ExpertPower 12.8V 5A Smart Charger for Lithium LiFePO4 Deep Cycle Rechargeable Batteries

Works as expected.

My goal was to build an uninterrupted power supply for my Odroid single-board computers, which use between 19V and less than 12V depending upon peripheral devices. To that end I purchased an XZNY 20Ah LiFePO4 battery and this 5A charger, that does not throttle down to a lower voltage when the battery is full as others do, with the intention of modifying the output to 13.5V so that it will not damage the cells when left permanently connected. The charger instructions state that it should be disconnected after the battery is charged, which makes sense for preserving the capacity of the battery but may also be to preserve the charger components. Nonetheless I observed less than a watt (my instrument’s resolution) of quiescent power and I see no cause for concern in keeping it plugged into AC power. Someone else here mentioned that he modified his charger voltage (thanks packetrat!), so this charger seemed like a low-risk choice.I first opened the case, then pried up the circuitboard, sometimes using a knife to cut through the flexible glue used to hold it down. I then located the surface-mount LM324 quad operational amplifier and R104 (14.7k), which is the top half of a voltage divider (3k to ground on the bottom half) and is used to compare to a 2.5V voltage reference. I calculated that a 195k resistor in parallel with R104 would change the “battery full” voltage from 14.4V to 13.56V, but I wanted to chose that option with a switch, so I soldered wires at convenient places (see photo) that are equivalent to either side of R104. The other photo is of the switch: two 1% resistors in series (180k and 15k), and an ugly reworked solder job (I got it wrong the first time). If the voltage option were available through some fancy menu (it’s not), it might not remember the setting when the AC power is interrupted, so a simple toggle switch is best.When I started testing the charger as part of my uninterrupted power supply, I was dismayed that around 10W load (guesstimate) the fan would slowly turn on as higher charging current resumed. It’s loud. So I put in a replacement fan: 40mm, 12V, 14dBA, made by Scythe (SY124010L). Others may work better for less money. There is no 2-pin connector; it must be soldered in. What a difference! Now I can’t hear it at all. I’m sure there’s a little less airflow but I don’t expect a lot of heat buildup for my use case and I could never get the heatsinks very warm.Two weeks later and I have no complaints. The load is usually under 2 watts and the voltage is steady around 13.5V, perhaps a little lower depending on which DVM I use.

Works well. The clips for the charging cable and the charging cables themselves are a little underwhelming. Not sure about long term durability. It does the job though and the entire unit is small enough that it fits into my small radio bag without adding any serious bulk.

Works great. Simple to use.

The unit died about 5 weeks after purchase, 3 days past the Amazon return window. Had used it about 5 times up to that point to recharge a 50 Ah LiFePO4 battery. Amazon directed me to contact ExpertPower for returning the unit - which I did via UPS printed label. Also filled out a one-sided form specifying the problem (unit died - no led lights, no power, after 12 hours overnight charging). No doubt it was my fault for expecting a charging unit to be able to work for a whole 12 hours, rather than baby-sitting the unit to turn it off at the exact moment the recharging process is complete - which seems to be the only way to use this charger.I don't know at what point it stopped working during the night, but asking it to work for up to 12 hours to recharge a 50 Ah battery at a rate of 5 Amps per hour should be within its abilities, and to light up with the appropriate red or green led during and at the end of the charging process.I requested a full refund on the form. but ExpertPower shipped me a replacement unit despite me saying I didn't want a replacement as the unit is not reliable, and just dies - they have check boxes for either refund or replacement on the form.Several comments on the review of the ExpertPower Lithium Iron Phosphate Smart Charger - Ham Radio Q&A on YouTube (you can Google it) - say the same thing - the unit dies after a few hours charging. So now I'm stuck with the replacement charger that I didn't ask for, that's prone to crap out at some point during the recharging process, and no refund offered from ExpertPower. Buy at your own peril.I don't trust this unit to do the job reliably. I ended up buying a separate, more expensive, hopefully more reliable charger, and expect I'll just have to eat the cost for buying this piece of unreliable junk. Live and learn.

This charger is great, specially for slow charging if you have a large capacity battery. It does use constant current charging then the current decreases as the battery get closer to 100% charge. Good value, I recommend it. Does not get hot while charging. It does have a fan, not very noisy.

I have 2 Battleborn 12v lithium battles that Have been in storage. They metered. At 13.2v. Hooked up the charger to one and it took about 1.5 hours to finish, the end voltage was 14.38. The units make moderate noise and did not heat up. So far fine. Briefly shorted connections, died and cannot repair.

works. 5 amps runs on a car outlet. has a not loud fan. half the price of the competition. quality is hit and miss. some units lasted several years and others less than a month. about what you would expect considering the very low price.