Inverter/charger for 14s80p Li-ion pack to 120v 60hz

Hi everyone,

I'm looking to build a li-ion battery for my travel trailer.It seems like a lot of off gird invertersare setup to have a charging voltage under the 58.8v that is required to fully charge a 14s lithium pack.

I've looked at seemingly countlessinverters and this is what I've found that may work for my situation

• AIMS picoglf20w48v120vr - this will charge at a max of 57.6v at 5a - i'd like to have more charging current, but 57.6 is too low for me
• MPP[size=small]3048LV-MK - I can't find the voltage range for this or a price. Does anyone know if the charging voltage is configurable for this?[/size]
• Singeneer APC3048NC - 58.4v at a 'Boot' voltage - close but still isn't the full amount
• SRNE 2500W SR-HF4825U60 - charging voltage appears to be configurable to 60v and current of 30a

[size=small][size=small]I'm leaning to the SRNE because it fits my needs, and the price is good- although I'm not too sure of the brand.[/size][/size]

[size=small][size=small]I'm planning on having a 14s BMS on the pack, but I do want the option to fully charge the pack but won't store it in that configuration. The BMS will manage the cutoff voltage for me.[/size][/size]

[size=small][size=small]Anyway, am I thinking about this to hard? Or are the other suggestions for a 2500-3000w off gird inverter? Specifically ones with an automatic transfer switch. At the foreseeable future I don't plan on hooking solar up to them, but it would be a nice option in case I change my mind. Also I'm hoping to stay at or around$600as well, but the more I look into it it seems unlikely.[/size][/size]

[size=small][size=small]Should I reconsider a 7s pack instead? It seems like this would expand the inverters available, but I'd have to use larger ga wire to compensate for the lower voltage.Or should I build a 13s pack instead of a 14s? The low voltage cutoffwould be triggered sooner on these inverters- seems like a lot of them cutoff of 40v, which would leave the cells at about 3.08 on a 13s pack - it will preserve the batteries a bit more but I'd like to use more of the capacity of the cells that a 14s pack would provide.[/size][/size]

[size=small][size=small]I've also considered just buying a standalone inverter, transfer switch, and charger - but I can't seem to find a standalone charger that will provide enough voltage with a decent amount of amps.[/size][/size]

[size=small][size=small]Anyway, thanks in advance![/size][/size]

You don't *have* to combine inverter and charger into 1 unit. For 14s charging - I have several "YZPOWER 58.8V 15A Lithium Battery Charger for 51.8V 14S Li-ion Battery XT60 Plug"
https://www.ebay.com/itm/283695940436 hooked in parallel. I'm not pushing these but at 15a each they were good for the price

I have 3 of them and can choose 15a or 30a or 45a etc.... Its useful to be able to turn on more or less depending on the amount of 120v power available. For example, 3 x 15a = 45a @ 52v = 2340watts / 120v = 19.5a. So 3 of them totally maxes out a 20a circuit and would be too much for a 15a circuit. For a 15a circuit I can use 2 of them - it gives me flexibility.

Turns out my Honda 3000w generator can only handle 2 of them. When I turn on the 3rd one the generator goes into uneven motor state - e.g. too much for it.

Can you adjust the output voltage of these? I have a 15s battery that charges to 4v/cell (60 total).

Is there a particular reason you have to have 58.8v?

later floyd

gpn said:

Can you adjust the output voltage of these? I have a 15s battery that charges to 4v/cell (60 total).

Click to expand...

It shows 'voltage trim' ability - but not sure it would go that high. If you could go to 14s it would give you the most options.




I'm a bit surprised to find this... maybe you can go directly for 15s charger(s).... Here's a YZPOWER 63v w/range of 7-12a options - https://www.aliexpress.com/item/32830876711.html?spm=2114.12010612.8148356.30.38897eb6w3nw9M

and a different one at 63v@5a...
https://www.aliexpress.com/item/329...earchweb0_0,searchweb201602_,searchweb201603_

ha, that's awesome. My original question was referring to adjustable output. But I phrased it poorly. But this thread got me thinking about being able to charge from a generator as a backup option but not primary operation.

This is great, thank you!

I may just go the independent charger route - seems to open up a lot of options for me. I didn't know some of the chargers could be opened up and adjusted, that is great! Looks like there are a few more options after researching a bit more on 14s chargers. 30A would be plenty in my application, and also good to know I can just put two 15A chargers together to get that kind of amperage.

I figured I needed a charger that went to 58.8v because to fill a full 14s li-ion battery I'd need 4.2 x 14 which would give me the 58.8v. Now I would just like that option, and set the voltage of the pack a bit lower to make the cells last longer (managing that though the BMS) but if I know i'm going on a longer trip I'd like to fill up the batteries as full as I can before I go.

So if I do buy a 15s battery charger and hook that up to a 14s battery, my BMS 'should' still work with that. Seems like most inverters have a high voltage cutoff at 63v so if the BMS cuts off the charger then the inverter shouldn't be damaged.

Ideally If I'm out boondocking I'd be able to charge this from a generator if I'm out there long enough. I won't be putting solar panels on this trailer yet, but maybe in a few years I will.

Just some personal advice. I would not use a 15s charger on a 14s battery bank and 'depend on BMS' for protection. I would stick with 14s charger and avoid even the possibility of overcharge. Overcharge - even just a few hours - is one of the main ways to cause a cell to catch fire and if 1 cell catches fire it's like a flare - it will likely cascade thru the whole pack.

Take a look at this youtube that shows exactly what happens whenovercharging (a few hours) of an 18650 battery pack. See 3:09'ish for the start of the fire and watch what happens as it burns.... "My first Tesla Battery Fire" -https://youtu.be/WdDi1haA71Q

Yeah I'll stick with a 14s charger for the 14s battery, thanks!