Charge 24v bank from alternator?

[MambaJack]

so close on buying the rest of my electrical system.
prob going a 2000 or 2400 watt inverter. Is there a way to go 24v to stay at lower amperage but still have the option in an emergency to install an isolator and charge form my bus alternator?

[john61ct]

If your alternator is 24V that's the way to go.

Otherwise look at DC-DC chargers like Sterling, or DC-DC converters, but too much of that and the cost is impractical compared to just putting in thicker wiring.

[Native]

Originally Posted by MambaJack

so close on buying the rest of my electrical system.
prob going a 2000 or 2400 watt inverter. Is there a way to go 24v to stay at lower amperage but still have the option in an emergency to install an isolator and charge form my bus alternator?

You might want to consider adding a second alternator (24V) for your house batteries.

[MambaJack]

Thanks, yea I decided to go ahead and go 24v may add that alternator later, good idea.

[BusLife4eva]

I've been reading through the threads and I'm curious if this would be a good option for assisting the solar to charge on cloudy/rainy days?

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F23 2689238556

[PNW_Steve]

Victron and a few others make chargers that will charge a 24 volt battery from a 12v source.

Or, add a second alternator (24v). That is what I am working on.

Take a look at: https://cwkits.com/

[TJones]

Originally Posted by PNW_Steve

Victron and a few others make chargers that will charge a 24 volt battery from a 12v source.

Or, add a second alternator (24v). That is what I am working on.

Take a look at: https://cwkits.com/

Steve,

Have you had any luck finding a bracket for a second alternator? I didn't see it for an ISC in the alternator section. Looks like they have hydraulic pump brakets.

I've thought about adding a second alternator as well and using an advance alternator regulator like what Sterling sells to charge it. It would put out more amps than a battery to battery charger.

Ted

[Native]

Originally Posted by TJones

Steve,

Have you had any luck finding a bracket for a second alternator? I didn't see it for an ISC in the alternator section. Looks like they have hydraulic pump brakets.

I've thought about adding a second alternator as well and using an advance alternator regulator like what Sterling sells to charge it. It would put out more amps than a battery to battery charger.

Ted

Not Steve ...

They did not have a kit for a second alternator for a CAT 3126, but they had a kit for an air conditioner compressor. They took the specs for the alternator I was purchasing and designed the bracket using the specs and the air compressor bracket as a starting point. I only had to do two modifications.


First, I had to make the adjustment slots in the bracket a bit longer to clear and interference point. It was a simple honing job.


Second, the replacement serpentine belt they sent with the kit was two inches too long. I figured out the correct length and got it at O'Reilley's. It has been working great since then.

[TJones]

Originally Posted by Native

Not Steve ...

They did not have a kit for a second alternator for a CAT 3126, but they had a kit for an air conditioner compressor. They took the specs for the alternator I was purchasing and designed the bracket using the specs and the air compressor bracket as a starting point. I only had to do two modifications.


First, I had to make the adjustment slots in the bracket a bit longer to clear and interference point. It was a simple honing job.


Second, the replacement serpentine belt they sent with the kit was two inches too long. I figured out the correct length and got it at O'Reilley's. It has been working great since then.

Nice that they will do a little custom work!

Thanks

Ted

[Jsneeb]

Yes you can charge a 24V bank from a 12v source.

THe second alternator is the superior option for accomplishing this. But also has it's challenges.

A unit like this would do the job. But is rather undersized for any kind of fast charging ability.

https://www.amazon.com/Converter-Adj...motive&sr=1-10

You could use several together but you need to set the voltages up just right and use similar gauge and length wire, or one module will take up all the load.

If you are just looking to help out the charging solar system then it would be a good cheap and easy option to acomplish that.

If you are looking to do regular full charges on your 24V battery pack in something under 8 hours then look elsewhere.

