Help with batt bank charger selection

c_rossz24

Hey everyone im new here so any help will be appreciated lots

so heres my plan im going to live off grid for the summer in my friends cabin, it has no power so im going to make my own, ill only be running maybe 4 lights, a lap top and stereo so maybe a few hundred watts at a time off my batt bank.

i have a 3000 watt gen that i want to use to charge 2 - 6v 225 ah golf cart batteries from Canadian tire, im looking at this :
-Iota DLS-30 12 volt 30 amp regulated battery charger
-Iota IQ4: plugin 4-stage controller for Iota chargers
its only going to cost me about 175 $ shiped to my door i assume i will only have to run my gen every few days to charge my batts and at that time i will run my pump to fill my water tanks and anything else i may need to run

is 30 amp a good charge rate for my batts and gen ? and will this charge work well if i run my batts down to 50% ?
thanks for any tips open to suggestions but also on a budget

icarus

Re: Help with batt bank charger selection

First, welcome to the forum. The are some pretty smart folks here who are more than willing to help you.

My first suggestion is dont buy anything until you do a proper load calc! All hardware items derive from the loading. It is a very diffent equation if you use 100 WH/day versus 200!

Here is a quick though calc. 4 lights 15 watt led/cfl for 4 hours per day is 240 WH.a small lap top might draw 60 watts, running 4 hours would be another 240 WH/day. A small stereo (like a car radio which is what I use) might draw 15 watt, 6 hours, another 90 WH. So that brings the total to about 570 WH/day.

So your 250ah of battery will deliver, (until it is drawn 50%) 1500WH. If you routinely draw your battery to more than 50% it won't live very long. I prefer to only draw 25% and then get it fully charged every few days at the very least.

So, your 225 ah better would like a max of about 30 amps of charge current.

The iota is a good charger, but you re going to be running a genny a lot. In fact you have more genny than you need, and ergo you are going to spend a lot more on fuel as a result. For example, a Honda Eu1000 should drive the 30 amp charger. (it won't quite drive The 40 amp Xantrex.) and will use a tiny amount of fuel. You could consider doubling the battery bank, doubling the charge capacity, and charge every 3-4 days depending on the loading, but charge more efficiently.

Please read and understnd the following, do some load calcs and ask oh our questions.

http://www.batteryfaq.org/

http://www.solar-electric.com/deep-cycle-battery-faq.html

Just for comparison, we live off grid in NW ON. We routinely use 5-800 WH/day, and we re very frugal. We have 450 ah of batteries and 400 watts of PV. I charge from a genny with an Xantrex 20 amp 4 stage charger, but only need it rarely.

Good luck and keep in touch,

Tony

vtmaps

Re: Help with batt bank charger selection

c_rossz24 wrote: »

-Iota DLS-30 12 volt 30 amp regulated battery charger
-Iota IQ4: plugin 4-stage controller for Iota chargers

The Iota is a rugged and inexpensive charger. If you plug it into the grid to charge your batteries, it will satisfy you.

If you power it from a generator you may, or may not be satisfied. The Iota has a very high inrush current that may swamp your generator. If you can get past the inrush, it has a very low power factor and may use up more of the capacity of your generator than you think. for example: an Iota that draws 1000 watts may have a VA of about 1650, and therefore it takes a 1650 watt generator to power a 1000 watt charger.

--vtMaps

Blackcherry04

Re: Help with batt bank charger selection

Your 3000 Watt Generator WILL power a DLS -30 without a problem and is a good choice for the battery bank you have. You can spend another $300 or so and buy a PFC charger, but you'll never know the difference when charging batteries if they work. The problem with PFC Smart chargers is the control circuitry in them will not allow them to work well with a battery bank that has any load while charging because it sees the load a fault and constantly adjusting it's output and you end up with a $600 brick.

c_rossz24

Re: Help with batt bank charger selection

Thanks for the speedy replies, i will have to do some calculations because basically im just going to be running batteries for light anything else i can use when i have the gen running, im single so their wont be much need to have more than lights.
this is really only an experiment for me too and a means of learning more.
you say this charger dosent like draw off the batteries while charging? so do you recommend i switch from batt power to gen power to run my home while charging?
and what do you guys think off this batt ??
http://www.canadiantire.ca/en/pdp/12v-eliminator-renewable-energy-deep-cycle-battery-0111879p.html#.Uzgjjs6Ttm4

vtmaps

Re: Help with batt bank charger selection

Blackcherry04 wrote: »

The problem with PFC Smart chargers is the control circuitry in them will not allow them to work well with a battery bank that has any load while charging because it sees the load a fault and constantly adjusting it's output and you end up with a $600 brick.

c_rossz24 wrote: »

you say this charger dosent like draw off the batteries while charging? so do you recommend i switch from batt power to gen power to run my home while charging?

