Camping/emergency battery pack

ptchernegovski

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Nov 5, 2019
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I am harvesting more cells when I get time, and now starting to test with an Opus BT-C3100.I want to move onto the planning/design phase, but need some thoughts/help with the plans and ideas I'm having for it.

My plan is to build a pack for camping and emergencies in a wheeled, waterproof plastic case. Would like the designto be modular, and expandable, so as I harvest more cells, I can expand the overall pack. Want it 7S for 24V. Was planning 10P per individual pack, as would be about 500Wh per individual pack, but it would depend on the size of the case. Would like to try get at least 2kWh overall.

How hard would it be to build modular 7S packs, so that as I get enough cells for another individualpack, I can add as another parallel to the existing setup? I do want these to be safe as well, so they are not moving about in the case, preferably held securely in place, and not at risk of shorting out with something else in the case.

Would I be best to run 1 BMS per individualpack as built, or get something so that I can have 1 BMS overall, and plug it into each individual pack as I build them? I am aware of batrium, but it is too expensive IMO for what I am building.

For power, I plan on having 100-150W solar panel, running through an MPT-7210A. And be able to add more panels if needs be. But also chargeable from an adapter from the wall.

I would like to mount the inverterinside the case too, and waterproof outlets on the side of the case, or would this be pushing it too far for heat or safety?

I am happy to fabricate stuff, and buy a small 3D printer if need to make some plastic parts.
 
As long as the 7s pack is the same voltage as the other 7s packs you can add them as you complete them. I do 4s pack and just add another pack or remove one as needed. Just make sure all the balance wires are connected between the packs so the batteries equalize. I use the xt60 connectors to connect my packs.

As far as bms, I recommend the chargery bms8, its what I use. Its the only bms I use with solar and lithium. Everything is programmable and it even has audio alarms to warn you of problems. Cost is around 95 dollars on ebay. You only need one bms, since all the packs will be connected together, it will be just one big 7s battery.

The inverter needs ventilation, you will probably need an exhaust fan if you install inside the case.
 
I built a 3000w DIY solar generator in a cooler w/wheels (pretty heavy)and it was a bit more work than I imagined as I included both solar panel and 120v charging options.

Here's a couple of videos on a DIY buildfrom @jehugarciathat I liked because it ticks off a good list of things to think about and some specific equipment that he used - such as a combined charger/inverter (whereas mine was seperate units for this).

DIY Inergy Kodiak Solar Generator -https://youtu.be/ZDSOIN0egMo

DIY Solar Generator still better than NEW Kodiak -https://youtu.be/C8ANNr_KEIE
 
OffGridInTheCity said:
I built a 3000w DIY solar generator in a cooler w/wheels (pretty heavy)and it was a bit more work than I imagined as I included both solar panel and 120v charging options.

Here's a couple of videos on a DIY buildfrom @jehugarciathat I liked because it ticks off a good list of things to think about and some specific equipment that he used - such as a combined charger/inverter (whereas mine was seperate units for this).

DIY Inergy Kodiak Solar Generator -https://youtu.be/ZDSOIN0egMo

DIY Solar Generator still better than NEW Kodiak -https://youtu.be/C8ANNr_KEIE

What did you go with for the solar side?
 
gpn said:
What did you go with for the solar side?

Used an MPT-7210a since its a (rare) boost charge controller that can take a wide range of DC input and is 100% customize able output charging voltage range. Itslimited to 10a output - so 10 * 24v = 240watt max charging for 1 and its cheap. But that worked great with my 2 x 100watt solar panel accessory.

Here's an example link on amazon and there are many youtubes on it
https://www.amazon.com/Docooler®-Ba...S1VJA4MNX73&psc=1&refRID=6HX8GQST9S1VJA4MNX73



The thread motivated me to take a picture. You can see the green MPT-7210a (top left) with a door (top left) to push out the Anderson connector for solar panel input and also the general 'messiness' of the wiring and cramming in all the associated components such as the 200a battery minder (to make sure inverter turns off within battery voltage range) and 120v power supply (top right) and heat monitor to activate fans and fusing and... That's why I admired the youtube build I listed above.

image_ssjswv.jpg
 
jonyjoe505 said:
As long as the 7s pack is the same voltage as the other 7s packs you can add them as you complete them. I do 4s pack and just add another pack or remove one as needed. Just make sure all the balance wires are connected between the packs so the batteries equalize. I use the xt60 connectors to connect my packs.

