Generator for charging batteries

[lkruper]

See PS in my post above for even more to think about.

Do the inductive loads account for a surge that exceeds the maximum amperage output of the charger?

[inetdog]

Thank you. I had no idea when I started researching this topic that it was this complicated. After learning some basics and mastering some initial concepts it is easy to get confidant, and that is a big mistake. Fortunately my first and second set of batteries that I have "ruined" have been virtual. When I actually get my first set of batteries, I am sure I will have more to learn.

See PS in my post above for even more to think about.

[lkruper]

On the generator sizing issue, some very basic battery chargers draw large peak currents at the peaks of the AC waveform. Some generators cannot handle this well even if they are capable of delivering the required average power.

Thank you. I had no idea when I started researching this topic that it was this complicated. After learning some basics and mastering some initial concepts it is easy to get confidant, and that is a big mistake. Fortunately my first and second set of batteries that I have "ruined" have been virtual. When I actually get my first set of batteries, I am sure I will have more to learn.

[inetdog]

That sounds good. I would like to get started without investing too much as my application is backup.

On the generator sizing issue, some very basic battery chargers draw large peak currents at the peaks of the AC waveform. Some generators cannot handle this well even if they are capable of delivering the required average power.

PS: Another factor is that if the battery charger contains a step-down transformer (most will) and it is relatively lightly loaded compared to its full rated output the transformer primary winding will look like a large inductive load in parallel with the resistive load associated with the output to the batteries.
Highly inductive loads can also cause problems for some transformers, and will also require the generator to be able to deliver more current than you would expect just from the power going to the batteries.

[lkruper]

The manual for it is at our vaca place(where the solar system is) and it'll be another couple of weeks before we get up there again, not sure if that info would even be in there. I suspect the A limit has to do with the connections but you might be able to find the info with a google search. It draws about 780W according to my kill-a-watt meter but it ramps up the draw. I should have a bigger charger for my bank but I liked the various voltages this charger would do and I only use it to EQ the bank. I've had it for 3 years now and it has been flawless on all sorts of different batteries.
At the vaca place, I have one of the harbor freight "1200W" 2 stroke gens, it is light and easily transportable, cost 79 bones with a coupon, but it will not run the charger full out, will only get to 7A on my 48v bank. I just tried it FSAG, the Yamaha 3000ISEb doesn't know it is hooked up hardly.
I think the batteries you're talking about are rebadged Penn-Deka FLA batteries, I'd stick to a C8-12 charge rate. I think the charger I posted will do well for you and allow you to expand later without buying another charger.

That sounds good. I would like to get started without investing too much as my application is backup.

[thastinger]

I am probably going to get 2 6v 225AH golf batteries from Sam's club. Your charger is sold there , I believe, for about $99. I like the fact that your charger also does 20A at 24v, as if I expand I would double the batteries to 24v. I do not understand how your charger can output the same amperage for 6/12/24 v. Do you know the 120v amperage draw for those voltage modes?

The manual for it is at our vaca place(where the solar system is) and it'll be another couple of weeks before we get up there again, not sure if that info would even be in there. I suspect the A limit has to do with the connections but you might be able to find the info with a google search. It draws about 780W according to my kill-a-watt meter but it ramps up the draw. I should have a bigger charger for my bank but I liked the various voltages this charger would do and I only use it to EQ the bank. I've had it for 3 years now and it has been flawless on all sorts of different batteries.
At the vaca place, I have one of the harbor freight "1200W" 2 stroke gens, it is light and easily transportable, cost 79 bones with a coupon, but it will not run the charger full out, will only get to 7A on my 48v bank. I just tried it FSAG, the Yamaha 3000ISEb doesn't know it is hooked up hardly.
I think the batteries you're talking about are rebadged Penn-Deka FLA batteries, I'd stick to a C8-12 charge rate. I think the charger I posted will do well for you and allow you to expand later without buying another charger.

[lkruper]

the charger I posted the link to is 20A @6/12/24V 12A@36V and 10.7@48V

What is the make/model are your batteries, for FLA you'd want to stay with a C8-C12 charging range

I am probably going to get 2 6v 225AH golf batteries from Sam's club. Your charger is sold there , I believe, for about $99. I like the fact that your charger also does 20A at 24v, as if I expand I would double the batteries to 24v. I do not understand how your charger can output the same amperage for 6/12/24 v. Do you know the 120v amperage draw for those voltage modes?

