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Cheapest DIY 12V 100Ah LiFePO4 battery build? 60Ah?

vts1029: Thanks for the info. Why a bus bar rather than cables connecting +/+ and -/- for 2 batteries connected in parallel? Does this have to do with balancing input and output to batteries? If so, I think I can accommodate that by connecting to + on one battery and - on the other.

I think I probably need to do some more research regarding cabling for BMS equipped batteries. I thought I could connect 2 same manufacturer and size batteries together pretty much like I would 2 lead acid or AGM 12v batteries of same manufacturer and size. Apparently, I'm missing something regarding these 2 12v LiFePo4 BMS equipped batteries? So, the Battery Management System (BMS) for an individual battery may have a conflict when 2 of the same batteries are connected together in series? Is there anything on the spec sheet that would tell me about this and if so what? I don't feel like I should have to contact a manufacturer every time I want to connect 2 identical 12v batteries together in series, but if so, it is another reason to use a 12v system versus a 24v system. Thanks again. Please advise.

The spade terminals are small on these batteries. a buss bar just makes it easier to connect together. In the end it really doesn't matter how you physically wire them provided they are sized correctly for the loads applied.

I do not know when it comes to the BMS. I have seen some sellers say that this battery can or can not be connected in series. An AGM battery is vastly different than one of these Lithium. If you really want a 24v system I would purchase individual cells and get an 8s BMS. Or just connect them and see if they let out the smoke. :ROFLMAO:
 
The spade terminals are small on these batteries. a buss bar just makes it easier to connect together. In the end it really doesn't matter how you physically wire them provided they are sized correctly for the loads applied.

I do not know when it comes to the BMS. I have seen some sellers say that this battery can or can not be connected in series. An AGM battery is vastly different than one of these Lithium. If you really want a 24v system I would purchase individual cells and get an 8s BMS. Or just connect them and see if they let out the smoke. :ROFLMAO:

Thanks. That makes sense! Now I can see creating some sort of mounting system for a Bus Bar and other components as I expand my electric generation and storage management system. I may decide to do that now rather than waiting until the next phase of my phased build project.

The idea of building my own 24v system is a very good one, however I'm not yet at that level of personal competency at this point. Maybe the next iteration! I guess for now I'll have to just do a little more research regarding series connection before I try the 24v with these batteries. Thanks again! This should get me started.
 
I just bought the following on Amazon as a proof-of-concept, I will report back later this week :)

I'm hoping the C rating is a typo? I am a relative newbie (my EE degree is very rusty) but here's what the data sheet shows, on a supposedly 16Ah battery:
  • Charger Current 10A
  • Max Charge Current 40A
  • Discharge Current 42A
  • Max Continuous Current 42A
  • Max Pulse Current 80A
My system will NOT have a permanently installed inverter or any individual load over 20A. Also, building a parallel system with 3-6 batteries should spread charge/discharge load...?


Yes, I really want to like the Jackery, but the problem for me is limited charge and discharge rates on the external DC ports. My ham radios can draw up to 15A on transmit, and most "generators" only have 10A cigarette lighter sockets. Additionally they charge from DC super slow!


Yes! The mobile radios I use are VHF/UHF local coverage, the same Motorola XPR4550 radios used in commercial fleet vehicles. They require a 12-36" antenna mounted somewhere on the exterior of the vehicle, and are single DIN sized just like a car's head unit. They draw ~1A on receive and 7-8A on transmit, and often times I'll have two running. I also have a Yaesu FT-891 HF (shortwave) radio which requires a much larger antenna, often hung from a tree. This draws ~1A on receive and 15A peak on transmit.