As far as bms, I recommend the chargery bms8, its what I use. Its the only bms I use with solar and lithium. Everything is programmable and it even has audio alarms to warn you of problems. Cost is around 95 dollars on ebay. You only need one bms, since all the packs will be connected together, it will be just one big 7s battery.

The inverter needs ventilation, you will probably need an exhaust fan if you install inside the case.

Yes, will make sure the voltages are the same when add new packs. Will not be keeping it fully charged when not in use, as it will be an as needed case. The XT60 connectors seem to be a good standard to use, will go with them, thanks.

The Chargery looks good, I like the look of the BMS8T 100A. The issue for me is adding another individual pack in, and connecting to the existing BMS. Idea I have is either ribbon cable, with plugs that when add a new individual pack, it can have the BMS leads to the same style plug, in male/female, and just plug straight in. Or a board that could have several of the same plugs, that each individual pack BMS lead goes back to, then the board goes to the actual BMS. If I make sense here. I can drawer pictures to show what I mean. Other issue is my planned panels do 12V, and pack plan is 24V, that's why want to go with MPT-7210A for charger, it can step up. Do you need to use the chargery for charging, or can it be run as just BMS?

I can easily hook up a fan or 2 for ventilation, and run it to a heat sensor, thanks.


OffGridInTheCity said:
I built a 3000w DIY solar generator in a cooler w/wheels (pretty heavy)and it was a bit more work than I imagined as I included both solar panel and 120v charging options.

Here's a couple of videos on a DIY buildfrom @jehugarciathat I liked because it ticks off a good list of things to think about and some specific equipment that he used - such as a combined charger/inverter (whereas mine was seperate units for this).

DIY Inergy Kodiak Solar Generator -https://youtu.be/ZDSOIN0egMo

DIY Solar Generator still better than NEW Kodiak -https://youtu.be/C8ANNr_KEIE

Your build looks cool, thanks for sharing. Is there a thread on this build, I can't see any in your threads? My thought is run the MPT-7210A like you have, but for wall charging have an external charger that can plug in to charge it at home, and not need to mount it inside the case.

Thanks for the links, will give them a watch today.

What are you using for heat monitoring? And what is the display on the front? I wouldn't mind having a display somewhere, that gave info on the overall state of the pack, power draw, etc
 
gpn said:
Nice! Are you just using amazon 100w panels?

Using a pair ofRenogy 100w that I had left over from my 1st 'foray' into solar - but it doesn't matter. They key thing is that a single MPT-7210a can only output 10a ... at 24v that's 240watts. So it would be a waist to use 3 x 100w panels at full tilt (i.e. 300watts) as the MPT-7210a would overload or simply not accept the extra 60 watts.


ptchernegovski said:
[quote pid='57174' dateline='1574265344']
I built a 3000w DIY solar generator in a cooler w/wheels (pretty heavy)and it was a bit more work than I imagined as I included both solar panel and 120v charging options.

Here's a couple of videos on a DIY buildfrom @jehugarciathat I liked because it ticks off a good list of things to think about and some specific equipment that he used - such as a combined charger/inverter (whereas mine was seperate units for this).

DIY Inergy Kodiak Solar Generator -https://youtu.be/ZDSOIN0egMo

DIY Solar Generator still better than NEW Kodiak -https://youtu.be/C8ANNr_KEIE

Your build looks cool, thanks for sharing. Is there a thread on this build, I can't see any in your threads? My thought is run the MPT-7210A like you have, but for wall charging have an external charger that can plug in to charge it at home, and not need to mount it inside the case.

Thanks for the links, will give them a watch today.