Some 'smart' chargers, when first connected to the battery, do some impedance and load tests to figure out what type of condition the battery is in. Other 'smart' chargers use charging protocols that primarily regulate current (rather than voltage). Both of these types of chargers assume that they are the only thing connected to the battery, and will be confused by loads or other charging sources.

But not all chargers are too smart to use in a RE (solar, generator, and loads) system. RE chargers (such as the Iota) and controllers do their primary regulation by battery voltage. They all see the same battery voltage and work together harmoniously.

Blackcherry04 is probably correct that your 3000 watt generator can run that Iota. Icarus is also correct that you will use a lot of fuel running a 3000 watt generator to push 450 watts or less into your batteries. A smaller generator would save you fuel. The point I was trying to make was that the Iota can be difficult to use with small generators.

--vtMaps

Blackcherry04

Re: Help with batt bank charger selection

All we need here is a List of those PFC corrected chargers and a verifiable test. The last $349 I spent on a Meanwell that was a not a viable charger that's still sitting in a box and is unusable. If you say that one charger is .065 PFC and one is .085 there is no way that one will save you 15-20% on fuel unless you have a test with results that show the difference. I see people say they save on fuel, as if something your using for two hours makes that much of a difference and you pay 3-4 times as much for the charger , if it will work.

The IOTA is as dumb as they come, It's a Constant Voltage Power Supply that had a controller added to it, but it works.

vtmaps

Re: Help with batt bank charger selection

Blackcherry04 wrote: »

If you say that one charger is .065 PFC and one is .085 there is no way that one will save you 15-20% on fuel unless you have a test with results that show the difference.

The PF of a charger should be expected to have very little effect on generator fuel usage. (the efficiency of the charger does affect fuel usage)

Continuing with the example I gave a few posts back:
Let's say charger draws 1000 watts and has a VA of 1650. Let's say the charger has an efficiency of 90%. The generator needs to be rated at the VA of 1650 watts, but its fuel consumption will be that of a resistive 1000 watt load. The 1000 watts represents real power... 1000 watts from the generator goes into the charger and then 900 watts goes into the battery. The charger dissipates as heat the 100 watts lost due to its 90% efficiency.

The VA was 650 watts higher than the 1000 watts of real power. That means the generator and its wiring must be able to handle the current flows of a 1650 watt resistive load. The extra 650 watts does NOT represent real energy expenditure... it's just a lot of energy sloshing around in the wires that is NOT dissipated as heat. If the generator was burning an extra 650 watts worth of fuel, that energy would have to be accounted for. If it's not going into the batteries, and it's not heating up the charger, then it isn't real. btw, you would know (by the smoke) if your charger was dissipating an extra 650 watts.

--vtMaps

Blackcherry04

Re: Help with batt bank charger selection

Great explanation VT, if it works for you, thats good. Meanwhile back Ranch we're still using a IOTA and charging batteries for 1/3 of the price of a PFC charger and it actually puts out it's rated output.

Iota vs Meanwell PFC charger

The Math :

Meanwell

Input 7.39 amps ac @ 120V

Output 51.4 amps dc @12.7 v

51.4/7.39 = 6.95 DC amp's for every 1 ac amp of input

IOTA

Input 8.64 amps ac @ 120V

Output 75.9 amps dc @12.7 v

75.9/8.64 = 8.78 DC amp's for every 1 ac amp of input

jcheil

Re: Help with batt bank charger selection

I agree, and had the Iotas and they are SOLID chargers and always do what they are supposed to tdo. However, as mentioned, the inrush and PF kinda stink. But for the price you cannot beat them. Plus they don't care about how crappy the voltage or waveform is on your generator. They still put out the power.

