Installing two sets of solar panel?

Slight thread drift....


What size battery charger would a little petrol honda 20i Genny with 1.6kw continuous output @ 240v run?

I'd like to bulk charge as many lead acid batteries up to 80% as quickly as possible.

Tia. :)
 
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RichardS said:
But surely as long as the cables are thick enough, it's better to use one run of correct cable ..... and I thought you'd covered that?

Richard
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I choose ti limit my comments to the thickness of the cables. As it happens I dont think the 10AWG is really quite heavy enough for the original installation.

6m at 3.4 m ohms/ m = 20 m ohms, which will cause 0.4 volts drop at 20 amps, (0.5 volts at 25 amps). If the regulator is controlling at 14.4 volts then only 14.0 volts, or a little less at full chat, will reach the battery
 
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rustybarge said:
Slight tread drift....


What size battery charger would a little petrol honda 20i Genny with 1.6kw continuous output @ 240v run?

I'd like to bulk charge as many lead acid batteries up to 80% as quickly as possible.

Tia. :)
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Quite big. 80 amp possibly
 
RichardS said:
But surely as long as the cables are thick enough, it's better to use one run of correct cable ..... and I thought you'd covered that?

Richard
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Better to run both controller outputs to the batteries, better yet, to different battery banks, or you make the OPs original problem even worse.
 
PaulRainbow said:
Better to run both controller outputs to the batteries, better yet, to different battery banks, or you make the OPs original problem even worse.
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That's interesting Paul. I've often said that electrics are not my forte but, ignoring considerations about cable size, I have always thought that connecting the controllers together near the controller was exactly the same electrically as connecting them together near the battery bank.

Why do you favour the two separate long cable runs needed to make the connections near the battery rather than one long cable run?

Richard
 
lw395 said:
I don't see any upside over putting all the panels into one decent charger/controller.
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Which is what I was thinking of doing when I add another panel. Is there a problem with this? Do the panels have to be identical? Do I connect them in series or parallel?
 
DJE said:
Which is what I was thinking of doing when I add another panel. Is there a problem with this? Do the panels have to be identical? Do I connect them in series or parallel?
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Panels must be the same rating if connected in series.
 
DJE said:
Which is what I was thinking of doing when I add another panel. Is there a problem with this? Do the panels have to be identical? Do I connect them in series or parallel?
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Depends on what panels you have, how they are connected and what you intend to add.
 
RichardS said:
That's interesting Paul. I've often said that electrics are not my forte but, ignoring considerations about cable size, I have always thought that connecting the controllers together near the controller was exactly the same electrically as connecting them together near the battery bank.

Why do you favour the two separate long cable runs needed to make the connections near the battery rather than one long cable run?

Richard
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I don't favour two long cable runs, i suggested having the controllers closer to the batteries. If the controllers are connected together, they detect each others voltages and not the battery voltage. It can still an issue, even if connected to the batteries, as the OP has found. Setting the controllers to identical profiles will allow at least one controller to detect the battery voltage, the other controller should then work along with it.
 
PaulRainbow said:
I don't favour two long cable runs, i suggested having the controllers closer to the batteries. If the controllers are connected together, they detect each others voltages and not the battery voltage. It can still an issue, even if connected to the batteries, as the OP has found. Setting the controllers to identical profiles will allow at least one controller to detect the battery voltage, the other controller should then work along with it.
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Errrrr OK.

I watched the final episode of "The City and the City" last night and, although I enjoyed it, there were times when I wasn't quite sure what was going on. I've got a similar feeling now but never mind, it's all good. :)

Richard
 
RichardS said:
Errrrr OK.

I watched the final episode of "The City and the City" last night and, although I enjoyed it, there were times when I wasn't quite sure what was going on. I've got a similar feeling now but never mind, it's all good. :)

Richard
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Yeah I'm not totally sure either. Electrically connecting the controllers together should be the same as connecting them to the same terminals on the batteries.

Paul says "If the controllers are connected together, they detect each others voltages and not the battery voltage"...

Why would a length of cable change this? Are you saying the small run of cable would create a small voltage drop and therefore the controllers will detected each other rather than the batteries?
 
northcave said:
Yeah I'm not totally sure either. Electrically connecting the controllers together should be the same as connecting them to the same terminals on the batteries.

Paul says "If the controllers are connected together, they detect each others voltages and not the battery voltage"...

Why would a length of cable change this? Are you saying the small run of cable would create a small voltage drop and therefore the controllers will detected each other rather than the batteries?
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Electrickery will take the path of least resistance. It's less resistance for the controllers to detect each others voltages than it is to detect the voltage of the battery, some distance away.

You're doing the same as Richard i suspect, only considering continuity.
 
PaulRainbow said:
Electrickery will take the path of least resistance. It's less resistance for the controllers to detect each others voltages than it is to detect the voltage of the battery, some distance away.

You're doing the same as Richard i suspect, only considering continuity.
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Ok copy that. Anyway i actually found a run of cable from the previous owners small solar panel so I'll use that for the new controller and then manually set its voltage a smidge lower than my main array and monitor for a week.

I'll come back with feedback in a little while if i find out anything conclusive after playing with settings of bulk voltage.
 
northcave said:
Ok copy that. Anyway i actually found a run of cable from the previous owners small solar panel so I'll use that for the new controller and then manually set its voltage a smidge lower than my main array and monitor for a week.

I'll come back with feedback in a little while if i find out anything conclusive after playing with settings of bulk voltage.
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Can i suggest setting both controllers with identical voltages for all phases of charging first, if that doesn't work try lowering the voltage of the smaller controller.

If you have a VSR, it's also worth considering connecting the Sunware to the engine battery. Look forward to your results :encouragement:
 
OK so... had the new panel on for a couple of weeks now and seems to be working alongside the existing panels (via moot Victron) fine. Will monitor some more but interestingly I'm getting 370w from 360w panels at the moment. Yes it's pretty sunny at the moment but the most I've ever seen before was about 330w.

Do you think the Victron controller is somehow picking up some of the power generated by the other panel via a different controller? Or is it just the Victron controller being not particularly accurate?

503EFF00-E6B5-44FD-B460-51FA6889F98C.jpeg
 
I would not be surprised at getting 370W from new '360W' panels, in bright sunshine and well-aimed panels.

Most panels are spec'd to give 80% of their nominal power after 20 years or some such.
Because their performance inevitably falls, it is normal to start with brand new panels giving 110% or more of their 'nominal power' under standard test conditions.
This will drop off over the years, usually down to about nominal in the first 1 to 3 years, then slowly declining, then maybe falling off a cliff after 25 years or so.

Then there is the fact that sunshine can be more than the standard test strength.
 
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