I’d been using inaccurate button volt meters and portable volt meters when I realised my watt meter has a digital volt meter accurate to two decimal places. Anyway, that measured 14.37 volts. I turned the panels off and waited for 30 minutes for the battery to settle down. So, after 30 minutes the battery voltage read 13.33v which is an unusual voltage for any form of lead acid battery. I’d have expected 12.6 through 12.8.
After leaving the solar panels hooked up for another hour or so, I disconnected the panels and set the extraction fans and one light going. The current draw was reported as 58W and 4.2A which would be about right. The figures varied about 5% despite there being no solar power coming in. After 8 minutes the watt meter was reporting 12.31v.
At this point I’d like to remind everybody that a 35AH battery used down to 40% should be at 11.9V and should have used 21AH with 14AH remaining. When the charge controller starts pulsing the power I will have no idea what my watt meter will have recorded as current starvation will have robbed it of its records.
After 20 minutes the fan speed dropped and the lights started flashing. Battery voltage was recorded as 10.9v. So, lacking a comprehensive record, a quick calculation of 58W over 20 minutes yields about 20 watt hours or 1.4AH. Doing the math, that battery is not 35AH but 3.5AH. It’s not even the 15AH that some people accuse it of. That’s hopeless!
I now have a starting point for the rest of my mission. I have to dump that battery. Now I know where the problem is. A cheap-ass Harbor Freight battery. The coupon made it worth buying but I still spent $50 on it. I can undoubtedly get a better bargain from pretty much anybody. No wonder I found my battery was getting drained from charging my tablet!
One dollar - that’s all the Harbor Freight battery should cost. In fact, given how singularly poor the one I have is, perhaps instead of paying for it, customers should be paid to take it - straight down to the dump!
Even using the C8 calculation where current draw should be no more than 1/8th of the battery capacity, 35 ÷ 8 = 4.375, I’m still slightly under the (recommended) maximum current draw for battery longevity. There is just no possible way that this battery could have been anything but bad when I bought it. When I bought it, I checked the package and the battery carefully. It did not appear to have been used nor even out of its box. This battery must have been a lemon waiting for some fool to pick it up!
So, where now? I’ll have to head down to one of the battery suppliers - perhaps Interstate - to buy a real battery rather than this Harbor Freight battery. Now in Harbor Freights defense - most of the stuff I’ve had from them has been pretty decent. Their grit blower tool needed a little adjustment. Their angle grinders don’t last too long and can be faulty from the start. Their batteries are so-so but the rest sees to be pretty much OK. They do sell too much of the garbage LED flashlight stuff though.
After leaving the solar panels hooked up for another hour or so, I disconnected the panels and set the extraction fans and one light going. The current draw was reported as 58W and 4.2A which would be about right. The figures varied about 5% despite there being no solar power coming in. After 8 minutes the watt meter was reporting 12.31v.
At this point I’d like to remind everybody that a 35AH battery used down to 40% should be at 11.9V and should have used 21AH with 14AH remaining. When the charge controller starts pulsing the power I will have no idea what my watt meter will have recorded as current starvation will have robbed it of its records.
After 20 minutes the fan speed dropped and the lights started flashing. Battery voltage was recorded as 10.9v. So, lacking a comprehensive record, a quick calculation of 58W over 20 minutes yields about 20 watt hours or 1.4AH. Doing the math, that battery is not 35AH but 3.5AH. It’s not even the 15AH that some people accuse it of. That’s hopeless!
I now have a starting point for the rest of my mission. I have to dump that battery. Now I know where the problem is. A cheap-ass Harbor Freight battery. The coupon made it worth buying but I still spent $50 on it. I can undoubtedly get a better bargain from pretty much anybody. No wonder I found my battery was getting drained from charging my tablet!
Even using the C8 calculation where current draw should be no more than 1/8th of the battery capacity, 35 ÷ 8 = 4.375, I’m still slightly under the (recommended) maximum current draw for battery longevity. There is just no possible way that this battery could have been anything but bad when I bought it. When I bought it, I checked the package and the battery carefully. It did not appear to have been used nor even out of its box. This battery must have been a lemon waiting for some fool to pick it up!
So, where now? I’ll have to head down to one of the battery suppliers - perhaps Interstate - to buy a real battery rather than this Harbor Freight battery. Now in Harbor Freights defense - most of the stuff I’ve had from them has been pretty decent. Their grit blower tool needed a little adjustment. Their angle grinders don’t last too long and can be faulty from the start. Their batteries are so-so but the rest sees to be pretty much OK. They do sell too much of the garbage LED flashlight stuff though.
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