Trojan Boat Forum

WayWeGo wrote: ↑Sat Nov 03, 2018 5:04 pm For charging while at the dock, ProMariner chargers seem to be a good balance between quality and price. We have a ProMariner ProNautic 1230P charger that is charging three batteries individually with a total charge rate of 30A. After a couple of years, I couldn't be happier.

Not trying to one-up WayWeGo, but I have the ProMariner 12P40......
And i concur -- i could not be happier. And yes, do consider the advice of the inverter/charger. I went new charger, then inverter because thats what my needs were at the time.

That ship having sailed, so to speak, when i needed an inverter, i cant speak to all the merits of the combined unit. But i can say that my inverter, connected to the battery serving one engine, and sized for 15A output, is appropriate for my needs. It has a low voltage cutout, so it will not completely discharge the battery. That said, the cutout protects the inverter, not the battery. The voltage setting is so low that routinely tripping the cutout will lead to early battery death. The point is, you need to shop carefully for your individual needs.

If you go the inverter/charger route, investigate whether all batteries supply the inverter, or whether you can use just one, saving the others for engine starting.

As for keeping the fridge running for x hours...... what i did was buy a kill-a-watt to measure actual energy consumption. That way i had real-life energy consumption numbers, and did not have to rely on nameplate ratings. Note that fridge energy consumption will vary with ambient temperature. Good luck!

Yes we should. I gave government workers a bad name lately. I took just ten hours of vacation between March and October. Spent exactly one night on the hook, and one night in a foreign marina, when i volunteered for the Bay Bridge Swim. I am already making a concerted effort to get out more next year.

As for the challenge, i may have some experience selecting the coldest beer based upon data obtained with my IR thermometer.....

BradZ wrote: ↑Sat Nov 03, 2018 4:34 pm Thanks everyone for the comments. I just need to figure out exactly what I need to keep the fridge running for 4-5 hours or again running for 8-10 hours would be the most I would ever need. I just don't want to tax my starter batteries and not be able to start the engines. But there will be times that we aren't at the boat could be two weeks between visits... I would want a maintenance charge going to the starter batteries while its idle at the dock.

Ok, here is an example based on just your fridge idea. If you have an older 120/12v fridge that is rated at 8amps at 12volts lets say( newer ones are much less with better insulation ) for the sake of argument, then we need to know what the amp/hr usage is, but the fridge only runs for 5 min every 20, so that equates to a total of 15min/hr or 1/4 of an hour. Based on this 1/4 x 8= 2 amp/hrs. Using this for the 10 hour max you have, this fridge's usage would be 2 x 10= 20 amp/hrs.
In another way with a 200amp/hr battery down 50% you could power that fridge for 100/2= 50 hours, all theoretical( not real world) but close enough I believe to give you more of an idea. Hope this is what you were asking.You will have to figure out what you actually have to go further. Mike

Just got home from working on the boat... New cockpit deck fun fun.. lol Thanks again for all the insight. I will be doing my research on my down time and try to layout a system...