Small project build

CrankyCoder

CrankyCoder

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Mar 11, 2017
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Ok. So I figure this is the best place to ask some questions on my little project.

I have a small 12v utility pump. It is 12v 10amp max. This is hooked to my rain barrels. I want to power it via my 18650's. I currently have 289 tested cells 1900mah+. I should hit the 320 goal with in the week.

My initial though is to make a 4s80p battery. I have done some testing already with a 4s5p small pack. I use this wire as fuse wire.

https://smile.amazon.com/gp/product/B01BDB8240/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

I have a small 12v solar panel setup to charge, again tested on my small pack.


So. Here are my questions.

1. will this fuse wire work ok?
2. Should I charge the whole thing as a 12v pack? or should I look into trying to charge each 3.7v "cell" separately?
3. for the power requirements for this pump, it looks like I need to run some pretty heavy duty awg wire. i am about 15-18 ft from pump to battery. thoughts?

That's all for now. But Im sure i will have more as I progress.

Thanks!
 
1. I would say its to thick. I would go for 30-35AWG but it depends on the current you plan to use from it. But since its laptop cells no more than 1-2A and then 30-35AWG is more than fine.
2. Charge it as a whole pack. Just make sure you have individual cell montoring or something protecting it if something happens. Preferable programable charger so you can set voltages
3. 10A is alot over some distance. But since you have 4s it doesnt make that much of an issue if you have some voltage drop since it may be to high otherwise. So frankly 1.5-2mm2 wire could work. I have not calculated the voltage drop nor the efficency loss in that wire so that could be wise to do.

Generally in my area for AC we say 1.5mm2 is good for 10A in houses and 2.5mm2 is for 16A. It does not translate 100% to DC but should work. And in those areas a couple of % loss make no issue :)
 
daromer said:
1. I would say its to thick. I would go for 30-35AWG but it depends on the current you plan to use from it. But since its laptop cells no more than 1-2A and then 30-35AWG is more than fine.
2. Charge it as a whole pack. Just make sure you have individual cell montoring or something protecting it if something happens. Preferable programable charger so you can set voltages
3. 10A is alot over some distance. But since you have 4s it doesnt make that much of an issue if you have some voltage drop since it may be to high otherwise. So frankly 1.5-2mm2 wire could work. I have not calculated the voltage drop nor the efficency loss in that wire so that could be wise to do.

Generally in my area for AC we say 1.5mm2 is good for 10A in houses and 2.5mm2 is for 16A. It does not translate 100% to DC but should work. And in those areas a couple of % loss make no issue :)
Click to expand...

1. roger, im on it!
2. any recommendations on a programmable charger? With the programmable chargers, if a cell gets over charged or discharged, does it stop charging everything since it's charging the full 12v pack? Or would doing with a balanced charger be better in this case? or just monitor and keeps tabs? I already have a mysensors node near the battery to monitor my water level, so i could put some voltage sensors on the cells and setup rules in my HA system
3. do you think 12v is the way to go based on the number of cells I have? or should I consider going to 24/48v? that would require new solar charger/panels and probably gets pricey. I like the 12v because it's still decent power but common enough to play with (small inverters, panels, ect)

Thanks!

Toochi84 said:
Average Joe tested my 40awg, kicks @~4amp. With some hilarity at the end of the vid.

Click to expand...

I have watched so many videos on this stuff I forget what/who I have watched :)

Joe is funny. I like his stuff. Especially when the cat kept jumping on his drawer trays
 
40Awg can be to thin if you ask me and will just create alot of resistance. But depends on application.

2. Any MPPT charger for solar kind of... That can be programmed. If you have your own monitoring you can just add so it disconects charging if something goes south. Thats the easiest way to solve it.

3. Depends on what more you going to run? If only 12V then go for that. Else you need hefty DC/DC converters to be able to run whats on 12V. Though note that some gear may not like 4S. its quite high. Also many chargers will not go up to 4S so its a bit strange voltage wise. Perhaps 7s and 24V is easier but you need to take a look at what you going to run. Create a matrix. With all gear you have and then its max and min voltages. If it will work with 4s then go with it. Else you need to look ad 7s or other and then go with DC/DC converters.
 
daromer said:
40Awg can be to thin if you ask me and will just create alot of resistance. But depends on application.

2. Any MPPT charger for solar kind of... That can be programmed. If you have your own monitoring you can just add so it disconects charging if something goes south. Thats the easiest way to solve it.

3. Depends on what more you going to run? If only 12V then go for that. Else you need hefty DC/DC converters to be able to run whats on 12V. Though note that some gear may not like 4S. its quite high. Also many chargers will not go up to 4S so its a bit strange voltage wise. Perhaps 7s and 24V is easier but you need to take a look at what you going to run. Create a matrix. With all gear you have and then its max and min voltages. If it will work with 4s then go with it. Else you need to look ad 7s or other and then go with DC/DC converters.
Click to expand...

So far allof my stuff is <=12v so I think it will be ok. This pump is really the only higher current load. Everything else like the solenoids I have converted to latching pulse solenoids so current is pulse and done.

My current charger doesn't charge it all the way to the top, but the max/min seem to be within the safety zone for the 18650's so I have been pretty happy with it.

Here is a good question though. Because of the distance for the 10amp I think I am going to have to put the batteries on the back porch (not crazy about that idea). So the question is, any recommendations on wall mounting a 4s80p setup on a back porch in florida. Heat and Humidity :)
 
Yep, Fl boy here too ;)

Outside is fine, just put them in an enclosure to keep the wet off of them. If you are soldering your cells together, what I would do is then take hot glue and cover your ends of the cells and many of your connections that aren't shrink wrapped. This will drastically minimize what our humidity will do to the connections.
But, you should be fine if you put the packs inside an enclosure, though.


Side Note: So where abouts in Fl are you located? I'm near Gainesville.
 
Korishan said:
Yep, Fl boy here too ;)

Outside is fine, just put them in an enclosure to keep the wet off of them. If you are soldering your cells together, what I would do is then take hot glue and cover your ends of the cells and many of your connections that aren't shrink wrapped. This will drastically minimize what our humidity will do to the connections.
But, you should be fine if you put the packs inside an enclosure, though.


Side Note: So where abouts in Fl are you located? I'm near Gainesville.
Click to expand...

nice. I like the hot glue idea. Where in fl? :)
 
*points to the bottom line of my previous post* ;)
 
you might be able to just make one, or could even use a tote, that'd be fine. You could make it out of wood, plastic, foam. anything really. You just want to keep direct moisture from getting on them.
Someone else actually made a container out of a weaved basket
 
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