Maxxim
New Member
- Joined
- Jan 2, 2021
- Messages
- 31
Hello all!
I have long been interested in acquiring a lithium battery for my small fishing boat bow thruster(trolling motor) due to the superior features of lithium(LiFePO4), the most important of which, in my opinion, is the ability to use the entire battery capacity without compromising the battery life. Sure not forgetting the lighter weight comparing to lead battery, and flatter voltage drop so it doens't affect the motor performance as much as lead acid battery does.
Of course, you can get ready-made lithium batteries locally, but the prices are quite high, like 600-1500 euros for a 100Ah lithium battery. So I decided to make the battery myself with these cheap Chinese LiFePO4 cells. But ordering the cells at an "affordable" price from Aliexpress in China proved surprisingly difficult. Two orders went unfulfilled, and about a couple of months in both cases were wasted waiting. The money did return immediately from Ali as long as the dispute was done. Apparently, the difficulties are due to the operation of the Chinese Post, no longer the so-called free shipping for larger shipments(shipping fees has gone up a lot). Well finally, one of the shipments arrived. 4 pcs 3.2V 100Ah cells, the price was 171 euros including all expenses. They where the new style with rectangular poles. They came pretty empty, with a voltage of 3.02V.
Although this order wasn't perfect either. One cell had been damaged in the transport, hit on the way, but when tested, there did not appear to be any electrical fault. After dispute I did get back the money for one cell.
I started by charging the cells individually to 3.32V voltage, after which I switched them all in parallel and I did the top balance, charged all connected in parallel to 3.6V until they no longer received any charge. The BMS I orderedfrom US. I wanted a well functioning and reliable BMS with temperature sensing that can cut off the charge in freezing temps. The choice fell on the Overkill Solar 120A 4S BMS. Certainly not the cheapest to get, $ 145 including chipping fees. The temperature sensor, a bluetooth receiver and pre-tinned power cables were included. BMS's settings can be managed and monitored with a free mobile app, which seemed to work very well. My first job was to make fastening clamps from 4mm aluminum and threaded rods to get those cells bundled together so that they stay firmly together and there is no risk of the poles being damaged. I will be adding more story and pictures to the thread...
Many thanks to Will Prowse and his youtube channel, has been very helpfull, and not forgetting this forum. Here is available a ton of info.
I have long been interested in acquiring a lithium battery for my small fishing boat bow thruster(trolling motor) due to the superior features of lithium(LiFePO4), the most important of which, in my opinion, is the ability to use the entire battery capacity without compromising the battery life. Sure not forgetting the lighter weight comparing to lead battery, and flatter voltage drop so it doens't affect the motor performance as much as lead acid battery does.
Of course, you can get ready-made lithium batteries locally, but the prices are quite high, like 600-1500 euros for a 100Ah lithium battery. So I decided to make the battery myself with these cheap Chinese LiFePO4 cells. But ordering the cells at an "affordable" price from Aliexpress in China proved surprisingly difficult. Two orders went unfulfilled, and about a couple of months in both cases were wasted waiting. The money did return immediately from Ali as long as the dispute was done. Apparently, the difficulties are due to the operation of the Chinese Post, no longer the so-called free shipping for larger shipments(shipping fees has gone up a lot). Well finally, one of the shipments arrived. 4 pcs 3.2V 100Ah cells, the price was 171 euros including all expenses. They where the new style with rectangular poles. They came pretty empty, with a voltage of 3.02V.
Although this order wasn't perfect either. One cell had been damaged in the transport, hit on the way, but when tested, there did not appear to be any electrical fault. After dispute I did get back the money for one cell.
I started by charging the cells individually to 3.32V voltage, after which I switched them all in parallel and I did the top balance, charged all connected in parallel to 3.6V until they no longer received any charge. The BMS I orderedfrom US. I wanted a well functioning and reliable BMS with temperature sensing that can cut off the charge in freezing temps. The choice fell on the Overkill Solar 120A 4S BMS. Certainly not the cheapest to get, $ 145 including chipping fees. The temperature sensor, a bluetooth receiver and pre-tinned power cables were included. BMS's settings can be managed and monitored with a free mobile app, which seemed to work very well. My first job was to make fastening clamps from 4mm aluminum and threaded rods to get those cells bundled together so that they stay firmly together and there is no risk of the poles being damaged. I will be adding more story and pictures to the thread...
Many thanks to Will Prowse and his youtube channel, has been very helpfull, and not forgetting this forum. Here is available a ton of info.
