24v sorta alternator(s) , 24v truck sorta , 1000w solar panels and lithium

[coachgeo]

complicated and looking for advice.

. 28v/14v 200* amp/50amp alt. on engine (yes dual voltage) will use 28v side for charging probably to primary 24v wet battery bank on engine first and house lithium battery second (yup military truck based camper) Yes truck has 12v accessories and lighting. Its 24v series/parallel wired batts get 12v pulled of one bank of two bats... I can add a balancer to prevent one bank getting harmed by this (not yet installed-- unit does NOT work with Lithium)

. 28v/14v 100 amp/50amp alt. on APU (yes dual voltage) will use 28v side for charging.... back up for cloudy day... top up.... again primary engine batts first.... then house

the alts both go up to 32v or 16v... so they need limited to not overcharge into lithium... again only 28v side for lithium house charging.. both have thermal protection of some sort on external regultor.

would like to NOT duplicate things to use APU alternator

. 1000w solar panels (already purchased) but do not yet have an inverter charger or anything else for that matter.

* technically up to 50 amp max on 12v side of each alt. is robbed away from the max amp output at 28v on these alternators.

sooooo what are options for also charging house and start batteries with solar AND alternators. Seems so far all I can find limits my use to half the potential of the 200amp alt at 28v side... that is sad. Paid a good bit for that alt. to only find out I may not can use its potential

 

[coachgeo]

have looked at the 24v set up page thru here at DIY solar..... but this page does not yet answer my higher output potential I would like not loose.

open to thoughts and ideas.

 

[coachgeo]

???? poor man going broke lol

 

[coachgeo]

So is my post's wording to confusing?

 

[coachgeo]

oaky doaky..... is it really that complicated?

OK.... how about deal with one thing at a time.... 24v alternator that can put out max 150amps.... want to use it to charge truck and house batts (both 24v) when driving (truck first... top up house second)

 

[Dzl]

Seems so far all I can find limits my use to half the potential of the 200amp alt at 28v side... that is sad. Paid a good bit for that alt. to only find out I may not can use its potential

Largest I have seen is a 120A dc-dc charger from Sterling Power. I can't remember if it was 12-12, 24-24, or 12-24. I wonder if not using the full 200 Amps is actually a good thing (for the longevity of the alternator)? From what I've read (which is very little), normal automotive alternators don't like and weren't designed to be run at near maximum for long periods of time, but I'm guessing this isn't the case with your aftermarket alternator. I would reach out to Sterling Power directly, they seem pretty knowledgeable about this sort of stuff.

Sorry I don't have much to contribute.

Who built your Alternator? is it OE or aftermarket?

I believe you are the owner of the LMTV right? Have you researched/asked around on expeditionportal.com or military surplus forums like steelsoldiers.com (which has an FMTV/LMTV subforum)? Marine forums might be a good bet too. I wonder if either of these outfits might be able to provide some input (they both specialize in LMTVs) AcelaTruck.com and GrisbyTrucks.com

 

[coachgeo]

Largest I have seen is a 120A dc-dc charger from Sterling Power.....

thanks.. I'll look them up

....Who built your Alternator? is it OE or aftermarket?...

I believe you are the owner of the LMTV right? Have you researched/asked around on expeditionportal.com or military surplus forums like steelsoldiers.com (which has an FMTV/LMTV subforum)? Marine forums might be a good bet too. I wonder if either of these outfits might be able to provide some input (they both specialize in LMTVs) AcelaTruck.com and GrisbyTrucks.com

200map Alternator is sorta OE, it is off a hummer. Same manufacture.. different dimensions/output. The 100amp Niehoff alternative to swap onto the APU is the OE.

any yes... it is an LMTV and alternators are beast built by Niehoff. the 200 amp as described in opening post is only capable of 150amp max I believe.. always keeping 50amp available for the 12v side.. The 100amp similar..... 50amp sorta reserved for 12v side so its 50/50@12v/24v


As you guessed am very familiar and long time member of all the pages your mention. Actually a moderator on similar pages too.

 

[Stupid Monkey]

50A B2B are quite common, might be easier/cheaper to get a couple of those, but depends how much power you want to pull.

My truck just has a 24-12 30A DC/DC charger and thats fine, also have a 30A mains charger. If I'm short of power I'll use the generator (rather than engine) to power stuff and while it does also charge the batteries). Is setting up to charge that amount from an engine not very very inefficient ? just get a mains charger and a small 1kw/2kw genny ?

 

[coachgeo]

thanks.. I'll look them up ...

grrr..... they say when you spend more to do it right (tis why got higher output alt) it cost you less.... WRONGGG.. the dang alternator/charger from Sterling is just under a thousand bucks

 

[coachgeo]

50A B2B are quite common, might be easier/cheaper to get a couple of those, ... If I'm short of power I'll use the generator

B2B?? you mean wire back to back more than one 50amp... somethings?

if it remains so costly to use my engine alternator.... and I need juice still guess will use genny too as Im driving.... well its an APU but same net effect. Just stupid to have two engines running at same time.

 

[Stupid Monkey]

Of course not if your moving anyway. But yes you can get 2 x 50A battery to battery DC/DC chargers instead of 1 x 100A just like you can have 3 x 30A MTTS or 1 x 100A ...

 

[Dzl]

B2B?? you mean wire back to back more than one 50amp... somethings?

