Info on reducing volts to regulator

TizTom · Veteran Member

Info on reducing volts to regulator

SnowT · Guru

Not a chance...

Sorry I don't know who told you that But they KNOW nothing...

Ok.. here is it in a nut shell..

IF the system is wired correctly..

Solar Panels >> Wired to Solar Regulator << Solar Regulator[VERY Close to Batteries]>> Wire to Batteries << Batteries>>

now a 12v system should have Solar Panels that are sized Correctly, ie their Voltage is over 15v Preferable at 18v..
- now the amp's is what every the Solar panels are rated[Less Loses for time of Year, Angle to the sun, amount of solar Radiation] if Lucky you will get between say 25-50% of Max current.. If you have a String of solar Panels say 3 Panels rated at 11A each all in Parallel you have an ideal Am's of 33A but due to Loses say 15-16A at the best of times..

Now the reason you want a Higher voltage from the panels is Due to Thing called Voltage drop.. the smaller the Cable, the longer the Run of the cable the greater the Power you lose.. So that is why you want a higher voltage out of the Panels thru the Cable..

the issue that you have is that you have a Load that is constantly drawing power from the batteries and you Do NOT have enough solar to Put back what is taken from the batteries..
- Now if you have AGM batteries, you have to understand that the AGM batteries have a fairly complicated charging system..

Ok here is AGM Beer jug charging...
you can use your Jug of Beer to 50% full.. [the Beer will stay good/not flat] if you go below 50% full it get's Flatter Quicker..
Now you take your Jug to the Counter and get it recharged..
The Bar Person starts to fill it at Full pace till they get to 80% of Full and then they slow down for the last 20% of charge..[they trickle the Beer in[It takes 3-4x longer to put in the last 20%]

Now the Issue is, if you Do NOT have enough solar to meet your Daily Demands the Batteries Will NEVER get to Full charge..

I would say that 3@110w solar Panels are not big enough to meet your Power Needs..
You need More Solar...

do not Tamper with the Setting of the Voltage, it's set at that to do the job..

I hope this helps you out..

On a side Not I don't think that your fridge is very efficient.. I have a new 228lt Inverter fridge that is rated at 80W draw..

Juergen

TizTom · Veteran Member

Thanks for that Jurgen, did your fridge cost $200 from Gumtree and have reversible doors? The equivalent 3 way fridge was well over $2,200, I'd rather throw this one away a few times as it's a common old F&P that's been sitting in here and running for close to a year without fault, it's been over corrugated roads and parked at steep angles for days on end without missing a beat.

You've confirmed what I thought, I think I'll need a portable 120w to kick start it early in the morning and afternoon, I do have a 2kva genny if needed and a 20a battery charger which I'd run off that though I might get another so I'm pumping 40w into them when charging. Yes AGM batteries.

The regulator is adjustable to .01 of a V input/output etc etc so I set it myself and the 10mm wire comes through the roof directly above the regulator/converter/battery's where all 3 are solars are linked together....so it's 3X110w panels @ 19 -20v ea going direct to the converter then from the converter into the battery's and from the batteries into the 2000w inverter (all within 2M distance in total) which then goes to a mains type switch near the mains inlet (which goes to a trip switch) so I can switch from 240v external to 240-12v inverter power once turning the inverter on obviously.

Do you think turning everything off standby like microwave, air con, tv, aerial booster, and isolating the van's working battery which is about 70ah lead acid and operates the alarm, radio, windows etc when the motor is switched off (also has same size starting battery which is isolated by the ignition) would help?

TizTom · Veteran Member

Bugger it I just bought this, same company as I bought the 3 I have on my roof now, I couldn't fault them compared to the first load of rubbish which I bought that wouldn't put out enough to charge a 10ah battery, luckily I got my money back.

Also bought another 20a 12v charger from the same company which is the same as the one I already have and that one works brilliantly, once the battery's are full you hear it kick in whenever a bit of power is needed I.E. use the water pump and it'll instantly replace the power used so two should give the battery's good kick in the guts over a couple of hours while the genny gives the 12v system a rest at the same time.

www.ebay.com.au/itm/160W-FOLDING-SOLAR-PANEL-FULL-WATERPROOF-PORTABLE-MONOCRYSTALLINE-COMPLETE-SET-/281162804550

-- Edited by TizTom on Monday 14th of July 2014 06:32:27 AM

Jaahn · Guru

Hi TizTom,

Some good suggestions already given here so I will just add my two cents worth !

