Learning and rethinking my cabin power system

System

I’ve been learning a lot on the forums. I have been looking to power my off grid cabin with a 2000W inverter system and a set of golf cart batteries. I wanted to be able to run a couple of small kitchen appliances, along with CFL lighting. At this point the appliances were a 1000W microwave and 800W toaster.

I bought a remanufactured Xantrex Prosine 2000W Inverter/Charger. I liked it because it has a built in charger, pure sine output, and a sophisticated remote display with a lot of monitoring functions and settings. However, I underestimated the cost, wiring size and battery bank to provide this inverter with 200 to 400 AMPS of 12VDC. 1500+ Watt loads would be short term, but still the system needs to be sized to handle what the inverter can pull.

When looking at my other AC loads, they are 165W of CFL (Assuming all the lights are on) and maybe a small TV or a Fan. I’m now rethinking my approach and considering a smaller inverter with the bigger loads run by the generator if needed. The generator would also charge the batteries whenever it’s running.

With taking the big loads out of the equation, I now estimate 450 watt hours per day. At 20% DOD, my battery capacity should be 222 A/H which can be met by a set of 6 Volt GC2(T-105) in series.

I’m looking for feedback on this new design and suggestions for the equipment. (My initial selections are in parens)

Inverter, pure sine. (300W MorningStar SureSine)

Battery Monitor (MorningStar Remote Meter connected to Inverter)

Charger, Could I use a solar charge controller and feed it with a DC power supply or unregulated battery charger run by the generator? When I add PV panels I could use a relay or diodes to allow either the generator DC power or PV panels to feed the controller? (Xantrex C35)

If I use a pair of T-105 225Ah Batteries in series, is 30A bulk charging current to much?

I know I need to fully charge the batteries on a regular basis, but do deep cycle batteries mind getting intermittent bulk charging as the generator is started and stopped for other uses?

Thank you,

Jerry

mike95490

Re: Learning and rethinking my cabin power system

Do you have any solar charging ?

I'm partial to the VEC1093 automotive battery charger. 40A, $150

40A in to a pair of batteries should be OK (40A @ 14V = about 600W)

Others are partial to IOTA 30 Amp charger, which gives longer gen runtimes, but goes online when power is on. http://store.solar-electric.com/dls-30.html

niel

Re: Learning and rethinking my cabin power system

"Charger, Could I use a solar charge controller and feed it with a DC power supply or unregulated battery charger run by the generator? When I add PV panels I could use a relay or diodes to allow either the generator DC power or PV panels to feed the controller? (Xantrex C35)

If I use a pair of T-105 225Ah Batteries in series, is 30A bulk charging current to much?

I know I need to fully charge the batteries on a regular basis, but do deep cycle batteries mind getting intermittent bulk charging as the generator is started and stopped for other uses?"


i don't know for sure if just any old cc will work in that capacity or if the c series will. i do know that i had a sunsaver10 and it did work in that capacity and my sb50 does not work in that capacity as i've tried it on both. maybe if somebody out there with a c series cc can try putting their automotive battery charger to it and see if it outputs regulated dc. my guess would be a c series cc would do it, but that is only a guess. btw the battery charger must have high enough voltage outputs capable of properly driving the cc under load for this to work. in other words a 16v 1a auto charger most likely won't drive the regulator circuits in the cc, but one at 18v and 6a could.

30a/225ah=13.333% this is borderline and will need higher maintenance and checked more often, but it should be ok.

i never asked one if they'd mind:p. less interuptions i suppose would be better, but they will still get a charge even on an intermittent basis.

System2

Re: Learning and rethinking my cabin power system

I plan on adding solar charging later this fall. We are currently building the cabin, have a lot going on and use the genset quite a bit for tools. Thus, I just want to charge off the genset for now.

Do you know if the VEC1093 charger will come on-line by itself when 120VAC is applied to it or does it need a button to get pressed to start the cycle?

mike95490

Re: Learning and rethinking my cabin power system

TheWire wrote: »

Do you know if the VEC1093 charger will come on-line by itself when 120VAC is applied to it or does it need a button to get pressed to start the cycle?

