Battery Backup charger

KentUB

First post here.

A little background: We are in a very rural area 7000 ft in the mountains. For some perspective there are 3 houses north of us, then it is 2 days on horseback to get to the next house. Our utility supplier has been getting progressively worse over the years, especially to responding to issues in our area as their priority is restoring power in the not so rural areas first. Last winter a transformer blew out 1/4 mile to the east of us and those 7 houses were without power for 4 1/2 days until they could get a truck up to replace it. That was way too close. During this thanksgiving week-end we had 7 outages and one of them was 7 hours and we are not even into the worst of winter.

Up to this point we had a couple of deep cycle marine batteries and an inverter on a dolly to run the gas stove which still required power to run it's electronics. We replaced it with a wood stove and tore down a wall to open our floor plan to allow better heating without power. Also a couple of critical items are now on small UPS's to ensure the fish and lettuce do not die, etc.

Current issue: We need to provide a reserve source of power to some items on a less than critical basis (i.e. run fridge, freezer intermittently, etc. and not things like lights, TV, etc.). Eventually we will put in solar and wind to the house after we finish installing wind and solar to the new barn, as getting grid power to barn will cost almost $10K.

I am putting together a larger battery bank and need to figure out how to charge the bank without frying the batteries. I would rather find something lesser in cost for now rather than go buy an Outback or Xantrex Inverter/Charger so I can put the money into more batteries. I want to charge off the grid when it is there or a generator. Eventually we will but one of the inverter/chargers when we put in the solar and wind.

Any suggestion on a decent charger? I had thought of continuing to use the car charger I use for the portable battery set, however it would require rewiring the bank to charge at 12 volts rather than the 24 volts the bank will be setup for.

Blackcherry04

Re: Battery Backup charger

IOTA DLS series, I like the plain one and buy the separate IQ-4 Module. It's plug in and gives you more options to charge in the future. You really need to know the Battery Bank size to size the charger.

http://www.solar-electric.com/bach1.html

westbranch

Re: Battery Backup charger

As a starting point you will need to define as best you can (get a Kill a Watt meter) all the loads you want to run and list also those you would LIKE to run. All good systems are built around the loads they need to support.
So go around the house and make a list of every light and power user you can find, you will be amazed at how long it will be, and be careful to list the plug-ins on power bars, not just the bar itself.

Good hunting.

In the interim look at Xantrex for stand alone chargers, True Charge 2 series or others like it http://www.xantrex.com/power-products/battery-chargers/truecharge-2-24v.aspx

the other alternative is a combined Inverter/charger check our hosts store, shown at the top of the forum page.

Cariboocoot

Re: Battery Backup charger

Welcome to the forum.

I'm going to make a suggestion which you probably won't like. You obviously have a serious on-going power problem which is not going to get any better. As such spending money on short-term solutions instead of long-term ones means you'll end up spending the money twice. As such, a larger battery bank is not necessarily what you need to do.

1st, evaluate those loads you need to keep going when the power is off. Get a Kill-A-Watt an measure the actual power requirement.

2nd, size a battery bank of true deep cycle type (not Marine/RV) to accommodate those loads.

3rd, get an inverter-charger that will both supply the power from batteries as needed and recharge those batteries when grid/generator is available. The chargers in these are better than any stand-alone type for this use.

4th, evaluate the generator need and see about getting an inverter-generator as opposed to a fixed RPM type. The extra expense may be made up in reduced fuel usage.

I know this is not what you wanted to hear, but buying the wrong equipment now means you end up spending the money twice.

P.S.: your choice of 24 VDC is wise. You may even want to consider 48 Volts once you have a handle on what your power requirements actually are.

BB.

Re: Battery Backup charger

For short term outages--A small genset sized for the loads is hard to beat... If all you have is a refrigerator+lighting and a few odds and ends... A 1,600 watt to 3,000 watt genset (quiet inverter generator from Honda/Yamaha/etc.) can be a good match.

For example... A Honda eu2000i will output ~400 watts for 9+ hours on 1 gallon of gasoline. And ~4 hours at 1,600 watts. You can add a fuel cap with a hose and drop the weighted end of the hose into a 5 gallon container (siphon) for extended run times.

