That could be an issue. If that is a 20 foot jumper cable, thats a 40 foot run of 4 gauge wire. My online calculator estimate puts your voltage drop over 2v.
Oh, i only used 20foot in my estimate⊠your right itâs double. but i still came out 1v. my estimate is still probably off. i used 0.2485mΩ/ft * 40 * 1000 * 100A = 0.99v hmm.
regardless I think this will just improve the wattage i can get no? which i alraedy got 1000w through it. and the lonestar charger is tripping at 550w. ⊠maybe if thereâs. a micro burst of 1200w, and I have better cabling i could survive it. 
⊠worth a test. that was on my todo, but better connection is a bunch more work.
Yeah thatâs tough to explain. Have you used a watt meter to check how much the lonestar charger is actually drawing?
no. i have no watt/ammeter type equipment. might be worth getting something? or is anything good super expensive?
Iâm just using the wattage display on the inverter. i donât see it spike when watching it and the event happens. but who knows what kind time resolution it has. you can see it visibly step up over like maybe 1s intervals or slightly less but that could also be the behavior of the load.
I have a neat clamp meter i use for that type of stuff, or you can get super cheap watt meters, but youâd need to put it inline.
Watt meters are great, and cheap, you should definitely invest if you like science.
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I got a small 238wh 600w battery+inverter. BLUETTI EB3A
ran the lonestar charger off it. it pulled ~375 watts off it for a bit under an hour and never tripped it.
the 357w was reported by the bluetti.
note quite the ~500 watts was reported on the ampeak 1200w inverter.
presumably because battery is charged more. so iâll have to repeat the experiment when itâs drained more again.
but it might mean that the bluetti inverter can handles somethign that that the ampeak canât. or something to do with the power sources.
oh this is wrong. this was a trick. I accidentally had the EB3Aâs âpower liftingâ mode on. whoâs documentation is very sparse. âincreased power for resistive loadsâ
with âpower liftingâ disabled the lonestar charger jumped to 630watts before overloading the EB3A which promptly shut off itâs AC circuit.
turns out i had a âkill-a-wattâ meter lying around.
the EB3A in âpower liftingâ mode was outputting 75v⊠oh⊠so âpower lifting modeâ gives more heat for resistive loads like heaters/kettels. interesting the lonestar charger took that power and actually charged at a lower wattage.
this kill-a-watt also displays a power factor.
iâve yet to fully understand what this means. I think itâs something like how much the AC loadâs peak current is out of phase with itâs peak voltage. power factor of 1 being in phase. not sure what this means to inverters. maybe it means it has a peak current thatâs being hit at a lower voltage and so lower wattage but still hitting a current limit.
so. using the kill-a-watt measurements with wall power:
lonestar charger at 550w PF 0.69
lipo charger and power supply at 850w PF 0.99 (lipo charger said input wattage was less. )
prototipo charger (some generic 12s 5a) at 330w PF of 0.69
will try these same things again on the inverter when i get a chance.
car inverter usually 200W power.i think this the issue
Back in my Van living days, I recall reading something about the Xantrax inverters not being a clean enough pure sine wave for many electronics devices to work properly.
I found the inverter to be a necessary evil, in that it wasted so much precious lead acid battery, with inefficiency under load, or just a high standby current just turned on powering nothing.
My Biggest load back then was my laptop, and using an inverter to power the original ACDC powerbrick was something like 20% less efficient than using a âcar adapterâ power supply which just stepped up 12v nominal to 19.5vdc. The actual efficiency improvement was determined by the task the laptop was performing and whether its internal battery was charging or not.
When I got into esk8 late â23 I already had the 12vdc mindset and started using CCCV boosters/ Step up converters from 12vdc nominal AGM batteries, rather than investing in a AC/DC charger.
I like the option to only charge to 4.1v per cell and to choose the rate at which it gets up there.
