superdiy

I would seriously consider the T105RE's instead of the regular T105's. Just saying...

Thanks Don

Those are stock standard computer fans. Cut off the corners / mounting tabs and glue it into a piece of PVC pipe... You don't need a vent cap to block the reverse flow of cold air in Cape Town.

DIY, without the smoke please.

Thanks for this, should not be very difficult to implement.

OK, so what does 1 flush mean? Does it mean that if I have 100 litres of air in a container I have to pump 100 litres of air into the container? Obviously the whole 100 litres will not be replaced, because the old and the new will mix inside, but some of it will be replaced. Is that technically a flush?

I don't know how knowledgeable you are with the chemistry, but maybe you can assist. If you look at it volume wise, the total volume of air in the box is not that much; 1100mm x 500mm x 100mm above the batteries and maybe about 10 litres all around, say 20 litres worst case, which equates to a total of about 75 litres. 4% of that is 3 litres - so it would be dangerous if 3 or more litres of hydrogen is present inside the box. The timer is currently set to turn the pump on for 1 minute daily. I'll try to measure how much air is pumped in that 1 minute, but I guess it might be in the region of 20+ litres. What I won't know is: how much hydrogen is generated during a charge cycle how much hydrogen will be removed during a pump-action of say 1 minute I'll measure the amount of air "moved" in 1 minute in the mean time.

I take note. If I have vents the size of the circulation fan, it will totally defeat the purpose and it will be impossible to keep anything inside cool enough and the compressor will have to run 24/7. The white pipe and black nylon fittings you refer to are the top and bottom outlets - the inlet is on the opposite side and the pump I'm using is an inflatable mattress pump which forces the air into the box at intervals set on the digital timer. I have a Hydrogen sensor and will install it at some point in time - it is still on the to-do list. Currently the batteries don't work hard - they are only charged when their voltage drops below 51.2 V and the self-discharge rate is quite low and apparently Hydrogen is only generated while the batteries are charged.

I think we have covered this enough now, if it is one serial string, as in this case, corrosion, thin interlinks, bad connections etc. etc. will not affect only certain cells in the string. The same amount of current will flow through everything in the string, so if there is a bad connection somewhere and less current flows, that same lower amount of current will flow everywhere in the serial string. He either has a bad cell or two or they are just not balanced (charged to the same state)

From the Trojan T105RE's datasheet: Chemical reactions internal to the battery are driven by voltage and temperature. The higher the battery temperature, the faster chemical reactions will occur. While higher temperatures can provide improved discharge performance the increased rate of chemical reactions will result in a corresponding loss of battery life. As a rule of thumb, for every 10°C increase in temperature the reaction rate doubles. Thus, a month of operation at 35°C is equivalent in battery life to two months at 25°C. Heat is an enemy of all lead acid batteries, FLA, AGM and gel alike and even small increases in temperature will have a major influence on battery life.

Hi Chris I've heard about others and have first hand experience with car batteries failing on cold mornings when you want to start the car - the day before it was still fine, but all of the sudden it is dead. Maybe it is just coincidence. The solar/battery room aircon definitely sounds ideal; keep us informed.

Have you googled yet, I've already posted a link earlier and there are other products available as well.

Like @Chris Hobson said, one cell in a series string won't charge differently because of a bad connection or alike. If the cells were in parallel, a bad connection etc. will affect the cell with the bad connection and it will be charged and discharged differently to the other parallel cells. Same rule applies to parallel batteries and battery strings - a battery is in essence just a string of cells.

2 Sets of interconnects will still not make any difference on one string of batteries/cells. The interconnects in parallel between 2 terminals just halves the resistance or doubles the current rating of it, but since it is one string, if you have a problem with one of the interconnects it will affect the current flowing through the whole string. Even if you have one bad cell, it will also affect the current flow through the whole string. Bottom line is that they are not charged equally - nothing new - happens to the best of them. You'll have to get them all charged to the same level and the best way to achieve that is by means of some form of balancer which will either take away from the fuller cells or take away from the fuller cells and add to the emptier cells.

That is only when I leave the garage door open on really cold days, otherwise during winter it is more in the region of 16 - 20°C. I'll monitor it later in the year - for now we only have high temperatures, lots of fires and no rain.

