$140 400wh LiFePO4 DIY

[hour]

Sorry about that, not my intention at all, just nit picking really, and clarifying where noobs might make assumptions or get the wrong idea.

Nice idea for a DIY boom box! Been lusting after a KEF LS50 Wireless system would lend itself to something like that for mobile use.

And yes, using such small cells for a 30-50Ah LFP pack is fine, so much easier to source than the prismatics. Crazy how limited distribution is for those in NA, just hate dealing with direct from China in case warranty service is needed, shipping back costs too much.

Too true, look at any Ali* product review and discover 90% are from across the pond. 75% are in Russia. It’s tempting, too tempting... i’ve found quite a few prismatic cell listings with Russian gibberjabber translated in to a solid evaluation of the product and a youtube link of their findings.

 

[deeznutz206]

Wow I did the same thing as you. Used K2 26650 LiFePO4 cells @ 3200 mAh each and made a 4S12P (approximately 461WH) configuration battery pack. Been using it for about 3 weeks now and works like a charm.

 

[Happy Joe]

Very briefly thought about making my own Li-pack; however, paranoia about fire and explosion (especially with "cheap"/unknown cells) has thus far stopped me.
https://batteryuniversity.com/index.php/learn/article/bu_304b_making_lithium_ion_safe

...Think that I will let others ride the bleeding edge until its proven safe... at least until the current battery needs replacement.

My small 30 -35 AH 12V tent deep discharge, sealed, lead acid battery is just fine until something better (including safer and easier to charge) comes along... I dont't see unwillingness to maintain a battery as a reason to change; but that is likely just me. The tent battery powers, and is maintained by this UPS in the off season, and would likely cost less than 75 dollars to replace..

Enjoy!

 

[hour]

Wow I did the same thing as you. Used K2 26650 LiFePO4 cells @ 3200 mAh each and made a 4S12P (approximately 461WH) configuration battery pack. Been using it for about 3 weeks now and works like a charm.

Awesome, hope my experience mirrors yours. Did you use batteryblocs too, or what?

Very briefly thought about making my own Li-pack; however, paranoia about fire and explosion (especially with "cheap"/unknown cells) has thus far stopped me.
https://batteryuniversity.com/index.php/learn/article/bu_304b_making_lithium_ion_safe

...Think that I will let others ride the bleeding edge until its proven safe... at least until the current battery needs replacement.

My small 30 -35 AH 12V tent deep discharge, sealed, lead acid battery is just fine until something better (including safer and easier to charge) comes along... I dont't see unwillingness to maintain a battery as a reason to change; but that is likely just me. The tent battery powers, and is maintained by this UPS in the off season, and would likely cost less than 75 dollars to replace..

Enjoy!

These are lithium iron phosphate batteries so safer than what you may be thinking. And i’m hoping to find them to be easier to charge, or faster at least. Solar + large battery charger run on the generator for an hour could probably get me close to topped off after a high drain evening

 

[luthj]

What logic does the balance board use? balance current? I am assuming its a bypass type? I may have missed it, but how are you handling disconnect (high/low voltage)?

 

[Happy Joe]

These are lithium iron phosphate batteries so safer than what you may be thinking. And i’m hoping to find them to be easier to charge, or faster at least. Solar + large battery charger run on the generator for an hour could probably get me close to topped off after a high drain evening

Yep; I see that and realize that LiFePo is safer than other chemistries, however, if making one, myself I would still go with a good Battery Management System, add on, as safety suspenders (so to speak) -a personal decision; much cheaper than replacing burned up vehicle and or camping gear. (or having to deal with the authorities & lawyers after a forest fire).
My biggest concern is the need for a (relatively) highly controlled charger (added complexity and more equipment to carry) as opposed to just hooking to the vehicle alternator (which can work in a pinch for lead acid) or trickle charging the existing lead acid with the small solar array (when camping for longer than a week. If I used more electricity I would likely consider this sort of project more strongly.

I will give the tech a few years so prices can come down, and better cells and BMS become available cheaper (unless the current battery dies this year or next... possible as it is 5 or 6 years old; at that point it will be decision time replace or upgrade)...

Enjoy!

 

[john61ct]

Do not expect raw cell prices for LFP to fall.

BMS yes, better quality and user adjustability will get cheaper.

Ideally more open-source hardware. . .