Using Inverter Charger as 2nd Charger?

[Gunni]

I currently have a 10 year old, 40 amp AC powered battery charger (Sentry) breakered from a 30 amp AC service. The service can come from either shore power, or from my 5.5 kW AC generator. I simply lock out the service not being used to power up the charger. It charges my ~400 amp hour house battery bank, and Gp27 starter battery.

Problem: After a day of sailing my batteries are drawn down and I fire up my ships gen-set to power the battery charger. My house load, which is considerable can often consume half of the charger's DC amperage output. So my Link battery monitor will often show a net charge amperage of 12-18 amps. It takes hours to recharge my batteries.

So I want to add another charger to increase capacity to run my house load PLUS quickly charge my big honking battery bank.

Solution?: I also have a 10 year old plain AC inverter (Heart). Would it make sense to replace it with an Inverter / charger to provide extra charging capacity. I need to get back to 40 amps (or more) of real DC charge (in addition to running my reefer, instruments, lighting, audio, pumps). The concept would be to gain a second DC charge source. I would also like to build in the ability to greatly increase my charge rate for the next generation of batteries (or even an AGM bank).

 

[Maine Sail]

I currently have a 10 year old, 40 amp AC powered battery charger (Sentry) breakered from a 30 amp AC service. The service can come from either shore power, or from my 5.5 kW AC generator. I simply lock out the service not being used to power up the charger. It charges my ~400 amp hour house battery bank, and Gp27 starter battery.

Problem: After a day of sailing my batteries are drawn down and I fire up my ships gen-set to power the battery charger. My house load, which is considerable can often consume half of the charger's DC amperage output. So my Link battery monitor will often show a net charge amperage of 12-18 amps. It takes hours to recharge my batteries.

So I want to add another charger to increase capacity to run my house load PLUS quickly charge my big honking battery bank.

Solution?: I also have a 10 year old plain AC inverter (Heart). Would it make sense to replace it with an Inverter / charger to provide extra charging capacity. I need to get back to 40 amps (or more) of real DC charge (in addition to running my reefer, instruments, lighting, audio, pumps). The concept would be to gain a second DC charge source. I would also like to build in the ability to greatly increase my charge rate for the next generation of batteries (or even an AGM bank).

Depending upon how it is wired this can be a good solution but you will need transfer switches for the gen to power the inverter as well as the shore pass through.. IC's in the 3kW range are usually a 120A +/- charger.. I would recommend Magnum, Victron or Mastervolt with the Magnum being a very good choice, good warranty and a US company. The MS2812 would be a good fit with a 125A charger portion & 2800W of pure sine AC power.

The Xantrex units like the SW2012/3012 are less expensive, but you get what you pay for....

 

[Johann]

I would second the Magnum. I recently installed the ME2012 and love it so far. I also have the ME-RC remote control which is great and the settings are very customizable. The packaging looks like it was designed to be airdropped from 500' sans parachute.

I use a separate charger for the start battery, and a ProIsocharge to charge both batteries via the alternator.

 

[Gunni]

Thanks Maine, my ABYC electrical guys are Mastervolt vendors, so I expect they will spec that solution. I have a spare unused twin BlueSea AC breaker (the one in use powers my two A/C heat pump units. Maybe they can repurpose that breaker to power the IC.

What is the state of affairs regarding Li batteries.

 

[CarlN]

I once had two chargers. They would confuse each other such that one would go to float too quickly -- pretty much dropping that charger's amps to zero. This can be addressed by setting both chargers to stay at absorption voltage for a minimum time (like two hours). After that, one charger has the capacity to finish the job if more absorption charging was still needed.