The solar panels fitted directly to the roof will not give their full rated out put when flat on the roof. They need to face the sun directly square on to get full power. Particularly in the morning and the afternoon the flat angle is limiting. They may be only putting out 50% of their power at best now. So portable panels can be moved around to get better power out of them. smile

A MPPT solar regulator can squeeze a bit more power out of the panels but cannot really compensate for a lack of solar power. If you use more than you generate then the batteries will die young. The better regulators will tally the power in and the power out and tell you what is happening. Also the voltage setting should be set correctly for the batteries or the batteries will die young ! Do not run the batteries down too low or they die young ! You must charge the batteries before they get too flat .Batteries commonly die young in a poor setup. Expensive. confuse

There are some good books on the subject by Colyn Rivers. Perhaps worth reading a bit on the subject and getting it sorted out, then it will just work. Turning off the standby power is good practice and I turn off the fridge overnight these cold nights, quieter also. In summer there is lots more solar power available to leave the fridge on.

Good luck Jaahn wink

oldtrack123 · Guru

TizTom wrote:
Hey all, I'm a bit of a noob to all this 12v solar and inverter stuff but I have a quick question,

[1] I currently have 2X130ah 12v batteries
[2]plus the working and starting battery's under the seat 60-70ah ea (Transit Van) which I normally isolate when parked,
[3] I have 3 x 110w fixed mono panels on the roof and a 2000/4000w inverter.
[4]I run a 240v 250L 2 door domestic home fridge which sucks about 135w when it's working which averages out to be about 20min per hour running and 40min off so averaging a constant 45w per hour, I also run the tv 21w a LOT and the aerial booster? and my small 10" laptop also a lot plus low v lights, everything otherwise on gas when camping.

[5]Now I can get about 2.5 days from a full chg until I'm down below 12v on average autumn weather days,
[6]each solar panel is pumping out about 20v or 7a and
[7] I have the inverter set to charge the battery's up to 14.7v but because of that I'm only getting 9-12a charge into the batteries so my question is ......
.[8]. If I lower the voltage going from the solar to the inverter down from 14.7v to say 13.1v will I get a higher amperage to my battery's. I've been told this will work but it seems to go against the logic in my head.

P.S. All the wiring I have used is very heavy duty from solar to battery's.....min of 10mm core.

HI
One at atime
[1 ]2 x130Ahr gives a recommended available use of around 130Ahrs MAX.[down to 50%SOC ]

[2] so they are not contributing to the loads.
[3] 3x110W panels will give an output ,depending on panel temp, orientation to the sun, sun brightness etc .up to 19.5A MAX
but you could get , over a normal good day ,of MAX 120Ahrs into the battery ,.If all the above conditions are optimum
More likely to get around 70<80Ahrs input
[4] the fridge is consumimg around 96Ahrs over 24Hrs,
[5] Add those other loads & you can see you are going down hill with the batterries
[6] How do you arrive at THAT figure for the VOLTS & Amps ??
What Regulator do you have??
[7] Why are you wasting energy by using an inverter to run the BATTERY charger? [or is there a typo in that section do you mean Charger??]
You have introduced additional losses of energy around 10<20 % for each
Why are you not using the SOLAR reg to charge the batterries direct??
[8]see [7] above Why not use the solar reg to charge the batterries direct from the solar panels

One thing is certin you do not have sufficient solar for your usage rate
Are those lights standard 12V lights?What Wattage? how many for how long each night?
PeterQ

-- Edited by oldtrack123 on Monday 14th of July 2014 12:47:16 PM

SnowT · Guru

Any Portable Solar Panel that comes With a Regulator on the Back of it is a WASTE of Time..

Your Solar regulator Needs to be as CLOSE as possible to the Batteries to help cut down on Voltage Losses..

You would be better off getting a Folding Panel that has No regulator and as Long as the voltage supplied from the panel is near the output of the panels on the Roof just supply yourself with a Parallel connect across the cable from the Roof solar.. Use an Anderson Plug for it..
-- Also make sure that you incorporate a Fuse on the circuit..
-- Also Have a Coated Stainless Steel Cable securing the Panel to your RV.. for security reason's..

Juergen

TizTom · Veteran Member

First, I don't run the battery charger off the inverter, I would only run it off the generator or a 240v external supply, running it off the inverter would defeat the purpose, bit like going round in circles.

Secondly, with the new portable solar I have 2 x 5m lengths of 10mm internal core wire spare which I will hook into the panel as close to the inverter as possible to reduce voltage drop, on a decent day I would imagine about 50ah just from this unit if faced in the right direction.

I have one of those multi position switches so I might set the fridge to run for 10-15 min per hour between midnight and 7am.

As I already proved earlier in another thread the convertor is well fused and also everything 240v goes to a household trip switch, all smaller 12v items have at least 1 or sometimes 2 in line switches.

-- Edited by TizTom on Monday 14th of July 2014 07:07:57 PM

SnowT · Guru

Tom I'm not sure what you have..

But a Basic of just the DC side.. At least What I understand..

Basic Solar-inverter system.jpg

Ok hope this helps you..

