so i can use a microwave but not brew coffee?

[tx2sturgis]

If using deep cycle type batteries you may need to switch to starting batteries, they will be able to deliver higher amperage, because of less internal resistance.

Yeah I know guys, deep cycle this...deep cycle that... but for large current ratings for short periods, starting batteries rule.

 

[jimindenver]

I used a 8-D starting battery for a few years. Yes it could puke up the power but it didn't last long because even with 490w of solar assisting the voltage still dropped when I ran a big load.

 

[Sabatical]

Yes HDR, 100ah is a huge number compared to an off grid frig that uses 25ah a day, but we have the frig and i was planning to add 2 batteries anyway. So i was happy to know that a 4 battery bank would be adequate for our needs. We'll run the numbers before any of this happens though.

As for battery choice, i'll probably make the switch to agm's and bigger wires.

Truth be told, i'd be happy not having any gas appliances, but that's probably not realistic.

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[Weight]

My math says 126 amp/hours per day from the battery. With efficiency of inverter and fridge and olly-shat it is hot in this van. Peukert is going to get you as well.

 

[user 37446]

So no chance you'd consider a small (1K-2K) inverter generator for the few times you want coffee or a microwave?  

It would not be good to use as a charge source for the battery bank but if you could store it and the fuel outside (say in a metal box on the tongue or bumper) then just fire it up as needed, you could retain your soon to be 4 golf carts, which would allow you to then use your "dorm fridg" (there's a YT video that "intothe mystery" made about a guy who wired his dorm type fridg differently and claims it works well).

Just a thought, unless I missed you dismissing a jenny...

 

[Trebor English]

The other day I plugged the pot in to try and brew some coffee and it didn't go well. Something was tripping and resetting but i decided to let it run it's course. 

What about fixing that breaker?  That and shorter or fatter wire may be all you need.

 

[jimindenver]

Just remember that you must have a means of putting that power back into the bank or that fridge will not be running in a few days. You must maintain the balance in your system and even I keep a small generator on hand just in case.

 

[Sabatical]

Good points by all and it seems you guys are better at math than me. Thank you for the corrected numbers. I'll look for that video on the dorm fridge. We don't really use a microwave, so that's not a factor in this scenario.

A genny has not been ruled out. I hava a small Champion that i like and was thinking of using with a $30 power supply wired into the charge controller for shady periods and winter time when the sun is lower up north. Much discussion has been had on this subject elsewhere on this forum. I have watched utube vids on the subject and a friend is currently doing this successfully, so I am confident it can work.

I have more solar also. I had two 260w panels on the roof but that was overkill so i took one off last year. When the battery bank is up-sized, i'll put the second panel back up for 520w.

As with everything, finding a balance is the key to happiness. My happiness is different than yours so we may get there different ways. I'd love to have a lightweight, maintenance free, no-cost to run setup but that there is the golden unicorn i'll be searching for forever. Until then we will continue to make subtle tweeks for the fun of experimenting and for some variety. If nothing else, it gives us all something to talk about either before or after we talk about what we are pooping in.

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[John61CT]

It would not be good to use as a charge source for the battery bank

Why not?

Not sufficient for getting the bank 100% full, but may allow a single panel to suffice fot the long tail, and at least provide SoC a boost while coffee and food's being prepared.

Also need a charger properly matched to the jenny, ideally one you can dial down the amps.

 

[Sabatical]

This power supply (see link below) could be driven by a fairly small generator, like my Champion 1800w. When wired into the existing solar charge controller, the cc's algorhythm does the work for you. In my mind, this is an excellent way to get around the issues with so-called "smart chargers".

Mean Well LRS-350-12 Switching Power Supply 348W 12V 29A https://www.amazon.com/dp/B0109IMRPS/ref=cm_sw_r_sms_apa_u4yuzb1CESGTB

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[Sabatical]

So no chance you'd consider a small (1K-2K) inverter generator for the few times you want coffee or a microwave?  

It would not be good to use as a charge source for the battery bank but if you could store it and the fuel outside (say in a metal box on the tongue or bumper) then just fire it up as needed, you could retain your soon to be 4 golf carts, which would allow you to then use your "dorm fridg" (there's a YT video that "intothe mystery" made about a guy who wired his dorm type fridg differently and claims it works well).

Just a thought, unless I missed you dismissing a jenny...

Any chance you remember which video that fridge info is in? I've watched a bunch now and can't find the right one.

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[Sabatical]

What about fixing that breaker?  That and shorter or fatter wire may be all you need.

At first i wasn't sure what you were referring to but let me confirm you were meaning the breaker inline from battery to inverter?
It is a resetting breaker and i suppose that could've been what was tripping but i don't understand why it would. Could you explain your thoughts?

