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How to wire batteries and inverter?

Posted: May 21st, 2022, 10:37 am
by Hudsteve
1990 32 foot carver Montego with twin 454's

2 - 30 amp shore power

One of them controls the a/c water, heater and receptacles...no problems there

other one controls radio, lights, all of the gauges, inverter and the battery charger

note...
last year the Hearth inverter/charger (pic attached) cooling fan went out (4 inch fan like a computer cooling fan) I never use the inverter anyways, but never disconnected it, and I replaced the battery charger with a new charger of a different type and everything worked normally for the rest of the year

Now I just installed 3 brand new batteries just because old ones were 5 yrs

I took a pic of how the batteries were wired to install the new batteries the same way.

When I connected the invertor cable (neg) it got hot and smoked for 2 seconds and I took it off immediately, disconnected both leads just to be safe.

I assume that for some unknown reason there is now a short in the invertor...The boat has been in the water for a month this year with no problems until I changed to new batteries.
btw I labeled the positive and negative from the inverter to make sure I wired it back together correctly

no harm no foul...I thought... a week later 2 of the 3 batteries were completely drained and did not charge back up even while on shore power.

? #1 Does that mean the shore power on that side goes through the invertor to charge up the batteries and run lights
gauges etc.? If so, may I just remove the old inverter and hard wire everything back to the batteries? Do I need an inverter that we rarely if ever used?

A question you might immediately have is why 2 of the 3 batteries died and not the 3rd one, (I think it didn't drain because there was no neg cables of any sort connected to that battery, remember I took off the inverter cables completely) which bring me to the next question?

Did I wire the new batteries correctly even though I took a pic and did it exactly the same...is it possible the marina installed the batteries incorrectly before they launched it?

Attached is a pic of how they were wired with the inverter cable attached at the beginning of this year. Now they (the inverter cables) are disconnected...with no negative connection of any kind, except for the battery charger cables...small black and red cables go to battery charger.

What is the correct way to wire batteries?

Also I have never used the battery switch since we bought the boat.

THANKS for you help and I know message is long but trying to give as many details to help get to the answer.

Re: How to wire batteries and inverter?

Posted: May 21st, 2022, 10:51 am
by Hudsteve
Forgot to attach pic of how batteries are currently wired for ease.

this pic is without battery charger wires attached

Re: How to wire batteries and inverter?

Posted: May 21st, 2022, 10:58 am
by Phrancus
Can't help much but I do see a thick black cable where I expect a red one on the top (in te picture) battery + side (left). If you have two black wires from that battery to the inverter perhaps something got mixed up there. Use red tape to mark a + cable if you really can't use a red.

Re: How to wire batteries and inverter?

Posted: May 21st, 2022, 11:20 am
by Hudsteve
Thanks
Two black wires are from the inverter box
Which I did label like you suggested
Thats kinda why Im puzzled...why did the inverter smoke?

where does the shore power line connect to charge batteries?

Re: How to wire batteries and inverter?

Posted: May 21st, 2022, 2:02 pm
by km1125
If your inverter/charger was the only charging source from shore power, then it looks like that would only charge the single battery unless the battery switch was in the "all" position.

Just my opinion, but the way it's wired is kinda "crazy". Normally you'd have two batteries combined together to provide a bigger house bank, which would be appropriate for a situation where you have an inverter. You might combine them like that for the engines if you have VERY LARGE (bigger than 7.4L) gas engines or diesels. Anything less than that and you don't need to combine them.

I agree on that large black cable being connected to the positive. That should NEVER happen. If you have to use a black cable for a positive connection, the end should be CLEARLY marked with RED shrink or tape. The only time this should really happen is if you're putting batteries in series, although I did have a boat where a previous owner used two large black cables for the power feed to the winch.

Not sure why you smoked the inverter, but the one sure way to do it is hook up the wires backwards for even one second.

Unless you have batteries in series somewhere, then ALL the negatives for the batteries should be tied together. I like using a large terminal block or buss bar, which can also be used to tie anything else that needs to go to "negative". This way you only have ONE good connection on each battery. Too many connections on those battery terminals is a recipe for problems.

I'm a little confused on this statement: "a week later 2 of the 3 batteries were completely drained and did not charge back up even while on shore power."

Was your new charger working?? Is it possible you blew out the fuses that connects the new charger to the two batteries?? Did you leave something on in the boat that would have drained the two batteries if there was no charger running?? Since the batteries are tied together, then it makes sense they were BOTH dead, but you need to find out why they had a drain and why they weren't getting a charge.

Re: How to wire batteries and inverter?

Posted: May 21st, 2022, 8:48 pm
by bud37
Until you get this sorted my advice would be to disconnect that inverter from both sides the AC and the DC......just in case there may be a dead short to ground in there........good luck.

Re: How to wire batteries and inverter?

Posted: May 25th, 2022, 10:43 pm
by Viper
First, I hope that inverter isn't in your engine compartment, I doubt it's ignition proof.

I agree with the wiring color code for the inverter's DC positive line, it should be red or clearly labeled as such.

Unless I'm missing it, I don't see a negative cable connecting the first battery to the other 2, it's also not noted in your diagram so I assume there is no connection there and there should be. I'm also curious to know how the inverter battery gets charged by the engines when the selector switch is not favoring that battery during engine operation. As KM mentioned, if anything, the inverter/house bank should be the larger bank if the inverter were being used.

KM mentioned one of the ways to blow an inverter, the other sure way is to back feed AC to it, in other words applying shore power to a circuit that the inverter is currently supplying AC power to. This is easy to do in an improper installation and is dangerous.

I don't think it does but does this inverter charge as well?

Re: How to wire batteries and inverter?

Posted: May 27th, 2022, 4:31 pm
by Hudsteve
Ok need advice again and Thanks

What is the correct way to wire the batteries?

I have 3 new batteries

One for each engine and one for the house...If this is correct?

Does the inverter pos and neg go to the same battery...I'll call it the house battery

I have 2 red cables from the battery switch.

I have 2 black cables from the engines...there also is a jumper cable from engine to engine (I believe grounded to each other)

Do I wire 1 red and 1 black to each battery? sounds like common sense but maybe not

Ex engine battery 1
Engine battery 2

Do I need to wire these two engine batteries together? As in jumpers from red to red and black to black?

Do I need to jump any of the engine batteries to the inverter/ house battery?

I also have 2 black cables that go to the radio/receipts, gauges, and bilge pumps...where
should these be wired too? house or engine batteries

Note I have a new 3 bank battery charger that charges each battery

Im willing to give my phone number if anyone has time to talk me through it real quick

thanks

Re: How to wire batteries and inverter?

Posted: May 27th, 2022, 5:14 pm
by bud37
Heh there....... Google Blue Sea , they have some very good battery wiring schematics and some faq's that could be of some help here for you. Take a look and see if the schematics help to clear things up.......good luck and take your time to do it right. There should be very few cables going to battery banks, use bus bars.....anyway have a look at Blue Sea.

Re: How to wire batteries and inverter?

Posted: May 27th, 2022, 5:29 pm
by Hudsteve
Thank You