A Question Regarding Excess Charge....

[goboatingnow]

Originally Posted by Lagoon4us

Dave we do that now, i'm looking at using all the power we generate more efficiently rather than wasting excess. Cheers Frank

There no real need to do anything. The excess energy will automatically be used by the invertor if required. In essence of you have capacity available it will used. There no need for load dumping ( in general)

Dave

[Lagoon4us]

Stu the inverter is not normally on and certainly not normally heating water via it, we start the genset for that what i'm trying to ask is once batteries come to 90% is it easy to have a sensing device to then turn the alternater on which for the exercise is switched to EITHER the DeSal or HWS..
Go Boating how is there risk? The HWS has a thermal switch same as if in port and the DeSal will flood the tanks?
I really see no issues....
Cheers Frank

[hummingway]

Originally Posted by Lagoon4us

Sorry if my question wasn't clear, what i'm asking is :-
When batteries are nearing full charge is it possible for an auto sensing unit switch to turn the inverter on so then the HWS or DeSal is running whichever of the 2 i've selected the inverter to power for the event.
We have the Inverter, DeSal, controller, some solar (soon to be added to) and HWS on board now all i'm trying to do is automatically store hot water or make water ONCE batteries are topped up because always there is the possibility of excess power that goes to waste....
Cheers Frank

We have had threads from people using a system for wind generators to do this. For some reason it seems a common thing with the wind gens whereas I haven't heard it done with solar. My MPPT actually reduces the amperage that is flowing into the batteries as they reach full charge, and I believe most of the good ones do, to improve the life span of the batteries; if I increase demand then the controller responds and provides more amps up to what's available at the time. I can imagine all kinds of difficulties with an automatic system but, like I said, folks have done it with wind gens.

[hummingway]

I should add that they've dumped to HW not the water maker.

[Lagoon4us]

Originally Posted by hummingway

We have had threads from people using a system for wind generators to do this. For some reason it seems a common thing with the wind gens whereas I haven't heard it done with solar. My MPPT actually reduces the amperage that is flowing into the batteries as they reach full charge, and I believe most of the good ones do, to improve the life span of the batteries; if I increase demand then the controller responds and provides more amps up to what's available at the time. I can imagine all kinds of difficulties with an automatic system but, like I said, folks have done it with wind gens.

Thanks i really think my question is quite simple, i guess what im meaning is as follows. As the MPPT reduces or tapers off the availible charge coming from whereever then THAT is the time to start sending the excess through an INVERTER firstly to our/my choice of end use i.e. HWS or De-Sal.
I don't see the point in having a solar array that has a huge output only to waste the energy by tapering, i would much rather see a load switched at that point that is useful.
If i'm sailing i don't necessaraiy have the timing to observe and switch.
I think everyone is missing my questions direction. The end use is protected by thermal overloads and the De-sal by excess product which bothers a membrane not one Iota.....
Cheers i think you are getting my point... Frank

[hummingway]

I think they call them a diversion load. The problem is, since wind gens are designed to run under load, they kick in when the battery is charged and if you have an MPPT controller it will be reduciing the flow and delaying when that happens. On the other hand I suppose you could skip the MPPT.

[Lagoon4us]

Originally Posted by hummingway

I think they call them a diversion load. The problem is, since wind gens are designed to run under load, they kick in when the battery is charged and if you have an MPPT controller it will be reduciing the flow and delaying when that happens. On the other hand I suppose you could skip the MPPT.

Not looking at adding any wind-gen as yet. I'm only talking energy from solar and main engines alternators.
My minimal understanding of circuits tells me i need to pirate something similar to the circuit from a simple battery charger, the components that detect resistance and start the ramping only i need to make that detection circuit switch a solenoid that kicks in the inverter.
The MPPT would stop ramping and start charging the batteries at a higher rate to compensate for the losses to the inverters designated load.
I know there are problems scavenging from other circuits BUT do you get my drift?
Cheers Frank

[hummingway]

I do. I wasn't suggesting you use a wind gen but actually the controller from one, since they are designed to do a similar thing to what you're asking for. When the batteries are charged they engage a shunt so that the energy coming in is continued to be used. The only way I know of them being used is with either a water heater or air heater but I believe that's because with wind you need to use whatever is available, which isn't true of solar panels. I suspect it would reduce the life of your batteries but maybe that would be a worth while trade off.

