connecting an inverter with 3 batteries

[nybor]

Gosh, I can't believe Ken (maybe others, sorry) has done such a fantastic job with this site. Ken, if you need anything for your boat (lets not get carried away), let me (I mean "us") know and maybe Santa has been delayed at the Sarasota Airport on his return trip to the North Pole.

Sorry, I forgot my question.. Not really. So, I have 3 - 4D batteries in parallel. Just bought a 2.3kW (pure sine) inverter to replace my 2kW. I had connected the old one to the first (closest to the inverter) two batteries (one + and the other -). However, should I connect the + (or -) to the closest one to the inverter and the other polarity cable to the furthest away? I know it shouldn't matter and the furthest one is only 3 feet away) but just was wondering. My cables are huge (maybe 0 or 00) so hopefully minimal losses.

Thanks
dave b.

ps, I really need an answer asap, so don't want to wait till next year! (joke)

[wolfe10]

To balance the load and/or charging, with two 12 VDC batteries in parallel, connect the positive to one battery and the negative to the OTHER BATTERY.

And, if indeed all three are on the same battery bank: positive to battery #1 and negative to battery #3.

[nybor]

Thanks Neighbor Brett. (Ft Myers is pretty close to Venice). Yeah, that is what I have been doing for charging as well. I just felt sorry for the middle battery having to "beg" energy from the charger (feeding 1 and 3) and then "lend" energy back to Numbers 1 and 3 for the inverter.

dave

[wolfe10]

When wired this way, the electrons flow through each battery (as they should).

If you connect positive and negative to "other than end batteries", those not in the loop will neither get a charge as quickly nor provide as many amps on heavy draws.

[nybor]

Thanks to all for the advice. Of course, now I want to expand this question. I have three new AGMs and they will all be connected in parallel. I will connect my solar output to the #1 and #3 batteries (14.4V Absorb). My wind gen would not charge them but simply help at night for the fridge/freezer so will connect it to #1 (13.3V. The output from the Charles charger (it is set on AGM) (not sure the voltage but looks like 14V+) will go to #1 and #3 as well. The inverter will also go to #1 and #3.

My question it the alternator. I don't have the schematic in front of me and don't know if it has that info. How is its output get to the batteries? Obviously its output would vary with RPM, but maybe it somehow goes into the Charles?

thanks in advance
dave

ps, My old ones were Lifelines and these are Renogy (cheap). HOWEVER, while they are 4Ds and I measured them (quickly) two of them will not fix in the housing! I even Dremeled a little bit of the fiberglass lip of the housing. No joy. So two of them are now in the long storage bin and I have a small AGM that is charged by solar next to #1.

[ElizabethG]

Dave,

I'm assuming you have a "stock" alternator with an non-adjustable, internal regulator.

That alternator feeds directly in the battery bank. It does not go through the 30 amp Charles battery charger.

I don't have the schematic at home, so I can't give you the wires to look for.

I think the alternator outputs around 50 amps and the internal regulator is set at around 14.1 volts.

The voltage output should be pretty constant from idle through maximum cruising RPMs.

Bill
C350, #193
Charleston, SC (Boat) / Atlanta, GA (Home)

[nybor]

THANKS. Yes I do have a standard alternator. So, 14.1 is fine since most of my battery charging is done with the panels giving them a little boost.

dave

[Olivia Mae]

I don't have a wiring diagram in front of me (it's in your manual), but if I remember right, the alternator output goes to the common pin on the battery bank switch, then gets distributed to the selected bank from there. The down side of that setup is it only charges the bank that the switch is on. I use a combiner to charge my second bank, which is just an emergency start battery.

[nybor]

Excellent. I too charge all three batteries at the same time with the one switch (on the left) to both and the right on (engine power) on. My solar controller has a secondary output to charge another battery and that is my emergency starter battery..,

Thanks.

dave