The van is a Ram Promaster City, the cargo version of a Fiat Doblo "people carrier". There are no seats in back, instead I've built a futon lengthways. It's quite comfortable to hang out in the back and play radio while camping, then put away the radios and pull out the futon for bed. My only real limitation to "operating mobile" thus far has been power while stationary, which is why I am here :)
 
As an experiment I purchased two of the Miady 12VDC 16AH LifePo4 batteries and 2 amp lithium charger in June and have been using them connected in parallel all summer running a 100 WATT ICOM 7300 or Kenwood 520 tranciever with tube finals. The Icom 7300 draws about 18 amps during CW transmit and 10-16 amps during SSB transmit operation. The 520 draws more as it has 2 x 6146B transmit tubes and the HV section need to be on during an on air conversation. I have been impressed on the Miady voltage/current performance as compared to the same test with two 14AH AGM ATV batteries and a 100AH deep cycle which have a tendency to fall off in voltage/current over time. Yesterday I order another 5 of the 16AH batteries and plan to parallel 6 or 7 of the Miady 16AH batteries to a common bus connection in a group 31 battery box enclosure with Anderson SB50 connectors and use as a power source for my drift boat's 55 pound thrust trolling motor which draws approximately 40 Amps at peak power draw. If successful as a trolling motor battery I will then test using a camp trailer that has two group 24 Interstate lead acid deep cycle batteries. I will report my findings back to this thread.
 
So they have them back in stock or listed. I was going to buy more but when I looked last they were not listing the 16ah ones. I took mine apart to fit into a pelican like case.
 
I have 2 of the 16AH running in a plano box. Nice setup for what it is. Still need to find a better charger for it at low amps. While building it I remembered I despise spade terminals.....

I also placed an order for an 80AH 4S pack for 157 shipped.
https://www.aliexpress.com/item/4001268403083.html

Seems to be the cheapest I've seen. I wanted a battery for the truck to run a 12V cooler. This should put battery+BMS <200 or so which is a good price point for 80AH.
 
The 16 AH battery has been relisted on Amazon for $49.99. Still a good value for a new 16 AH battery and has a 18 month warranty.
I'm glad it's performing well for folks, and that it's back in stock. Unfortunately I needed to finish my van build when it was sold out, so I ended up with a 70Ah AGM RV battery from the local auto parts store. It's not as slick as lithium but it's been meeting my needs well for two 2m/70cm ham mobile radios, 150w inverter, and lights. No issue with voltage drop, stays above 12.0v, but I do not discharge below 50%.
 
As an experiment I purchased two of the Miady 12VDC 16AH LifePo4 batteries and 2 amp lithium charger in June and have been using them connected in parallel all summer running a 100 WATT ICOM 7300 or Kenwood 520 tranciever with tube finals. The Icom 7300 draws about 18 amps during CW transmit and 10-16 amps during SSB transmit operation. The 520 draws more as it has 2 x 6146B transmit tubes and the HV section need to be on during an on air conversation. I have been impressed on the Miady voltage/current performance as compared to the same test with two 14AH AGM ATV batteries and a 100AH deep cycle which have a tendency to fall off in voltage/current over time. Yesterday I order another 5 of the 16AH batteries and plan to parallel 6 or 7 of the Miady 16AH batteries to a common bus connection in a group 31 battery box enclosure with Anderson SB50 connectors and use as a power source for my drift boat's 55 pound thrust trolling motor which draws approximately 40 Amps at peak power draw. If successful as a trolling motor battery I will then test using a camp trailer that has two group 24 Interstate lead acid deep cycle batteries. I will report my findings back to this thread.
Update: The home brew 96AH battery pack consisting of six x 16AH Miady lifepo4 batteries wired in parallel continues to run very strong as a 55 pound thrust trolling motor battery. I now have about 10 charge cycles on the battery. The first time out I ran the trolling motor wide open for an hour drawing about 45AH. I inspected the battery pack for any signs of wiring or heating issues...no problems found. I fished as normal the rest of the day with variable speeds from minimal to full throttle using the battery for two days of mixed slow/fast trolling fishing before recharging.

