Planning for an upgrade

Rybren

Re: Planning for an upgrade

I haven't posted on my thread for a while, so here are some ramblings.

So between Christmas shopping trips, I've also been doing some searches for batteries to see what is available and to get a better idea of costing out my build.

Unfortunately, the Costco's here in Ottawa don't carry Golf Cart batteries, so it looks like "cheapies" are out. So far, I've only been able to find one vendor in the city that carries True Deep Cycle batteries. Their U.S. Batteries brand 200AH 6V batteries are $139. I haven't read much about this brand anywhere.

I may have to take a day trip to Montreal to see what they have to offer. I did see an ad from a store there that is selling Crowns. The 6V 200AH are $149 and the 6V 225AH are $169. Is the bit more for Crowns worth it over the local US Battery ones?

It sure would be nice to find a Canadian Vendor who carries the Classic at the same price as our sponsor. While I haven't priced out Wind-Sun's shipping cost yet, the Customs & brokerage fees are usually a real killer for us Northerners. If I can't find reasonably priced Canadian suppliers, I may have to get everything shipped to a UPS store in Upstate NY and then drive down to pick everything up. Luckily, the closest US based UPS store is only about 1 1/2 hrs away.

I'm still vacillating over the 12V vs 24V system. For the short term, 12V is all I need and will easily work with my existing 12V lighting. I do know that once I'm retired and I start using the camp more, the loads will grow. At that point, I suspect that the 24V system would be nice.

Here's a question - if I put in a 225AH 24V system now and it only gets regularly drawn down to ~90% SOC for a couple of years, are there any issues to be aware of?

Thanks for 'listening'

Jerry

vtmaps

Re: Planning for an upgrade

Rybren wrote: »

Here's a question - if I put in a 225AH 24V system now and it only gets regularly drawn down to ~90% SOC for a couple of years, are there any issues to be aware of?

From our host's battery faq:

a battery that is continually cycled 5% or less will usually not last as long as one cycled down 10%. This happens because at very shallow cycles, the Lead Dioxide tends to build up in clumps on the the positive plates rather in an even film.

from batteryfaq.org:

Avoid shallow (less than 10% DoD) discharges of deep cycle batteries because lead dioxide builds up on the positive plates.

Here is a quote, from another thread, by RCinFLA. I have never met "RC", but he is quite knowledgeable about batteries. I judge (by his screen name) that he lives in a Flooded Lead Acid battery.

RCinFLA wrote: »

Lead dioxide build up is not fatal but it does eat up positive plates. This is one reason why positive plates are alway thicker then negative plates on deep discharge lead acid batteries.

Float charging voltage is a compromise between the negative plate desiring a higher float voltage to keep sulfate formation down and a lower desired float voltage on the positive plate that will only build up lead dioxide coating and create support grid corrosion.

Lead dioxide is what makes a positive plate a positive plate but too much coating is not a good thing. First it is a poor conductor so too much coating drives up battery internal resistance resulting in greater terminal voltage drop during high current demands. Second, as more of the positive plate is eaten away it can expose positive plate support grid to acid which under cuts the electrical connection to the plate's support grid.

Lead dioxide is a white powder that will 'dust off' and sink to bottom of battery if there is an excessive build up, as soon as a significant current load is applied to battery. Don't get too hung up on the positive plate being eaten away. It is a fact of life for a lead acid battery. The alternative, with a lower float voltage, is sulfated negative plate which is not reversible.

Many AGM's use pure lead plates without an alloy grid support structure so they don't suffer from grid corrosion. They get their structural integrity from the tight packing of the glass matt separator. Most large kW commercial standby UPS systems use AGM batteries which are on continual float charging.

Rybren

Re: Planning for an upgrade

You know, there was something rolling around in the back of my mind about it being detrimental, but do you think that I could find any reference to it? I've read those FAQs before, but I guess that my brain was in float mode.

Thanks vt

raydias

Re: Planning for an upgrade

As far as snow, could you build the new solar panel rack so it can go from the proper angle to vertical when you leave. So when you button up the camp you can adjust the angle to vertical which would prevent snow buildup and keep the batteries charged. Just a thought

icarus

Re: Planning for an upgrade

jerry,

Last time I looked, my local CT had Trojan Gc batteries.

Tony

Rybren

Re: Planning for an upgrade

Thanks Tony,

I did check with the CT that was closest to me and they said that they couldn't get GC batteries. They carry the hybrid starting/Deep Cycle batteries (which is what I'm currently using and don't want to use again) I haven't had time to follow up with any of the other stores.