Juergen

TizTom · Veteran Member

van electrics 2.bmp Yeah that's what I've got Jurgen .... except I don't have the portable solar yet and as it's regulated I figured I'd go direct to battery's via clamps once I boost the size form 4mm to 10mm cable for easy removal, I can't really see the difference (pretty much like adding a portable 9ish ah battery charger from another source).

-- Edited by TizTom on Monday 14th of July 2014 10:29:33 PM

oldtrack123 · Guru

HI Tom

Ok It seems you are now referring to the solar REGULATOR As as converter

The sole pupose of that REGULATOR is to control the charging of the batterries

IT SHOULD be set,[If such sttings are available] for the BATTERY type

Model umber of the REGULATOR may help in that regard

It should be as near as possible to the batterries so it sees the true battery voltage & REGULATES accordingly

It also seems you do have an INVERTER to run 240V gear

As pointed out earlier you will have energy losses between 10&20% using an inverter.

Do you have the Specs for theINVERTER & please read Snow's thread on inverters

Depending on the inverter it will have a no load current or sleep mode

it will be drawing power the whole time it is CONNECTED to the battery, even if not supplying a load

THe Cable run length & cable size between the battery & the INVERTER can play a significant part in the INVERTER performance especall yunder heavy loads

Is the Fridge the only 240V .appliance you run from the inverter??

The solar will do very little for & should not supply the inverter direct.

Both should be connected DIRECT to the Battery

In Snow's thread tyou will find an explanation by me, of the effect of lower voltages at the inverter's 12V input.

I would still suggest you need to recalculate your TOTAL daily Ahrs or WATTS use.

IMHO, you are underpowered & the batteries may be coping a flogging

Do you have a low voltage cut out fitted for battery protection from over discharge

Best if you can give useage during Solar charging time & when solar is not inputting [ say from 2PM to 10AM]

Charging Lead acid batterries requires about 30% more Amphrs than was taken out & that varies with battery age & health, so night time [nonosolar time] can be a significant problem

That will assist in determining how much solar you may need to keep the batterries near fully charged

PeterQ

-- Edited by oldtrack123 on Monday 14th of July 2014 11:23:44 PM

TizTom · Veteran Member

Sorry mate, I always get regulator, inverter and converter mixed up so here is what I have, all battery cross cables are ex starter cables from Subaru's with 13mm+ and 10mm- core black or black and yellow thin wall plastic, all battery's are linked and earthed separately.

Sorry, the solar on the roof is connected to the CONVERTER only
The Converter is connected to the battery's
The battery's are connected to the INVERTER
The portable solar will be connected to the Battery via 10mm copper core cables and Anderson plugs once modified for ease of removal

I hope my stupidity is now understood and thank you for your patients, I've been living in here hard parked for 8 months so it must be pretty right though only a couple of weeks free parking, I just want to know if I'm getting the optimum from the cheap nasty crappy system that I have bought

The convertor is about 400mm from the batterys and uses 13mmcore copper cable, the batterys are 300mm from the inverter also using 13mm copper core cables. The cables from the 3 panels are joined above the roof at the entrance, they are approx 1.6m from the converter, they are 10mm copper core +&- joining them.

The REGULATOR is a Solar 60 from fleabay

www.ebay.com.au/itm/60A-LCD-Solar-Battery-Regulator-Charge-Discharge-Controller-12V-24V-With-USB-GL0-/251397406725

The inverter is a no name Inverter 2000/4000

www.ebay.com.au/itm/Pure-Sine-Wave-Power-Inverter-2000w-4000w-12v-240v-AUS-plug-Car-Boat-Caravan-/261397460310

Battery's are POWER AGM battery's ........ 130ah ea

www.ebay.com.au/itm/130AH-AMP-HOUR-BATTERY-AGM-SLA-12-VOLT-12V-DEEP-CYCLE-DUAL-FRIDGE-SOLAR-/400634846771

-- Edited by TizTom on Tuesday 15th of July 2014 12:45:15 AM

-- Edited by TizTom on Tuesday 15th of July 2014 01:26:52 AM

SnowT · Guru

Tom.

Can you copy the instruction manual for the Solar regulator.. of do you have a PDF that I read thru..?

I would like to see what they say it can do..

Juergen

TizTom · Veteran Member

Sorry mate but no scanner, I'm pretty sure I saw the specs on one of the sites that was selling them, I'll have a look.

From memory it was pretty crappy as far an any info went.

EDIT, this has all the info that was on the instruction page that I got....... get what you pay for but I really can't complain, it's been on for 8 months so far.

http://www.ebay.com.au/itm/60A-Solar-Regulator-Charge-and-Discharge-Controller-with-LCD-Display-5V-Charger-/261381241984?pt=AU_Solar&hash=item3cdb893c80

-- Edited by TizTom on Tuesday 15th of July 2014 09:56:12 PM