Alternators for dummies

[RandyDaytona]

Hey guys,

I wasn’t sure if this should go in SQOD, but I thought it might get lost among all the questions there. I also did a search, and the feedback people are getting on alternators are from folks who are apparently way smarter than I am.

I have a 3000 W inverter which powers my EcoFlow battery, which in turn powers my fridge and a small fan.

I have noticed that the inverter works just fine and charges the battery normally when I’m driving at highway speeds, but when I slow down to make a turn or similar, my inverter starts giving me an error message and a warning beep. As soon as I speed up, the message and the beep go away.

It was suggested to me that I might want to look at a higher output alternator. I’ve seen others say that that OEM alternator is just fine (I have 265,000 miles on my 2014 LC) and others who say that it’s possible that the factory alternator cannot keep up with the duties I have tasked it with.

Does this make any sense? I have a very vague knowledge of how alternators work, probably the same knowledge as anyone else who doesn’t know anything about cars. If this is the case, can any of you recommend a replacement alternator?

I realize this is an oversimplified question, so thank you in advance for reading this.

 

[TeCKis300]

Yes, you'll need to do something with the alternator. The factory setup will not tolerate that long term and will burn out. Especially at idle, where it doesn't have the input RPM to generate that kind of power and will overheat and burn out.

Here's a like to some potential options. I would look into the higher power alternator replacement linked there by @FrazzledHunter

You might also consider a DC-DC solution instead of an inverter. They are much more efficient long term.

Thread 'More Power! Alternator on Overdrive'

Apr 30, 2024

Following in the footsteps of @FrazzledHunter and his full 390A alternator upgrade:
Alternator upgrade - done! - https://forum.ih8mud.com/threads/alternator-upgrade-done.1329033/

What​

A smaller alternator overdrive pulley and matching belt to spin the OEM 180A alternator ~16% faster. Not necessarily to expand max output, but to add low rpm output support and longevity against added loads.
Stock pulley is 2.25". Overdrive pulley is 1.93".
Stock engine to alternator drive ratio is 3:1. Overdrive ratio is 3.65:1
Min alternator RPM of 2,000 (stock 1,650) at 550 engine...

• TeCKis300
• Replies: 15
• Forum: 200-Series Cruisers

• 

 

[kcjaz]

I use EcoFlow’s alternator charger to charge my EcoFlow battery. It’s really just a DC-DC charger. It will charge up to 800 w but you can set it to whatever you want. IMO 800 watts is too much for the stock alternator long term as that is adding 67 amps to all the other loads. The EF app lets you set the amp draw directly and I generally set it at 20 amps which is about 250 watts.

I’m no battery system expert but I think that if you use a 3000w inverter, it will let the EF battery pull its max AC wattage. Thats 1200 watts for a Delta2. There would also be some efficiency loss through the inverter so you might be pulling something like 1500 watts from the alternator. That would be 125 amps which is way too much.

 

[FrazzledHunter]

Yes, you'll need to do something with the alternator. The factory setup will not tolerate that long term and will burn out. Especially at idle, where it doesn't have the input RPM to generate that kind of power and will overheat and burn out.

Here's a like to some potential options. I would look into the higher power alternator replacement linked there by @FrazzledHunter

You might also consider a DC-DC solution instead of an inverter. They are much more efficient long term.

Thread 'More Power! Alternator on Overdrive'

Apr 30, 2024

Following in the footsteps of @FrazzledHunter and his full 390A alternator upgrade:
Alternator upgrade - done! - https://forum.ih8mud.com/threads/alternator-upgrade-done.1329033/

What​

A smaller alternator overdrive pulley and matching belt to spin the OEM 180A alternator ~16% faster. Not necessarily to expand max output, but to add low rpm output support and longevity against added loads.
Stock pulley is 2.25". Overdrive pulley is 1.93".
Stock engine to alternator drive ratio is 3:1. Overdrive ratio is 3.65:1
Min alternator RPM of 2,000 (stock 1,650) at 550 engine...

• TeCKis300
• Replies: 15
• Forum: 200-Series Cruisers

• 

Just a quick update on the alternator and overall setup. It’s performed flawlessly since day 1. I'm able to charge my Yeti 1500X (380W) and my travel trailer (600+ W) while under tow at the same time. I'll be replacing the Yeti with Bluetti unit (probably) which allows charging up to 800W.

 

[bloc]

What do you have the AC charge rate of the EcoFlow set to? It is adjustable.. but by default it is set to 1500W (iirc) which would rightly hammer the stock alternator.

If it hasn’t been set to a lower rate you should do so, and that would buy you some time.

Also consider getting the EcoFlow alt charger or a DC DC unit as outlined above. The setup you are using now is quite inefficient.. the alt is making AC, which is getting converted to DC before it leaves the unit, converted back to AC in your inverter, then the EcoFlow is converting it back to DC to charge the cells. Each of those conversions introduces losses.

When set up correctly you don’t really need the inverter, considering the EcoFlow has AC outputs built in.

I have the alternator charger and it works really well, fully integrated into the EcoFlow software even.

 

[Fisher23]

Did I read this right, You are using a 3000w AC inverter to charge your EcoFlow battery?

Why do need a 3000watt inverter, is it used for other things?

If the 3000 watt inverter is ONLY used to charge the ecoflow battery then you should remove the 3000 watt inverter and use the ecoflow alternator 500 watt charger.

If you need to keep the 3000 watt inverter then you need alternator -> dc charger -> lithium battery -> 3000 watt inverter -> ecoflow battery

 

[RandyDaytona]

You guys rock!! Beers for all of you if you’re ever near the Chesapeake Bay!

I’m not sure on the charge rate of the EcoFlow. I will check it when I hit the road.

Yes, the 3000w inverter charges just the EcoFlow. I guess it’s overkill and not in a good way. I’m interested in their alternator charger and will have to check that out.

When I was looking at inverters, my local shop suggested and installed the 3000 watt unit. It’s obviously my fault for deciding to go with it, but I didn’t know squat about inverters. And apparently still don’t.

I also DO idle quite a bit. AC and Heat, season depending, obviously. That can’t be helpful.