HELP: Inverter is draining battery almost instantly! Why?

[lkruper]

Yep, the caravan wiring was all in situ when I bought it. The only load we use straight off the battery like that is the LED lighting. The inverter will have it's own fuse.

So I'l really only need a 5 or 10a fuse max. Even with all my lights on at once, thats only 18w.

18w is 1.5amps at 12v. 10 amps sounds high for a fuse. But this is not my forte, hopefully someone with experience will weigh in.

[spoon]

Are you referring to running DC loads directly (ie led lights?) There was a discussion recently and I believe inetdog had a formula of sorts. The fuse needed to be a bit larger than the legitimate load (??? 20% or so ???) to prevent nuisance blowing of the fuse but protect against a failure.

Yep, the caravan wiring was all in situ when I bought it. The only load we use straight off the battery like that is the LED lighting. The inverter will have it's own fuse.

So I'l really only need a 5 or 10a fuse max. Even with all my lights on at once, thats only 18w.

[lkruper]

Point taken, I have emailed Numax about it.. But I've also started looking at alternative battery banks for when the time comes.

So the victron charge controller does not have a 'load' input, like my old cheap PWM unit. Does this mean I will need to add an in-line fuse, after battery on the 'load out' cables if that makes sense... If so, what ampage should that fuse be? 30a same as the CC?

Are you referring to running DC loads directly (ie led lights?) There was a discussion recently and I believe inetdog had a formula of sorts. The fuse needed to be a bit larger than the legitimate load (??? 20% or so ???) to prevent nuisance blowing of the fuse but protect against a failure.

[spoon]

The C20 AH rating is 110AH. With those two batteries in parallel that makes 220AH. 0.1C or 10% of that rating is 22 AH. For some reason the chart showed lower at 8. You can safely double that to 16 for input amps. I would call the manufacturer and ask for the acceptable RANGE of input amps. I am fairly certain 10% would work too.

This could help you if you keep your discharge low and don't use all the capacity you have. If I recall you were going down to 20% DOD with one battery. Going to 90% with two batteries would mean you can charge 2X as fast. However, with your low insolation, it is unlikely you will have enough hours in the wintertime to fully charge your batteries. Unless you can hook up to mains power the only other alternative is to have a small generator to supplement power. Does your location ever have clouds for a week? If it did, you would have enough capacity at 10% DOD to make it through the week, but then it would take two weeks to charge back up which would likely risk sulphating your battery.

Point taken, I have emailed Numax about it.. But I've also started looking at alternative battery banks for when the time comes.

So the victron charge controller does not have a 'load' input, like my old cheap PWM unit. Does this mean I will need to add an in-line fuse, after battery on the 'load out' cables if that makes sense... If so, what ampage should that fuse be? 30a same as the CC?

[lkruper]

I do have 2 of these batteries. If I linked them in parrallel it would be 220ah @ 12v, would the bench charge rate stay at 8a or increase because of two units.

The C20 AH rating is 110AH. With those two batteries in parallel that makes 220AH. 0.1C or 10% of that rating is 22 AH. For some reason the chart showed lower at 8. You can safely double that to 16 for input amps. I would call the manufacturer and ask for the acceptable RANGE of input amps. I am fairly certain 10% would work too.

This could help you if you keep your discharge low and don't use all the capacity you have. If I recall you were going down to 20% DOD with one battery. Going to 90% with two batteries would mean you can charge 2X as fast. However, with your low insolation, it is unlikely you will have enough hours in the wintertime to fully charge your batteries. Unless you can hook up to mains power the only other alternative is to have a small generator to supplement power. Does your location ever have clouds for a week? If it did, you would have enough capacity at 10% DOD to make it through the week, but then it would take two weeks to charge back up which would likely risk sulphating your battery.

[Raul]

If you paralel the batteries the ah will increase as yourself said it already , it will be a 220a bank so your charging ah will double aswell with the capacity increased.
Look on eBay UK for a DC power analyser watt volt amp meter. They're about 9 quid delivered and wire it between the array and cc , it will give you a inexpensive idea of the power production/harvest and then you can adjust your system accordingly.
Check your mail.

[spoon]

Given a limit on safe charge and not enough sun hours in the day to recharge the battery at that rate, on thing you could do is point your two panels in different directions, one east of south and the other west of south so that instead of doubling the peak current, which you cannot use, you extend a high current over a longer period of time. There is a limit on how much that can help though.
If your daily needs cannot be met by one (or two) panels charging at the maximum rate of the battery, you have no choice but to get a larger battery bank or a different kind of battery (i.e. AGM) which can be recharged at a higher current.

