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Small Cabin Forum / Off-Grid Living / battery charging with honda 2000
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bc thunder
Member
# Posted: 17 Aug 2015 20:33
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I don't know the spec's of my battery (it's at the cabin), but its a standard marine type. I'm wondering how long it would take to charge it, using a 10 amp charger running off my honda 2000i. Plan on using it to power an led light and a small pump for a quick shower.

MtnDon
Member
# Posted: 17 Aug 2015 20:55
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AH (amp-hour) capacity divided by the charger output amps = hours to charge.

Theoretically.
That is if the battery is stone dead.
If half charged then it's about half.
Except, most chargers amps output tapers off as the battery gets towards full. So the last 10 - 15% of the charge takes much longer, uses more gas.

Rough rule of thumb... for fastest charging and longest battery life, the charger amps should be equal to about 10 - 15% of the battery AH capacity.

Talking standard flooded lead acid batteries.

bc thunder
Member
# Posted: 17 Aug 2015 21:18 - Edited by: bc thunder
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Thanks MtnDon,
Longer than I was thinking, but should still work well when I'm running a fridge ect.... Might have to splurge on a small solar panel dc set-up.

MtnDon
Member
# Posted: 17 Aug 2015 21:45
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A small PV setup is much better than totally relying on a generator and battery charger. The gen / charger can help out rebuild the battery charge and then the PV finishes it off with no expenditure of gasoline. ..... Similar rules apply to selecting how much PV capacity to choose, though moderately more PV is generally okay.

bc thunder
Member
# Posted: 18 Aug 2015 21:02
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Ended up buying a 140 watt panel and a 120 amp sealed battery. Try that for a year, and do some learning.......

MtnDon
Member
# Posted: 18 Aug 2015 22:39
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Sealed battery... AGM, Gel or simply a maintenance free lead acid type? Gel is a bad choice. AGM has some good points but expensive and some bad points. Maintenance free are generally automotive cranking and a poor choice.

Is there a charge controller?

A better learner battery would actually be two; golf cart 6 volt in series = 12 volts. True deep cycle.

bc thunder
Member
# Posted: 18 Aug 2015 23:23
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Yes the AGM, and yes expensive! There is a charge controller but can't remember what make (I don't pick everything up till monday). As for the two 6 volts in series, looks like I'm learning already........

MtnDon
Member
# Posted: 19 Aug 2015 00:21
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You want that AGM to be a true deep cycle battery. Many are not. Deep cycle batteries will have a 20 hour rate for the AH (amp hours) printed right on the label.

One of the quickest ways to kill an AGM battery is to charge it too fast. That creates bubbles in the electrolyte blanket and those do not go away and slowly kill it. So the battery should come with a recommended charge rate. Be certain the controller is capable of performing within the battery charge recommendations.

offgridjunkie
Member
# Posted: 21 Aug 2015 11:06
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Your Eu2000i sips the fuel at 10 AMPs. I use a 25 AMP charger with mine and never raises off eco mode. I installed a 210 Watt solar panel to reduce my generator use, it works so well, I only use the generator for running the vacuum or power tools. Your 120 watt panel will be ok for maintaining your battery, but if you start drawing heavier loads, it will not be able to keep up. Just run your generator each morning for a couple hours and then let the sun finish off.

davestreck
Member
# Posted: 30 Aug 2015 16:35
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Interesting. I've been trying to figure out if my Yamaha EF1000iS genny will be able to charge my 315Ah AGM bank. I'm considering installing this inverter/charger.

My main limitation is that I have to hand carry the generator quite a way into the woods to my camp, and the little Yamaha is super light at only 28 pounds. A 2000 watt is almost 45. Plus, I already paid for the EF1000iS.

Would this setup work? I'd hate to have to drop another $1000 to up-size my generator, but my last trip to camp was 10 days of almost no sun. With no direct way to charge the battery bank via generator I has to disconnect all the loads to make sure the bank didn't totally die, and run everything continuously on the genny. So I definitely need to come up with something.

MtnDon
Member
# Posted: 30 Aug 2015 17:44 - Edited by: MtnDon
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A quick look at the user manual indicates it has a charge current control. But the manual is a little hard to follow as it covers a host of variants. See if you can figure it out or check with AIMS. It seems to be pictured in some drawings and not others. The instructions also say to turn carefully, so it may not be advised to use it a lot. At first I was thinking that was goood as it would allow the current output to be reduced for when you atart the charge and then turn it up. Many chargers have a huge in rush when a charge is started. That can sometmes cause a small generator to trip off the output.

That current control could be handy to ensure the generator can handle the demand from the charger. AIMS is not high on my list of well made long lived equipment, but it may give you what you need.

davestreck
Member
# Posted: 30 Aug 2015 18:02
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Thanks Don, I'll see if I can figure that out. Do you have a manufacturer of inverter/chargers that you like? I'm looking for something in the 1000 watt range. We only use the inverter for 3 weeks a year or so.

MtnDon
Member
# Posted: 30 Aug 2015 18:18
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Quoting: davestreck
Do you have a manufacturer of inverter/chargers that you like?


Here's the thing... The manufacturers I like and know about do not make inverter / chargers in the smaller size range. Outback, Magnum and Xantex / Schneider XW all have much larger output and larger $$.

Do you already have an inverter? If so and because this is a part time place you might consider buying an Iota charger of a size appropriate to the battery bank. I believe they can all still be tweaked but the case has to be opened. I can't verify that, but my newest one has the adjustment pot inside. Only a year old. By tweaking I mean adjusting the voltage output higher to facilitate a faster charge on a generator. Iota's are really designed to be used plugged into the power grid and left plugged in for long periods.

Iota's do not have a current adjustment though so you buy to match the battery. A 12 volt 30amp would be good for charging but the inrush start might be too much for the generator if the battery(s) were low. Can't say for sure w/o trying. They also have a 12 volt 15 amp that should be no problem but would require more gen time.

MtnDon
Member
# Posted: 30 Aug 2015 18:20 - Edited by: MtnDon
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Xantrex does have an inverter / charger in their "consumer" range. They are pretty good quality but not as great as the $$ ones I mentioned. Many of the consumer range can not be repaired readily. That goes for many of the less expensive equipment.

davestreck
Member
# Posted: 30 Aug 2015 20:00
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All good info Don, thanks. I'll look in to the Iota for sure.

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