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Bah Solar

Bah Solar

Bah Solar

(OP)
5 consecutive days of thoroughly overcast weather has left my 200Ah batteries empty. The trusty diesel generator runs for an hour each day, which keeps things going, but I seem to be caught in a trap, the battery charger current tapers off to 10A at 54V (from 20A), whereas at least once a week I like to take the batteries up to 54.4V resting, say 56-57V under charge. I can do that with the solar as it has a float capability built in. Well I just thought I'd have a grizzle.

Of course, despite the noise, the good thing about the genny is we can run the microwave, the water pumps, the toaster, and the electric chainsaw all at once.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Bah Solar

Relocate the generator farther from the house (also reduces the carbon monoxide hazard and the exhaust odor annoyance), or put up a noise abatement wall.

Mike Halloran
Pembroke Pines, FL, USA

RE: Bah Solar

That's odd, my undersized solar panels can hold a float voltage of 27.2V, or higher, even when it's cloudy, provided something else has already completed the bulk and absorb cycles.
I have AGM batteries in a 28V system, so my 27.2 float voltage is equivalent to 54.4V in your system. Your charger is tapering off the bulk charge, but only holding 54V... should be 55V or so.
Maybe it's just your battery charger voltage set-point that is set too low. What set-points does your charger use? Is it a 3-step charger or just 2?

STF

RE: Bah Solar

It sounds more like a voltage regulator problem more than a charger problem.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

RE: Bah Solar

You should have an engineer check it out.

RE: Bah Solar

(OP)
I'll take a photo of the guts of the charger, it is a pretty ancient device.

The easy solution is to whack a bunch more panels on the roof, I can just about double the plate capacity for a thousand bucks (plus installation). That'll give me room to maneuver in winter, and in summer means we can run the immersion heater.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Bah Solar

Your answer doesn't inspire confidence... "photo of the guts" implies a lack of a digital control panel. Even my 25 year old Xantrex (Trace) inverter has a LCD.

Of course, a well tuned PV system can still be a slouch in solar doldrums.

STF

RE: Bah Solar

(OP)
That's right it is probably 20 years old like my oldest panels, may even be 30 - I don't think so as the original installation was 12V. I'd have liked to have seen the inverter they used then. We used to use inverters in test cars then, about the volume of a racal reel to reel 14 track 1/2" tape recorder, and as heavy, say 25 kg.

The solar controller is a different beast altogether, still a current model, PL40, which I'd like to upgrade to a true MPPT device when those get a bit cheaper. At the moment it is more cost effective just to bang more panels up.

Anyway yesterday the sun came out and I got about 60 Ah into the batteries which is more like it.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

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