Using a 7909 Splitter/Combiner to Increase Charging Rate on an EB150

I have more than one EB150. I was thinking about combing two of the chargers in parallel (output of the two connected together) to double the charge rate. Currently, the AC chargers put out 42V @ 5A. If I do that, I could get 42V@ 10A which is within the DC input specs of the EB150. I see no reason why this would not be OK, but just wanted to check to see if anyone else has done it without any issues.

Should be fine, haven’t tried this myself but this would be no different than running more solar panels in parallel increase amps. Not sure if there’s a ready-made Y splitter DC 7909 adapter though or if you’d have to make one yourself.

I agree. It is very basic electronics (like paralleling two power supplies or batteries). There are ready made and also can make yourself. I found a cable that is 7909 on 3 ends, but not a simple T adaptor.

Hi Ben
Good idea in theory and it would probably work…
Something to consider is the strain on the batteries. Heat is their enemy which shortens their life. Jamming 10 amps in will cause extra heat, “For every action there is an equal and opposite reaction”.

Think of a balloon, Fill it with a hand pump, it would be easy to control the rate of inflation and how much volume it gets. This is a pretty controlled environment. Now try filling the balloon with an air compressor at 120psi. That would equate to “all speed, no control” and the strain on the balloon is much greater, the risk of an overfilled/popped balloon is huge.
Whenever possible, I charge at the low/slow/“silent” rate.

Hope this helps.

I charge slow as well. However, there may be times when faster is better (especially where I live because of frequent power outages), Some of these power generators charge with much more power. It is well within the specs of the unit. The EB150 is spec’d for 58V at 10A. So, 42V at 10A (420W) is well within that spec. Many people here are charging with 500W or more of panel capacity. That is what the unit is designed to handle. The MPPT and BMS handle the charging internally and prevent overcharging. My question was, has anyone tried two power supplies in parallel? I was not concerned with charging with too much power because it is will within the specs. I assume that the power supplies have diodes on the output to prevent reverse current. However, that assumption could be incorrect. Anyway, if the power supplies are the same voltage, and they are, I don’t think it would be a problem. I measured both of them and they were both 42V. It would cut the charging time down to about 4 hours instead of 8 hours. If Bluetti has any input, I would appreciate it. Or, if anyone has done this already, please let me know. I could always put a diode on the output of each power supply and then it would be OK, but I don’t want to do that if not necessary.

Hi @Ben , About the practice you described above, it is possible but the operation is more troublesome. We suggest you just charge it directly with the T500 adapter.

What is troublesome about it? Please explain. I have an electronics background, so please feel free to go into detail. After spending quite a bit of money on Bluetti Generators, I really don’t want to spend much more for a while. Even if I did want that product, it is not available in the country that I live in. I really do not see any problem with combining two chargers (especially if there is a diode to prevent counter flow. I have paralleled power supplies when top balancing LifePo4 batteries and many others have as well.

Hi @Ben , sorry for hassle.
If you do not want a T500 adapter, it is possible to use your own charger while ensuring safety.

It is no hassle at all. I appreciate your response. Maybe, I didn’t explain well enough in my first post. I just want to know from your tech department (if possible), would it be OK to combine two of the chargers that come with the EB150 (42V at 10A each) using what is essentially a 7909 T branch?

Hi @Ben , The technical engineer replied that it is possible to use a combination of two chargers.

That is what I thought, I appreciate your efforts and research. Thank you.

would this work: iGreely 8mm Splitter 8mm Female and Male Y Splitter Adapter Cable for Solar Panel RV Automotive Marine Portable Power Station Compatible with Jackery Goal Zero (8mm Male to 8mm Female x 2) : Patio, Lawn & Garden

and would it work to combine the dc output of two B300 batteries?
would it combine the voltage or combine the amperage?

if voltage it would boost up to 24v and work with the eb3a/eb70s

Based on the Amazon reviews it is a DC7909 Y splitter. However, the B300 only has a cigarette lighter DC output port, no barrel. You would need to find a combination of cables and adapters to covert the cigarette lighter port to DC7909 adapter for each B300 and then use the cable. Your voltage would remain the same but you could theoretically pull up to 20A @ 12V, just make sure your cable doesn’t overheat. I read that most DC7909 cables are 14AWG and rated to 30A but don’t take my word for it.

i keep thinking the B300 has a DC7909 output like the power stations.

Frankly it should. (plus a true 24v output as well)

Anyway it sounds like it adds up the amperage not the volts so you’re still better of with a box that increases voltage from 12v/10a to say 24v/5a. This would let you plug into the pv port of the eb3a/eb70s.

Yes, probably better to go with something like this: SUPERNIGHT DC Boost Converter DC 12V Step Up to 24V. One reviewer even said this: “Used to boost 12-volt lead-acid battery to charge Bluetti EB70 inverter in reasonable time (est. 4-5 hours @ 180Watts)”.

If you want to try something more fancy that lets you adjust the output voltage then check out this DROK DC Boost Converter

No Bluetti power station has DC7909 output ports, you’re likely referring to the DC5521 output ports on most of the smaller Bluetti power stations and the AC200 series.

Yes, that will work. The tech department said that it would be OK to combine 2 Bluetti EB150 Chargers. The chargers have an output of 42V @ 5A (210W). With that splitter, it would double the current and thus power (42V @ 10A to achieve 420W). That splitter is nice because it also has two gender changers which gives versatility. It will work for an EB150/240 because they both have 7909 connectors on the power supply output and DC input of the unit.

I have something similar to extend the capacity of my EB150. Some of them need cooling if you run near the maximum power rating. I got a higher power module and run it lower to prevent the need for a cooling fan. The DC to DC converter consumes some battery power, so I really do not want to run a fan and consume more. Mine also has adjustable voltage and current. It can be run in CC or CV mode.

The two small adapters are not gender changers, they are DC7909 to DC8020 to fit Jackery solar input ports. A gender changer adapter has the same port or receptable on both sides (ex. male-male or female-female). These are male-female adapters.

However, you can buy the cable variation you need as Amazon sells one variation with combining two male DC7909 inputs to one female DC7909 output:

…or the other variation with one male DC7909 input splitting into two female DC7909 outputs:

Which one do you have? I just purchased a 1000W DC step-down buck converter on Ebay which supports 10-110V input and 0-100V output with 20A max output below 50V and 10A max output above 50V. This should let me squeeze out more watts from my own EB150 because I’m maxing out the input amps at 8.75A @ 39V with 4x 100W panels in a 2s2p configuration. I would be able to switch to a 4s config with the DC step-down converter.

I got this one.