Today my second watt meter arrived and I put that between the charge controller and the solar panel. Now I have two in use - the first goes between the charge controller and the load. Flipping the switches at 3pm to clear the data on both wattmeters should prove interesting. As I sit writing I have just a circulation fan blowing over my desk. The circulation fan is a 0.25A CPU fan. It makes a loud whirring noise but it’s not objectionable.
As you can see, with the two diagnostic watt meters in place, the wiring looks worse than ever. It’s going to be helpful at about 8pm to compare the figures. I’ll just compare amp hours but I have a feeling that it’s not going to match. I’m probably going to be putting more into the battery than I’m getting out due to internal leakage. I’m at this point trying to find a reason for the battery to be playing up rather than a reason to buy a new battery.
One of the problems about figures for batteries in the absence of a data sheet is that the only information is online. We all know exactly how wonderfully accurate the internet is, don’t we? I remember a cartoon of Little Johnny holding up a report card with a big red F on it, exclaiming “but I copied it exactly as it said on the internet”. I saw a very nice graph the other day that said AGM batteries are 100% charged at 13.8v. Today I found one that said 13v. Another the other day claimed temperature made a difference and that in low temperatures 14.3v was full and the hotter it got the lower the capacity. These sites are not forums nor other questionable sites but allegedly authoritative sites. With a variation like that, the fountains of blood from the average rock seem easier to capture than the truth.
Just as a little titbit, the power usage at 45 minutes was 0.184AH and the power from the panels was 0.204AH. The batteries were not quite full when I started operations. That’s 2.5 watt hours used and 2.7 watt hours in.
I did a little research about batteries and apparently there’s some kind of formula where one should not draw more than 1/8th of the battery power. Thus with a 35AH battery one should not draw more than 4.375A. My twin extraction fans use 3.74A between them. I’m comfortably under the C/8 figure. There’s another school of though that used C/20 which would be 1.75A which I’m well over. But there you go - a morass of different figures. At this point I’m not going to be conservative and pick the lower figure. I’m not going to run around screaming with my hands in the air either. I’m going to say that there are so many unverified figures that these have to be more of Little Johnny’s facts.
Looking into batteries, there seem to be a huge number of different types. AGM, Gel, FLD, Lithium and SLA. Lithium is just rohibitively expensive as it’s the trendiest. AGM seems pretty good but is unsupported by the vast majority of charge controllers. That just seems bizarre. Going further there is also ordinary, deep cycle and marine. This latter option is what I want to talk about today since the first are just different chemistries and thus pretty much like the choice between raspberry sorbet, cherry parfait and tiramisu.
An ordinary battery (usually FLA (flooded lead acid) is intended for starting cars etc and is not intended to go below 75% capacity. Below 75% and there’s a risk of damaging the battery. In a lawnmower size, these cost about $20. The deeper the discharge the shorter the life.
A deep cycle battery is intended to be charged slowly, discharged slowly and is supposed to last a good long time because all the articles say the plates are thicker. Without a data sheet on the Harbor Freight battery, I wonder whether the discharge rate is insanely low.
A marine battery marries the deep cycle with the FLA. It’s designed for use with trolling motors. I always thought trolling was going onto a White Supremacist forum and posting messages like “Hey Dude, I just did your wife and I’m black”. Apparently there are electric motors driving small boats. Who said the hobby fishing industry hadn’t tried to go green though they could get some exercise in by using their oars! Anyway, looking at the marine figures it seems at 5A draw one should get 7 hours out of a 35AH battery.
Now, let’s look at that figure - seven goes into 35 very nicely but brings the battery down to zero so the figure is theoretical rather than practical. I’m going to say that at 80% maximum draw from a marine or deep cycle battery, the lowest one should go is probably to 8ah or use a maximum of 27AH. At 5A that’s just over five hours, not seven. That’s the problem when Little Johnny writes out all these internet tables and figures.