[thastinger]

the charger I posted the link to is 20A @6/12/24V 12A@36V and 10.7@48V

What is the make/model are your batteries, for FLA you'd want to stay with a C8-C12 charging range

[lkruper]

Oh so the cart batteries are not FLA, they are AGM?

You say you have a 55A charger, meaning it outputs 55A at 11-12 volts but then it will trail off the Amps as the battery voltage and internal resistance go up like a "smart charger" does or it just stays at 55A output? Even worse case 55Ax14V=770W, that should only be a 6.5ishA draw from your electrical outlet on the gen.

FWIW, I run my battery charger from a Yamaha inverter gen, never had any issues. I think you'd be just fine.

Cart batteries are FLA but they are hybrid and can take a larger amp charge, or so I have been told. Don't have them yet. Evidently they do have a low resistance and can take a quick charge. I have read in more than one place that any Lead Acid battery, FLA or AGM can take a larger amperage up until the voltage reaches the level where gassing occurs. I think that is usually 14.4 v. Personally, I am happy following the rules set by the manufactures in their guides until I get experience. My inclination was to get a manual charger where I can set both voltage and amps so that it can grow with different chemistries and with my own abilities.

I don't have a charger yet either. I am still researching. What I have been told is that it is hard to predict what chargers will work with a particular inverter generator. Now I know that your Amazon purchased Stanley charger works with your Yamaha inverter generator. Looking on Amazon, it appears that this is 10a at 48v ... do you know if you get 40a at 12v?

[thastinger]

http://www.amazon.com/Stanley-GBCPRO-Vehicle-Battery-Charger/dp/B005DKIIJW/ref=sr_1_1?ie=UTF8&qid=1440703958&sr=8-1&keywords=battery+charger+6%2F12%2F24%2F48

this is the one I use on my 48V battery bank, it does take some time for my bank but would be much faster at 12V. It'll do 6v/12v/24/48v and it auto senses the battery voltage, it takes my 48V bank to 59V before it says full and then I switch to the panels to finish the EQ charge. EQ is all I use it for though, I wouldn't want to run a gen every day. Just some other options, not trying to steer you in any direction as I have never used one of the continuous rate chargers.

I tried to add this to the above post but the site wouldn't let me

[thastinger]

Oh so the cart batteries are not FLA, they are AGM?

You say you have a 55A charger, meaning it outputs 55A at 11-12 volts but then it will trail off the Amps as the battery voltage and internal resistance go up like a "smart charger" does or it just stays at 55A output? Even worse case 55Ax14V=770W, that should only be a 6.5ishA draw from your electrical outlet on the gen.

FWIW, I run my battery charger from a Yamaha inverter gen, never had any issues. I think you'd be just fine.

[lkruper]

I'm confused. You have 2 cart batteries? i.e. 12V 225AH battery bank? If so, that is less than a 300W load on a generator at a C10 charge rate. You're worried about a 1500W gen being able to do that?

Yes. I was looking on a web site that sells PowerMax chargers. I have been told by smart people on this forum that I can pretty much charge a hybrid golf cart battery at any amp input that I want because they can take it. So I looed at the 55 amp PowerMax charger and on the web page for this vendor they say that the surge is 3X the max amp draw (12 amps) and to make sure inverter generators have high enough capacity. My 2200 ix Generac pulls at best 18 amps (surge is 2200), and at 5500 feet elevation I lose power as well, according to the manual. So I emailed the vendor and they said that they do not recommend PowerMax with inverter generators because they are Switched Mode chargers. I asked why they don't warn against IOTA which are also Switched Mode and they said IOTA is not as bad.

In addition, I did want to have some load on the generator at the same time I was charging to simplify switching between generator and battery power, but I may re-think that.

[thastinger]

I'm confused. You have 2 cart batteries? i.e. 12V 225AH battery bank? If so, that is less than a 300W load on a generator at a C10 charge rate. You're worried about a 1500W gen being able to do that?

[lkruper]

It's really hard to speculate what one generator will do with a charger in combination. A Honda EU2000 will start and pull a IOTA DLS-75 charger without issue and pull 8 amps while charging. It'll idle in ECO throttle with a DLS-30. A DlS-55 is in between and the engine is lugging and it uses more gas. You have to figure out how you want to charge. A 30 amp charger uses a gallon of gas in 8 hrs of run time ( 25% load ) , a 75 amp uses a gallon in 3 + hrs. For most people the longer and quieter time seems to make them happier.

