Voltage Setting for Solar Charger

[sailingpeanut]

Hi,
this might be a stupid question but anyway here I go:

I have 4 Torjan 105s in series/paralell and 4 130 Watt solar panels with a Xantex C60 charge controller.

Now form the Trojan web site it says
Daily Charge Voltage: 14.8
Float Charge Voltage: 13.2
Equalize Voltage: 15.5

Solar Panels go into Charge Controller, Charge Controller is connected to Battery. So if I set the Charge Controller to 14.8 V - all my 12 appliances (fridge, gps etc.) will hav a voltage of 14.8 Volt whilst im charging aka the sun is shining.

Read in my Alder Babour Manual that overvoltage might kill the fridge or it simply will not start since then it believes it's a 24 V system and assumes undervoltage.

But the basic question is: if I use the 14.8 volt to charge my trojans - will I burn any gps/depth sounder etc. which are supposed to run on 12 volt.

thanks in advance,
Olaf

[zeehag]

no. that is within normal charging for batteries. batteries do not charge under 13v. the batteries come to max 12.71v IFF in GOOD(new) condition. dont sweat the voltage unless is way too high or way too low-- then check your vr for fault. sounds like is working well. have fun . do no tforget to check out th e battery site-- there is a good battery maintenance revue for even dummies like me-just push battery maintenance and find it... i even know about the mallet trick when the systems say sulfated or internal short..LOL..... is easier than it looks right now-- dont fear-- many will have answers for you in much more complex terms, but it boils down to what i sed in many different words. and i learned the mallet trick froma battery "distributor"{. he says he does this for 50 dollars..LOL....battery reconditioning..ROFL!!!

[Captain Bill]

Optimum battery charge/float voltages depend on the temperature as well as battery type. It would seem unusual for a company to suggest a single set of voltages. My C40 has a temperature sensor that lowers the voltage as the temperature rises. Most 12 volt devices made for boats are good up to 15 volts. Danfoss controllers for refrigeration units may have a problem, at least that's what a NovaKool tech told me. He told me to definitely disconnect the fridge when equalizing. Since most electronics are rated to 15 volts, it's probably a good idea to have them all shut off when equalizing. These should be shut off at the breaker or external switch. Most modern electronics are not really off when turned off by their internal switches as power is still on their power supplies, which might have a problem with 15+ volts. Some are good to 30 volts so that they can work on 24 volt systems, so you really don't need to worry about these.

[GordMay]

The Adler Barbour Cold Machine has an operating range of up to 15V DC.
If voltage reaches 17.0 V DC, the module “thinks” it is a 24 V DC system suffering from low voltage, and LED will display one flash. The module will probably survive. The fan(s) and pump (optional) may not.
A-B Warns:
EQUALIZING (WET TYPE BATTERIES ONLY)
During periodic equalizing, the battery voltage can exceed 15 or even 16 volts. To prevent possible damage to your unit, shut the Adler/Barbour system off before starting the equalizing process.

[djmarchand]

Olaf:

I think that 14.8V is too high. It sounds like your solar regulator is a simple adjustable voltage model. I once had a boat with 4 T-105s and a simple engine alternator regulator that had a pot that let you adjust its voltage like your solar controller. It was originally set for 14.6 V. This boiled a significant amount of battery water and required checking and filiing monthly. I dropped it down to 14.1 volts and the filling interval went to three months.

Then I replaced it with a Balmar three step regulator. The voltage rarely went above 14.5 at the end of absorption mode and then it dropped back to float at 13.5 V.

This tells me that something in the low 14s would be better for your batteries. But if you religiously check water level, it probably doesn't matter.

David

[colemj]

The 14.8 bulk charge voltage recommendations is Trojan's recommendation for their T105 battery. The Trace controller is a full automated 4-stage controller, not a simple single voltage pot adjustment.

We have the same battery, solar, controller and reefer setup as the OP (except we have 6 T105's instead of 4). Our Adler-Barbour Cold Machine is quite happy running at 14.8V, although the temperature sensor keeps it well below that now that we are in the tropics.

Mark

[hellosailor]

Peanut, a typical "12" volt system is running at 14.4 volts from an alternator, and most of the "12" volt equipment has some tolerance beyond that. You'd have to check with the maker to find out specifics, but it might actually be rated "13.8VDC +-10%" or even 15%, when it is sold as nominal "12" volt equipment.

