charging lithium-ion battery from alternator

[edvanland]

Just installed a neg-to-neg battery charger for the lithium-ion batteries. first had to get a new alternator as the old one was shot. Then put in a new lead acid battery. It took a while but seems to be working. Since most functions on the bus run off my house batteries they should now be charged as we drive. Previously had to run the generator to charge them off the inverter.

[luvrbus]

What is a neg to neg charger ? ,I installed a DC-to DC Renogy 60A charger on my daughters RV, she has solar panels and I had to change her solar charger to a Renogy that would take away the solar charging when under way, if, you have a large amp battery bank it will take a while to charge a 60 amp was the largest charger I could find her bank is 400 ah with a 160 amp alternator a12V system 

[freds]

Interesting topic.

Most people install a DC to DC charger and accept only charging at say 400 watts off of the bus electrical system.

The problem with lithium-ion batteries an a alternator is that if they are fully discharged they can suck down hundreds of AMP's which cause them to burn out the alternator.

Full admission my alternator regulator on my bus hasn't worked since I bought it six years ago.

I do have a DC to DC charger that maintains the buses lead-acid battery off of the solar house battery system.

Hence I do tend to not drive after dark (also not really satisfied with the headlights on my bus).

In marine environments they use an after market regulator specifically the WakeSpeed alternator controller that communicates to the battery management system and let it control the charging of my house 24V lithium-ion battery pack . It is configurable so you can dial back the load and monitor the current output from the alternator, plus a temperature sensor to mount on the alternator. Other features like WiFi, etc.

Been kicking around the idea letting the bus alternator directly charge my house 24V lithium-ion battery pack and only use the lead acid batteries just for starting the bus.

Cogitating on maybe dumping the basically INOP house generator and lighten up the bus, which would give me more space for the house battery pack, etc.

[luvrbus]

The solar will keep her house batteries charged when parked most of the time when she is on the pole the inverter will top the Lion Energy lithium's, she has 2 lead acid starting batteries, I used a echo charger off the inverter to keep those charged, the next project in April is remove the loud, high amp draw Dometic Penguins roof tops, and replace those with either the new 12v low amp units or the 110v units the jury is still out on that, but I know I am not going with the mini split units     

[windtrader]

Not sure just what OP is wanting to charge, Li-ion house or lithium or lead acid starts?


What has worked for me is charging the house bank with solar which works 100% while parked and on the road under normal weather during the summer. During off season where multiple days of overcast/fog/rain reduces solar production may force me onto the pole or generator to fully recharge house battery. This happens 5% or less.

The starts are kept full via a cheap 120vac 12/24 DC battery charger. It has extended their working life as low capacity ut fully charged batteries are plenty to kick it over. I did finally break down this year when I grabbed group 31 Napa batteries for 99 bucks. I was seriously planning to use the house bank for starts and never found any reason why it would not work. Just needing 0000 wire from house to start bay. I have numerous times jumped the bus off the starts when forgetting to keep the charger on the starts and no issue at all. And that is with jumper cable wire of much less size.


And I agree that using standard alternator to charge house bank of any size is a loser. Yes, you will overload the alternator in no time. Since I park way more than drive, this was not an option I pursued to find a solution which are there but not work chasing to me.

[luvrbus]

Most 12v alternator have built in regulators with a max of 13.8 volts my daughter fried 2 trying to charge the lithium batteries,24v alternators are around 27.8 volts. The lithium batteries are great but a charging system can suck and be expensive, a regular battery charger won't charge the lithium I found out, I thought about adding a solar panel just for the starting batteries but decided on the Echo charger, so far all is good

[windtrader]

The problem with vehicle alternators is they are not engineered to charge lithium that can consume just about all the current you put to it. Voltage regulation is a factor as it has to match (ie 24v alt. and 24v battery). They are designed to charge lead acid or maybe AGM not lithium.


In practice, if your lithium SOC is high and it needs topping off then your auto alternator may do the job before melting down but 100% will fail if trying to charge a low SOC large capacity lithium battery.

[luvrbus]

I was told Balmar makes a alternator that will charge the lithium batteries for marine use, but for over $600.00 for a 170 amp alternator I passed on it because the voltage regulator was going to cost another $350.00 but I do like the Balmar regulators. I replace the old Delco regulator on buses with the 50d alternator with Balmar regulators you can buy those with Bluetooth and Lithium programing I never tried one because of the cost and the chassis batteries are lead acid