If you have a big well pump--A large cistern/couple of pressure tanks and a ~3.5-5kW "noise maker" you can run for a 1/2 hour per day (or couple times a day when taking showers/baths/etc.) will (usually) run a 240 VAC well pump.

Having several generators of different sizes allows you to match loads to genset capacity (good fuel efficiency) and the larger genset is good for backup to the backup genset/run power tools, etc.

My heating/cooking/hot water is natural gas... I need a small genset to run the central heat and a couple refrigerators/freezers. In theory, 20 gallons of gasoline (fuel stabilizer, changed once a year) will keep me running for ~10 days.

I live in an urban (suburban?) area and 10 days without power is probably going to start looking bad for the region (water & sewage issues at the very least).

-Bill

Cariboocoot

Re: Battery Backup charger

The frequency and longevity of outages the OP is describing is practically "third world country" power. I'm not the least surprised he wants battery back-up and think it's a very sensible thing under the circumstances.

KentUB

Re: Battery Backup charger

I have used the Kill-a-Watt. The intent is until we have the chance to actually get a bigger system into the house, about a year away, go with something smaller to keep us at minimal level. This includes using an extension cord to plug in specific loads as needed. We are still missing some data points that are preventing proper sizing of a battery bank, like the new fan for wood stove which arrives next week and the new freezer.

So far the biggest load is the big freezer at 435 Watt running and 920 watt start. Although it only runs about every 4 hours during fall and is in a cooler room that will allow it to probably sit for days during the winter without running. However with over $1,000 worth of Elk alone in that freezer, it is cheap insurance.

I can pull the 1800 watt 24V inverter from the trailer in under 10 minutes, including the walk to the trailer. But the charger built-in is major work to get to it, so I am shopping for a charger. I was not aware of the IOTA or Xantrex chargers until now. Everything I found through my first couple of Google searches did not seem to match up. So that gives me a path to start to finalize my numbers.

The genset I have is enough if I was willing to settle for one failover. However they can be cranky in very cold weather and I just want to make sure I have yet one more failover. As Cariboocoot said the power issue out here is only going to get worse. Fortunately our water comes from a reservoir further up the mountains and without power we would have over a years worth of water if it never rained.

westbranch

Re: Battery Backup charger

Sounds like you have a good start on things. What size is that cranky gen-set?

vtmaps

Re: Battery Backup charger

KentUB wrote: »

I am putting together a larger battery bank and need to figure out how to charge the bank without frying the batteries. I would rather find something lesser in cost for now rather than go buy an Outback or Xantrex Inverter/Charger so I can put the money into more batteries.

The heart of your system is the batteries, and a mistake in designing the battery bank can be an expensive one. Tell us more about the battery bank you are building. Which batteries? Where will the batteries live? what ambient temp? how far will they be from the inverter? How many strings? If more than one string, how will you interconnect them?

KentUB wrote: »

I want to charge off the grid when it is there or a generator. Eventually we will but one of the inverter/chargers when we put in the solar and wind.

Be aware that the Iota charger is not power factor corrected. That means that it will use more of your generator's capacity than a PF corrected charger. If you have a huge generator, it won't be an issue. It is an issue for those who have some of the smaller inverter generators.

--vtMaps

KentUB

Re: Battery Backup charger

Cariboocoot wrote: »

The frequency and longevity of outages the OP is describing is practically "third world country" power. I'm not the least surprised he wants battery back-up and think it's a very sensible thing under the circumstances.

This is what you get when you choose to live in the mountains year around where you are 35 miles from the nearest supermarket, 70 miles from Wall-Mart and over 100 miles from a Starbucks. The local co-op has minimal regulation with fantastic pricing of power, but the majority of the shareholders naturally live in the towns and city, so that becomes priority one. I was just at the road a few minutes ago and noticed an icicle handing off the transformer, using the rifle scope I discovered it is about 1/2 inch from shorting out. Looks like I need to make sure that portable battery is charged up.

