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Author Topic: Multiple Chargers  (Read 2286 times)
sleepybubble
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« on: March 17, 2009, 07:10:29 PM »

I could search the internet for ever but as there is so much knowledge here I'm asking here first before finding anything myself... (lazy I know  surrender)
We have in our attic an APC1000 UPS, it is connected to two deep cycle leisure batteries instead of the provided sealed Gel batteries. It was given to me for nothing as it was 'broken' turned out the batteries were cooked.
The UPS powers our heating gubbins, solar pump, heating pump, programmers T/Stats etc as well as a Slug (NLSU2), router and a couple of USB hard drives.
When we have a power cut all the above carries on functioning, longest run time before I connected up the genny was about 16 hours, so it works.
A future plan is to hang the lighting ring off it too, but my wife is resisting as she thinks candles in power cuts are romantic?!? (if all the lights in the house were on total extra load would only be about 150w so this is feasible)
What I want to know is....
THe UPS obviously has a charger built in which keeps the batteries tip top, if I was to connect another charge controller to this battery bank, powered by something else, eg, wind/Micro Hydro does anybody foresee it causing my UPS problems.
I would like to drop the UPS off daytime rate electric and onto the economy7 circuit, so it will only charge from mains at night time if it needs to.
I'm not keen on spending a fortune, never am, hence the round about approach... I know that I ought to grid tie and sell my spare units back but I will proberbly use an immersion heater as the dump load. If I find that I start to have far too much electricity then I might grid tie in the future when I can afford too.

Any comments/thoughts/Suggestions welcome.
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Justme
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« Reply #1 on: March 17, 2009, 08:01:23 PM »

You should be ok with the solar / wind controllers as thats basicaly what every of grid system is. I do see a problem with your planned E7 only charging on days with no solar or wind (trust me you do get them) them the UPS charger will not be able to recharge the bats in such a short time. UPS are designed to only have to recharge occasionaly after an occassional power outage & to trickle charge / maintain the bats between outages. As such low charger amps. they have a ver


Justme
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Navitron solar thermal system
30 x 58mm panel 259L TS
1200watts solar 120vdc
FX80 Solar controller
Victron 12v 3000w 120a
6kva genny
6 x 2v cells 1550amp/h 5C
24 x 2v cells 700amp/h 5C
Total bank 4350 amp/h 5C
RichardKB
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« Reply #2 on: March 17, 2009, 11:16:23 PM »

Hi your only problem is to stop the inverter coming on during the day when not powered, as that is what it is supposed to do i.e. turn on when the power is off. Unless you are physically going to turn it off.

If you are going to let it run during the day and charge at night without any solar/wind input you will just about break even with E7 prices due to charging losses and inverter efficiency.

Rich
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sleepybubble
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« Reply #3 on: March 17, 2009, 11:48:57 PM »

Richard,

I agree with you on the charge/discharge economics of the economy seven. Thats why I am not yet doing that, plus I was concerned about cycling my batteries too deep and too frequently, I'd want a bigger bank for that I think to protect the batteries a bit.
Wih regards isolating the power during the day, we are on split meters and two consumer units already, the night(?) meter and board come live on a timeswitch, so I had thought of powering the UPS off that consumer unit on its own trip. I've already removed all the night storage heaters that used to be wired to that consumer unit.
I think my main concern was with regards harmonics from a (wind/hydro) loadcontroller feeding through the bank and messing the UPS up... I confess I dont know anything about that sort of thing though, and an oscilliscope was something that sat in the corner of the school science lab looking shiny to me.

I'l need to disconnect the annoying sounder on the UPS for when the mains is off as well... really interferes with your sleep!

You should be ok with the solar / wind controllers as thats basicaly what every of grid system is. I do see a problem with your planned E7 only charging on days with no solar or wind (trust me you do get them) them the UPS charger will not be able to recharge the bats in such a short time. UPS are designed to only have to recharge occasionaly after an occassional power outage & to trickle charge / maintain the bats between outages. As such low charger amps. they have a ver


Justme

Oh I believe there are days with no sun and no wind, they are the midge'y ones in september. Maybe I ought to look up how long the economy seven is on for then... I thought it was most of the night from about midnight through till 6'ish with a boost at about 4pm for an hour. That amount of time would be plenty for the UPS to recharge its bank. We went without power for 2 days in January, and only started to run the Genny when the UPS finally gave up the ghost... wish I had got to it sooner as the start up load of powering it back on was too much for my teensy genny.
But I checked the battery state after it had been on charge again after six hours or so and it was back up to max. I think the UPS actually shuts itself off before taking the batteries too low, but I'd have to run it down again to check that.

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Justme
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« Reply #4 on: March 18, 2009, 02:06:36 PM »

Low battery shut off are not to protect the battery most are set around 10.5v which is far to low even under load.