For reference, I ran a DLS-27-40, 40amp 24v one on a Champion 3500 and it consumed a good part of it's capacity. If the fridge started, it almost bogged down the generator to the point of stalling. However, this was 40amp at 24v so that would be like running an 80amp Iota on your 12v system (if they made one that big). Since you are only taking about the 75, it will be a tad better.

vtmaps

Re: Help with batt bank charger selection

jcheil wrote: »

so that would be like running an 80amp Iota on your 12v system (if they made one that big).

They do make one that big. DLS-90. --vtMaps

Blackcherry04

Re: Help with batt bank charger selection

No one charging scheme is going to fit everyone, it all depends on your use and desires. Finding the right combination of Generator and Charger can be a bigger job then designing the main system. I can think of at least 10 different ways that someone might want to use a Back-up / Stand-by system. If your only going to put a charge in the batteries then all you have to do is find the max combination of Generator / Charger that will work @ 75%-80% output. If your going to use bypass for your loads, then it becomes a different choice. If you want Generator Support, then is a different choice. Finding what works is a expensive experience, you end up with a lot of useless equipment. Generator run time and fuel consumption is a huge factor to be considered. Inverter / Chargers all implement things differently, what may work on one , may not on another.

Another Factor that could be considered is not having a Battery charger at all. Depending on your commitment to your battery bank and the combination of battery voltages a variable output power supply may be a better investment. Where I have 2v , 6v and 12 v batteries, I could not get by without one. I can change the output to a .001 of a volt from 0-100v dc @ 30 amp . If you have laggers you don't even have to disassemble the bank. You can charge a string, Equalize from one battery or all of them. Yeah, it's manual and you have to be a little careful, but once you set the voltage it's steady as a rock.

c_rossz24

Re: Help with batt bank charger selection

thanks for all the help my iota is shipped and on its way, i have a couple more questions, i found a local guy that sells solar panels and im thinking of a 60 or 90 watt just to play around with, when choosing my solar charge controller does it have to be sized for the solar panel ? or can i get a 20 or 40 amp controller to allow for more solar panels someday ?

can i draw off my batteries while the solar panel is charging or will that trick the controller into thinking the batteries are discharged more than they are??

Cariboocoot

Re: Help with batt bank charger selection

c_rossz24 wrote: »

thanks for all the help my iota is shipped and on its way, i have a couple more questions, i found a local guy that sells solar panels and im thinking of a 60 or 90 watt just to play around with, when choosing my solar charge controller does it have to be sized for the solar panel ? or can i get a 20 or 40 amp controller to allow for more solar panels someday ?

can i draw off my batteries while the solar panel is charging or will that trick the controller into thinking the batteries are discharged more than they are??

No worries: you can use a larger-then-needed charge controller. The Amperage rating is the upper limit.

No problem pulling from the battery while charging either; it will not confuse the controller (it sees only Voltage and current going out and doesn't care where to) although the load does reduce the effective charge rate.

For example if you apply 7 Amps to a 100 Amp hour battery that's a 7% rate. If you add a load that draws 2 Amps then the actual current going to the battery is 5 Amps even though the output of the charge controller is still 7 Amps. In worst-case scenario the draw of the load exceed the output of the charge controller and the battery discharges (to make up the difference in current demand) rather than charges.

c_rossz24

Re: Help with batt bank charger selection

so can i have my solar charge controller hooked up while i am charging off my gen with my iota with out causing any damage to either one? or should i just disconnect my solar while charging from gen ?
and does anyone have any pics or schematics of their small setups that i could look at or point me in the right direction where to find ones to look at?

vtmaps

Re: Help with batt bank charger selection

c_rossz24 wrote: »

can i have my solar charge controller hooked up while i am charging off my gen with my iota with out causing any damage to either one?

Yes. No problem for the equipment. Depending on how large your batteries are, with multiple charging sources, it is possible to push too much current into them during bulk charging. Are you planning to run the generator while the sun is shining?

--vtMaps

jcheil

Re: Help with batt bank charger selection

c_rossz24 wrote: »

so can i have my solar charge controller hooked up while i am charging off my gen with my iota with out causing any damage to either one? or should i just disconnect my solar while charging from gen ?
and does anyone have any pics or schematics of their small setups that i could look at or point me in the right direction where to find ones to look at?

