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superdiy

Battery cooler box

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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

01_frame.jpg02_castor.jpg03_compressor.jpg04_controls_top.jpg05_controls_front.jpg06_controls_side.jpg07_controls_back.jpg08_temp_sensor.jpg09_heat_exchanger.jpg10_batteries_top.jpg11_batteries_side.jpg12_vent_outlet.jpg13_side.jpg14_front.jpg15_box_temp.jpg

 

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WOW - AWESOME! 

And it looks like it is bought.

Respect.

Mine are in a wooden box on wheels. Temp is acceptable for the hot braai room.

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On 1/13/2017 at 8:57 PM, PaulF007 said:

Just out of interest how much power does the cooler use?

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.

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That's not bad to keep them nice and cool.

Just one more , do you have a fail safe / alarm for IF the compressor were to klonk out? If you can keep the outside temp out then the inside temp can also not get out and this could be a problem if there is no natural ventilation and the compressor doesn't word. 

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1 minute ago, PaulF007 said:

That's not bad to keep them nice and cool.

Just one more , do you have a fail safe / alarm for IF the compressor were to klonk out? If you can keep the outside temp out then the inside temp can also not get out and this could be a problem if there is no natural ventilation and the compressor doesn't word. 

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.

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On 1/13/2017 at 3:27 PM, superdiy said:

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

01_frame.jpg02_castor.jpg03_compressor.jpg04_controls_top.jpg05_controls_front.jpg06_controls_side.jpg07_controls_back.jpg08_temp_sensor.jpg09_heat_exchanger.jpg10_batteries_top.jpg11_batteries_side.jpg12_vent_outlet.jpg13_side.jpg14_front.jpg15_box_temp.jpg

 

nice! how will you heat-up the batteries, if needed? OR does not get that cold at your place?

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22 minutes ago, SilverNodashi said:

nice! how will you heat-up the batteries, if needed? OR does not get that cold at your place?

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

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Come to think of it, I was talking to a guy who knows a guy (we were standing in my garage and he was looking at all my blue stuff).... you know how it goes... this guy he knows installs PV setups in remote places for telecoms, some of those places being very cold. Mostly blue stuff of course. They get a call, it is not working, so out they go to this remote site. They get there, everything is working just fine, but the batteries are frozen so there is no capacity :-)

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1 hour ago, plonkster said:

Come to think of it, I was talking to a guy who knows a guy (we were standing in my garage and he was looking at all my blue stuff).... you know how it goes... this guy he knows installs PV setups in remote places for telecoms, some of those places being very cold. Mostly blue stuff of course. They get a call, it is not working, so out they go to this remote site. They get there, everything is working just fine, but the batteries are frozen so there is no capacity :-)

Gel batteries don't like the cold at all. Even the 2V flooded batteries seem to "gel up" in cold conditions. 

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Just now, SilverNodashi said:

Gel batteries don't like the cold at all. Even the 2V flooded batteries seem to "gel up" in cold conditions. 

True, but does it shorten their life? I'm sure extreme cold will shorten it it quite quickly because of mechanical reasons (!), but as I understand it the whole temperature thing has to do with how fast the chemical reactions goes at a certain temperature. Higher temperature, more useful capacity, faster reactions, shorter life. Lower temperature, less useful capacity (as in you might not be able to do the same peak currents for the same length of time), slower reactions, and above freezing point I would also expect a longer life.

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2 minutes ago, SilverNodashi said:

That, to me, is too cold. I would prefer to run / store / keep batteries between 20 and 25 degrees

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.

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31 minutes ago, plonkster said:

True, but does it shorten their life? I'm sure extreme cold will shorten it it quite quickly because of mechanical reasons (!), but as I understand it the whole temperature thing has to do with how fast the chemical reactions goes at a certain temperature. Higher temperature, more useful capacity, faster reactions, shorter life. Lower temperature, less useful capacity (as in you might not be able to do the same peak currents for the same length of time), slower reactions, and above freezing point I would also expect a longer life.

I don't know if it shortens battery life, but I know one client's equipment didn't work very well during the winter due to this issue. He added some blankets and insulation material to the builder and it was fixed. 

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Hi Superdiy, I am really impressed. Well done! It really looks like an off the shelf unit.