7 hours of E7 might recharge the small UPS batteries but will never fully charge a proper bank especialy if you keep the USP charger. The physics of acid bat charging mean to fully charge you need far more than 7 hours no matter how big the charger. Failure to fully charge will result in sulphation & reduced bat capacity. However if you get cheap bats it "could" be cost effective to under charge especialy if charging via a genny. That way you can keep the charger running at a high output for longer. I have times when I want to fully charge & I am running a 6kva genny & a 120amp charger thats only putting less than 15 amps into the bank. I try to do that one a week / fortnight. The rest of the time it gets a shorter charge thats stopped at about 20-25 amps (plus the wind & solar).


Justme
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Navitron solar thermal system
30 x 58mm panel 259L TS
1200watts solar 120vdc
FX80 Solar controller
Victron 12v 3000w 120a
6kva genny
6 x 2v cells 1550amp/h 5C
24 x 2v cells 700amp/h 5C
Total bank 4350 amp/h 5C
EccentricAnomaly
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« Reply #5 on: March 22, 2009, 02:25:09 PM »

7 hours of E7 might recharge the small UPS batteries but will never fully charge a proper bank especialy if you keep the USP charger.

Doesn't that rather depend on:

1. How much energy has been taken out of the batteries in the previous day (sleepybubble says it gives 2 day's worth) and

2. How much energy has been put in.

If the E7 is only to top up solar and/or wind (there's always some sunlight in a day) then it's not obvious to me that there would be a problem.
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Justme
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« Reply #6 on: March 22, 2009, 08:44:53 PM »


Doesn't that rather depend on:

1. How much energy has been taken out of the batteries in the previous day (sleepybubble says it gives 2 day's worth) and

2. How much energy has been put in.

If the E7 is only to top up solar and/or wind (there's always some sunlight in a day) then it's not obvious to me that there would be a problem.

Yes obviouisly will depend on energy taken out. But you still cant change the physics. To more accuratly work it out we would need to have better info than provided so far. Battery charging is not a simple hours times charger amps = energy into battery. The charge rate will depend on SOC of the battery & will fall as the charge progresses & you loose about 30% due to physics.

You will get days with NO solar power. I think I have had 3 or 4 so far this year (if I remember I will check the stats tommorow).
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Navitron solar thermal system
30 x 58mm panel 259L TS
1200watts solar 120vdc
FX80 Solar controller
Victron 12v 3000w 120a
6kva genny
6 x 2v cells 1550amp/h 5C
24 x 2v cells 700amp/h 5C
Total bank 4350 amp/h 5C
sleepybubble
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expect the unexpected, then its expected


« Reply #7 on: March 22, 2009, 11:01:27 PM »

OK just checking back on this thread, I think my Question has been answered by a lack of responses. i.e. is there a probelm to the battery if it is recieving charge from more than one source at the same time.
I appreciate that my E7 plan might not be enough, I guess a remote bettery monitor needs to be designed in to keep tabs on the battery state, in case it is not getting charged enough during periods of low wind.

NB. I have no intention of solar charging at the moment, purely wind. With a possibility for micro/hydro later on.

Thanks for all the replies.
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billi
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« Reply #8 on: March 23, 2009, 07:26:24 AM »

Quote
is there a problem to the battery if it is receiving charge from more than one source at the same time

I would not think so , most off grid people have several sources to charge the battery
During the bulk charge it is fine here with me , but when it comes to absorption charge  a bid fine tuning is needed

For example : My solar charge controller has a temp sensor and would like to charge the battery with 30.2 Volt ( before absorption) , but the windturbine controller starts dumping parts  of the  produced electricity ( from Wind and Sun ) at 29.6 V into a Heat element , i didnot care too much cause free anyhow

That wouldnot be the ideal  idea then with E7     Tongue 

Billi

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1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
Justme
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« Reply #9 on: March 23, 2009, 10:45:55 AM »

OK just checking back on this thread, I think my Question has been answered by a lack of responses. i.e. is there a probelm to the battery if it is recieving charge from more than one source at the same time.
I appreciate that my E7 plan might not be enough, I guess a remote bettery monitor needs to be designed in to keep tabs on the battery state, in case it is not getting charged enough during periods of low wind.

NB. I have no intention of solar charging at the moment, purely wind. With a possibility for micro/hydro later on.

Thanks for all the replies.

I think you will find I did answer it in my very first post.

Multipul charging sources is fine. You do need to set one to be the master (by setting its setting higher than the rest).

Justme
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Navitron solar thermal system
30 x 58mm panel 259L TS
1200watts solar 120vdc
FX80 Solar controller
Victron 12v 3000w 120a
6kva genny
6 x 2v cells 1550amp/h 5C
24 x 2v cells 700amp/h 5C
Total bank 4350 amp/h 5C
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