Battery operation was excellent as compared to my 10 month old Interstate group 24 lead acid deep cycle battery. Typically after a full day the the Interstate has been drained to 50% and I am unable to run full throttle on the trolling motor as it will cutout due to low voltage...not so with the Lifepo4 battery after two days of operation. The trolling motor ran strong as the voltage drop during the lifepo4 discharge is minimal.

I am currently charging with a 3 Amp standard lead acid Deltran Battery Tender Charger and plan to purchase a 10A rated lifepo4 charger to get the maximum AH out of the battery pack.

Temp Construction:
I ended up purchasing a Flambeau 18" dry box to house the 6 batteries and 6 1/4"spade fuse holders with 4" 12AWG legs, 6 x 15A spade fuses. There is room for two additional batteries if ever needed for a a total of 128AH capacity.

I made six 8" 12AWG ground leads with a 1/4" female spade connector on one end and 1/4" diameter stud ring crimp on the other. I added female spade and ring crimp connectors to the fuses/pigtails. I purchased two brass 1/4 diameter threaded stud bolts and nuts. I connected all positive fused leads from spade connectors on the batteries to the positive brass stud bolt. Fuses are left out until grounds leads were connected. I tested all positive leads prior to installing the 15 amp fuses. The positive and negative studs where wrapped with electrical tape. I use a SMH SY175 Series 4 AWG 175A breakaway DC power connector pigtail with 60 amp breaker for connection with my trolling motor and other 12VDC devices. There is a SAE fuse connector cable for connection to the battery charger. There are 4 of the 16AH batteries in the bottom of the box and two on top. I used foam to pack around the batteries for cushioning during transport. The entire 96AH power box weighs 28.5 pounds. I plan to reroute the charging and power connectors/60A breaker through the box lid and will also add 15/30/45 amp Anderson powerwerx connections in the future. Future repackaging may include adding two 8AH or 16 AH batteries and adding ground and positive brass/copper bus rails for battery connections.
 

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I just bought the following on Amazon as a proof-of-concept, I will report back later this week :)

I'm hoping the C rating is a typo? I am a relative newbie (my EE degree is very rusty) but here's what the data sheet shows, on a supposedly 16Ah battery:
  • Charger Current 10A
  • Max Charge Current 40A
  • Discharge Current 42A
  • Max Continuous Current 42A
  • Max Pulse Current 80A
My system will NOT have a permanently installed inverter or any individual load over 20A. Also, building a parallel system with 3-6 batteries should spread charge/discharge load...?


Yes, I really want to like the Jackery, but the problem for me is limited charge and discharge rates on the external DC ports. My ham radios can draw up to 15A on transmit, and most "generators" only have 10A cigarette lighter sockets. Additionally they charge from DC super slow!


Yes! The mobile radios I use are VHF/UHF local coverage, the same Motorola XPR4550 radios used in commercial fleet vehicles. They require a 12-36" antenna mounted somewhere on the exterior of the vehicle, and are single DIN sized just like a car's head unit. They draw ~1A on receive and 7-8A on transmit, and often times I'll have two running. I also have a Yaesu FT-891 HF (shortwave) radio which requires a much larger antenna, often hung from a tree. This draws ~1A on receive and 15A peak on transmit.

The van is a Ram Promaster City, the cargo version of a Fiat Doblo "people carrier". There are no seats in back, instead I've built a futon lengthways. It's quite comfortable to hang out in the back and play radio while camping, then put away the radios and pull out the futon for bed. My only real limitation to "operating mobile" thus far has been power while stationary, which is why I am here :)
I too ordered 4 of these Miady 16AH for battery box projects - then found they have a 36AH for $99.99, had to buy one of those of course, will see how it is.
Trying to fit about that many AH into smallest box possible, so when they arrive I'll go box searching.

How is that 5.5amp charger working for you?
 