I have a 2000 Watt GenSet and a "portable" battery pack with 2 135 AH marine batteries and 1KW inverter mounted to a dolly. I have even thought about getting a 135A alternator for the compact tractor and putting an inverter on the side of it just to have one more backup.

I am not far enough down the road on sizing and designing the battery bank as of yet to even give you numbers since I am missing 2 appliances that will be coming soon. The most likely configuration is going to be 6V Golf Cart batteries wired series-parallel for a total of 24V with 2 rows, but until I know every detail of every load I will not do the math to determine what I need.

We do have enough non-electric lighting/Cooking and Heat that we will not need to run any of that off the batteries, with the exception of the fan for the wood stove to move heat around as much as possible (it gets cold at 7000 ft). The manufacture says it is 45W, but we will see once it arrives Monday. Second Freezer is a couple of weeks away yet.

westbranch

Re: Battery Backup charger

we use one of these http://www.caframo.com/hearth/ on the cookstove (wood) 4 years and still works fine, found we can also use it on top of the propane wall heater, it just runs a bit slower as not as hot as the wood stove.

You might want to consider powering some of the largest load with the gen running to keep the battery size a bit smaller. Look into Generator support in Outback inverters GF series I believe, and read the thread started by Chris Olson on Gen support, its long but well detailed

Cariboocoot

Re: Battery Backup charger

I know what you mean; hour's drive to civilization from my cabin, and Wal*Mart another hour beyond that. What's a Starbucks? Not around here!

Suggestion on the woodstove fan: get an eco fan and turn of the squirrel cage entirely. We use one here and at the cabin and they work quite well. The AC fan that can with the stove here made a lot of noise and moved a little air. The eco fan moves as much air and makes no noise.

Freezers (any type of refrigeration) are big power users. 2kW hours per day in Summer is not unrealistic for an old one. Newer ones are much better. With two of them being powered you might want to think harder about a 48 Volt system as it accommodates greater Watt hour storage in an easier form. A bit about that: http://forum.solar-electric.com/showthread.php?15989-Battery-System-Voltages-and-equivalent-power

vtmaps

Re: Battery Backup charger

KentUB wrote: »

The most likely configuration is going to be 6V Golf Cart batteries wired series-parallel for a total of 24V with 2 rows

If you have 8 GC batteries, they can be configured as two parallel strings at 24 volts, or one single string at 48 volts. Either way you have the same energy storage. A single string of batteries is the optimal configuration for most systems. A 48 volt system is more efficient than 24 volts. A 48 volt system also means your solar controller will not heat up as much for any given size solar array, and that you can use thinner wires (less expensive) for all the DC wiring.

KentUB wrote: »

I have a 2000 Watt GenSet

Then you should definitely look for a PF corrected battery charger.

--vtMaps

Blackcherry04

Re: Battery Backup charger

vtmaps wrote: »

Then you should definitely look for a PF corrected battery charger.

--vtMaps

It would be nice for someone to do a test and actually prove that it makes a difference. I Bought the $349 charger that was posted in here over and over, it was a piece of junk, never put out it's rated output, would Fault if the bank had any load on it while charging and had a worse I/O than the IOTA.

Cariboocoot

Re: Battery Backup charger

Blackcherry04 wrote: »

It would be nice for someone to do a test and actually prove that it makes a difference. I Bought the $349 charger that was posted in here over and over, it was a piece of junk, never put out it's rated output, would Fault if the bank had any load on it while charging and had a worse I/O than the IOTA.

I agree with you. The PF issue for charge controllers is, in my opinion, exaggerated. If anything the PF is at its best when the charger is putting out maximum Amps and declines as the battery charges. As such the net load on the generator does not vary that much due to PF to be a real issue. We are definitely not looking at the kind of horrible difference it makes with an induction motor.

Quite often it is pointed out that generators work best when loaded to over 50% of their capacity. By the same token they don't work that well if loaded to 99% of capacity, and that would be asking for trouble anyway. Nothing is ever a 100% accurate number in electronics, so you'd better have a little plus/minus leeway to take that into account in all aspects of the system, including the generator capacity.

vtmaps

Re: Battery Backup charger

Blackcherry04 wrote: »

It would be nice for someone to do a test and actually prove that it makes a difference.

