Sunday, May 29, 2022

Re: [electricboats] Generator to recharge battery bank

Hi Ryan

Ok, handy points on the generator fumes - plan to have that up on the deck well clear of the cabin as a backup only - but yes potential danger there so thanks for pointing that out.

Also cheers to Bobkar for the clear explanation.

Specs for charger below - 15amp at 48volt so would that push in 15 amps per hour?? 80 ( 50%DOD) / 15 = 5.3 hours to charge give or take??

Ideally solar and wind generators will mean I never use the petrol generator. All the old salts at the boatyard keep telling me "you need to motor out of danger..etc.etc...".

Matson 4 in 1 Multi Volt Battery Charger 12, 24, 36, 48V

Description

Absorption YES Analysis / Fault Find YES Battery Type Deep Cycle and automotive VRLA/ AGM/ SLA/ Flooded & Lead Acid Case Construction Aluminium Charge Rate 14.7V, 29.4V, 44.1V, 58.8V Charging Stage 3 Stage Desulphation YES Dimensions 300 x 223 x 101mm Equalisation YES Fan Cooled YES Input Voltage - DC 240VAC IP Rating N/A Min Start Voltage 12V - 8.0 V, 24V - 16.0V, 36V - 27.0V, - 48V - 40.0V Output Current 30/ 25/ 15 Amp Output Voltage 12 / 24/ 36 / 48 Volt DC Permanent Mount YES Recondition YES Size 10 - 400 Ah Soft Start YES Weight 5Kg

The Matson 4 in 1 Multi Volt charger is all you need for all your at home or workshop charging needs. Ideal for your family car battery right through to heavy duty 48 volt systems like golf buggies, forklifts and trucks Simple to use, simply select the required voltage, attach the clamps and the charger will take care of the rest. LED indicators will let you know what is going on during the charging cycles. Full safety protections including overheating, reverse polarity protection and short circuiting. Charges Lead Acid, NiMH, AGM and Sealed batteries.

4 different charge voltage settings
12V - 30 Amps
24V - 30 Amps
36V - 25 Amps
48V - 15 Amps
3 stage fully automatic Switch Mode charging and maintenance capabilities
Offers protection against short circuiting, reverse connection and overheating
LED display bar indicates what voltage has been selected and percentage charged
Charges Lead Acid, NiMH, AGM and Sealed batteries
Heavy duty Aluminium housing Charger Output Nominal Output Voltage 12V 24V 36V 48V Max Output A 30A 30A 25A 15A Max Output Power 450W 900W 1000W 900A Charge Voltage 14.7V 29.4V 44.1V 58.8V Float Voltage 13.6V 26.6V 39.9V 53.2V Minimum Start Voltage 8.0V 16.0V 27.0V 40.0V This item is sold by Blue Bar Industries, an offshore business located in Brisbane, Queensland, Australia, and may incur NZ customs duty or tax. Find out more at http://trade.me/whatsmyduty

On Mon, 30 May 2022 at 14:35, Ryan Sweet <ryan@ryansweet.org> wrote:

What what kind of charger do you have? That will determine whether the generator can fully supply the charger or not. Most likely, the generator cannot charge your batteries one to one with consumption, so a model might be run the motor for an hour, it takes two hours to charge via generator or something like that. But really it's all speculation without knowing what kind of charger you are using. With a portable generator on the water you do need to be really careful with exhaust. There is a reason marine generators typically mix the exhaust with water: it is really easy for the wind on the water to send the exhaust back into your cabin or whatever area your people are congregating in and give everyone carbon monoxide poisoning. So when using portable generators on a sailboat just make sure that you're paying attention to the wind etc. the same way you do when sailing.

On May 29, 2022, at 16:29, bobkart <couch45@msn.com> wrote:

You have ~7.7kWh total capacity in those VRLA batteries. Considerably less 'net' capacity, when considering lead-acid DOD limits.

Around 3.5 hours of your 2.2kW generator will generate that much energy. Of course the charger won't be 100% efficient from AC to DC, then lead-acid batteries are not very efficient input-to-output. So call it four hours, then roughly halve that to keep within a 50% DOD limit.

So yeah, that generator is plenty for that size battery bank. In the ballpark of two hours should be enough to get from 50% to 100% SOC.