Battery Charger for Lagoon 440

[solecollector]

Hi there all!

Okay - I just updated my battery system and have dumped the Optimas (OG owner put in 6 optimal for the house in parallel) and went with (4) 4Ds for the house (going to add an extra one at some point in time) as well as a 4D for each engine.

I also put in all the "upgrade" stuff like Balmar regulators and a center fielder as well as a ProIso and a LinkPro battery monitor.

Now that I have the battery monitor on I see that the charger never gets above 13.3 volts for the house batteries. I let the batteries go down to 12.6 Vs and then charged them up - never gets to the absorption charge rate which I assume would be over 14Vs.

We have a battery charger - it is Italian (Dolphin) with three 30 amps out.

Can someone recommend what I should be looking at? I assume mine isn't doing very good and needs to be replaced.

Thanks!_steve

[djmarchand]

Your Italian charger does sound like it isn't up to snuff. A shore power charger should peak at 14+ V before it drops back to about a 13.5 float voltage.

How big a charger depends on what is the power source and how big a battery bank that you have.

With 4-4Ds you have about 800 amphours and general practice is to not charge at over 25% of the battery capacity for flooded cells. So that criteria limits you to 200 amps.

If you are charging with shore power over night then almost anything will work as you have many hours to get the job done. Your 30 amp charger would do the job if it had a good three step algorithm, which it seems not to.

If you are charging from a genset, then you want the largest charger that your genset can provide power for. A 100 amp inverter/charger typically pulls 15+ amps AC at maximum output, sometimes more for inefficient ones. That is about 1.8 KW and any built in generator can handle that much, but the ubiquitous Honda 2000 EU can't continuously. In that case the best you can do is about 75 amps.

David

[ontherocks83]

Where are you getting your voltage readings? Is it from a monitor or with a multi-meter directly at the batteries?

[smac999]

the battery monitor should be directly connected to the batteries to read battery voltage.

30a charger is way too small for 4x4D you want 100+.

leave the 3x30 amp on the 2 engine batteries and buy a big one for the house.

consider inverter / chargers they aren't much more money.

[solecollector]

Thanks for the insight all! What would be a good brand to buy?

ontherocks83- Both same the same (within a few .1s

[ShaktisBoy]

Very happy with our Magna Sine 2800

[solecollector]

Any other suggestions? And how many amp hour charger should I look at getting?

[ontherocks83]

Originally Posted by solecollector

Any other suggestions? And how many amp hour charger should I look at getting?

Roughly up to 20% of total bank amp hours. Less takes longer more can cause damage.

[Rusty123]

Check out this tutorial: http://www.pbase.com/mainecruising/i...attery_charger

As far as sizing - depends on characteristics (acceptance rate) of your bank, budget, and needs. FLA max acceptance is about 20% of bank capacity. Add to that the nominal draw of your pier side loads and you establish the upper end of sizing. Going larger just wastes money, since the battery will only accept what it will accept. Going smaller is cheaper, but at the expense of charging time.

10% of bank size, plus pier side loads, is often recommended ( for FLA) since that's enough to get a full charge overnight.

[solecollector]

Thanks all! Huge help -