind along with adding 3 additional batteries to the existing 2 house batteries (all in parallel with fuse etc).

I have run a cord/outlet from my inverter to the back main house plug in and plan to plug the whole house in while driving across the country so the kiddies can watch tv, play nintendo etc. I did this in my last motorhome with success by turning off the breaker switch to the air conditioner and the converter (as converter buzzed for some reason when inverter on?)

I only had 1 house battery in my former RV which was clearly not enough. Someone told me that having the five 12-volt batteries, it may be too hard on my alternator and also mentioned something about a possible converter issue too?

I'd think the more battery power u have the easier it would be on your alternator as its not struggling trying to keep up with the power usage as there is plenty battery power to draw from?

I'm driving from Ottawa Ontario to B.C and want to make sure this isnt gonna be an inconvenient/aggravating and/or pricey mistake? Any thoughts or suggestions pls?

DAN L · 05-24-2011, 02:11 AM

Quote:

Originally Posted by BadBoy

I have installed a 1500 watt inverter into my 99 Southwind along with adding 3 additional batteries to the existing 2 house batteries (all in parallel with fuse etc).

I have run a cord/outlet from my inverter to the back main house plug in and plan to plug the whole house in while driving across the country so the kiddies can watch tv, play nintendo etc. I did this in my last motorhome with success by turning off the breaker switch to the air conditioner and the converter (as converter buzzed for some reason when inverter on?)

I only had 1 house battery in my former RV which was clearly not enough. Someone told me that having the five 12-volt batteries, it may be too hard on my alternator and also mentioned something about a possible converter issue too?

I'd think the more battery power u have the easier it would be on your alternator as its not struggling trying to keep up with the power usage as there is plenty battery power to draw from?

I'm driving from Ottawa Ontario to B.C and want to make sure this isnt gonna be an inconvenient/aggravating and/or pricey mistake? Any thoughts or suggestions pls?

imho you can't have too many batteries except that they weigh a lot. how you hook them up makes a big difference.

SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank

RV Wizard · 05-24-2011, 04:36 AM

If the two original batteries are not in new condition; you could cause problems for the three new batteries "you added". If they do not charge at the same rate as the new then the new may be overcharged. This could lead to damaging the new batteries.
Here are a few links on battery info to help you out:

U.S.Battery/Leader in Deep Cycle Batteries
Frequently Asked Questions (FAQ) - DC Battery Specialists
Deep Cycle Battery FAQ
http://www.rvsolarelectric.com/sources.htm
Car and Deep Cycle Battery FAQ, Battery Manufacturers and Brand Names List, and

Cruzer · 05-24-2011, 07:26 AM

I have twelve batteries on my 3,000 watt inverter/charger. No downsides. They are all identical batts and of the same age.

BadBoy · 05-24-2011, 07:27 AM

I checked the batteries out with a business called "Battery Experts". I have one deep cycle battery (used) and 4 international transport truck batteries (about same age). They said they should be fine but optimal would have been all deep cycle. I know a guy that dismantles crashed heavy duty trucks and he got me the batteries for $20 each.

I was more worried about the alternator not being able to handle that many batteries (as I'd heard- not sure if true?). I had always heard muchos muchos battery is a good thing...except for the added weight of course.

When you hook up an inverter does that interfere somehow with the converter? I still cant figure out why it softly buzzed in my old MH when the inverter was on?

Thx again all

Cruzer · 05-24-2011, 07:36 AM

I installed a 2500 watt Prosine inverter/charger on my old Suncruiser and never disconnected the converter. They both charged the batteries and never overcooked them nor did I need to add water. Never had any buzzing.

BigV · 05-24-2011, 07:54 AM

My experience only cheap non-voltage controlled converts buzz. You may want to spring for a good multi-stage charger/converter instead.

Your alternator is only going to produce as much energy as it is rated for. You are not going to fry it by adding more batteries.

I will state that most gas engines come with too light a wire for the capacity of the alternator. Most have an 8ga wire running from the alternator to the battery. That is fine for one or two batteries. My guess is your batteries will only take about 10A each to charge. Fine for 2 batteries, but for 5 you are looking at supplying 50A charge. Probably should upgrade your alternator wire to a 2 ga wire.