Also, there is a small adjustment screw (not sure exactly where it is on your model iota, usually on the end and accessed with a small precision Philips screwdriver - some need to have the cover opened). You would want to adjust the voltage with no load, and the little phone-jack plug IN to be set to your absorb voltage. They come set a little low (14.4 if I recall). It is a very fine adjustment, doesn't take too many turns to get it to where you would want it to be.

c_rossz24

Re: Help with batt bank charger selection

vtmaps wrote: »

Yes. No problem for the equipment. Depending on how large your batteries are, with multiple charging sources, it is possible to push too much current into them during bulk charging. Are you planning to run the generator while the sun is shining?

--vtMaps

ill probably only run the gen at night if i have too and i will have a disconnect for the solar charge, so to be on the safe side i will disconect it ....
i have another question i know i could research this my self but id rather hear it from people who know....... batteries last determined on how many times you cycle them right ? so say i drain 20 AH from my batts in the night and the next day its nice and sunny and my solar panels top them back up , is that considered a cycle for the batts? if it is would it be bettter to not charge the batts till i drain them down a bit or just let the solar panels keep them toped up all the time? just curious...

Cariboocoot

Re: Help with batt bank charger selection

c_rossz24 wrote: »

ill probably only run the gen at night if i have too and i will have a disconnect for the solar charge, so to be on the safe side i will disconect it ....

That would be unnecessary at night. VtMaps was referring to running the gen & charger on a sunny day when you have full current potential from the panels as well. That's when you could have too much current going to the batteries.

i have another question i know i could research this my self but id rather hear it from people who know....... batteries last determined on how many times you cycle them right ? so say i drain 20 AH from my batts in the night and the next day its nice and sunny and my solar panels top them back up , is that considered a cycle for the batts? if it is would it be bettter to not charge the batts till i drain them down a bit or just let the solar panels keep them toped up all the time? just curious...

Sort of. And discharge amount follow by recharging is considered a cycle.
In reality batteries die over time no matter what. You can slow the rate, but they are going to die.
Low discharges levels aren't economic as the cycle life varies little until you start dipping below about 25% DOD. That's the usual target depth that usually gives you the best lifespan/cost.
So discharging 10% is about the same as discharging 20% for practical purposes. But discharging 50% is much harder on them than even 30%. This is why we try to plan battery bank size for a 25% average daily DOD. It will usually allow you two days of autonomy before you have to start the gen, and is far less expensive than longer autonomy while being of best value for daily operations if the panels can recharge on their own. It's not terribly practical to turn off the solar and draw 10% for each of two or three days and then turn it back on to recharge. For one thing you may forget to flip the switch.

vtmaps

Re: Help with batt bank charger selection

c_rossz24 wrote: »

if it is would it be better to not charge the batts till i drain them down a bit or just let the solar panels keep them toped up all the time? just curious...

That's a very good question. For one thing, it depends on the battery. For some batteries it is more cost effective to do a deep discharge and a full recharge daily. Many forklift and other industrial batteries are routinely discharged to 20% SOC.

Midnite's Classic controllers, and also some of the European controllers allow you to skip charging for a few days until a certain DOD is reached.

One thing to note: in the industrial or forklift battery situation, the batteries are rapidly discharged and rapidly recharged. They don't spend a lot of time at low SOC. If you try to do 80% DOD in an RE system, it may take days to get down to 20% SOC and take days to get back to 100% SOC. That's too much time at low SOC. Also, in RE systems there is a lot of partial charge and discharge cycles. These cause stratification of the electrolyte.

None the less, I think that some systems with shallow daily discharges would benefit from skipping a day or two of charging.... provided that when the battery is recharged it is done so in a day.

--vtMaps

Rybren

Re: Help with batt bank charger selection

c_rossz24 wrote: »

and what do you guys think off this batt ??
http://www.canadiantire.ca/en/pdp/12v-eliminator-renewable-energy-deep-cycle-battery-0111879p.html#.Uzgjjs6Ttm4

I'd run away from that one. $350 for a 100ah (100hr rate) is way too much in my books. Do you really need an AGM? You can pick up 2x6V 232ah GC batteries for about the same price. Plus, with the GCs, you'll be able to measure the SG and determine how well your charging routine is working.

