Lithium Battery Alternator Charging | Don't Blow Up the Alternator | DIY Truck Camper
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- เผยแพร่เมื่อ 30 ก.ย. 2024
- Our Ford F350 / Maximus rig has a Lithium Battery Alternator Charging system.
We heavily used our 2nd alternator charging system last summer to charge the Lithium Battery bank when our solar panels failed. 4 out of 5 solar panels failed! But that's not what this video is about.
Relying heavily on a 2nd alternator without taking overheating into consideration will burn out your alternator. Steve takes you through the work on his 2004 Ford 2nd alternator update to relocate the diodes away from the hot alternator and provide a method to provide cooling to the device.
**NOTE**
We originally published this video in March 2022. The work was done, but it wasn't tested. Testing failed and I discovered the alternator wasn't wired in the correct configuration after all. It needed to be re-wired as a 3 phase wye configuration. Originally, I had not located the Ford documentation and since then I have located the documentation to confirm the correct configuraton.
#charging alternator
#charging lithium battery
#maximus 4x4
Some initial testing done on two separate occasions: 1) At 98F ambient on level to slight uphill freeway at 210F engine coolant temp, I could charge at 28.8V/90A (about 2.5kW) with alternator at 228F/114C, continuously. 2) At 40F ambient with about 140F engine coolant temp (in a snowstorm) on a winding downgrade 2 lane, I could charge at 27.4V/100A (2.7kW) with the alternator at 180F/78C, continuously ( and clearly could have tested much higher if not for the winding road). Overall I feel performance has improved at least 30%. It is difficult to replicate operating conditions for comparason. With the original alternator, in conditions similar to test 1, I would not have expected to get much more than 60A because of the high ambient and engine temps.
Its expensive but I installed a Litens OAD decoupler pulley on my 180 amp small case denso alternator. Most modern vehicles have a clutch or decoupler pulley to prevent issues with belt vibration. Seems like some people have an issue with using a solid pulley and some do not.
I believe decoupling pulleys are more common on smaller vehicles with fewer cylinders where power strokes occur every 90 degrees of crank rotation. I think acceleration and deceleration (of smaller cars) also has a greater effect on belt pulsation. I don't believe that 'most vehicles' have them but since I have never owned a vehicle with one, I have no real experience with their effects.
I love your videos. I'm just wondering why you wouldn't use maybe 4 awg silicone tinn plated wire so maybe there wouldn't be as much heat in the wires. I think that heat means there is power being lost in the wires but maybe the power lost isn't a concern but that kinda heat would worry me especially over long term use. I love the way you put that heat sink into the fan shroud. That was the best place for sure.
I used 8AWG wire because that was physically substantially as big as I could make a connection to the 3-15AWG windings in the space available inside the back of the alternator. 8AWG/200C wire is also capable of carrying the 137A that each phase could operate at if the alternator were ever to produce 200A. I already knew that the 220A rated alternator would exceed 120C producing around 100A with a 85F ambient air and 200F engine temp. I was hopeful that removing the heat produced by the diodes that I could maintain or slightly exceed the 100A output at up to 100F ambient and 220F engine temps. The silicone insulation is more about surviving operation at these temps produced by the engine and alternator heat than the Ohmic heating of the wire itself since I'm intending to operate at about half of it's max current capacity. The 8AWG silicone only runs 3ft between the alternator and diode bridge then I run 2AWG welding cable from the diode bridge to the battery which is somewhere around 16-18ft for each conductor.
Are you using MR2535 diodes for your TVS?
Littlefuse 5KP33CA...5kW, 33V standoff, CA= Bidirectional for my 24V system. I've used some 18V standoff versions for 12V systems. They make 3 series that will work for 12v systems; P6K is 600W, 1.5KPC(?) is 1.5kW, 5KP is 5kW. They also make bigger series that have bad leakage characteristics around 12v system voltages. If you want more info, I'm working on a blog post that will get posted in a week or so.
Clever. Like Clark's big brain stuff I understood about 5% of it, but get the gist. Think I'll have to date an electrical engineer when I fit out my boat 😉
Lana,
I think Clark and I have taken similar approaches to similar problems. That makes us kindred spirits in a world of 'lesser obsessed' people, most of whom would like to be enlightend....we are hear to help and disscuss..
Great information 👍
I use a 60 amp dc to dc charger on a 2021 Ford E350 cutaway van with the 7.3 gas motor.
The brochure says the alternator is rated to 240 amps.
At idle with the ambient temperature 95F the alternator runs at 190-198F with ac and lights on.
Turn on the dc to dc charger and the temperature spikes to 240 - 247 F.
So I only switch the dc to dc charger once I actually driving the van and I switch it off when in traffic or idle.
Have you watched the victron video about cooking an alternator?
th-cam.com/video/jgoIocPgOug/w-d-xo.html
Yes, I have seen Victrons video and it is accurate. That is why measures must be taken if charging from an alternator. Lots to unpack on the subject.
1) I have a volt/amp/temp readout on my second alternator that is used only to charge my battery. The temp readout is also a thermostat to shut off charging when the alternator temp reaches 120C. I manually adjust charging to my operating conditions and only use the thermostat as a safety.
2) See my blog for alternator thermal overload protection with a DC charger; workingonexploring.files.wordpress.com/2022/04/alternatorthermalprotection.pdf
If you want one, send me your address and I will mail it to you free of charge in return for installation photos and evaluation information.