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[John61CT]

Any chance you remember which video that fridge info is in?

http://intothemystery13.com/diy-hybrid-fridge-cheap/

 

[John61CT]

This power supply (see link below) could be driven by a fairly small generator, like my Champion 1800w. When wired into the existing solar charge controller, the cc's algorhythm does the work for you. In my mind, this is an excellent way to get around the issues with so-called "smart chargers".

Not all controllers are happy to get input from a power supply, or anything but PV panels.

Some will in fact damage the power source or break themselves as a result.

In fact I would like to collect a list where the vendor says it's OK.

Bogart SC-2030 is one, controlled by a Trimetric monitor.

 

[John61CT]

the breaker inline from battery to inverter

Better off using a fuse there anyway.

 

[highdesertranger]

do you have a link to that auto resetting breaker? highdesertranger

 

[Trebor English]

At first i wasn't sure what you were referring to but let me confirm you were meaning the breaker inline from battery to inverter?
It is a resetting breaker and i suppose that could've been what was tripping but i don't understand why it would. Could you explain your thoughts?

In the original post the complaint was that something was tripping and resetting not just making the coffee.  If the tripping and resetting didn't happen and the system just made the coffee then it would be doing what you want and not be broken.  If there is a breaker rather than a fuse between the battery and the inverter that might be what is tripping and resetting.  A voltmeter applied to the input to the inverter could confirm that as the source of the tripping and resetting.  

Why would it trip?  If it is a 60 amp breaker feeding 60 amps to the inverter it would trip because it is supposed to so that the wire doesn't overheat.  A 60 amp breaker can, depending on the part, pass 120 amps for several seconds or it can trip at less than 60 after a minute.

Without diagnosis you can change parts until you happen to change the right part.

If you need a bigger breaker to make it not trip then you probably need a fatter wire.  If the wire is too long and too skinny the inverter will, lacking volts, take more amps to get the watts it needs.  A bigger breaker still has the disadvantage of being a breaker.  They have more voltage drop than fuses.  

My suggestion is to put a voltmeter on the inverter plus and minus inputs and start a brew cycle.  When it trips see what the voltage input to the inverter is.  If it is zero the culprit is between the battery and the inverter.

Next connect the voltmeter to the battery plus terminal and the inverter plus terminal.  If they are farther apart than the test leads can reach use any scrap of insulated wire to extend the test lead.  It doesn't need to be fat at all, #22 will be fine.  Start or restart a brew cycle.  If there is more than .125 volts,  1/8  volt,  drop on that wire from the battery to the inverter it needs to be fixed.

Repeat the process measuring the voltage between the battery minus and the inverter minus terminal.  

If the two voltages add up, for example, to a half volt that is not good.  When the battery puts out 12 volts the inverter only gets 11.5.  At some point the inverter shuts off when the input is too low.  The inverter doesn't know or care why the voltage is too low.  The battery might not be too low

You have several suggestions of what to replace to fix the problem.  Since you have not yet identified what is not working correctly, do that first.  If the problem is between the battery and the inverter neither a new battery nor a new inverter will fix the problem.  

Most people on these forums have a volt meter or can borrow one.  That is adequate to diagnose this problem.  If you have access to a DC clamp on amp meter you could measure the amps being used by the inverter and you could compare that to the rating of the breaker.  That would only tell you that you are using a current more or less than the rating of the breaker.  The voltmeter will tell you if your breaker tripped.  It may or may not perform according to its rating.

 

[IGBT]

We have a pretty small battery bank (two Lifeline 12V 125AH batteries in series feeding a 24V 4kW Magnum inverter).

We use our Mr. Coffee 10 cup maker every morning, even after the 24V compressor refrigerator has been running all night.

Amp draw from the batteries according to the Magnum is about 44 amps.   The batteries are usually at about 75% when I wake up and making coffee drops them to about 69%.   By the time I am done with the second cup the sun is up enough on the 1100 watts of panels that the batteries are above 70% and a few hours later they are at 90%.

No huge bank, just a lot of solar and good coffee.

 

[Sabatical]

do you have a link to that auto resetting breaker? highdesertranger

No i picked it up at the local truck and trailer supply store.

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[Sabatical]

@Trebor English
Awesome explanation. Thanks!!
I did identify that i hadn't maintained my batteries properly and needed to correct the issue with destilled water and an equalization charge to bring specific gravity back to 12.75 on all cells.

I haven't tried the coffee pot again, yet. Between work and house guests, it took a back seat, but i am gonna get back to it. Tha ks for being patient with me.

When i get back to it, i will take voltage readings and report back.

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