I also agree. Did you see this other concurrent thread:

jcheil wrote: »

The Iotas are great but do have a super crappy power factor. But they are the best for the money IMO. And they last forever. but the power factor DOES make a huge difference on the generator.

The 40a one I have, which needs a 20a circuit draws around 16a (according to a shunt I have on the ac line feeding it) when in bulk mode. However, I know it is drawing way more than that from the generator because when I run it on the 3500w generator it really bogs it down to the point where if I were to (as a test) plug in a 500w heating element at the same time, the generator just about stalls. I have loaded that 3500 with 3300w of heating elements (the most I had hanging around) as a test and it is pretty stable. So that leads me to believe the IOTA is using close to 3000w from the generator.

--vtMaps

Cariboocoot

Re: Battery Backup charger

The numbers vtmaps cites from jcheil example would be a pretty horrible PF of about 0.64, if the 3kVA generator draw is right. Keep in mind that the straightforward 16 Amps @ 120 VAC would be 1920 Watts which is about 2/3 of that. But unfortunately this is still anecdotal. The Iota could be plugged in through a K-A-W if it weren't exceeding the limits of it (16A is just over the 15A max the meters are meant for - things could go wrong). You'd also need to check that the gen is actually capable of its rating under the operating circumstances. Mine, for example, need to be derated due to altitude. His resistive heating load is a good if imprecise test of this.

I believe his charger is 40A 48V, which is also 1920 Watts. The input and output power would never really line up like that (100% efficiency) so the charging was probably not quite at maximum.

Blackcherry04

Re: Battery Backup charger

vtmaps wrote: »

I also agree. Did you see this other concurrent thread:



--vtMaps

This is a Test ?? Of what ?? Something named IOTA ??

jcheil

Re: Battery Backup charger

Cariboocoot wrote: »

The numbers vtmaps cites from jcheil example would be a pretty horrible PF of about 0.64, if the 3kVA generator draw is right. Keep in mind that the straightforward 16 Amps @ 120 VAC would be 1920 Watts which is about 2/3 of that. But unfortunately this is still anecdotal. The Iota could be plugged in through a K-A-W if it weren't exceeding the limits of it (16A is just over the 15A max the meters are meant for - things could go wrong). You'd also need to check that the gen is actually capable of its rating under the operating circumstances. Mine, for example, need to be derated due to altitude. His resistive heating load is a good if imprecise test of this.

I believe his charger is 40A 48V, which is also 1920 Watts. The input and output power would never really line up like that (100% efficiency) so the charging was probably not quite at maximum.

Just for clarification, I am on a 24v system and the Iota is a 40a 24v charger.
I am also at 70' above sea level (literally).
I considered testing it thru the KAW meter but the plug on the Iota is a 20amp plug (with the sideways pin) so I would have to make an adapter and hope it doesn't let the magic blue smoke out of it. I might do it just as a test. Heck it is only $30 for a new meter. But somewhere I do remember reading that the PF was around 0.65 for the Iotas.

Oh yeah and also the inrush current is HUGE. Which in my case doesn't stall the generator but it does make it cry for a second or two when the Iota is first turned on. If I watch my shunt meter on the AC line of the Iota it jumps up near 30amps for just a second.

Blackcherry04

Re: Battery Backup charger

I have Personally used my Honda EU 2000 on 3 different IOTA chargers listed below. I start them with the ECO off and then turn it on after the charger has started. The Chargers do have a in-rush some generators my not like them, some may not be capable pulling one. I have read that some will plug them in once to load the caps and then can replug them and they will run on some small generators. I have also read that if you start them with the plug in the jack that will lessen the starting current.

