Questions about solar power

[Paul Braun]

That looks like it will do you well. I had a similar conversation with Interstate batteries, they were more emphatic that the golf cart batteries I have should be charged at absorption rate of 15.4 volts. Apparently the battery chemistry has changed for Trojan and Interstate 6 volt batteries in recent years and the controller manufacturers have not kept up.

I did not realize Schneider owned Xantrec, you may be more familiar with American Power (APC) also owned by Schneider. Xantrec makes a C35 controller that gets pretty close to recommended charge rates. The only other controller I have been able to find with sufficient charge rates is Blue Sky Sun Charger 30.

I, for one, look forward to your application of that semi flexible panel. Keep us posted.

[Paul Braun]

I was looking into installing an RV panel system and came across this web site, it has a good discussion of fusing your system.

Chrome Molly Wally is a bicycle enthusiast who like to boondock at remote mountain bike locations. His other recommendations regarding solar seemed sound.

[Briantb]

Trojan Battery Company

I'd recheck with your battery man..while every battery has its own settings I'd be surprised at an abosorb rate over 15.0..equalize yes..
the link is the generic table for Trojan batteries

[Mike Magee]

Originally Posted by KevinScamps

so with a panel fixed on the roof, the battery will never sit for long periods discharged. In fact it will get charged every day which is the ideal conditions for storing a battery. Therefore sulphating should not be an issue because the battery is always charged. MPPT vs. PWM controller will not have an effect either way, though some have functions that periodically apply pulses to reduce sulfation.

If however you use a foldable array that you put away, you then need to make sure you keep your battery charged while in storage and leaving the battery discharged will result in sulfation which will decrease the life of your battery.

No need to put away a portable panel, if one stores the trailer in the back yard like I do. My panel is propped against the coupler and is plugged in, doing its thing daily.

[carlkeigley]

Looking forward to the results Denny.
Thanks for all the hard work and research.

[Bryan L.]

I like the idea of a slide in solar panel as you could use a very low-profile slider system. I'm not too keen on traveling with a solar panel on the roof. Has anyone done a framed system where the Z-brackets have Velcro on the bottom and the panel gets placed on Velcro mounted to the roof? It wouldn't create drag when traveling since the panel would be in the trailer and it would look like a permanently mounted system when parked with the panel affixed to the roof with the Velcro.

I have to admit that all of this talk is a bit nauseating. I want to use solar but I just don't enjoy the details like many here do. I just want to know what to get. It's like me and my collection of 70's mopeds. I could talk about them for hours and someone else might just ask me what's the best kind to get so they can just start riding one. Thank you for posting what you got. It gives me a good starting point.

[Paul Braun]

Brian
I did call Interstate customer support, not a local battery store. Here is the link to their web site, it clearly state the charge rate at the absorption level for their 6 volt "golf cart" batteries is 7.75 volts. Since when using 6 volt you must have two, the voltage recommended for absorption is 15.5.

How do I charge certain deep cycle 6-volt and 12-volt batteries?

I point this out only because Interstate is a popular brand and it is necessary to be aware of all the components in a solar system. Not many people will look up their battery specs.

[Carol H]

Originally Posted by Bryan L.

I'm not too keen on traveling with a solar panel on the roof. Has anyone done a framed system where the Z-brackets have Velcro on the bottom and the panel gets placed on Velcro mounted to the roof? It wouldn't create drag when traveling since the panel would be in the trailer and it would look like a permanently mounted system when parked with the panel affixed to the roof with the Velcro.

.

Mine rides in the trailer - bungeed to the front outside wall of the side bathroom. I have a PVC stand I use when I need to move it away from the trailer to find some sun. When camping in open areas I often just lay it on my rock guard if the sun is coming from the right direction as the rock guard when propped up has a bit of an angle to it. Have left it up there many times while in state/provincial parks & gone off for a walk or drive and in 6 years and it hasn't walked. When attending busy places such as music festivals I put it right up on the roof and you can't even see it unless you are flying overhead and no one can tell if its secure or not. But just in case someone did notice the wire running up from the tongue around the front window I purchase a little travel alarm that when pulled apart sets off a high pitched sound - have it tied on one end to the panel and the other to the awning. Theory being if someone did try and reach up and pull it off they are probable going to do it from the none awning side as its easier to reach from there and the little alarm will get someone close at hand attention..... never had it go off so have no idea if that theory is a practical one or not

[Briantb]

Long story short.. You will boil your batteries..

[peterh]

" . . . the purpose being to remove lead sulphate crystals (I think)."

The "equalize" function helps even out the distribution of a battery's charge across the plates and cells. It's particularly useful when a bank of multiple batteries wired in parallel. It can reverse sulphation, but that's not its main purpose, and most solar controllers don't cook their batteries long enough to actually drive the sulphate out.

There are electronic circuits that can and do slowly reverse the effects of sulphation in a battery. They are the BatteryMinder and devices like the Wizbang. Both work basically the same way, by sending a high-frequency radio wave through the battery at the exact frequency that causes the bonds between lead(IV) and its two satellite sulfate ions to vibrate and become more likely to fall apart.

The difference between the BatteryMinder and the Wizbang is the Wizbang, can be attached directly to a battery and works with just about any charging system, so you can pair it up with an existing MPPT or PWM controller as well as use it with a hookup-powered converter, like the Progressive Dynamics units that come with many newer trailers. The disadvantage of a Wizbang is it consumes power, whether or not your battery is being charged, so, unless you plug your trailer in or leave it out in the sun so the solar panels can keep your battery topped up, it'll gradually drain your battery down to nothing.