3) Understand that 'rated' capacity means what the alternator puts out at 6000RPM during its 2-minute performance test, into a resistance load bank, on a bench test, with 70F cooling air. It is only useful to compare alternators and has NEXT TO NOTHING TO DO WITH WHAT IT WILL PUT OUT CONTINUOUSLY IN YOUR VAN. Assume an alternator can put out ~1/2 of its rated capacity in your vehicle.
4) Assume your A/C condenser, coolant radiator, oil cooler, transmission cooler, charge air cooler (if you have an intercooled turbo) etc will raise your underhood temps by 40-60F from ambient and that is what your alternator will have for 'cooling air'.
5) I have several videos on charging with an alternator as well as some docs on workingonexploring.com/techdocs.
6) You MAY have enough reserve capacity for a 60A charger but understand that a 60A charger OUTPUTS 60A at around 14-15V (900W max) into your battery. When your smart alternator is running at 'normal' output, it is only delivering 13-13.5V. The DC converter is only 93% efficient. To deliver 900W OUT of the charger, the input will need to be 900W/.93 = 968W. INPUT AMPERAGE of a 968W load at 13.0V is over 74A. That is the load on your alternator.
7) Alternator capacity at low RPM is barely enough to operate the engine because the alternator has very little cooling air from the fan.
8) Alternator capacity at high RPM (above normal engine speed) is greatly decreased because alternator efficiency drops from ~75% at low engine speed to ~40% at high engine speed. Loss of efficiency means lots of extra heat created in the alternator.
9) You need to measure your vehicle/engine demand over the range of accessory operations you are likely to encounter at around 2000 engine RPM and see if you have a reserve of 74A to operate your DC charger. Put a clamp meter on your alternator cable and turn on your lights and heater, etc to find peak demand. 240A/2 = 120A - peak operating load = reserve capacity (at nominal engine RPM). This is the MOST YOU WILL EVER BE ABLE TO COUNT ON. Low engine speed will be less, high engine speed will be less, and adverse driving conditions will be less.....
10) alternators have no thermal protection. They respond to overloads by overheating till they fail. You have already figured that out. If you put a device able to overload your alternator, you had better have a way of unloading it when it overheats.
I suggest you watch this video and possibly the second one. th-cam.com/video/gDIsOaEI9Wo/w-d-xo.html&ab_channel=WorkingOnExploring
The more I see your rig you built the more I like it. I'm still building out my holiday travel trailer for off grid living but being on the road in this semi 3 weeks at a time is making for slow progress on the camper. I'm wanting to build a 24 volt charger from a diesel 24 volt alternator and a harbor freight engine next
Sorry I missed your comment
Automotive alternators are very inefficient and if you want to do the best possible, get a brushless alternator. They are around 75% as compared to about 60% for a claw pole design (standard automotive). Military surplus alternators are brushless and were cheap 4 -5 years back. I bought several which I am now not planning to use. I have 2-24V/400A and a 12V/24V/200A. These things are very heavy and big. I converted a 12V/220A Ford 4G to 24V. It works fine but its not something I would want to use a lot (poor efficiency and heat) but it was the only option I had.
@@WorkingOnExploring do you think I'd be better off just using my 120 volt to 24 volt chargers and a generator when I don't have enough sun to charge? I'd say going to harbor freight and buying a generator might be my best bet but I do like the alternator set up
I think a small portable 120V inverter generator would be more economical, reliable and lighter. THE KEY is to get a battery charger that can put a max load on the generator. You don't want to have a 2kw generator and a 1kw charger. The likely best way to do that is with a low frequency inverter-charger. My Samlex EVO 4024 allows me to set how much power it can draw from an AC source. I can set it to the max of a generator capacity OR the max of a shore connection. It allows me to draw whatever AC I want in the camper and the rest goes to charging. Charging is a second priority so AC appliances always have priority. The charger is 110A (at up to 29.4V) so is capable of fully loading a 3kw generator. If I am drawing max battery charge and I stick something in the microwave, the microwave gets what power it needs and charging decreases. When the microwave goes off, charging increases. This is most helpful when my 120V/30A shore cable is connected to a 120V/15A circuit at someone's home that may also be powering something in the home. If I set it to 10A to make sure I don't pop their breaker, that isn't enough to run the microwave. If I try to use the microwave, it switches to inverter and draws battery power to operate the microwave then goes back to charging. Mine does not have a power sharing where it augments the insufficient shore power by adding inverter power to make up the difference but several inverter manufacturers have that too.
@@WorkingOnExploring I have a low frequency sungold but it's the 4000 watt split phase. It will do charging but it would take a 220 generator. I also have a 3000 watt all in one powmr that I can adjust the charge buy it will only do 40 amps and I'd like something that can charge at 150 or even 200 amps. Maybe even more.
You Sungold is only charges at 50A (about 1400W) which is a problem because you'll likely not find a 240VAC generator less than 3kW. Requiring a 240VAC shore input is also a problem as it is likely only available at a premium site in an RV park. I rarely need shore power and don't have a generator. When I do plug in, There are lots of times where I run on 10A/120V.y A/C only needs 8A max to run with no starting surge. Do you have a need for 240V output? If not, you'll be better off with a 120VAC only. I'd look at what you really need for AC power both in and out. Inverters are very inefficient if run at less that 30% load (1200W). I wanted 3kw but it was harder to find in 24v. I also run an 800w PS inverter continuously to support the domestic fridge and small 120V loads 24/7 but that might be a bit big too.