Today I had been going to run my ventilation with a single fan just to see whether it would have taken 50 minutes to get to the same level it did yesterday. As my watt meter arrived, the plans changed and I decided to compare solar input versus power used. So, looking at the power usage I’m currently using just over 12 watts and generating just over 4 watts. Given that I have 95W of panels that has to have something to do with the battery’s absorption rate. I can honestly say I don’t truly understand that.
The fans both cut on automatically as intended a few minutes ago. That proves that the charge controller is way better than the previous controller. The fans brought power consumption up to 60W and yet solar generation or pull from the 95w of panels did not raise over the 4 or 5 watts. That’s just very strange, especially considering the sun is directly shining on at least 20w of panels with the others picking up reflected light.
In a few days my battery connecting plug arrives. I will try running the bus off a used lawnmower battery for comparison. I bet I’ll get better results! What I can’t fathom is why I’m not getting more power off the solar stuff at the moment.
Turning off all the major power using stuff - the fan, the phone charger etc and just leaving the 160ma door lock working, the figures read in favor of charging the battery. The input wattage rose to 5, the output down to 0.1w.
To be brutally honest, my original plan had been to power everything off D cells. It was pointed out to me that D cells at $1 a pair was a costly way of doing things. Somebody then talked me into solar. While I have had some success from solar, looking at the costs, it would have been way cheaper to have put a switch in the cockpit that allowed me to charge a house battery from the engine when the engine is running and to carry a $90 Harbor Freight generator. In terms of cost the switch is a negligible cost so say $20 max. Add the Harbor Freight Generator at $90 then add a 100AH battery at $100. Total cost $210. Instead I have spent:
A few days ago, in a review of one of the solar items I saw somebody had written that by the time all the needed components had been purchased, solar power was uneconomical. I think I agree at the moment with that argument. This is why when I was asked today about an inverter and a battery to power two 160watt fans I suggested that a $90 harbor freight generator be used.
If I was starting from scratch again, I’d still be extremely tempted by the false promises of solar power. I think though that the reality is that solar just isn’t ready for mainstream use. I’m certainly not findit it worthwhile at the moment. This could all be down to the battery though causing problems.
The crazy thing is that after having used 27.1 watt hours and generating just 11.9 watt hours, the battery is recorded as being at 100%. Something just does not seem quite right there. Where did the missing 15.2 watt hours come from? They have to have come from somewhere! Power does not miraculously appear. I shall have to see what happens next. This is more frustrating than gripping.
When the battery connector plug arrives, I’ll be able to dismount the current questionable battery and use a questionable lead-acid battery. That will, at least, have some known characteristics. I don’t actually know for certain exactly what this harbor freight battery really is.
One thing I have not done is to compare the two watt meters to see whether they both read the same. I’d totally forgotten about doing that! I could be going by swayed figures. Still, switching the battery out will be very interesting. If I charge the battery fully on a car charger, set the charge controller parameters and the time the system until it all cuts out from low voltage (having reached the cut off preset voltage) I’ll know how many AH I’ll have to play with. The I can let the solar system charge the battery and see how long that takes and how well the whole system works with a totally different battery chemistry.
I really feel I want a nice simple thing like the Harbor Freight battery being bad. Then I can just curse Harbor Freight and question the parentage of their Managing Director before going with a different solution. Nothing has ever been this simple and straightforward however.
As far as replacement batteries go...
A 35AH Deep Cycle SLA Duracell battery is $86 at BatteriesPlus.
A 35 AH Lawnmower FLD battery by an off brand is $21 from Walmart.
A 35AH Marine battery is $110 from Amazon.
I bought my Harbor Freight battery about a year ago. In fact, checking my blog it seems I mention at the end of August last year having bought it a “few weeks ago”. As it’s now July, the thing hasn’t even lasted a year if my analysis of it being a dead battery is accurate. Logically though - everything else in the system seems to work so logic dictates it’s more than likely to be the battery that’s bad. Wednesday will be the reckoning though as that’s when my connector arrives. I shall be able to disconnect my battery, connect a straight lead acid and try that as well as being able to take the AGM to some place like Batteries Plus or Autozone for testing.
