48v Ammo Box battery

pierre

Somewhere down South
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Dec 21, 2019
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808
Shown here is a 48v 100aH battery built into an ammo box ( ZA version ) The build consists of 16 x A grade LiFePO4 battery cells controlled by a 200A JBD BMS.
Only problem at the moment is that I do not have a 48v mains charger , so I charged the battery in 4 x 12v groups with a Victron Blue Smart charger. I am waiting for the delivery of 2 x 48v MPPTs SCC from China, to be connected to a 1680 watt solar array ( 4 x 420w Canadian Solar ) and then to evaluate the complete system. I would like to use Victron MPPTs but I want to first test the Chinese units.
At the moment I feed the energy from the PV directly into the household geyser ( hot water cylinder ) but without MPPT as yet. Lots of potential energy wasted when geyser is on temperature. So the idea is to add the MPPSs and 48v battery to store the potential energy. As 48v is a bit low for the geyser I will add a boost converter ( yes , conversion efficiency and all that blah blah , but hey , it is free energy and I can live with 83% conversion eff ) to boost to 120v at about 10 amps.
Later on I will add an inverter/charger to the mix and power appliances in the home.
Will post updates as I go along.
 

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Short_Shot

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If I read that correctly you're trying to boost 48v to 120v?

Why do you need 120v dc? Hopefully you're aware that 120vac and 120vdc are *very* different things.

Are you using this dc voltage to power the heater?
 

pierre

Somewhere down South
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808
Aware. There is a microprocessor module connected to the geyser. The geyser element is rated at 230v AC 3kW . The thermostat contacts are only used to send a signal to the processor , therefor no 'current' is switched. The resitive heating element does not care if it gets AC or DC.
Did a trial run with a boost converter connected to the 48v battery and all is fine.
 

Short_Shot

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Life is good then.

Send it.

I'm curious to have more/better lit pictures of the battery assembly.
 

pierre

Somewhere down South
Joined
Dec 21, 2019
Messages
808
Life is good then.

Send it.

I'm curious to have more/better lit pictures of the battery assembly.
Will retake the pics and post asap. Must find the best lit place in the house ;) The darn thing is so heavy to lug around from the garage - weighs about 35kg.
 

pierre

Somewhere down South
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Dec 21, 2019
Messages
808
If I read that correctly you're trying to boost 48v to 120v?

Why do you need 120v dc? Hopefully you're aware that 120vac and 120vdc are *very* different things.

Are you using this dc voltage to power the heater?
The reason for wanting to use DC is to be independent of the power utility. Our electricity tariffs are increasing to such an extent due to mismanagement / corruption and theft at our national power utility.
 

pierre

Somewhere down South
Joined
Dec 21, 2019
Messages
808
Just to clarify : these ammo boxes may not be the traditional ammo box known to most. These boxes have detachable lids ( 4 x clips ) and are stackable. In ZA these are used extensively for storage in 4x4, offroad vehicles, RVs and for camping etc. These are cheap at about $US15.
a Few more photos attached as well. There is a 100amp inline fuse for protection but I would still like to add a 1 or 2 pole disconnect / isolator.
The output on the side of the case is by means of 2 x 10mm threaded posts with a 250amp rating.
 

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Short_Shot

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The reason for wanting to use DC is to be independent of the power utility. Our electricity tariffs are increasing to such an extent due to mismanagement / corruption and theft at our national power utility.
I mean... that's not a reason to use dc.

You can use ac for that reason too, just as long as it's not coming from the greedy utility company lol
 

Short_Shot

Photon Sorcerer
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Just to clarify : these ammo boxes may not be the traditional ammo box known to most. These boxes have detachable lids ( 4 x clips ) and are stackable. In ZA these are used extensively for storage in 4x4, offroad vehicles, RVs and for camping etc. These are cheap at about $US15.
a Few more photos attached as well. There is a 100amp inline fuse for protection but I would still like to add a 1 or 2 pole disconnect / isolator.
The output on the side of the case is by means of 2 x 10mm threaded posts with a 250amp rating.
Don't suppose you can get a link together for those?
 

pierre

Somewhere down South
Joined
Dec 21, 2019
Messages
808
I mean... that's not a reason to use dc.

You can use ac for that reason too, just as long as it's not coming from the greedy utility company lol
I agree but the initial planning did not include an inverter and still does not at this stage.
 

pierre

Somewhere down South
Joined
Dec 21, 2019
Messages
808

pierre

Somewhere down South
Joined
Dec 21, 2019
Messages
808
Further to my 48v battery and putting DC energy into my water heater , I have now added 2 x PowMr 48v 60 amp MPPTs sourced from China at $90 each. I am a Victron fan by heart but at this price ( about 1/4 of Victron equivalent ) I am willing to give them a go. The max PV input voltage is limited to 150v , some 50v lower than my 4 panel string , so now have 2 x series strings each with their own MPPT , charging the battery. So far so good and harvested quite a bit of energy today. Tomorrow I will hook up a 48 to 120v boost converter and feed that energy into the 150lt water heater. Will keep updates coming on the performance of the system.
 

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pierre

Somewhere down South
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808
So, the MPPTs worked out fine - good product for the price , but the boost converters did not . Claiming 900w at 54v to 120v boost never materialised. The unit started off at around 7 amps but this soon tapered off to about 1amp due to the current limiting as a result of inadequate cooling from the tiny built-in fan. Once again a Chinese product with overrated specifications. Ah well , just pumping energy from the PV panels directly into the water heater element via the micro controller. This summer I will not even need any AC grid energy for the water heater , saving about 30% on my electricity bill.
 
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