It NEEDS a button push. That's why I mentioned the other one will start un-attended.

HOWEVER - If you are thinking of going with an inverter to run the cabin, many of the large inverters, have a charger built-in. I know the XW series has a special input for AC from a generator, and will automatically charge from it.

So juggle the price of a

combined inverter/charger $$ [ and read the charger specs, see that it can really charge, not just a trickle ]
Along with needing a Solar Charge Controller $

OR

Inverter $
& AC/generator charger $
Along with needing a Solar Charge Controller $

Mike

Telco

Re: Learning and rethinking my cabin power system

I don't like "do it all" machines; when one function breaks, the whole thing needs to be replaced. A failure that ordinarily would have been a cheap to repair inconvenience now becomes an expensive outage. While the all in one does make for an easier and cleaner install, having individual components that perform one function is easier and cheaper to deal with from a maintenance standpoint.

System2

Re: Learning and rethinking my cabin power system

mike, is 40A better than 30A charger ?.
thanks

mike90045 wrote: »

Do you have any solar charging ?

I'm partial to the VEC1093 automotive battery charger. 40A, $150

40A in to a pair of batteries should be OK (40A @ 14V = about 600W)

Others are partial to IOTA 30 Amp charger, which gives longer gen runtimes, but goes online when power is on. http://store.solar-electric.com/dls-30.html

mike95490

Re: Learning and rethinking my cabin power system

I don't know that it's "better" but it will charge batteries faster. You need to be aware of the max charge rate for your batterys, different mfg have different rates, flooded cells donlt like more than 20% of their capacity, as a bulk charge current. So a 100AH battery would not want more than 20A charge. You can fudge this a little bit, as long as you are aware of the state of the batteries, or if someone else says I'm wrong, I'm just pulling this out of semi-forgetful memory.

System2

Re: Learning and rethinking my cabin power system

thanks for response, i guess bigger does not mean better, that is getting more difficult or expensive if it not well plan, any time i adding more battery i have to get a new charge control that is the right size for the total ampa. i assumed this example are true for inverter, solar panels etc...

mike90045 wrote: »

I don't know that it's "better" but it will charge batteries faster. You need to be aware of the max charge rate for your batterys, different mfg have different rates, flooded cells donlt like more than 20% of their capacity, as a bulk charge current. So a 100AH battery would not want more than 20A charge. You can fudge this a little bit, as long as you are aware of the state of the batteries, or if someone else says I'm wrong, I'm just pulling this out of semi-forgetful memory.

niel

Re: Learning and rethinking my cabin power system

it is alright to oversize a charge controller as the bulk current will be determined by the pvs and if you have mppt or not and not the current rating of the cc, unless you exceed the output ratings of the cc for then it will be held back to that rating. this can make expandability for more pvs or batteries a possibilty in the future without have to repurchase a cc providing you aren't near the max capability of the cc now. utility type chargers are another matter as these come usually with a fixed current output capacity. to expand this then one needs to buy another charger to either replace that one or to be paralleled to that one to obtain the right charge current. also note that many cc's are able to be paralleled for future expansions as well.
efit to add:
i'll add here that most times we recommend charging standard lead-acid batteries between 5 and 13% of their rated capacity. this can be more if the manufacturer says they can take more, but even at that the extra boiling of the electrolyte can cause more maintenance to minimumly be encountered and even possible boilovers if severe boiling occurs with a normal to high electrolyte level as it will make its way to the top and out of the battery.

System2

Re: Learning and rethinking my cabin power system

It seems like a lot of inverters and chargers don't have current adjustments on them. They output their design current even if there is a reason why you want to cut it back. Like not gassing out the electrolyte when charging or putting to many amps out of a battery bank when inverting.

My Xantrex Prosine has a 100A charger in it, but you can limit the charging current by telling it the "shorepower" breaker is smaller than it really is.

Its seems with most AC chargers out there, you need to buy one smaller and wait longer for a charge or buy one to big and risk gassing the batteries.

Are there multi-stage chargers out there with adjustable current outputs?

Thanks,

Jerry