Cariboocoot

Re: Help with batt bank charger selection

Do you know how Canadian Tire sells so many batteries?
They're open on Sunday.
:roll:

Rybren

Re: Help with batt bank charger selection

:-)

Sad, but so true.

zoneblue

Re: Help with batt bank charger selection

vtmaps wrote: »

Midnite's Classic controllers, and also some of the European controllers allow you to skip charging for a few days until a certain DOD is reached.

vt, days between bulk doesnt completely avoid charging, just skips absorb. Our situation may not be normal becasue our summer loads are light, but the bank still reaches 100% each day under days between bulk.

It does take longer to reach EA level of charge acceptance, maybe 75% longer. However the benefit in skipping absorb, particularly for AGMs that are lightly cycled (85%-90% SOC) is reduced catylyst wear.

By doing the absorb every 5 days i use a low EA value (0.3% of 20hr rate), so the absorbs are generally a decent length.

eg: Today is a skip day:

Attachment not found.

vtmaps

Re: Help with batt bank charger selection

zoneblue wrote: »

vt, days between bulk doesn't completely avoid charging, just skips absorb

My understanding is that it also skips bulk. It does, however do float. When the sun comes up, it may appear to be in bulk... until the float voltage is achieved.

From the Midnite Forum:

Halfcrazy wrote:

what I would do is this.

Set days between Bulk charges to say 14
Set ReBulk for a safe number. Say 24.4 ish?
Set EndAmps for 1-2% of the AH capacity of the battery
Set Float slightly lower than normal by say 3-4 tenths

This will basically just maintain a float (Lower than normal) charge for 14 days or until the battery falls to 24.4 and then it will do a new bulk and absorb charge

Ryan

--vtMaps

Cariboocoot

Re: Help with batt bank charger selection

vtmaps wrote: »

My understanding is that it also skips bulk. It does, however do float. When the sun comes up, it may appear to be in bulk... until the float voltage is achieved.

From the Midnite Forum:


--vtMaps

It can't be skipping Bulk if it's pushing batteries up to Float Voltage; they don't rise on their own.

The only way to avoid a charge cycle is to disconnect the charge source. Frankly it's not worth the effort. If the battery bank is sized properly every day will bring sufficient discharge and recharge to constitute a cycle. If the battery bank isn't being drawn down around 25% each day then it's too large and you've wasted your money.

c_rossz24

Re: Help with batt bank charger selection

Can i use stranded copper primary wire to go from my panel to my charge controller? i ordered a couple more conectors with my panel and i figure ill need around 10 gauge wire to run the length ill need to the 100w panel
whats the best/ cheapest type of wire to run >?

Cariboocoot

Re: Help with batt bank charger selection

c_rossz24 wrote: »

Can i use stranded copper primary wire to go from my panel to my charge controller? i ordered a couple more conectors with my panel and i figure ill need around 10 gauge wire to run the length ill need to the 100w panel
whats the best/ cheapest type of wire to run >?

It is normal to use stranded wire on DC circuits.
Wire size depends on the expected current, Voltage, and length of run. It has to be largest enough to handle the current and also large enough to prevent significant Voltage drop over the distance involved.
Wire type depends on where it's installed, as in exposed to elements or inside conduit or underground.

BB.

Re: Help with batt bank charger selection

For typical applications, coarse stranded wire (like you find at the home stores), is fine.

If you get fine stranded cable (like welding cable with 100's of strands), those can be a lot more difficult to work with. Difficult to get a "reliable/safe" connection with standard building code devices (breakers, bus bars, etc.). The fine strands make for a larger cross section (i.e., air gaps) and the typical screw clamp connections do not make solidly with the fine stranded cable.

-Bill

c_rossz24

Re: Help with batt bank charger selection

Cariboocoot wrote: »

It is normal to use stranded wire on DC circuits.
Wire size depends on the expected current, Voltage, and length of run. It has to be largest enough to handle the current and also large enough to prevent significant Voltage drop over the distance involved.
Wire type depends on where it's installed, as in exposed to elements or inside conduit or underground.

im not 100 percent sure yet but i think ill be mounting it on the roof or at ground level on the south side so most of the wire will run inside to the batt bank
so am i looking for coarse stranded wire ?, i found a decnt ware gauge calculator for dc so once i find out my wire run i can figure out what gauge i need

c_rossz24

Re: Help with batt bank charger selection

www.ebay.com/itm/100-ft-Total-8-Gauge-50-BLACK-and-50-RED-Car-Audio-Power-Ground-Wire-Cable-/220897872992

this seems like a good deal????