What are you using for heat monitoring? And what is the display on the front? I wouldn't mind having a display somewhere, that gave info on the overall state of the pack, power draw, etc
[/quote]
>Is there a thread on this build,
Thanks for thumbs up but no, just a side project as I was first getting into solar.

>What are you using for heat monitoring?
Inkbird Dual Stage DV 12V Digital Temperature Controller
https://www.amazon.com/gp/product/B019I3...UTF8&psc=1

>And what is the display on the front?
Simple voltmeter (in the USB / 12v section). The middle square is the Temperature Controller (above).

I see that @Jehu used YUNAWU Digital Multimeter DC 0-90V 0-100A Voltmeter Ammeter Power Monitor W Hall Sensor https://www.amazon.com/gp/product/B07J5D5N18
which has way higher 'cool factor' than simple voltage.
 
OffGridInTheCity said:
Thanks for thumbs up butno, just a side project as I was first getting into solar.

>What are you using for heat monitoring?
Inkbird Dual Stage DV 12V Digital Temperature Controller
https://www.amazon.com/gp/product/B019I3YCFS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1


>And what is the display on the front?
Simple voltmeter (in the USB / 12v section). The middle square is the Temperature Controller (above).

I see that @Jehu usedYUNAWU Digital Multimeter DC 0-90V 0-100A Voltmeter Ammeter Power Monitor W Hall Sensorhttps://www.amazon.com/gp/product/B07J5D5N18which has way higher 'cool factor' than simple voltage.

Damn to thread, cool side project though.

I recognise that temp controller, use it for beer fermentation temp control. I'm guessing you just have cooling output to the fan in the side?

The multimeter does have a "Cool factor", but also looks like it does do a lot via the control, and has a lot of information I would be after. Thanks for the link.

Have watched the videos you linked earlier now that had some time, some helpful, and good information in there thanks. I think I need to work out next how to build the 7S packs for the case, like what to mount them in, and wire them up.
 
ptchernegovski said:
Does anyone have an idea for the modular cell pack design I could do?

After reading some other posts, and modular tool cases, I am thinking of going with this Tactix case for the cells and charger: https://www.bunnings.co.nz/tactix-562-x-432-x-635mm-rolling-chest-toolbox_p05821075

Than having this case on top for inverter, BMS, and outputs: https://www.bunnings.co.nz/tactix-modular-deep-tool-chest_p06120421

I designed my cooler to use the same packs I have in my home powerwall - so I could interchange them. Don't know if you have a home powerwallbut maybe find a design so they can interchange? Just a thought.
 
OffGridInTheCity said:
I designed my cooler to use the same packs I have in my home powerwall - so I could interchange them. Don't know if you have a home powerwallbut maybe find a design so they can interchange? Just a thought.

Only just saw your reply.

No home powerwall as I rent, and don't want to upset the landlord.

Is it best to design a pack to the case, and 3D print it, or buy some of the holders there already are?
 
ptchernegovski said:
OffGridInTheCity said:
I designed my cooler to use the same packs I have in my home powerwall - so I could interchange them. Don't know if you have a home powerwallbut maybe find a design so they can interchange? Just a thought.

Only just saw your reply.

No home powerwall as I rent, and don't want to upset the landlord.

Is it best to design a pack to the case, and 3D print it, or buy some of the holders there already are?
Its all up to you. In my case, I made a PVC pipe framework/box to keep the batteries 1" off the bottom (what if someone spilled a drink in there)and make a 'top' I could put a piece of wood to mount the inverter etc. This all 'wasted' some space. Here examples from @jehugarcia

I like this one in particular as a complete package and very compact with a pretty complete parts list: DIY Inergy Kodiak Solar Generator
(these flat cells are available from ebay.com alarmhookup - https://www.ebay.com/itm/42-SPIM08H...210597?hash=item2f266e11a5:g:MAYAAOSwBwNcv2G8)

Here's one with 18650s: 600,000mAh DIY Power Pack build [size=small]

Part of my trouble was just getting 'off the dime' and doing something as there are many choices :)
 
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