I suspected that the salesperson might have been wrong - they do have GC batteries listed on their website, but the sales guy insisted that the website was out of date.

gww1

Re: Planning for an upgrade

About a month ago battery joes had crown 350ah batteries listed for $209 but I tried to look it up so I could post the link and they said their online shopping was down and you should contact the store. I know nothing about them but every one else was listing these batteries for around $350. Some one on a differrent forum pointed them out to me but I was not ready to buy at the time. I was going to buy sams club when this was mentioned as an alternative.
cheers
gww

Rybren

Re: Planning for an upgrade

Battery Joe's wouldn't be a player for me. Shipping from Texas to Canada would be astronomical.

Thanks

westbranch

Re: Planning for an upgrade

Any golf courses around that 'require' golfers to use a cart? They probably have electric ones and would know of a GC source...

Rybren

Re: Planning for an upgrade

Good idea. I will have to call around to some of the courses.

Thanks

Rybren

Re: Planning for an upgrade

More thinking and wondering out loud here.

With a MPPT controller like the Midnight or Outback, my four panels have the potential of putting out up to ~54A. On a 225 to 250AH battery bank, that is significantly more than the 5 - 15ish% charge rate that is most often recommended.

In a previous post, 'Coot said

The >50 Amps potential with the MPPT controller is pretty high for a 220 Amp hour battery bank. It's over 20% charge rate. Depending on what controller you get you could limit the output Amps just in case. Otherwise, use half the panels for that size battery bank.

I didn't follow up on this comment. What is the risk to the battery bank if I were to stick to the four panels? I assumed that the CC would limit the current and the batteries would just reach 100%SOC in a shorter period of time with little to no risk to the batteries. Now, on rereading 'Coot's post, I'm not so sure.

inetdog

Re: Planning for an upgrade

Rybren wrote: »

More thinking and wondering out loud here.

With a MPPT controller like the Midnight or Outback, my four panels have the potential of putting out up to ~54A. On a 225 to 250AH battery bank, that is significantly more than the 5 - 15ish% charge rate that is most often recommended.

I assumed that the CC would limit the current and the batteries would just reach 100%SOC in a shorter period of time with little to no risk to the batteries. Now, on rereading 'Coot's post, I'm not so sure.

I think what Coot was stressing was that some CCs only limit current to their rated value, and to get a lower value you would have to cut back on the panel input. Others (the good ones) allow you to set a current limit anywhere below their maximum rating.

Cariboocoot

Re: Planning for an upgrade

Even the good ones won't limit current unless you tell them to.

Why should you? A short, occasional over-abundance of current won't do much harm. But if you have a situation where the batteries are drawn low enough daily that they would accept the max current available and you did this day after day ... the extra heat created in the battery from the high current will have a detrimental effect on them. It could even be a very sudden detrimental effect if the heat gets to be too much for a plate and it breaks or bends and shorts out the cell.

Why would you want to have lots more current potential than you need? Because not everywhere is sunny every day. As such it could be advantageous to "over panel" your controller and limit its current to the max the batteries would normally have. Then when you have those dull days and the panels are putting out <100% you could still get 100% charging.

BB.

Re: Planning for an upgrade

Rybren wrote: »

With a MPPT controller like the Midnight or Outback, my four panels have the potential of putting out up to ~54A. On a 225 to 250AH battery bank, that is significantly more than the 5 - 15ish% charge rate that is most often recommended.

10% of 220 AH ~ 22 amps charging range... But remember that it is times the Bank Voltage (12/24/48 volts)--So this affects the size of the solar array:

• 22 amps * 14.5 volts charging * 1/0.77 array+controller deratings = 414 watt array
• 22 amps * 29 volts charging * 1/0.77 array+controller deratings = 829 watt array
• 22 amps * 58 volts charging * 1/0.77 array+controller deratings = 1,657 watt array

What solar panels are you thinking of using?

I didn't follow up on this comment. What is the risk to the battery bank if I were to stick to the four panels? I assumed that the CC would limit the current and the batteries would just reach 100%SOC in a shorter period of time with little to no risk to the batteries. Now, on rereading 'Coot's post, I'm not so sure.

Batteries cannot take "unlimited" charging current (Maximum Charging Rate is very dependent on the battery brand/model/type--The rules of thumb usually work out to be around 5-13% nominal (usually solar charging) and around 25% not to exceed (such as a an generator/AC battery charger).

-Bill

Rybren

Re: Planning for an upgrade

Thanks for the replies guys. I think that my understanding is getting there - slowly.

As I understand it, both of the controllers that I'm considering - Classic and the FM60 - will allow me to regulate the output current, so there shouldn't be an issue.

Bill, I already picked up the panels (the price was too good to pass up). I only needed two to meet my current needs of a ~220AH 12V battery bank, but I picked up two extra ones because I plan on retiring within the next year or two and my camp will go from weekend use to longer term stays. Knowing that the loads will likely grow as we spend more time at the camp, I decided to oversize my setup.