I was wondering a lot about heat and cold and the effect on batteries. Here in Bloem, I think the cold might be worst than the heat.

On the other hand, what about car batteries. I have seen a lot of cars with frozen radiators etc. which you just could'nt start, but the battery was still working??

I am actually speaking to a company in India who claims to have a proper solar aircon available, with cooling and heating functions. A small 3000 - 5000 btu unit would be the ideal thing, low consumption  and effective - I don't know but maybe we would be able to get a small unit for the guys with small solar rooms and at an affordable price!

 

If unsuccessful, I will have to ask you to help out on this one, as you definitely have the capabilities!

Cheers

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I agree that the hotter a battery gets the shorter it's life as the internal chemical reactions increase in speed. However as long as they are temperature compensated while charging by voltage adjustment that is linked to their temp as per the Trojan leaflet, that largely prevents them having their lifespan shortened.

Sent from my SM-G920F using Tapatalk

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8 hours ago, Chris Rossouw said:

On the other hand, what about car batteries. I have seen a lot of cars with frozen radiators etc. which you just could'nt start, but the battery was still working??

I am actually speaking to a company in India who claims to have a proper solar aircon available, with cooling and heating functions. A small 3000 - 5000 btu unit would be the ideal thing, low consumption  and effective - I don't know but maybe we would be able to get a small unit for the guys with small solar rooms and at an affordable price!

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.

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1 hour ago, Gerald_db said:

I agree that the hotter a battery gets the shorter it's life as the internal chemical reactions increase in speed. However as long as they are temperature compensated while charging by voltage adjustment that is linked to their temp as per the Trojan leaflet, that largely prevents them having their lifespan shortened.

 

1 hour ago, Gerald_db said:

25°C is merely the point at which no temp/voltage adjustment is required. Increase below and decrease above.

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.

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On 1/13/2017 at 3:27 PM, superdiy said:

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.

superdiy, very impressive battery cooler box. This is something you can be proud of.

With the internal fan running, the Hydrogen and Hydrogen Sulfide will mix and be all over the show, irrespective of their specific gravity, while the fan is running. I assume the white pipe on the side with the black rubber connectors are the air pump pipes to ventilate the box. I cannot see the outlet, but assume it it is probably the same size. In my opinion, this is totally inadequate to properly ventilate the box. If you have a concentration of 4-46% Hydrogen Sulfide in the box, all you need is a spark and it will set off the bomb. 

I would make two holes the size of that internal fan behind the evaporator and put spacers (6-10mm) in between the evaporator and the side of the box. Any air flowing into the box will then flow over the evaporator and be cooled if the compressor is running. Then fit that fan you have blowing onto the evaporator on the opposite side of the box where you have your air inlets and let it extract the air out of the box. Air will thus enter the box, flow in over the evaporator, then flow over the batteries and out on the other side. 

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7 minutes ago, Don said:

With the internal fan running, the Hydrogen and Hydrogen Sulfide will mix and be all over the show, irrespective of their specific gravity, while the fan is running. I assume the white pipe on the side with the black rubber connectors are the air pump pipes to ventilate the box. I cannot see the outlet, but assume it it is probably the same size. In my opinion, this is totally inadequate to properly ventilate the box. If you have a concentration of 4-46% Hydrogen Sulfide in the box, all you need is a spark and it will set off the bomb. 

I would make two holes the size of that internal fan behind the evaporator and put spacers (6-10mm) in between the evaporator and the side of the box. Any air flowing into the box will then flow over the evaporator and be cooled if the compressor is running. Then fit that fan you have blowing onto the evaporator on the opposite side of the box where you have your air inlets and let it extract the air out of the box. Air will thus enter the box, flow in over the evaporator, then flow over the batteries and out on the other side. 

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.

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Yes, Hydrogen is generated when the batteries are being charged and Hydrogen Sulfide when the batteries are over charged. I just think that the airflow produced by the mattress pump is insufficient to properly ventilate the box, maybe I am wrong. 

53 minutes ago, superdiy said:

I have a Hydrogen sensor and will install it at some point in time - it is still on the to-do list.

I do the same, fit the safety devices last when I have nothing else to do, while we should actually fit them first. 

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