One of the problems about figures for batteries in the absence of a data sheet is that the only information is online. We all know exactly how wonderfully accurate the internet is, don’t we? I remember a cartoon of Little Johnny holding up a report card with a big red F on it, exclaiming “but I copied it exactly as it said on the internet”. I saw a very nice graph the other day that said AGM batteries are 100% charged at 13.8v. Today I found one that said 13v. Another the other day claimed temperature made a difference and that in low temperatures 14.3v was full and the hotter it got the lower the capacity. These sites are not forums nor other questionable sites but allegedly authoritative sites. With a variation like that, the fountains of blood from the average rock seem easier to capture than the truth.
Just as a little titbit, the power usage at 45 minutes was 0.184AH and the power from the panels was 0.204AH. The batteries were not quite full when I started operations. That’s 2.5 watt hours used and 2.7 watt hours in.
I did a little research about batteries and apparently there’s some kind of formula where one should not draw more than 1/8th of the battery power. Thus with a 35AH battery one should not draw more than 4.375A. My twin extraction fans use 3.74A between them. I’m comfortably under the C/8 figure. There’s another school of though that used C/20 which would be 1.75A which I’m well over. But there you go - a morass of different figures. At this point I’m not going to be conservative and pick the lower figure. I’m not going to run around screaming with my hands in the air either. I’m going to say that there are so many unverified figures that these have to be more of Little Johnny’s facts.
Looking into batteries, there seem to be a huge number of different types. AGM, Gel, FLD, Lithium and SLA. Lithium is just rohibitively expensive as it’s the trendiest. AGM seems pretty good but is unsupported by the vast majority of charge controllers. That just seems bizarre. Going further there is also ordinary, deep cycle and marine. This latter option is what I want to talk about today since the first are just different chemistries and thus pretty much like the choice between raspberry sorbet, cherry parfait and tiramisu.
An ordinary battery (usually FLA (flooded lead acid) is intended for starting cars etc and is not intended to go below 75% capacity. Below 75% and there’s a risk of damaging the battery. In a lawnmower size, these cost about $20. The deeper the discharge the shorter the life.
A deep cycle battery is intended to be charged slowly, discharged slowly and is supposed to last a good long time because all the articles say the plates are thicker. Without a data sheet on the Harbor Freight battery, I wonder whether the discharge rate is insanely low.
A marine battery marries the deep cycle with the FLA. It’s designed for use with trolling motors. I always thought trolling was going onto a White Supremacist forum and posting messages like “Hey Dude, I just did your wife and I’m black”. Apparently there are electric motors driving small boats. Who said the hobby fishing industry hadn’t tried to go green though they could get some exercise in by using their oars! Anyway, looking at the marine figures it seems at 5A draw one should get 7 hours out of a 35AH battery.
Now, let’s look at that figure - seven goes into 35 very nicely but brings the battery down to zero so the figure is theoretical rather than practical. I’m going to say that at 80% maximum draw from a marine or deep cycle battery, the lowest one should go is probably to 8ah or use a maximum of 27AH. At 5A that’s just over five hours, not seven. That’s the problem when Little Johnny writes out all these internet tables and figures.
Today I had been going to run my ventilation with a single fan just to see whether it would have taken 50 minutes to get to the same level it did yesterday. As my watt meter arrived, the plans changed and I decided to compare solar input versus power used. So, looking at the power usage I’m currently using just over 12 watts and generating just over 4 watts. Given that I have 95W of panels that has to have something to do with the battery’s absorption rate. I can honestly say I don’t truly understand that.