I just bought the following on Amazon as a proof-of-concept, I will report back later this week :)

I'm hoping the C rating is a typo? I am a relative newbie (my EE degree is very rusty) but here's what the data sheet shows, on a supposedly 16Ah battery:
  • Charger Current 10A
  • Max Charge Current 40A
  • Discharge Current 42A
  • Max Continuous Current 42A
  • Max Pulse Current 80A
My system will NOT have a permanently installed inverter or any individual load over 20A. Also, building a parallel system with 3-6 batteries should spread charge/discharge load...?


Yes, I really want to like the Jackery, but the problem for me is limited charge and discharge rates on the external DC ports. My ham radios can draw up to 15A on transmit, and most "generators" only have 10A cigarette lighter sockets. Additionally they charge from DC super slow!


Yes! The mobile radios I use are VHF/UHF local coverage, the same Motorola XPR4550 radios used in commercial fleet vehicles. They require a 12-36" antenna mounted somewhere on the exterior of the vehicle, and are single DIN sized just like a car's head unit. They draw ~1A on receive and 7-8A on transmit, and often times I'll have two running. I also have a Yaesu FT-891 HF (shortwave) radio which requires a much larger antenna, often hung from a tree. This draws ~1A on receive and 15A peak on transmit.

The van is a Ram Promaster City, the cargo version of a Fiat Doblo "people carrier". There are no seats in back, instead I've built a futon lengthways. It's quite comfortable to hang out in the back and play radio while camping, then put away the radios and pull out the futon for bed. My only real limitation to "operating mobile" thus far has been power while stationary, which is why I am here :)
I am using two 12VDC 8AH Miady lifepo4 batteries in parallel to run my Icom 7300. I run 100w PEP when runnin SSB and dial it back to 50w when operating CW. I can get three 2-3 hour evenings of mixed SSB/CW operation on a charge. The lifepo4 batteries out perform the 20AH lead acid battery I have and maintain 13 to 12VDC till discharged. The 14AH lead acid battery starts dropping off voltage within the first hour of operation.
 
Please save yourself the agony if using the cheapest available battery. If you want a good example why, search this forum for shun bin batteries.
 
Please save yourself the agony if using the cheapest available battery. If you want a good example why, search this forum for shun bin batteries.
I agree there are higher quality batteries to be found. However I enjoy playing with new-to-me technology. The Miady batteries with built in BMS seem to be manufactured ok internally and include an 18 month warranty. With the the 12VDC 8AH and 16AH Miady batteries I can custom configure AH for various applications such as trolling motor, LED lighting in hunting camp, Ham radio operation, and Cpap use when the power goes out or while camping. When using six 16AH batteries in parallel for trolling motor if one or more battery fails there is still battery left to use...built in redundancy.
 
I too ordered 4 of these Miady 16AH for battery box projects - then found they have a 36AH for $99.99, had to buy one of those of course, will see how it is.
Trying to fit about that many AH into smallest box possible, so when they arrive I'll go box searching.

How is that 5.5amp charger working for you?
I'm looking at buying 4 or 6 of the 36ah ones and parallel them for 144ah or 216ah for my travel trailer. I have 2 questions if I do so will it support a 1000 watt inverter, with the only big draw being a mini deep freezer2fridge conversation? Not 100% sure of start surge I'm thinking around 300 watts or so. Second question what highest amp charger I could put on either configuration? Looking to be able charge fastest possible without damaging packs. Bc I will be using my generator until solar is done. Your advice would be very appreciated.
 
I'm looking at buying 4 or 6 of the 36ah ones and parallel them for 144ah or 216ah for my travel trailer. I have 2 questions if I do so will it support a 1000 watt inverter, with the only big draw being a mini deep freezer2fridge conversation? Not 100% sure of start surge I'm thinking around 300 watts or so. Second question what highest amp charger I could put on either configuration? Looking to be able charge fastest possible without damaging packs. Bc I will be using my generator until solar is done. Your advice would be very appreciated.
Miady the seller answered my question about # in series/parallel saying not to connect many, as the more connected, greater chance of issues.
I’m planning to use them for small loads.
There is a $10 off coupon on amzn now, so $89 for 36ah.
So far so good, have only used 5.5a charger on them, and discharged sparingly.
 