B2B = Battery to Battery I believe. And I think he is talking about wiring two B2B chargers in parallel like some people do with charge controllers.

One thing that I learned last night is that the nominal amp output of an alternator is not what you should plan on, the nominal ratings is a 'cold rating' and efficiency drops as it heats up. At best, take the nominal amp hours and multiply by 85% for a normal operating efficiency. So 150x.85 - 127.5 amps. But then this is apparently only achieved at max engine RPM, real world will be less in normal driving conditions (although with an LMTV on the highway maybe max RPMs isn't that unlikely .

Take this with a grain of salt, I'm just reciting what I recently learned in regards to marine alternators. I'm not sure if it applies to conventional alternators, smart alternators, or both, and I'm not sure how having a much larger medium-duty cat engine and a beefy alternator might effect things.

Here is the source: Marine Electrical Seminar | Jeff Cote, Pacific Yacht Systems)

 

[coachgeo]

question...... can you just install a cut off point..... from alternators charge say...... when lithium needs to move into a charge phase that is not the norm for alternator charging systems..... then just have it cut off the alternator connection from the lithium set (I know it must remain connected to something though.... ) and let the solar do the rest?

Or is it more to it than that...... such it in charging at too high voltage (which is something I seem to recall being an issue)

 

[FilterGuy]

@coachgeo : What is the size of the battery bank? What is your daily amp-hour need? The reason I am asking is that if your battery and solar is large enough to cover your need, getting that last electron out of the alternator is a lot less important.

Some people live on less than 1000W solar on their camper and don't even charge the batteries from the alternator.

 

[FilterGuy]

Here is the source: Marine Electrical Seminar | Jeff Cote, Pacific Yacht Systems)

Funny.... as I was reading through this thread I was thinking I should reference this video as well.

Jeff Cote is a great resource to learn from even if you don't do marine work. Most of what he covers is applicable to far more than Marine.

 

[Dzl]

Funny.... as I was reading through this thread I was thinking I should reference this video as well.

Jeff Cote is a great resource to learn from even if you don't do marine work. Most of what he covers is applicable to far more than Marine.

Yeah, it seems like for mobile systems (and to a lesser degree off-grid in general), Marine systems and the marine community/industry is one of the best sources for information. They are very serious and in general need to pay a lot of attention to robustness and resilience of the system and factor in harsh operating conditions. There is not much research for land based mobile systems out there, so having the marine community to rely on is super helpful and most aspects of marine electrical are applicable to land based mobile systems as well.

 

[coachgeo]

@coachgeo : What is the size of the battery bank? What is your daily amp-hour need? The reason I am asking is that if your battery and solar is large enough to cover your need, getting that last electron out of the alternator is a lot less important.

Some people live on less than 1000W solar on their camper and don't even charge the batteries from the alternator.

working backward..... more electric I can produce the more electric devices I will use and the less LP. I have 1000w solar..... but will drive most days.... and sit only few days. Probably LiPo batts... either Leaf or Tesla repurposed

 

[coachgeo]

Delete me

 

[FilterGuy]

I am not familiar with dual-voltage alternators and I am having a hard time picturing the existing set-up. A drawing/diagram would be useful.

However, the bottom line is that you want a high-amp way of charging from the 28 V side of the alternator.

working backward..... more electric I can produce the more electric devices I will use and the less LP. I have 1000w solar. built from five 100w two panels banks/24v arrangements.... but will drive most days.... and sit only few days. Probably LiPo batts... either Leaf or Tesla repurposed

The tesla battery modules you can acquire are NCA chemistry, or Nickel, Cobalt, and Aluminum (LiNiCoAlO2) chemistry . I am less familiar with the leaf battery packs but they use a LiMn2O4 with LiNiO2 chemistry. Both of these require a different charge profile than LiFePO4 but can still be used with a lot of the commonly available solar equipment (as long as the charge parameters are configurable).

I believe both the leaf and tesla batteries are susceptible to thermal run-away, so you will need to be careful with charging or discharging them. However, even with your large alternator you will probably be OK. (but it is something to check). Do you know what size inverter you will be using? This will tell you the current draw on the batteries while you are discharging. Normally I would not worry but you seem to be building out a hefty system, so it is worth checking. Of course, you can always hook the cooling system up, but that is probably not what you were planning.
Back to charging from the alternator.
For now, I will assume you will be using one tesla module which is ~5500 Watt hours or 230 amp hours. If you use two of the 40 amp chargers wired in parallel, you would generate 80 amps and be able to charge a depleted tesla module in 230/80=2.8 hours. Call it 3 hours. Since you said you will be driving a lot, this may be all you need.

https://www.amazon.com/Renogy-Battery-Batteries-Multi-stage-Charging/dp/B07Q4SVX3M

You mention that you also have an APU but you would prefer not to duplicate equipment to charge from the APU. Is the 28 V from the APU wired into the same 28 volt of the alternator or is it completely separate? (I assume it is separate, but your description sounds quite unique)
Assuming they are separate circuits you would need to use some kind of battery selector or high current switch to switch the chargers between the two sources.

https://www.homedepot.com/p/Blue-Sea-Systems-E-Series-Selector-Battery-Switch-9001E-BSS/309892353

(Be careful, this switch has a 1+2 position that would tie the two 28V circuits together. If this is a problem, you probably want to find something else.)



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