This is ongoing as parts are still arriving. Background: built my first LFP setup using 90ah "new" cells from eBay, K2 greens if you've been scoping listings this year, and found that they were from 2010 with one terribly out of whack cell. This setup served me well all summer long running a fridge and other camp gear, discharging ~30Ah daily and resupplying from 200w of roof rack mounted solar. Never struggled with fridge set to 36*F per compartment on 110*F days and my Victron BMV was set to 57ah capacity - about all I could draw and replenish while babying the weird cell.
This had limitations. DC-DC charging options were pretty much off the table. Using something like a Renogy DC-DC 20/40a unit would have rocked and likely destroyed my weird cell.. and that finally got me irritated enough to build this new setup. Everything is scaled for my personal uses - I camp a lot and my 300w PSW inverter has mainly been used for load testing the first (and now this) build. In short, I've embraced USB-PD, hacked USB-PD, and everything else I personally own is DC. The inverter still comes along for a friend with a plug-in air mattress.
Some of this stuff is being scavenged off of my outgoing pack, but here's the GEAR:
I'll be writing software to interact with Chinese Bluetooth BMS units (my trade - firmware, cross platform mobile development, a little microcontroller assembly, and specializing in Bluetooth LE communications) but until then I'm monitoring stuff at my leisure with a security camera, either the hobby charger or the RC cell monitor
Talk about an ammo can... I've already built a portable solar controller box in a pelican case knock-off that operates an exhaust fan when it's getting toasty - driven off of CC load output. That's a backup unit for ground deploy stuff, but I'll be using the same approach to heat the box for year-round charging in this setup. Lots of adhesive backed heat strips in a wide range of wattages, and how hard could it be to heat a near-sealed metal box? If I include the charge controller inside I'll cut out a window on the box behind where it mounts. If I have ANY issues at all with it getting too warm, I'll be able to use adhesive thermal paste to affix a low profile heat sink. Not too worried about it getting knocked off because while this setup will be somewhat portable, I have one primary expedition vehicle and the other is now reduced to abusing off road on day trips.
This can could easily fit a 24v 190ah setup if you put all your accessories above the cells as there's plenty of headroom. What I'll be doing is putting stuff above the cells on a platform and also filling the front half of the box with fuse block and panel mount connectors for in/out.
Cells will be sandwiched together using a large aluminum backing plate on one end, and threaded rod going out of the narrow side of the ammo can. This should keep things tight, and I'll run a strap over the cells to prevent vertical movement.
This warping has somewhat reduced as I've charged and discharged the cells, and that middle bus bar fits properly. Seller is sending some curved copper bus bars in the mail though which I may entertain using. They'll be clamped together soon enough, though... For the same price and 10ah less you can get CALB cells off Alibaba - that would have probably been the better choice but I had to know what was up with a blue wrap cell distributor that passed the sniff test. Plus, I bought maybe my 10th scratch ticket in my lifetime a few weeks ago and won $500 - covering the bulk of the new setup.
Initial charging on the iSDT Q6 Pro. If you have an extra $40 absolutely get the iCharger X6. It's a beast paired with a large PSU and has achieved balance to 1mV - quicker, too.
Stay tuned. I'll continue to update and take build pics.
This had limitations. DC-DC charging options were pretty much off the table. Using something like a Renogy DC-DC 20/40a unit would have rocked and likely destroyed my weird cell.. and that finally got me irritated enough to build this new setup. Everything is scaled for my personal uses - I camp a lot and my 300w PSW inverter has mainly been used for load testing the first (and now this) build. In short, I've embraced USB-PD, hacked USB-PD, and everything else I personally own is DC. The inverter still comes along for a friend with a plug-in air mattress.
Some of this stuff is being scavenged off of my outgoing pack, but here's the GEAR:
- 190ah blue-wrap Aliexpress LFP cells that have given 150ah without a sweat and are likely as advertised.
- 2 x 100w Renogy mono panels in series, custom tilting setup on a Yakima Megawarrior rack
- Victron SmartSolar 75/15
- Victron BMV712
- Victron 65a BatteryProtect
- Victron TR-Smart DC-DC 30a charger (or two in parallel) the second they release 'em
- Deligreen 6a/10a active equalizer - probably won't necessitate or incorporate, save for whatever old pack gets repurposed in to
- iCharger X6
- Meanwell 600w 120/240v -> 24v PSU
- Anderson PowerPoles for everything including panel mount housings. The oddball XT60 here and there but I'll more likely build adapter cables to standardize on PP
- BlueSea gear
- Various RC cell meters, current meters, capacity meters, stuff that won't make it in to the final pack but really helps with getting this built
- An enormous 30mm ammo can (not 30cal) to house everything
I'll be writing software to interact with Chinese Bluetooth BMS units (my trade - firmware, cross platform mobile development, a little microcontroller assembly, and specializing in Bluetooth LE communications) but until then I'm monitoring stuff at my leisure with a security camera, either the hobby charger or the RC cell monitor
Talk about an ammo can... I've already built a portable solar controller box in a pelican case knock-off that operates an exhaust fan when it's getting toasty - driven off of CC load output. That's a backup unit for ground deploy stuff, but I'll be using the same approach to heat the box for year-round charging in this setup. Lots of adhesive backed heat strips in a wide range of wattages, and how hard could it be to heat a near-sealed metal box? If I include the charge controller inside I'll cut out a window on the box behind where it mounts. If I have ANY issues at all with it getting too warm, I'll be able to use adhesive thermal paste to affix a low profile heat sink. Not too worried about it getting knocked off because while this setup will be somewhat portable, I have one primary expedition vehicle and the other is now reduced to abusing off road on day trips.
This can could easily fit a 24v 190ah setup if you put all your accessories above the cells as there's plenty of headroom. What I'll be doing is putting stuff above the cells on a platform and also filling the front half of the box with fuse block and panel mount connectors for in/out.
Cells will be sandwiched together using a large aluminum backing plate on one end, and threaded rod going out of the narrow side of the ammo can. This should keep things tight, and I'll run a strap over the cells to prevent vertical movement.
This warping has somewhat reduced as I've charged and discharged the cells, and that middle bus bar fits properly. Seller is sending some curved copper bus bars in the mail though which I may entertain using. They'll be clamped together soon enough, though... For the same price and 10ah less you can get CALB cells off Alibaba - that would have probably been the better choice but I had to know what was up with a blue wrap cell distributor that passed the sniff test. Plus, I bought maybe my 10th scratch ticket in my lifetime a few weeks ago and won $500 - covering the bulk of the new setup.
Initial charging on the iSDT Q6 Pro. If you have an extra $40 absolutely get the iCharger X6. It's a beast paired with a large PSU and has achieved balance to 1mV - quicker, too.
Stay tuned. I'll continue to update and take build pics.