[Lagoon4us]

Ok you suggest using that switching action to energise the inverter solenoid?
The reduction in battery life you are thinking of is that the taper charge at the end of the charging rate?
If so i think all i'm doing is delaying it because as the HWS thermostat closes because the HWS has attained its designated temp the power load would come off.
Likewise as the overflow started running from the tanks the unit can be shut down leaving charging to taper as per whatever sun is left....
Actually a wind gen could do the taper...... Cheers and thanks for your input ....

[hummingway]

Originally Posted by Lagoon4us

Ok you suggest using that switching action to energise the inverter solenoid?

With the wind systems they just dump the full load as 12v. The point of them is to keep a load on the generator, the heat is just a useful byproduct in a system that can be damaged by running it without a load.

Here's an example which they say works for solar as well: 440 Amp Charge Controller with Divert Relay For Wind and Solar 440 Amp Charge Controller with Divert Relay [MW440ECC] - $119.99 : Missouri Wind and Solar, DIY Wind and Solar Energy

To run a desalinator though you'd also have to be sure there was enough amperage available, where as a heating element is just a soak, pardon the pun.

[Stu Jackson]

Frank, KISS

Your battery bank is a BIG storage tank. If you have the capacity to fill it in the morning and then use it during the day is NO different than if you use it in the morning and fill it up during the day. The energy budget is exactly the same.

90% soc was suggested 'cuz I don't know how long you want to use your inverter or how big your house bank is.

If you want to know what state your soc is, buy a battery monitor. Less than $200, Victron is a good one.

Lots of the responses here are very helpful. Wind needs a diversion load, and solar tapers off with a good controller. BUT, once the batteries are drained, say by the inverter, the solar controller will start replenishing it.

[noelex 77]

Yes what you want to do is possible.
The better solar regulators have a auxiliary function that will drive a relay to turn on anything you want. In the more sofisticated systems the parameters can be chosen to switch the relay when the SOC is above a certain level, when the batteries have reached float, or when the voltage is above a certain level.
This will work fine with something like heating a hot water system, or fuel polishing system. It is a bit more difficult with a Watermaker as the unit cannot be switched on for a short time then off when the charge level falls then back on etc, but it could be made to work.
I would set up the regulator to turn on the auxiliary when the SOC was above 90%. A multi position switch would divert he power to whatever you desired.

Like most crusing sailors I do this manually, staying with the kiss principal, and turn on systems like fuel polishing when the solar output exceeds what the batteries will accept, but if you want to automate this it is possible.

[Lagoon4us]

Thanks for your replies each one has added to my understanding, i will investigate the controller with the switching to a relay (thanks Hummingway) ability as i can get it to bring on the HWS at a regular point that's fine.

After looking at the systems used on modern boats for Navigation these days i cannot see that a pre-determined charge level that switches on a HWS et al is extremely sophisticated?

The Solar Regulator currently fitted, is as i noted a 'Morning Star', it doesn't bristle with info so once i purchase our new panels i will be happier to use a more sophisticated unit that will at the very least give an idea of charge/content levels.

Cheers All.......Frank

[Lagoon4us]

Originally Posted by hummingway

With the wind systems they just dump the full load as 12v. The point of them is to keep a load on the generator, the heat is just a useful byproduct in a system that can be damaged by running it without a load.

Here's an example which they say works for solar as well: 440 Amp Charge Controller with Divert Relay For Wind and Solar 440 Amp Charge Controller with Divert Relay [MW440ECC] - $119.99 : Missouri Wind and Solar, DIY Wind and Solar Energy

To run a desalinator though you'd also have to be sure there was enough amperage available, where as a heating element is just a soak, pardon the pun.

Hummingway i just looked at the controller with diverter, i can use their thermostat heater element to convert our HWS to 12 volt (provided the Quick Boiler is 1" NPT)and be happy that energy that would normally be shed will automatically be diverted.

When we are not on the boat that circuit can simply be in the off position same as most other "non-essentials".

Makes sense to me.... Thanks Frank

[hummingway]

Originally Posted by Lagoon4us

Hummingway i just looked at the controller with diverter, i can use their thermostat heater element to convert our HWS to 12 volt (provided the Quick Boiler is 1" NPT)and be happy that energy that would normally be shed will automatically be diverted.

When we are not on the boat that circuit can simply be in the off position same as most other "non-essentials".

Makes sense to me.... Thanks Frank

Let us know about how the conversion goes.