The panel specs are:

Max Power (Pmax), (Wp) 210
Max Power Voltage (Vmp) 29.1
Max Power Current (Imp) 7.2
Open Circuit Voltage (Voc) 37.0
Short Circuit Current (Lsc) 7.7
Max System Voltage (VDC) 600

Jerry

BB.

Re: Planning for an upgrade

Jerry,

Looks like a good start there.

-Bill

Photowhit

Re: Planning for an upgrade

Rybren wrote: »

...It sure would be nice to find a Canadian Vendor who carries the Classic at the same price as our sponsor. While I haven't priced out Wind-Sun's shipping cost yet, the Customs & brokerage fees are usually a real killer for us Northerners....

OK, please excuse my ignorance, heck they wouldn't even let me into Canada (I just wanted to go down hill on my bicycle trip, and they thought I was trying to imigrate to Canada). But... what happened to NAFTA? The classic is made in USA so it should be free of any fees?

And as an aside NAWS is having a sale "Enter the code XMAS at checkout for a 5% discount " if your computer literate, might consider the Classic lite at $500 (less $25) in the states I think it gets free shipping as well, though that might be for purchases over $500, so add a breaker or 2 and see if they will toss the USA shipping against shipping to Canada...

Rybren

Re: Planning for an upgrade

Photowhit wrote: »

(I just wanted to go down hill on my bicycle trip). ...

Are you saying that once you enter Canada, it's all downhill from there?

Photowhit wrote: »

But... what happened to NAFTA? The classic is made in USA so it should be free of any fees?

It would be free of duty, but I'd still have to pay Canadian sales tax. The big issue with buying stuff from the US and having it shipped by FEDEX or UPS is that these companies charge a fortune to process the goods through customs. USPS, on the other hand, doesn't nail you for these fees.

Thanks for the heads-up on the sale code.

kellylipp

Re: Planning for an upgrade

Just in terms of medical care...

Cariboocoot

Re: Planning for an upgrade

kellylipp wrote: »

Just in terms of medical care...

Why yes, our "free" Canadian medical system only costs us 50% of every $ earned. :roll:
Anyway he was referring to the United States Postal Service, which is usually the best way to get stuff across the border without exorbitant fees.

The inherently high taxes in Canada make everything more expensive all around. If only the system were as efficient as ... and inverter perhaps. Heck, we'd settle for a government that was as efficient as an amorphous panel!

Okay that's far enough off into the wilderness for now. Back to whatever it was we were talking about.

Rybren

Re: Planning for an upgrade

I do believe that we were talking aboot:

1. sending too much current to a battery bank,
2. courier service highway robbery, and
3. how we Canadians have to spend so much more for things than our friends south of the border.

I've come to the conclusion that for items 2 and 3, the solution for me will be to buy from the US and have everything shipped to a UPS Store in Upstate NY. I'll then take a drive down to pick everything up. Domestic UPS shipping rates are much cheaper than the rates to Canada and I'll avoid those horrific brokerage fees. I'll still have to pay the Canadian taxes, but I'll avoid the middle man.

As for item 1, it sounds to me like it won't be an issue with the better CC's.

Now, if I could only get off the fence regarding the decision to go with a 12V v 24V system. Deep down, I know that I'll eventually need to go to 24V, but I could get away with a 12V for a couple of years. My cabins are wired for 12V DC lighting, I have 2 400W MSW inverters that I've used many times to run (from my car) my main AC loads - laptop, cell phones, and tablet. I don't know whether they'd start a Shurflo AC pump. Max running current is published to be 0.9A, I don't know what the start surge would be.

I've been toying with the idea of picking up 4 x 6V 225AH batteries and initially hooking them up as a 450AH 12V system. Once I'm ready to move to a 24V system, I could reconfigure them to 24V (assuming that I haven't killed them by then). There are probably all kinds of risks and cons to doing things this way - uneven charging with parallel batteries, and a bunch more that I'm sure you'll tell me about.

Anyway, the boss is coming....

Volvo Farmer

Re: Planning for an upgrade

What are the wires used to wire the cabin for 12V lighting? Did they use regular old 12 or 14 gauge NM wire? Regular light switches? That would be pretty easy to switch to 120V lighting. Also, what kinds of light bulbs are you using on 12V? Incandescent? I would bet that cheap 120V CFL bulbs would get you more lumens per watt than incandescent 12V lights.

If you want to fiddle around for a while, and then have to buy a bunch of new equipment in a couple years, stick with 12V. If you have the budget and are certain you want to live off grid full time in the future, I would highly recommend doing it right the first time, because you will want to do it over.

Rybren

Re: Planning for an upgrade

The cabins are wired with 14/2 household wiring and most fixtures have standard switches. The LEDs have automotive 12v switches. The. Other lights are 12V 13W CFL. It would be fairly easy to switch over to AC.