The BatteryMinder has the same kind of desulphator circuit, but with an integrated trickle charger, so it applies both high-frequency, sulphate-busting energy pulses and keeps your battery charged.

[Raz]

Peter, do you know what frequency they operate at? Raz

[peterh]

Raz, at about 2000mHz. If you're curious, there's a classic article written by a home-made solar advocate from 2000 that details how a desulphinator is built and how it operates.

http://www.alton-moore.net/graphics/desulfator.pdf

[Raz]

Originally Posted by peterh

Raz, at about 2000mHz. If you're curious, there's a classic article written by a home-made solar advocate from 2000 that details how a desulphinator is built and how it operates.

http://www.alton-moore.net/graphics/desulfator.pdf

Good article. The authors circuit is a simple current pulse generator running just above the AM radio band. How he determined that was the resonant frequency of the battery isn't made clear. Unfortunate. With his circuit, desulfation appears to be a very slow process. I wonder how much faster the commecial units are. Thanks for the link, Raz

[peterh]

"How he determined that was the resonant frequency of the battery isn't made clear."

Sigh, isn't that the truth. Worse (at least for me) is I keep finding that same 2000mHz figure, but can't find a definitive source showing how it is derived. Perhaps it was established by experimentation?

None of the commercial desulphinators work quickly, by the way. My guess is, if they worked quickly, they'd cause the battery to heat up.

[Raz]

Originally Posted by peterh

"How he determined that was the resonant frequency of the battery isn't made clear."

Sigh, isn't that the truth. Worse (at least for me) is I keep finding that same 2000mHz figure, but can't find a definitive source showing how it is derived. Perhaps it was established by experimentation?

None of the commercial desulphinators work quickly, by the way. My guess is, if they worked quickly, they'd cause the battery to heat up.

2 MHz. Not 2000 MHz. Two thousand MHz is microwaves i.e. Upper cell phone frequency I think. This gadget will produce harmonics all over the HF band. In fact you might need an FCC license to use it.

When I was an engineering student one of the most interesting things was that the same differential equations appear through out the disciplines. For example the equation for a spring and damper is the same for a series RLC circuit. Resonance is one solution of that equation. The battery resonance might be electrical or mechanical. I've added it to my Internet research list. . Raz

[MCDenny]

50 hours into our dry camping test, the battery meter reports 80 ah consumed, 71% state of charge. Water tank a little more than half full. So far so good.

Note 80 ah would indicate we should have a state of charge of 64%. I believe the meter is right, it is taking into account the peukert exponent for the battery (1.24). Since we are drawing the battery at much less than the C20 rate, the effective capacity is greater.

[multi-task]

Originally Posted by P. Raz

My PD 4045 has a similar function. I believe they increase the voltage to boil the electrolyte in an attempt to make it homogeneous, mimicking the mixing effect of a moving vehicle. I believe it is preventative and will not remove already existing crystals. Newer chargers are using high frequency pulsing to reverse sulphate crystals. If anyone knows the magnitude and frequency that is being used, I'd love to know. Raz

I bought a PulseTech 12v battery maintainer, it's spec's are as follows:

Desulfating Pulse Peak Amplitude: 2 Amps
Desulfating Pulse Frequency: 18kHz to 37kHz
Pulse Rate Time: 20mS at 2 second intervals

I bought it out of interest. The company seems pretty confident it works however I'm always skeptical. I haven't used it yet as I maintain my 6v batteries with a 6v BatteryTender in the winter months.

[Raz]

Originally Posted by multi-task

I bought a PulseTech 12v battery maintainer, it's spec's are as follows:

Desulfating Pulse Peak Amplitude: 2 Amps
Desulfating Pulse Frequency: 18kHz to 37kHz
Pulse Rate Time: 20mS at 2 second intervals

I bought it out of interest. The company seems pretty confident it works however I'm always skeptical. I haven't used it yet as I maintain my 6v batteries with a 6v BatteryTender in the winter months.

That's two orders of magnitude lower in frequency. Ultrasonic. That's what I was guessing i.e. Ultrasonic cleaners but the resonance idea has me curious. I'm going to chew on it. If it's electrical resonance I think I can measure it. Raz

[peterh]

"2 MHz. Not 2000 MHz."

Conversion error. My bad.

[MCDenny]

Originally Posted by MCDenny

50 hours into our dry camping test, the battery meter reports 80 ah consumed, 71% state of charge. Water tank a little more than half full. So far so good.

Note 80 ah would indicate we should have a state of charge of 64%. I believe the meter is right, it is taking into account the peukert exponent for the battery (1.24). Since we are drawing the battery at much less than the C20 rate, the effective capacity is greater.

A follow up to this after 68 hours, soc= 57%, 120 ah consumed. I found a discharge time calculator here http://planetcalc.com/2283/ that indicates the state of charge is being calculated as if the battery had a steady 2.8 amp drain (actual average consumption is 1.7 amps per hour). Anyway this calculator says my battery capacity at THIS 2.8a RATE is 305 amp hours - about 50% more than the C20 rate. How about that!

I've been checking the consumption every morning and evening and find it is steadily rising, from 1.1 ah/hour the first night to 2.0 ah/hour the third night. I believe this is due to ice buildup on the evaporator coils. It has been six days since it was last defrosted and it was pretty frosty. I just defrosted it again and will know by this evening if the power consumption has dropped back to the previous level.