Your solar contribution needs to be figured into your charging scheme. Usually it's to charge early with the generator in Bulk charge and let the solar finish the absorb, but not always so you need some flexibility built in. I run 2 chargers at times, a 30 amp and a 45 amp, I can choose one or both. I can run one all the time and pull the other one in and out with a relay when say the A/C cycles. The ECO throttle takes care of the Generator output. I can also use the generator to power the AC loads directly and forget the battery charging losses.

Charger Cut Back Mode : This on a lot of chargers where the output of the charger will cut back the output based on the internal temperature of the unit, usually never documented in the manual. The question you have to ask to someone that actually uses the charger you intend to buy. Will the charger maintain it's rated output for 24 hours or for 15 minutes. Don't be surprised, most won't.

Thanks, your experience with the IOTAs is very helpful. I think I would like to run my inverter generator in ECO mode, and while I would like a faster charge, the quiet would probably be worth it.

I am starting to better understand why my first set of batteries will be training batteries. There is no way to predict 100% how my equipment will work together. I will eventually need to take the plunge and see what happens in the real world. My particular situation is this at my cabin:

1) Have installed manual transfer switch.
2) Have acquired inverter generator. Current model is Generac ix 2000 from Costco. Replaced Smarter Tools 2000 because I filled it up with too much oil and was worried I damaged it. If Costco sold battery chargers I would be good to go with their replacement policy!

That is phase 1. I am on the grid and we rarely have had power outages. We did have one a few weeks ago for 8 hours and my generator was a big help even without the switch installed. But I am planning for El Nino for next year and want to make sure our emergency backup is in place. So phase 2 is this:

Get enough battery capacity to power my essentials overnight. Keep batteries grid charged and on float. Use the generator until it is time for bed and go onto batteries until morning. If the power is still out, charge the batteries and my load with my generator. Keep this up until my gasoline runs out or we go home.

I have identified the following challenges to my purchase decision:

a) I need a charger that allows me to have a load on the batteries at the same time as charging and need the generator to handle both charging and load at the same time.
b) I need a charger that does not have a surge beyond what my inverter generator can handle.
c) I would like a charger that allows me to manually set the voltage and current range.
d) I would like a charger with temperature compensation (or be manually set) as the batteries are in an unheated basement.
e) I would like a charger that can handle 24v should I decide to increase capacity later beyond 2 golf cart batteries.

If I do not try to run my refrigerator on batteries I don't have to worry about the compressor surge or get a larger inverter, and my power company in any event will probably reimburse me for any spoiled food. My loads in survival mode can be limited to about 1/2 the capacity of my two batteries or 100 AH per day. So I figure that 2000w from the inverter generator should be able to handle a charger and the load at the same time, but which charger? If I pick the wrong one, it won't handle the surge of the charger. That is why I was thinking that a charger for which I can manually ramp up the amperage slowly would prevent the surge, and I don't even know if that would work or not.

Another thought is to purchase a second non-inverter generator like the Champion 1500w for about $200 at Amazon just to run the charger (and possibly the refrigerator as needed) and save money by getting a less expensive charger. Your experience with IOTA is compelling as is what a vendor said about it working better with Inverter Generators than PowerMax.


Phase 3 will be to add solar capacity to handle potential longer outages that my 10 gal of gas or so can accommodate.

I really do appreciate recommendations and criticisms to my approach.

[Willy T]

It's really hard to speculate what one generator will do with a charger in combination. A Honda EU2000 will start and pull a IOTA DLS-75 charger without issue and pull 8 amps while charging. It'll idle in ECO throttle with a DLS-30. A DlS-55 is in between and the engine is lugging and it uses more gas. You have to figure out how you want to charge. A 30 amp charger uses a gallon of gas in 8 hrs of run time ( 25% load ) , a 75 amp uses a gallon in 3 + hrs. For most people the longer and quieter time seems to make them happier.

Your solar contribution needs to be figured into your charging scheme. Usually it's to charge early with the generator in Bulk charge and let the solar finish the absorb, but not always so you need some flexibility built in. I run 2 chargers at times, a 30 amp and a 45 amp, I can choose one or both. I can run one all the time and pull the other one in and out with a relay when say the A/C cycles. The ECO throttle takes care of the Generator output. I can also use the generator to power the AC loads directly and forget the battery charging losses.

Charger Cut Back Mode : This on a lot of chargers where the output of the charger will cut back the output based on the internal temperature of the unit, usually never documented in the manual. The question you have to ask to someone that actually uses the charger you intend to buy. Will the charger maintain it's rated output for 24 hours or for 15 minutes. Don't be surprised, most won't.