I do have 2 of these batteries. If I linked them in parrallel it would be 220ah @ 12v, would the bench charge rate stay at 8a or increase because of two units.

[inetdog]

Given a limit on safe charge and not enough sun hours in the day to recharge the battery at that rate, on thing you could do is point your two panels in different directions, one east of south and the other west of south so that instead of doubling the peak current, which you cannot use, you extend a high current over a longer period of time. There is a limit on how much that can help though.
If your daily needs cannot be met by one (or two) panels charging at the maximum rate of the battery, you have no choice but to get a larger battery bank or a different kind of battery (i.e. AGM) which can be recharged at a higher current.

[spoon]

The instructions in the first link I provided from Numax in a previous post warns against overcharging the battery. You should not charge over a certain amperage for this battery (usually C/10 for a flooded battery, but the table in the second link is even lower for some reason) but don't have enough sun in the winter to get a full charge at the lower amperage. So you cannot charge at a higher rate to cram in all that power if you exceed what the battery can handle or you will damage it.

It has C20 on the side of the battery, along with the other specs... So I'm confused as to what the actual safe charge ampage is. As on the data sheet it says 8amp?

[lkruper]

Sorry, I've just got to try and simplify everything to be sure I'm getting it right. The crux is that, even with my current batteries, I should go for the 100/30 victron CC and the second panel?

Even though with the current weather it may not ne enough to fully charge by 110ah battery everyday, that setup is the best chance I have at the moment.

The instructions in the first link I provided from Numax in a previous post warns against overcharging the battery. You should not charge over a certain amperage for this battery (usually C/10 for a flooded battery, but the table in the second link is even lower for some reason) but don't have enough sun in the winter to get a full charge at the lower amperage. So you cannot charge at a higher rate to cram in all that power if you exceed what the battery can handle or you will damage it.

There is another possibility that might help you. The insolation numbers assume that the panels are being put on the roof of a house. I don't think that is the case for you, is it? There are some sites for calculating not just by location and direction (eg S) but on the angle of the panel. In my case the winter insolation would be 2.82 but if I place the panel at an angle optimized for the winter sun it goes up to 5 or so. I think this link should do this for you: http://www.solarelectricityhandbook....rradiance.html

Finally, getting a generator to make it through the winter would also be a possibility.

[spoon]

It wouldnt hurt to check the Voc of your panel (not sure if that has been posted here yet), as long as it is less than 37V you would have the option of hooking up 2 panels in series, or parallel, if Voc is over 37V parallel only.

Just checked and the panels (s) are actually 235w and VOC of 36.8v.

[spoon]

You not gonna see 30a from even 2 panels let alone one in this wether . What you need is a good reliable cc and a second panel . With 2 panels you barely gonna charge 1 batt until March April .
I hooked 3x300w on my workshop and I get max 12-16a in this wether . In the summer I will do fine with just one .
You need a cc to take it and to do a proper absorb otherwise your battery will be undercharged everyday .

Sorry, I've just got to try and simplify everything to be sure I'm getting it right. The crux is that, even with my current batteries, I should go for the 100/30 victron CC and the second panel?

Even though with the current weather it may not ne enough to fully charge by 110ah battery everyday, that setup is the best chance I have at the moment.

[Raul]

You not gonna see 30a from even 2 panels let alone one in this wether . What you need is a good reliable cc and a second panel . With 2 panels you barely gonna charge 1 batt until March April .
I hooked 3x300w on my workshop and I get max 12-16a in this wether . In the summer I will do fine with just one .
You need a cc to take it and to do a proper absorb otherwise your battery will be undercharged everyday .

[spoon]

That's good to know , magic eye indicator has to float on electrolite . Makes sense that the chances are is fla. Thank you Sir for this info , you learn something new every day .Thats why I like this forum with lots of knowledgeable people .

It is fantastic, I've learned so much... very quickly. So am i right in thinking that I actually need a battery with a bench charge rate of 30a to be of any use wit that victron CC?

[Raul]

That's good to know , magic eye indicator has to float on electrolite . Makes sense that the chances are is fla. Thank you Sir for this info , you learn something new every day .Thats why I like this forum with lots of knowledgeable people .