So there's probably no issue with running your system at 14.8 volts, although that will make any incandescent lamps on board burn a little brighter--and with slightly shorter lives. Any LEDs that aren't properly regulated (i.e. ones that just use dropping resistors) would have similar issues.

Gord-
" To prevent possible damage to your unit, shut the Adler/Barbour system off before starting the equalizing process. " A good reason to use a 15V Zener diode set up with a fuse, as crowbar protection to cut off the power to that unit, or anything else that might be damaged by over 15 volts. If, of course, 15 volts was enough to harm it. less than two bucks with good suppliers, less than ten in any case.

[KestrelBuck]

Zeehag, what is the mallet trick for desulphating?

[GordMay]

Originally Posted by hellosailor

... " To prevent possible damage to your unit, shut the Adler/Barbour system off before starting the equalizing process. " A good reason to use a 15V Zener diode set up with a fuse, as crowbar protection to cut off the power to that unit, or anything else that might be damaged by over 15 volts. If, of course, 15 volts was enough to harm it. less than two bucks with good suppliers, less than ten in any case.

Can you specify parts for your 15V crowbar?

A 20% to 40% spike, as described herein, wouldn't work as intended ➥ SCR Overvoltage Crowbar :: Radio-Electronics.Com

[hellosailor]

"Can you specify parts"
Not offhand, that would be WORK.<G>

You install a fast-blow fuse, ratted just large enough to carry the design load, in the positive supply 'at' the reefer or other device. In between that fuse and the device, you attach one side of a zener diode, rated for a higher wattage, and the other side of the zener to the ground lead. If there's a spike, the zener will conduct creating a short circuit (as if a crowbar was thrown across the wires) and blowing the fuse.

Yes, a zener has to be installed with the correct polarity to work.

There are faster devices than zeners, but zeners are cheap and reliable, and they'll clamp most of what could hurt whatever they are protecting. Surplus houses usually carry them, Rat Shack carries them...often it is a matter of who's got something "good enough" in stock at a good price, as opposed to minimum orders from parts houses. It doesn't have to be an exact match to work.

The SCR circuit is more sophisticated. Or, you could install a transzorb (surge supressor) in the line, that's what are used in power strips as a first line of defense. But just a plain zener and a fastblow fuse (damn, the fuse blew again, and there are no spares when yo need them!) is, as your link notes "Despite its drawbacks this is still a very useful circuit which can be used in a variety of areas."

Every power protection device can or will eventually wear out (physically!) or be overloaded under some conditions. Short of that point, every one of them still adds some degree of protection, and "some" beats all hell out of "none".

[seasick]

The mallet trick is a variant of the drop trick if I'm not mistaken. I prefer the drop trick.

Just lift your batteries about three inches and let go. This settles the sulfide piles that built up on the bottom below the plates. This material will short out your plates in time and a good whack, a vigorous shake or a good drop, will spread this sulfide out across the bottom and extend the life of your batteries.

[socaldmax]

Originally Posted by djmarchand

Olaf:

I think that 14.8V is too high. It sounds like your solar regulator is a simple adjustable voltage model. I once had a boat with 4 T-105s and a simple engine alternator regulator that had a pot that let you adjust its voltage like your solar controller. It was originally set for 14.6 V. This boiled a significant amount of battery water and required checking and filiing monthly. I dropped it down to 14.1 volts and the filling interval went to three months.

Then I replaced it with a Balmar three step regulator. The voltage rarely went above 14.5 at the end of absorption mode and then it dropped back to float at 13.5 V.

This tells me that something in the low 14s would be better for your batteries. But if you religiously check water level, it probably doesn't matter.

David

Trojan specifies 14.82v for bulk charging @ 77*F (25C.) Charging at a voltage of 14.4v or lower is never going to fully charge the batteries. Assuming the batteries are at 90% charge, you've only got 40% usable power before you hit 50%. This is a 20% loss of actual usable power, since you can only use the upper 50%.

FLA batteries should be topped off with water every month. If it's difficult to do because of their location, that's when battery watering systems become worth their weight in gold. You can refill the batteries without taking the caps off, without even needing to see the batteries.