That is probably what people were trying to warn you about.

wa8yxm · 05-24-2011, 09:20 AM

Bad plan, unless you do a lot of extra work. Here is why. First that inverter will complain big time if you hit it with a big load (Water Heater, Air Conditioner) second 350 watts of Refrigerator is going to suck hard on the batteries with your plan.. Better to have these items wired so they can ONLY be run on mains power.

Microwave may be usable though since it normally runs for short time only.

Also your converter is going to be trying to re-charge the batteries using power from the inverter,, Which means you have a lovely loss there too.

I would recommend a proper transfer switch/sub pnel system, where you move TV's and microwave and the bathroom/kitchen outlets to a sub panel and either use a manual switch (50-100 dollars) or an auto switch (30 amp ones are not too expensive) to transfer from Inverter to Mains.

Move only the circuits you want to move. DO NOT move the fridge, (Though yo umay move the ice maker if you can seperate it), the water heater or air conditioners.

BigV · 05-24-2011, 10:18 AM

My inverter will just shutoff if someone turns on an A/C.

I have my inverter wired to a 30a RV plug in the storage bay. I just plug in the shore cord to it. The converter is connected through a remote switch. That way when I start the generator I can just hit the switch to turn on the charger. Transfer switch takes care of switching in the genny.

I just have a 10cu ft electric refrigerator. No ice maker. I don't have any issues running of the inverter. It is actually why I put it in. Microwave draws 900 watts, coffee maker the same. Just can't run them all at once. Usually don't run either when on inverter power. Wife has made coffee while we were driving with no issues.

alvinc · 05-24-2011, 11:03 AM

Quote:

Originally Posted by BadBoy

Someone told me that having the five 12-volt batteries, it may be too hard on my alternator and also mentioned something about a possible converter issue too?

I'd think the more battery power u have the easier it would be on your alternator as its not struggling trying to keep up with the power usage as there is plenty battery power to draw from?

As stated earlier, the alternator will put out its rated capability, you will not harm the alternator. Why, because it is basically a pump, the batteries will not draw from the alternator. That being said, the alternator will get warmer from the energy being produced and this could shorten its life, but this is a minor issue.

If the alternator is still the original 1999, then I would consider upgrading it with an alternator that would be used in a emergency vehicle, say a 200 amp or larger.

The last thing to talk about (already mentioned) is the wire size from the alternator to the battery bank. All wire exhibits a voltage drop. The amount of drop depends the amperage, size of wire and length of wire (assuming 12V here). If the wire is too small or too long there will not be enough voltage at the battery to charge the batteries. A table I like to use for 12V wire sizes is provided by West Marine: West Marine Wire Size Table From the tables you can see there is a huge penalty at 12V for wire length.

Note that at 12V a 10% drop is 1.2 volts, if the alternator is putting out 14V, a 1.4V drop puts it at 12.6V, not quite enough to properly charge the batteries. This is why on my RV it takes a long time for the alternator to charge the house batteries if they are depleted, the wire is not large enough for a bulk charge.

If you plan for the alternator to take a significant share of the house load, you will need to upgrade the wiring from the alternator to the house batteries.

How far are your house batteries from the alternator (round trip wire length)?

wa8yxm · 05-24-2011, 03:01 PM

The Prosine is a very fine and very smart intelegent charger, It will co-exist with other converters as a rule.. Basiclly one of them (Assuming the other is a smart charger too) will simply shut down. (Go to float mode)

Page 2: The buzzing... If the inverter was wired as the O/P suggests (Plug in whole rig) then if the inverter was an MSW, Buzzing is a posibility.

Oh, the Prosine.. is also a True Sine Inverter.. Best of both worlds. It also takes care of the transfer functions I described in my earlier post.

About the only thing it won't do is push...... I take it back it can push the start button on the coffee pot in the morning if the pot has a timer function

MSW's can mess that one up.

BadBoy · 05-24-2011, 05:13 PM

All great advice thx folks! I paced off my alternator to my house batteries (under the step). Seems to be about 8 feet is a solid number (without climbing under and gettin dirty

I will look into the heavier cable on the alternator but not before my big trip I'm afraid. That buzzing was from my old rig on the actual converter. This one doesnt make any buzzing sound at all which is good.

I will make it a practice to shut off Air conditioner and switch the fridge to propane. The microwave in the old one would work but didnt like it much at all...in fact I think I heard it curse once or twice haha.

I saw those Intellichargers but didnt really know how they worked nor how to hook it up. It has a small solar panel but I'm sure that charge is close to nil.