I won't be living there full time as the road doesn't get plowed in the winter. I do know that a 24V system makes sense for the long term, but it could be years before I'm ready or need it. Aside from reconfiguring the battery bank and hooking up a 24V inverter, what am I missing if I switch from 12V to 24V?

Volvo Farmer

Re: Planning for an upgrade

I think higher voltage systems tend to be more expandable than lower voltage systems. I guess you have the right idea in the case of wiring if you wire for 12V and later expand. Depending on your charge controller, it might have to be replaced as well. I just know that I have expanded and modified my 24V system a few times over the last six years and there have been several times where I wished I had gone 48V. If you want to maintain a seasonal cabin lifestyle, 12V is probably fine. If you want to run televisions, satellite receivers,, toasters, microwaves and hair dryers, I believe that higher voltage battery bank and inverter make wiring and expansion less costly in the long run.

Rybren

Re: Planning for an upgrade

Well, luckily we're not TV watchers and my wife doesn't use a hair dryer (and I don't have much hair to dry ) I could, however, see a microwave at some point down the road, thus my thinking of eventually needing a 24V system.

Photowhit

Re: Planning for an upgrade

Knowing I would switch to a 24V system in a year or so, I went to 4 golf cart batteries for my small 12 volt system and it worked out prettty well, I got 5 years service out of them, 1 in the 12 volt setup and 4 in a 24 volt. just be sure you have enough array to charge them.

Rybren

Re: Planning for an upgrade

Thanks for sharing your experience on the transition from 12V to 24V. At 840W, I should have enough panel for a 24V 220AH bank. From one of Bill's earlier posts:

22 amps * 29 volts charging * 1/0.77 array+controller deratings = 829 watt array


Jerry

BB.

Re: Planning for an upgrade

Jerry,

That is for a 10% rate of charge--Very healthy/balanced system usually (5% to 13% rule of thumb as a start).

Will this give you enough Watt*Hours (or Amp*Hours) for the loads you plan in a day? Using PV Watts for a fixed array (to latitude) in Ottawa:

Month
      Solar Radiation
(kWh/m2/day)
1      2.86     
2      4.70     
3      5.27     
4      5.01     
5      5.21     
6      5.47     
7      5.53     
8      4.99     
9      4.56     
10      3.54     
11      2.27     
12      2.60     
Year      4.33      

Toss the bottom 3 months, gives you October at 3.54 hours of sun per day, or for an off grid system 4x 210 watt panels:

• 840 watts * 0.52 system eff * 3.54 hours of sun = 1,546 Watt*Hours per day

Close to being enough for a fridge (can you use some sort of "cold box" in your weather?).

And there is the question of mounting the panels--And being able to take them near vertical (assuming you are in the snow belt) and take advantage of a snow field in front for reflection. And security (cabin locked up for many months of the year?).

-Bill

Cariboocoot

Re: Planning for an upgrade

BB. wrote: »

Toss the bottom 3 months

I'm just going to go off to one side here to explain something that doesn't come up very often but perhaps should.
If you were planning a 100% off-grid year-round system you can not ignore those 3 months of low solar production. You have to plan on some way of coping with that. This is why solar has problems up here in the Great White North.

So with basically only 2 hours of sunlight to charge your batteries with you would either need some back-up generating power or a very large array.
How large? Suppose you want 3kW hours per day. You've got 2 hours to do it in. That's 1500 Watts per hour. With the usual efficiency of an off-grid system that would be 2885 Watt array. And that assumes you get the sunshine. If you need several days of autonomy you end up with a tremendously large array and battery bank, which during the Summer months is ridiculously huge. Okay, you could run AC off it then, but we usually don't need that up here.

450 Amp hours @ 48 Volts with a 3kW array ought to just about do it (for 2 days autonomy). :roll:

End of thread spur.

BB.

Re: Planning for an upgrade

What Marc says... I do the toss the bottom three months with the 4th month at the "break even" month. And, it is not that the array cannot capture a fair amount of energy during the sunny days of those three winter (typically) months--It is that there are days or weeks at a stretch where there is no direct sun--Where your average solar radiation may be 10% of a sunny winter day.

You are going to need an alternative energy source during those times anyway (or cut usage to match available sun). A 2x larger array will probably reduce generator run time, but it will probably not eliminate the run time. You would probably have to have a 10x larger array to accomplish that (with a very large battery bank). And that is what is usually unjustifiable.

Or, you can go Chris Olsen's route and install wind turbine(s) on 90+ foot tall towers (and in Chris' case, he designed/built his own turbines because of poor winter sun and iced over arrays). If you have the wind and abilities--It could be a viable option. But even Chris still has a 4kW backup genset.

-Bill