SHUNBIN Lifepo4 Battery 250ah 310ah 400ah 500ah 620ah 12V Lithium ion Battery for Solar System/Motor Home/Boat/Golf Carts/Electric car (12V 500ah×1set with Quick Charger)

=== BUYER BEWARE === UNSCRUPULOUS SELLER === DANGEROUS PRODUCT ===1. There is NO WARRANTY on these batteries at all!! Seller will require you to return the battery which you will not be able to do because shipping LFP batteries is considered dangerous cargo. They can ship to you but you cannot return them effectively negating any warranty.2. They are built with used cells - performance will easily be 10-15% less than advertised.3. Internal electrical construction is unsafe using soldered copper to aluminum cell terminals that rapidly fail. Undersized copper strips for cell interconnections. My batteries experienced internal failure after just 3 months - in STORAGE!!4. Amazon A-Z warranty for these batteries was denied without any explanation even after an appeal.Seller is re-listing the same product under different listings to avoid bad reviews like mine.Here are the details:On December 18, 2019 I purchased two 400Ah batteries from this seller. I had been researching LFP batteries for marine use for the last 2 years. In the course of my research I had come to discover that many LFP batteries were poorly constructed internally and so after reviewing this seller's product it appeared to be superior to the majority of Chinese built batteries. In addition I figured that purchasing from AMazon would provide some more protection against being ripped off. Sadly I have found out that I am wrong on both counts.One of the attractive features of this seller's LFP battery is the stainless steel case which I felt would provide better protection against the possibility of a catastrophic battery failure and this was important for use in a boat. In addition the seller was willing to customize the BMS to my specifications. I had the two batteries fitted with a bluetooth enabled BMS that was capable of delivering 120A and 100A charge. In addition I would be able to monitor the battery's health. The transaction with the seller went fine and the batteries were delivered within 3 weeks of my order.Visually the batteries looked good. The stainless steel cases are good quality, non-magnetic grade stainless steel - better than most stainless steel BBQs. Unfortunately all of the hardware is nickel plated steel so the hardware will rust quite quickly in a marine environment.I subjected both batteries to a series of 0.2C discharge and charge cycles. This is where I discovered that they would only deliver about 350Ah, well below the 400Ah that they should have been at. This is likely due to the fact that the internal LFP cells are used and at the end of their useful life in spite of the seller claiming that they use new cells. This was the first major issue I had with the batteries. The seller offered to compensate me with a partial refund of about 10% of the purchase price to offset the roughly 10% less performance and I accepted it as I was willing to take a chance on the remaining cell life and overall capacity to be suitable for my purposes.The batteries were scheduled to be installed on my boat in late February and then the Corona virus pandemic hit and stopped everything. The batteries had been charged to about 90% and left in storage and not connected to a charger. In late March I checked their condition and discovered that one of them had a severe cell voltage imbalance internally. Cell #3 had dropped to 2.8V and #4 had risen to 3.862V - quite an odd situation given that all cells were balance to within 0.01V when the batteries were placed in storage in February.I reported the problem to the seller and was offered a cell charger and told that in spite of one cell being at the upper limit, that "when you charge the low voltage cell separately, the other high voltage cell will go down, no problem." This was a highly suspect answer.After about 2 weeks I received an individual cell charger. At this point I had to remove the cover from the battery to figure out which cell had to be charged. I measured each cell with a meter and they were all within 0.01V of each other. So the voltage reported by the BMS was incorrect. I started checking the sense wire connections and quickly discovered the problem. They were crudely soldered onto the aluminum cell terminals and had come loose. I found the same issue with ALL of the cell sense wires. The cell interconnects for similarly soldered copper strips (not even buss bars) to the aluminum cell terminals. Everything was slathered with white RTV and the solder joints were abysmal for all of the cell interconnections. While they still worked it was unlikely that they would last over time.There are no screw terminals on the cells and their terminals are pre-connected in cell pairs. It is not possible to solder onto the terminals without running the risk of overheating the cells and there is no way to tap a screw into the cells without puncturing the call case.I reported my dis-satisfaction to the seller and they turned cold. The seller quickly informed me that if I wanted my money back I would have to ship them back to China and to be aware that it wasn't possible for me to ship an LFP battery as they were considered dangerous cargo. In effect - sorry - no warranty since you cannot return them.I reported the issue to Amazon under the A-Z warranty and while the customer service reps were quite nice at taking the information I was summarily denied any warranty coverage - even after an appeal.So buyer beware - you are purchasing a product that is made of used LFP cells, using abysmal internal quality that could easily result in the catastrophic failure of the battery due to a high resistance internal cell connection. In my case I suffered an internal failure after just 3 months and found that their 3 year warranty is a cruel joke and that Amazon will not provide any A-Z coverage at all.Take a look at the pictures of the internal cell voltages, interconnections and sense wires.