With one string of batteries, a bad connection somewhere will affect everything in the string, not only specific batteries / cells. Dissimilar interconnects, dissimilar cable lengths etc. etc will also not have any effect on one string. On parallel strings it is a different story though.

Does not get too cold here, lowest I've seen was about 11 or 12°C.

Your batteries need balancing. I highly doubt that the fuses are problematic, since the readings are acceptable when the battery voltage is lower, but goes more out when the voltage rises - that is a typical indication of unbalanced cells. As per the suggestions above you should invest in some sort of balancer, the HA02s should work and should definitely make a difference if you pair the batteries, but with 2V cells the best option is probably to balance each cell. There are many options available and a quick google might help. One of the suppliers, with a few different product options, is Balancell.

At the moment I don't have a compressor fail safe / alarm - it is definitely something to keep in mind and it is on the to-do list.

Very neat installation. Just check your roof, looks like 2 panels have already been stolen.

The compressor uses about 90W, the fans consume about 3-4W and the electonics about 2W. The compressor runs approximately 5-10 minutes approximately once an hour when the room temperature is in the lower 30's.

My wife and I had to move ours - about a meter up onto a terrace and then about 5 meters further - luckily she is used to do physical work. She also helped when we did the slab for the tanks - to be honest, I think she might have worked harder than me that day. It was a really hot Saturday and we started mixing by about 15:00 and I finished floating the last concrete by about 19:00 - we mixed by hand, just the two of us.

The 2500l tanks were the biggest I could fit onto my tiny property - the base of the 2500l tank has a diameter or 1.42 m and the next size up, the 5000l has a base diameter of 1.82 m iirc. I almost ordered 2 of those when I realised that I will not be able to get them from the road to where the needed to be installed. I'm also catching the washing machine's water, but into a combination of buckets and containers and then we carry it to the garden - even the kids eagerly help with that. I am still trying to figure out a way to get it to the garden by means of a pipe, but the problem is that the pipe will always cross doorways or walkways if I want to use a gravity flow option... I also have a bucket in the shower, had 2, but the wife complained - she is OK with 1.

Another recent project of mine - rainwater harvesting. The 2 x 2500l tanks were installed on 22 Dec 2016 and we got some rain on the 23rd, but only enough to fill about 300mm on both tanks - not sure how much that would be in liters, but no rain since. I've also bought a JoJo pump kit which still needs to be installed. The water will be used to irrigate my small garden, a lawn of about 20m2 and maybe to fill up the toilets after flushing.

One of my recent projects, the battery cooler box. The temperature in my garage easily reaches 35°C in summer - on average it is in the lower 30's. According to the T105RE's datasheet, any lead-acid battery should be kept at 25°C or lower and an increase of 10°C halves the expected life of the batteries. Therefor I decided to keep them cool... The box is constructed from 50mm coldroom panels and is attached to a plywood base fitted onto an angle-iron frame with castors. The inside of the box is watertight and coated with stone-chip - the stuff used to coat the chassis of trailers and caravans. The compressor assembly is from an old ice-machine The temperature is controlled by a temperature controller bought on ebay - it is set to turn the compressor on at 25.2°C and off at 24.8°C The internal circulation fan is on when the compressor is on and switches off approximately 20 minutes after the compressor has cycled off. The air pump is controlled by a digital programmable timer and used to force air into the box and to force any gas build-up out of the box - the outlet still needs to be connected to a hose to take the gasses outside. Hydrogen, which is highly explosive, is released during charging and Hydrogen Sulfide, which is extremely poisonous, might be released during over-charging. Hydrogen is less dense than air and Hydrogen Sulfide is more dense than air and therefor the need for two gas outlets, one at the top and one at the bottom of the box. The control panel contains a battery fuse The shunt of the Vicron battery monitor is mounted inside the control-section of the box and the RJ12 connection is extended to the rear panel A 40mm drain connection is mounted on the side of the box in case the box needs to be flushed. The drain connection is kept closed by a lever valve. Swimming pool hoses fit tightly into the 40mm drain connection and can be connected to take the water etc. to the outside of the building, if needed. An Anderson connector for the battery connection is mounted on the rear panel