Allen Jackson

I've recently been getting BB submissions approved, and the way the rules are set up, I can't qualify for the entry "Sand" level badge in electricity, without submitting a "small DC solar system", because I can't do several things on the "Sand" list.

I have:

No lead acid batteries to maintain
No electric water heater or electric dryer
No place to set up a solar water pump
No use for a "Micro heat bubble" - I wear shorts/short sleeves, even in Chicago winters because I'm too warm...
No fans in bathrooms (in rented house, so adding them is questionable...)
& no extension cords needing repair

So, I'd come up short of 5 points without duplication, unless I submit a small DC solar system, even though I now have 27 out of 35 points to apply toward the "Straw" level...

Because of this & and the fact that everything I'd need to submit for this is sitting in the room with me, I'm going to stop adding features & post what I have (no rain in tomorrow's forecast, but expected to be cloudy all day), and hope I can get enough power from solar to make it worth dragging all this out into the back yard to take beautiful pictures of the assembly.  Wed and Thurs are options if the weather/solar aren't available & cooperative.

I don't know if I'll get the 2nd balancer installed prior to, but I figure I need to get past the sand and straw levels before I post my higher capacity "Charge and Carry" lithium power station, or I won't get full points for it.

Stay tuned!

Thanks - I'm not likely to ever work with lead acid batteries again, so anything on any list that requires such, is out of reach to me. Not that I can't or haven't, but rather I've transcended that technology, and I'm not going back.... Even the few that are still within my reach are sealed units that I couldn't add water to, or check their electrolyte if I wanted to.

I also wear shorts and short sleeves year round (even outdoors in the Chicago area), so I have no use for it micro-climate bubble - I'm usually looking for cooler areas... But reading it out loud made my wife laugh!

Yeah, the list is pretty short for me...

I'll try to vary the submissions as much as possible 🙂

Shawn Klassen-Koop wrote:electricity
instruction, regulation, insurance, safety, etc

...

straw badge

35 points required
Get at least 5 points from new items from the sand badge.
No more than 20 points of duplication allowed
Oddball points allowed

Please clarify

Does this mean 5 points from items on the sand list that we've never done before (if so, that list is too small...), or 5 new ones that may be duplication of ones we've already done, but different tasks, like installing a different outlet/light/switch, etc?

Mike Haasl wrote:This is a badge bit (BB) that is part of the PEP curriculum.  Completing this BB is part of getting the sand badge in Electricity.

In this Badge Bit, you will repair a lamp.

Lamps and their wiring vary greatly, just be safe when pursuing this BB

To complete this BB, the minimum requirements are:
  - repair a lamp
  - this is a true repair, not just replacing a light bulb

To show you've completed this Badge Bit, you must provide:
   - a before picture of the damage that is causing the lamp to not function
   - an after picture of the repaired part
   - an after picture of the lamp illuminated
   - OR post a 2 minute video of you fixing the lamp and it working

This is intended to be for the straw badge level, which requires 5 points from the sand badge list.

For this submission, I also replaced the housing and upgraded the incandescent lamps to LED on the driver's side of the car.
That housing was functioning, but it was very yellowed and crazed with age, so it was on the dim side.

In response to the request for proof of function/power, I submit pics from the job where this sub-panel is installed
(From the already approved BB installing a powerwall)

My powerwall BB

Everything in these pics are feeding from the sub-panel, as are the servers in the other room and the minisplit AC unit.

Update:  Apparently this model balancer has a shutoff voltage of 2.7 volts/cell, so it's claimed to be safe to leave on & connected to the battery all the time, although one is still free to replace the solder bridge with a switch.

If left on, it will keep the battery balanced all through the entire range of operation.

The built-in balancer is controlled by your BMS, and it will be shut off as appropriate, when appropriate, but balancers can be installed in parallel, and any additional ones need to have a power switch to turn them off when not actively charging the battery, or they will unnecessarily drain the battery.

I have a 5-amp balancer I bought when I was still trying to get the 40 amp BMS to work. I don't expect to want any other 12 Vdc system I could use this with, so I might as well use it on this one.

There's a blob of solder on the lower left corner area, with the word "RUN" stenciled above it. There are 2 pads below that the blob is bridging, and the blob should be replaced by a switch, so it can be turned on only when needed.

On the topic of the measured voltage when the balancer is off - is the balancer actually off, or did it just shut off charging?

I'm led to believe that these BMS units will always have some sensing that's active, so they can tell if a charger or a load is connected, so they can't just cut the connection entirely or it will require a mechanical switch to turn back on.

To that point, one could install a main battery switch on the negative terminal before anything else, and it would fully shut down the entire system, including the BMS, which might be suitable for longer-term storage... Otherwise the BMS will slowly drain the battery, but it's probably cheaper to just disconnect the battery terminal.

On a related note, if anyone installs any additional balances to their systems, MAKE SURE to also install a switch on them to disable the balancer during any long-term storage, or they'll probably kill the entire battery - use them when you need to, and then turn them off!

Don't sweat the "13.3 volts" part. That's normal, and something Andy at the Off-Grid Garage YouTube channel was trying to explain.




These cells are 3.2 volt cells. That makes the nominal voltage of the pack, 12.8 volts. If every cell were perfectly matched, you could theoretically charge the whole pack up to 14.6 volts, but it won't stay there, even if you just let the pack rest for a day without any use. The voltage will always drop off to the resting voltage, and it will STILL be fully charged. Trying to get more into it will only risk cell degradation and/or acceleration of aging.

This can be seen from the charge/discharge curves more clearly, but once the cells have absorbed all the energy they can hold, further charging will drive up the voltage, but it won't put significantly more available power into the cell. That's why he suggests only charging to 3.45 volts/cell, but stretching the absorb time out for an hour or so, contending that the result is a cell that's just as "full", but lives much longer.

The major case for charging to a higher voltage/cell, is the speed of charging, so if one is in a hurry or impatient, charge to 3.65 volts/cell, and they'll get to that same "fully charged" level faster, but they'll also degrade faster, and they'll still drop down to their resting voltage afterwards...

Oh, and congrats on your balancer knocking it out of the park!

Out of curiosity David, what if they aren't "lithium" batteries?