I think anyone wanting to charge their esk8 from a vehicles 12v nominal system, Unless they already have the inverter and charger set up, are better off using the â1800 wattâ CCCV booster that looks like this:
The 1800 watts is a bit of a joke when the input is 12v nominal. Basically it is limited to 40 amps input, which is 480 watts.
If you are running the engine so the alternator can power it, then hopefully it is receiving at least 13.6v so that would be 544 watts, input.
The efficiency of the booster goes down the lower the input voltage and the higher the output voltage.
Even a large 12v car battery tops out at around 100 amp hours capacity, so 1200 watt hours is not a lot, and most vehicles have far smaller capacity batteries.
Alternators are very inefficient and create a lot of heat, especially at Idle speed, and inside a hot engine bay can quickly overheat. The vehicle might cut back the alternatorâs output voltage, and thus current to prevent this. Basically, if one is pulling 40 amps or more to power an inverter or CCCV booster, then their engine battery is still being depleted despite the engine idling and powering the alternator.
How any given alternator will perform at idle speed depends on the vehicle.
I had spent a good amount of time and effort optimizing my charging system and Idle speed.
At a red light, foot on the brake, in drive, and I would watch the output go down and field current to alternator maxxed out. My VRegulator temperature and alternator temperature acted like they were on the business end of a propane torch, but at highway speeds, everything was good to go.
Lead acid car batteries are little whiny bitches too. If you cycle them deeply, and do not fully recharge them ASAP, they lose capacity quickly. They take forever, when new and healthy, to get from 80% to 100% state of charge, no less than 3.5 hours when held at absorption voltage, and after a few cycles when not reaching 100% this 3.5 hours can easily double.
If the Lead acid battery is not then held at absorption voltage for the time required to reach true full charge, the capacity and performance degradation accelerates. It happens very quickly and is basically unrecoverable.
So many drivers assume the alternator in some instant and free power source and that if the lead acid battery can still start the engine, that it is âstill going strongâ.
Modern fuel injected engines allow a very weak, aged, abused, capacity compromised battery to still easily start the engine.
I had one battery I cycled to its very end, and it could easily start my engine, but if I asked the battery to charge my flip phone, then start my engine, I just got a click.
So charging an ESK8 battery from a vehicle is very possible, but there are a lot of caveats. Lead acid batteries and Alternators are not happy when feeding greedy high voltage high capacity lithium at high rates, either through an inverter or a CCCV booster. Cooking your alternator is a definite possibility, so beware of Idling the engine to do so. You really need to be driving so the alternatorâs fan is spinning faster and there is fresh underhood airflow. If your battery voltage is less than 13.4v when powering a inverter and charger, or CCCV booster with engine running, it is likely your engine battery is being depleted despite the engine running and the LA voltage still being above nominal.
Lots of newer cars also play with the voltage regulation to try and squeek out a tiny % more fuel efficiency, so trying to second guess what the vehicle is trying to do regarding keeping its battery in an accountant determined acceptable zone, can be a fustercluck of confusion and tail chasing.
If you have an old lower voltage Esk8 battery that is still OK-good and needs a job, using that to power the CCCV booster, say stepping 10s voltages to 12s voltages, that works much better than stepping up 12v nominal to 12S voltages.
I have a bunch of different sized CCCV boosters and will feed them from 3S to 7S voltages to charge my 10S esk8s. I have carried 4 times the watt hours in 5,6,and 7S battery just to roll and charge or park and charge, and quadruple my range.
I still have my camper van and its 6v GC-2âs AGMâs are still somehow functional at 9 years old. It is parked about 5 miles away and I keep a â400 wattâ booster in there and will stop in and charge at 200 watts with a powerful fan blowing over it. It has about 180 watts of roof solar and will get the ancient GC-2âs back to full charge then next sunny day.
It also has 2 alternators, but if I idle parked to recharge they will overheat in about 20 minutes delivering 55 amps. If I drive they can deliver their 120 amp rating at ~1750 engine rpm, and stay far cooler.
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