I just bought one of the 20 Ah Miady batteries and want to know the best inexpensive solar charger controller for this battery
 
I too ordered 4 of these Miady 16AH for battery box projects - then found they have a 36AH for $99.99, had to buy one of those of course, will see how it is.
Trying to fit about that many AH into smallest box possible, so when they arrive I'll go box searching.

How is that 5.5amp charger working for you?
They don't seem to have those listed anymore, sadly. The 36AH I mean.
 
Update: The home brew 96AH battery pack consisting of six x 16AH Miady lifepo4 batteries wired in parallel continues to run very strong as a 55 pound thrust trolling motor battery. I now have about 10 charge cycles on the battery. The first time out I ran the trolling motor wide open for an hour drawing about 45AH. I inspected the battery pack for any signs of wiring or heating issues...no problems found. I fished as normal the rest of the day with variable speeds from minimal to full throttle using the battery for two days of mixed slow/fast trolling fishing before recharging.

Battery operation was excellent as compared to my 10 month old Interstate group 24 lead acid deep cycle battery. Typically after a full day the the Interstate has been drained to 50% and I am unable to run full throttle on the trolling motor as it will cutout due to low voltage...not so with the Lifepo4 battery after two days of operation. The trolling motor ran strong as the voltage drop during the lifepo4 discharge is minimal.

I am currently charging with a 3 Amp standard lead acid Deltran Battery Tender Charger and plan to purchase a 10A rated lifepo4 charger to get the maximum AH out of the battery pack.

Temp Construction:
I ended up purchasing a Flambeau 18" dry box to house the 6 batteries and 6 1/4"spade fuse holders with 4" 12AWG legs, 6 x 15A spade fuses. There is room for two additional batteries if ever needed for a a total of 128AH capacity.

I made six 8" 12AWG ground leads with a 1/4" female spade connector on one end and 1/4" diameter stud ring crimp on the other. I added female spade and ring crimp connectors to the fuses/pigtails. I purchased two brass 1/4 diameter threaded stud bolts and nuts. I connected all positive fused leads from spade connectors on the batteries to the positive brass stud bolt. Fuses are left out until grounds leads were connected. I tested all positive leads prior to installing the 15 amp fuses. The positive and negative studs where wrapped with electrical tape. I use a SMH SY175 Series 4 AWG 175A breakaway DC power connector pigtail with 60 amp breaker for connection with my trolling motor and other 12VDC devices. There is a SAE fuse connector cable for connection to the battery charger. There are 4 of the 16AH batteries in the bottom of the box and two on top. I used foam to pack around the batteries for cushioning during transport. The entire 96AH power box weighs 28.5 pounds. I plan to reroute the charging and power connectors/60A breaker through the box lid and will also add 15/30/45 amp Anderson powerwerx connections in the future. Future repackaging may include adding two 8AH or 16 AH batteries and adding ground and positive brass/copper bus rails for battery connections.
9 month update on the 96 AH Lipo4 (6 x 16AH, Miady batteries wired in parallel): This home brew 96 AH battery pack continues to be a solid work horse while camping, fishing, portable HAM operation, and at home during power outages. We had a windstorm here in NW Montana in January losing power to the house for 4 days. I deployed the 96 AH battery to provide for LED lighting using my hunting camp lights, power the DSL modem and landline phone system when needed, small inverter for charging two Lap tops and mobile phones, running two C-Paps for 8 hour/night, and occasional amateur HF ICOM 7300 Transceiver use at low power. My backup is several deep cycle lead acid batteries which we never used. The main current draw was LED lighting (1-2 AH) and the two C-Paps (8AH) used every night. All other use was occasional.
 
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