The fans both cut on automatically as intended a few minutes ago. That proves that the charge controller is way better than the previous controller. The fans brought power consumption up to 60W and yet solar generation or pull from the 95w of panels did not raise over the 4 or 5 watts. That’s just very strange, especially considering the sun is directly shining on at least 20w of panels with the others picking up reflected light.
In a few days my battery connecting plug arrives. I will try running the bus off a used lawnmower battery for comparison. I bet I’ll get better results! What I can’t fathom is why I’m not getting more power off the solar stuff at the moment.
Turning off all the major power using stuff - the fan, the phone charger etc and just leaving the 160ma door lock working, the figures read in favor of charging the battery. The input wattage rose to 5, the output down to 0.1w.
To be brutally honest, my original plan had been to power everything off D cells. It was pointed out to me that D cells at $1 a pair was a costly way of doing things. Somebody then talked me into solar. While I have had some success from solar, looking at the costs, it would have been way cheaper to have put a switch in the cockpit that allowed me to charge a house battery from the engine when the engine is running and to carry a $90 Harbor Freight generator. In terms of cost the switch is a negligible cost so say $20 max. Add the Harbor Freight Generator at $90 then add a 100AH battery at $100. Total cost $210. Instead I have spent:
- $80 on charge controllers
- $160 on solar panels
- $55 on a Harbor Freight battery
For a grand total of $295 or $75 more than if I’d just used a generator. And the system still isn’t functioning as it should. $75 would have bought 30 gallons of gas. More than that, it would have brought me battery charging when it’s dark, stormy or rainy.
A few days ago, in a review of one of the solar items I saw somebody had written that by the time all the needed components had been purchased, solar power was uneconomical. I think I agree at the moment with that argument. This is why when I was asked today about an inverter and a battery to power two 160watt fans I suggested that a $90 harbor freight generator be used.
If I was starting from scratch again, I’d still be extremely tempted by the false promises of solar power. I think though that the reality is that solar just isn’t ready for mainstream use. I’m certainly not findit it worthwhile at the moment. This could all be down to the battery though causing problems.
The crazy thing is that after having used 27.1 watt hours and generating just 11.9 watt hours, the battery is recorded as being at 100%. Something just does not seem quite right there. Where did the missing 15.2 watt hours come from? They have to have come from somewhere! Power does not miraculously appear. I shall have to see what happens next. This is more frustrating than gripping.
When the battery connector plug arrives, I’ll be able to dismount the current questionable battery and use a questionable lead-acid battery. That will, at least, have some known characteristics. I don’t actually know for certain exactly what this harbor freight battery really is.
One thing I have not done is to compare the two watt meters to see whether they both read the same. I’d totally forgotten about doing that! I could be going by swayed figures. Still, switching the battery out will be very interesting. If I charge the battery fully on a car charger, set the charge controller parameters and the time the system until it all cuts out from low voltage (having reached the cut off preset voltage) I’ll know how many AH I’ll have to play with. The I can let the solar system charge the battery and see how long that takes and how well the whole system works with a totally different battery chemistry.
I really feel I want a nice simple thing like the Harbor Freight battery being bad. Then I can just curse Harbor Freight and question the parentage of their Managing Director before going with a different solution. Nothing has ever been this simple and straightforward however.
As far as replacement batteries go...
A 35AH Deep Cycle SLA Duracell battery is $86 at BatteriesPlus.
A 35 AH Lawnmower FLD battery by an off brand is $21 from Walmart.
A 35AH Marine battery is $110 from Amazon.
I bought my Harbor Freight battery about a year ago. In fact, checking my blog it seems I mention at the end of August last year having bought it a “few weeks ago”. As it’s now July, the thing hasn’t even lasted a year if my analysis of it being a dead battery is accurate. Logically though - everything else in the system seems to work so logic dictates it’s more than likely to be the battery that’s bad. Wednesday will be the reckoning though as that’s when my connector arrives. I shall be able to disconnect my battery, connect a straight lead acid and try that as well as being able to take the AGM to some place like Batteries Plus or Autozone for testing.
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