voltage regulator from engine alternators to house batteries

[hellomister]

Hi all
brainstorming the electrics for a new build 50ft alloy sailcat. 600 or 800 ah of house battery [probably gel, and i know the arguments regarding battery selection but in this case its whats available], with charging option from engine alternators 12v 125a
Question..... is a voltage regulator required between alternators and house bank? or can i wire direct? if so any suggestions of best practice for a mid budget owner built cruiser
Cheers

[john61ct]

Yes VR required. Often included in the alt. Better to use an external unit, Balmar MC-614.

[Privilege]

I'm with John. An alternator just does its thing and puts out as many volts as it can. Often, cheap alternators have a built-in regulator which bumps down the voltage to make it suitable for a 12v battery but if this is not a new alternator, don't assume that it has one. The output doesn't take into account the size or state of your batteries, their charge regime etc. I decent regulator like the ones from Balmar are intelligent multi-stage regulators and will supply your bank with the proper voltages and the proper current.

[smac999]

connect direct to house bank. then you need a way to charge from house bank to engine bank.

[hellomister]

Actually the system is a lot more sophisticated than that with 2 x 800 solar panels in through a solar regulator and 2 New 125a alternators. 800 ah of house battery storage and a third bank of a single 240ah cc battery for windlass only
My question is, disregarding the genset charge and the solar. which have their own regulators, is the system ok with just routing the charge manually via battery switches after monitoring via bank volt meters. OR. Do i need REALLY need a designated regulator that monitors and controls charge to banks as it decides required
Thanks

[smac999]

Originally Posted by hellomister

. Do i need REALLY need a designated regulator that monitors and controls charge to banks as it decides required
Thanks

every working alternator already has one. normally built it otherwise every car and boat battery would fry in 30 mins.

an external regulator alt would need an external one. would work better. but would only work if already had one.

[Pizzazz]

Here is a more detailed answer to help you decide. Batteries are typically charged at a specific voltage. Once full, the voltage should be reduced to a maintenance (or float level) to prevent overcharging. Typically, gel cells are charged at up to 14.2V and float is 13.5V. You should download the spec sheet for your batteries and set all your charge controllers to the respective voltages for your particular battery type.

I would recommend you get an external charge controller for each of your alternators to maximize battery life.

Gel cells are sensitive to being obercharged, so it makes sense

[hellomister]

Thanks for that
I guess i should clarify further
This is a new build. New system
Im really after information on a smart meter/charge regulator
I can control charge from alternators to banks manually easy enough but one of these units does that and more as in reads battery state. Directs charge where it thinks req etc.
Without me monitoring voltmeters and clicking switches over
Just not sure if i really need one and if so where in the system it goes cause theyre expensive but with 800 ah of house and 330 ah of start capacity theres a bit to manage
Thanks again for all the feedback

[ErikFinn]

Originally Posted by hellomister

any suggestions of best practice for a mid budget owner built cruiser
Cheers

If you haven't already done so I strongly recommend you study the excellent articles by our pro guru contributor Maine Sail regarding marine electrical subjects like batteries, charge controllers, alternators, solar. Cheers,

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[john61ct]

I think you are confusing the VR native to the Alt - which is mandatory - and the "intelligent combiner" fancy ACR/VSRs that stage/prioritize the order, which banks get charged first rather than just paralleling all of them.

The latter is not needed.

Best practice is to put all charge sources directly on the House bank, which is usually the one drawn down most frequently and deeply.

Dedicated voltage sense and temp sensing wire for fine compensation and heat de-rating must be directly connected to the bank.

Then the smaller, less used banks get charged from there with either quality ACR or DCDC charger if needed.

Hope that helps.