Update #3, Sept. 6, 2020: We have owned 2 - 500Ah Shun Bin batteries since Nov. 2019, using them in our Sprinter chassis RV with a Xantrex Freedom X 3000 watt inverter, an Outback Flexmax Charge Controller and 660 watts of solar. Also installed a Thornwave Labs BT battery monitor. Immediately after purchasing the batteries almost a year ago I ran a load test, the results showed the batteries did not have the capacity as advertised, but still enough to be a decent deal if they withstood the test of time. The rough estimate was around 650Ah for the two batteries.I set up the Outback controller as recommended; 14.4V bulk/absorption, 13.4V float, equalization off. While traveling over the past year the batteries just never had the capacity I anticipated, we were only getting about 400-500Ah per charge above 13.3V, less than half of the 1000Ah they should be. I was pretty unhappy and tried to get a refund. During email communication with Shun Bin the company finally sent me the owners manual which was not included with the batteries (what?) and also a photo of their load testing results. Their results showed 480Ah @ 96% SoC for a single 500Ah battery. Also, the first item on page 3 of the manual is; "1. The battery shall be fully charged before the first discharge of the battery. After the battery is fully charged and discharged 3 ~ 5 times, the battery can reach the optimal capacity." Thinking the batteries aren't being charged sufficiently I purchased the upgrade for the RV load center charger to a lithium charger and added a DC-DC lithium charger to the alternator charging circuit. After returning from a trip recently I installed the lithium charger and charged the batteries with shore power. The batteries really charged for the first time at 14.6V. After disconnecting the charger the battery voltages stayed at 13.5V/13.6V. I began another load test, ran a small space heater drawing about 1400 watts. The test lasted about 9 hours, the voltage dropped from 13.5V down to 10.5V with load applied. The results showed an Amp-hour rating of 835Ah. Wouldn't drain the battery down to 10.5V in normal use but not too bad. That is a cost of $4.70 per Amp-hour. A little more since it's more like 800Ah (12V) of usable capacity.The lesson learned is that charging the LiFePO4 batteries correctly is most important to get the full capacity out of them. The next thing that needs follow up is the settings for the Outback Flexmax controller, it is apparently not charging the batteries fully and I notice the controller rarely goes into bulk or absorption mode (14.4V), it appears to sit at the 13.4V float voltage even when the batteries are drained. Need to figure this out and more testing still needed. Not sure I would buy these batteries again, in hindsight I think I would spend the bucks strictly on Battle Born (already own a few) with the 10 year warranty, you can actually speak to them on the phone and because they're over designed the 100Ah is 100% usable.Update 4, 09/10/2020: I just received new information, for me anyway, when connecting the batteries in parallel they must each be charged 100% at 14.4V before connecting them together. You would think they could have mentioned that in one of the 7 previous email communications. I found this information elsewhere and had to ask them if it was necessary.Update 5, 09/13/2020: Although other information on YouTube and forums contradicts the ShunBin statement in their manual ("After the battery is fully charged and discharged 3 ~ 5 times, the battery can reach the optimal capacity.") it is apparently correct. After charging with the proper charger and discharging several times the batteries now hold the no load fully charged voltage at 13.8V. It had been 13.2V until using a true lithium charger, then 13.6V, and now 13.8V. I anticipate another load test may have even better results than 835Ah (2 x 500Ah). Increased absorption time on the Outback CC to 8 hours, it now stays in bulk mode (14.4V) most of the day.I am pretty happy with the batteries now that I understand them better. They might be 5 star batteries except for the difficulties with the companies communication, returns are not possible as stated in other reviews and not providing a manual with the product.

Arrived as described. My battery came with a 20 amp charger, not 30 amp as advertised. I am not concerned about this however as I am fine with 20 amps charge rate. Hooked to a SUG Pure Sine Wave Inverter 2500 watt / 5000 Peak ( bought from Amazon warehouse deal). This battery easily handled the 185 amp average pull-down I did on this battery through the inverter. The BMS was warm but not hot. All terminals and wiring were cool or warm. No concerns on how this battery is built. The 3.2 volt cells are tagged 232 AH (see picture). The handles on the lid are spring-loaded and stay down and don't rattle.......nice touch! The push button on the front just turns on the voltmeter. The packaging was acceptable, however, I would like to see the shipper add more foam for future customers. It is a lot of weight to get tossed around in transit.Update Nov 2022. No complaints. This battery has received a good workout over the past 3 years with my inverter setup and has not disappointed me.