Big battery charger / small generator. Looking for solution to not overload generator.

turbothrush

Member
I have a Power Max PM 4 60 Amp charger that am going to use to charge my 100 amp Fortune lithium 12 v battery. Besides shore charging I would like to use the same charger to charge from a Westinghouse 1200/1000generator.

This would overload my small generator so I was wondering if I could use this

And adjust the duty cycle as to not overload the generator .
If this won’t work I am looking for a solution as I prefer not to carry 2 chargers. Any help much appreciated
 
Last edited:

67cj5

Man On a Mission
I have a Power Max PM 4 60 Amp charger that am going to use to charge my 100 amp Fortune lithium 12 v battery. Besides shore charging I would like to use the same charger to charge from a Westinghouse 1200/1000generator.

This would overload my small generator so I was wondering if I could use this

And adjust the duty cycle as to not overload the generator .
If this won’t work I am looking for a solution as I prefer not to carry 2 chargers. Any help much appreciated
At 60Amps that would be 768w So you should be able to use a 1200w Generator with a margin for error,

Hope that helps.
 

john61ct

Adventurer
The proper way is a reliable DC-to-DC charger like Sterling, that lets you set the current as well as voltage.

ex-industry secondhand lab-style PSUs with those features from top quality western makers can be found cheaper on eBay, much better than cheap Chinese stuff brand new

but then you need to figure out automating the stop-charge.

Really, the most cost-effective reliable solution is to buy the right wattage charger to suit your genset, or vice versa.

There are ACR type devices that effectively limit current draw too, but rare and only available in certain ampacities.
 

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turbothrush

Member
Thanks for the replies. Generator arrived and it does the job ..... kind of
I had hoped to charge the battery at a fixed 13.8 volts (charger has an adjustable setting) but it overloads the generator. But I can charge at 13.58 volts which gives me a 48 hour resting voltage of 13.32 which I think gives me
about mid 80% SOC. Does this sound right ?

I’m ok with this as I can finish off the charge with solar or alternator if I need to
 

67cj5

Man On a Mission
My 35A battery charger will reach over 15v in all modes if it is left on for long enough, If I am Charging 2X 110Ah batteries I will put it on the mid setting which is between 16 to 20+/-A but it will reach over 15v if left in about 2 to 4 hours it can charge the batteries from around 75% SoC until full, Once the DMM reads about 14.2 I switch the charger to Low which is about 8 to 12Ah but once it has reached 14.2v on the mid setting when I switch it Low it is reading about 2 to 4Ah which slowly drops as the batteries reach Full and at around 14.7-14.8v I switch it off, The batteries will hold about 13.4v for around 48 hours+/-, These natteries are 3 years old and they will run my fridge for 24 hours before their voltage drops below 12.9v.

I let the charge voltage reach 14.7-14.8v because On "Battery University" they said to charge them to that voltage to get rid off any Calcium on the plates, But charging them that high can reduce the battery life But if you only charge them to 14.4v will give a good service life but Calcium deposits will build up, This mainly effects batteries that are used on and off, If your battery is being used by your fridge and then charged up daily then Calcium should not be an issue which will also boost Battery life,

Hope that helps.
 

dreadlocks

Well-known member
I charge my LFP off genset with a dumb 48v constant voltage power supply feeding the portable Victron SmartSolar that is capable of limiting output current to whatever I want, and is fully programmable to be copasetic w/LFP, got diodes isolating em but since my panel is higher voltage I gotta unplug it.. If I fed the SC w/a voltage higher than the panels then shore power would take priority.
 

john61ct

Adventurer
Nope resting Vpc of 3.33-3.34 is as Full as you want to get

To speed things up if you want, start low V then raise, toward the end 13.8V will do.

Don't let it sit that Full when you're not cycling, bring V down to well under 13, 12.8V is fine
 

turbothrush

Member
Nope resting Vpc of 3.33-3.34 is as Full as you want to get

To speed things up if you want, start low V then raise, toward the end 13.8V will do.

Don't let it sit that Full when you're not cycling, bring V down to well under 13, 12.8V is fine
ok great. Thanks for quick response. I’ll drain it down some when not using
 
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