[Jsneeb]

This module looks like it would be up to the job. rated at 22A output.
In fact Im going to buy one and try it out, as I have wanted to do the same thing as you are describing. ( aid recharging of the 24V batteries from my bus while it's running )

https://www.ebay.com/itm/1pc-1800W-D....c100752.m1982

[PNW_Steve]

Originally Posted by TJones

Steve,

Have you had any luck finding a bracket for a second alternator? I didn't see it for an ISC in the alternator section. Looks like they have hydraulic pump brakets.

I've thought about adding a second alternator as well and using an advance alternator regulator like what Sterling sells to charge it. It would put out more amps than a battery to battery charger.

Ted

I sent CW pictures of my ISC and they are working on it.

I have dealt with the Belmar regulators and their alternators. Pretty good stuff.

The dc-dc charger is probably better than getting poked in the eye with a sharp stick but the dedicated alternator is the bomb.

[john61ct]

Using a DCDC converter, or any straight PSU as opposed to a proper charger, means you the human must act as voltage regulator and manually terminate the charge cycle when (you believe) the target bank is Full.

Too early, PSOC abuse, reduce lifetime

Too long, overcharging, deadly for sealed batt types.

The Sterling 12-to-24V being purposefully and well designed for exactly this purpose, makes things much easier, being automated, and will likely result in much better battery lifespan.

[Jsneeb]

Not the case with any of the units I linked too.

The cheap Amazon one can be setup to CV mode with the potentiometer , and a simple half ohm resistor would cap the current.

Other unit I linked has CC and CV adjust-ability. Set it to 26V for lead acids and 15A CC and forget about it. Will never need human intervention and will begin charging at any time that the pack is below the setpoint CV and the ignition circuit has power, ( I.E Alternator running )

I think the dedicated alternator is the way to go, but if the effort is too great, and all you want is 10-20A of charging whenever the bus is running, then the Dc-DC converter would be the easiest way to accomplish this goal.

[john61ct]

Sorry, but have to challenge that.

Dropping to Float or completely terminating output once Full has been reached, are required if you care about longevity of an expensive bank.

As is following mfg specs for Absorb setpoint and endAmps trailing current.

No decent bank will spec 26V, will easily lose 20-40% of its cycle lifespan never getting to Full.

Even the best charge sources **designed as chargers** need tweaking of Absorb / CV Hold Time in order to do so properly.

Feel free to do whatever you like for your own setup, with cheap Wally batts no great loss,

but bad advice can cost other members a lot of money, or in some cases even be dangerous.

[TJones]

Originally Posted by PNW_Steve

I sent CW pictures of my ISC and they are working on it.

I have dealt with the Belmar regulators and their alternators. Pretty good stuff.

The dc-dc charger is probably better than getting poked in the eye with a sharp stick but the dedicated alternator is the bomb.

I'll be watching to see what you get put together for a system. Are you still thinking 4-6 L16-H batteries for your bank?

Ted

[PNW_Steve]

Originally Posted by TJones

I'll be watching to see what you get put together for a system. Are you still thinking 4-6 L16-H batteries for your bank?

Ted

Well......

Yes I am. Four L-16's in series yields a 24v 400a/h bank. Not sure what you could do with 6?

[PNW_Steve]

Originally Posted by Native

Not Steve ...

Not Steve and happy about it?

I would think that you would be ecstatic to be me....

[Doktari]

I haven’t found a easy or inexpensive solution for charging a 24 volt battery from a 12 volt system. Adding a second alternator would not be worth it for me as my bus is not run for long periods. I wouldnt want to run the bus engine to charge batteries. I’d run a inverter technology generator and a 24 volt PFC charger instead.
There is a more powerful buck boost converter on Amazoon. It’s advertised as 1500 watts but my electronics friend said not to run more than 900 watts through it. I read an article about a guy using one of these bucks to run his 48 volt electric bike from a 36 volt battery.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[john61ct]

Go ahead and do cheap charlie redneck engineering as a temporary workaround.

Meantime save your pennies, scale back on meals prepared by ithers a while and soon you can just buy a Sterling 12-to-24V DCDC charger and do it right.

They do come up on eBay sometimes, secondhand boating gear places, etc.