DLS-55 12 V, 55 amp output
DLS-75 12 V, 75 amp output
DLS-27-30 24 V 30 amp output.

jcheil

Re: Battery Backup charger

Blackcherry04 wrote: »

I have Personally used my Honda EU 2000 on 3 different IOTA chargers listed below. I start them with the ECO off and then turn it on after the charger has started. The Chargers do have a in-rush some generators my not like them, some may not be capable pulling one. I have read that some will plug them in once to load the caps and then can replug them and they will run on some small generators. I have also read that if you start them with the plug in the jack that will lessen the starting current.

DLS-55 12 V, 55 amp output
DLS-75 12 V, 75 amp output
DLS-27-30 24 V 30 amp output.

I didn't think they made a 30a 24v one, did you mean the 25?
And if so both that one and the DLS 75 12v must be really maxing out that 1600/2000 generator.
Wonder if somehow an inverter generator vs my non-inverter generator has something to do with it?

vtmaps

Re: Battery Backup charger

jcheil wrote: »

Wonder if somehow an inverter generator vs my non-inverter generator has something to do with it?

I doubt it, SteveK had problems with an Iota and a Honda eu2000: http://forum.solar-electric.com/showthread.php?10123

--vtMaps

Blackcherry04

Re: Battery Backup charger

jcheil wrote: »

I didn't think they made a 30a 24v one, did you mean the 25?
And if so both that one and the DLS 75 12v must be really maxing out that 1600/2000 generator.
Wonder if somehow an inverter generator vs my non-inverter generator has something to do with it?

Probably back when I bought mine they did, now maybe they don't. Call it a 25 Amp if you like. I didn't know they made a 40 Amp. As a matter of fact the Honda will run it on the ECO Throttle.

Attachment not found.

jcheil

Re: Battery Backup charger

Blackcherry04 wrote: »

Probably back when I bought mine they did, now maybe they don't. Call it a 25 Amp if you like. I didn't know they made a 40 Amp. As a matter of fact the Honda will run it on the ECO Throttle.

Attachment not found.

Yeah I have seen that picture before.
But that doesn't represent what the generator is "actually" drawing/seeing correct?

I don't know what to say either, I know the results i get and some neighbors also.
Would the fact that I have the voltage cranked up to 29.6 make any difference?

Maybe they changed something in the newer models? Perhaps yours is older and built "better"?
Also, I did hear they were starting to make them in China now. I am sure that is the one I got since I bought them only a year ago.

Blackcherry04

Re: Battery Backup charger

jcheil wrote: »

Yeah I have seen that picture before.
But that doesn't represent what the generator is "actually" drawing/seeing correct?

I don't know what to say either, I know the results i get and some neighbors also.
Would the fact that I have the voltage cranked up to 29.6 make any difference?

Maybe they changed something in the newer models? Perhaps yours is older and built "better"?
Also, I did hear they were starting to make them in China now. I am sure that is the one I got since I bought them only a year ago.

Well, I don't know what the Generator is " Seeing ", I know my amp meter is showing 8.62 amps Input. and 75.9 amps output.

IOTA only started Marketing their Power Converters as battery chargers since 2007 or so. Before then they only marketed to the RV market. As that market headed south they found a new market, as did WFCO, Progressive Dynamics, Magnetek, Inteli-Power and others. I am not a fan boy for them, The sponsor sells them at a great price and if they work for people that makes me happy. I bought a Meanwell PB-1000 after it was posted over and over, it's not worth a darn as a RE stand alone charger.

I loaned my brother in law a 40 Amp charger over Thanksgiving, he calls me saying it was throwing a breaker. I go over he's got in on a 100' # 16 extension cord. You just know what folk's are talking about without knowing all the details.
.

KentUB

Re: Battery Backup charger

2 days without power has put some priority to this project. I would like to go 48V at this time, however this is an in-between project. Most of the money for power needs has to be dropped into the off-grid system in the new barn packing shed due to cost of bringing grid power to that spot.

The inverters I have are rated at 12 or 24 volts. The only thing I really need to run selected critical items off the batteries is a cheap charger to last about a year. At that time a tractor and greenhouse will be paid off and the barn off-grid project will be done and I can focus on a system that is properly setup with solar, wind and grid interactive charging. Batteries will be able to be reused in that system or with the inverters on "portable" battery packs used in the fields.