What happened to the 24v DIY system web page?

[Dzl]

Oh, great. $4,500 later I find out 24v isn't the way to go.

Will has opinions and preferences just like anyone else; based on his own experiences and priorities and research. And system voltage is one of those things where everyone's got an opinion, and everyone's got valid reasons why they prefer what they prefer, often it has more to do with specific context and what you prioritize, rather than one or the other being objectively better or worse in general. Will's opinion (or anyone's opinion) on what system voltage is best or worst in the abstract are valid but shouldn't make you regret the choices you made for your specific situation/priorities. If it made sense when you designed the system, anyone else's opinion doesn't change that. As to the cost, Battleborn Batteries were never the choice if cost was your #1 priority, I assume you had other reasons for going that direction.

 

[pda1]

Will has opinions and preferences just like anyone else. Based on his own experiences and priorities and research. And system voltage is one of those things where everyone's got an opinion, and everyone's got valid reasons why they prefer what they prefer, often it has more to do with specific context and what you prioritize, rather than one or the other being objectively better or worse across the board. Will's opinion (or anyone's opinion) on what system voltage is best or worst in the abstract are valid but shouldn't make you regret the choices you made for your specific situation/priorities. If it made sense when you designed the system, anyone else's opinion doesn't change that. As to the cost, Battleborn Batteries were never the choice if cost was your #1 priority, I assume you had other reasons for going that direction.

Well, here, let me explain why I got BB batteries. In my situation BB were the best choice considering how long they're expected to last, given proper care, reliability and safety considerations. Yes, FLA, AGM are cheaper but considering how many I'd go through over the estimated system lifetime they're cheap. And....considering [the high current and future] inflation, the rise in prices over the next 5 years will make the BB's look cheap. Also, BB batteries are domestically made so I didn't have to deal with ships anchored off of california...while waiting and waiting.

BB does a very good job in promoting their batteries and the benefits of same. Most FLA makers don't do anything similar and thus "I voted with my money".

BB does a very good job in providing technical assistance.

 

[Rednecktek]

Well, here, let me explain why I got BB batteries. In my situation BB were the best choice considering how long they're expected to last, given proper care, reliability and safety considerations. Yes, FLA, AGM are cheaper but considering how many I'd go through over the estimated system lifetime they're cheap. And....considering [the high current and future] inflation, the rise in prices over the next 5 years will make the BB's look cheap. Also, BB batteries are domestically made so I didn't have to deal with ships anchored off of california...while waiting and waiting.

BB does a very good job in promoting their batteries and the benefits of same. Most FLA makers don't do anything similar and thus "I voted with my money".

BB does a very good job in providing technical assistance.

Don't feel bad at all. You got Tier-1 stuff and the system does what you need it to so it's the right system. Nobody here is going to argue that BB batteries are a bad choice if you can afford it. $4500? That's not too bad. $4500 with 2x BB batteries? Pretty good deal!

 

[HRTKD]

As with many things, the "optimal" system voltage depends on your situation.

I can fit eight 280Ah cells in my RV trailer. 16 cells? Not going to happen.
As @chrisski said in his post, the selection of properly rated devices decreases above 24 volts.
I simply don't need 24 volts. 12 volts simplifies the landscape of my system. 24 volts increases the complexity.

 

[Cajunwolf]

Yeah, I have a 1988 28-foot class C RV, and pondering how I'm going to cram my four batteries, MPPT, inverter, and accessories somewhere that leaves me adequate living space. I was going 12-volt but soon realized there was a 1900-2000-watt wall. I bought one more 12-volt 200AH battery (all LiFePO4's) to go 24-volt and going with a 4000-watt 24-watt inverter. I'm going to have a hard time fitting enough panels on the roof as is and will have two on the WJ Jeep while towing; ground deployed when boondocking. I just don't see going to 48 volts as an option. If I were made of money, I would have bought a bigger class A with 48-volts all the bells and whistles, but I'm a poor old fart on retirement. I can't afford tier-1 stuff, not even close. I got this little RV for $4k, cash money, she's all mine, and it's where I'll be living.

 

[Hedges]

I'm going to have a hard time fitting enough panels on the roof as is and will have two on the WJ Jeep while towing; ground deployed when boondocking.

Charge from engine while driving?
Alternator output is limited, probably mostly by diodes for positive side (poorer heatsinking).
I once tapped off the three stator windings and added an external rectifier.
24V? Boost converter. Or 12V/24V transformer(s) fed from AC of stator.
An over-temperature shutdown on the charger load would be a nice feature.

I got this little RV for $4k, cash money, she's all mine, and it's where I'll be living.

Congratulations, a roof of your own is what matters.

After I bought a mountain lot, I looked into porta-potty and holding tank service. Old RV was cheaper.
Late '80's, cost me about $1000 for an 18 footer, registration penalties, replacing missing fixtures.

 

[Cajunwolf]

Charge from engine while driving?
Alternator output is limited, probably mostly by diodes for positive side (poorer heatsinking).
I once tapped off the three stator windings and added an external rectifier.
24V? Boost converter. Or 12V/24V transformer(s) fed from AC of stator.
An over-temperature shutdown on the charger load would be a nice feature.



Congratulations, a roof of your own is what matters.

After I bought a mountain lot, I looked into porta-potty and holding tank service. Old RV was cheaper.
Late '80's, cost me about $1000 for an 18 footer, registration penalties, replacing missing fixtures.

Yep, and Victron makes a sweet 12ro 24-volt 15 amp charger. I could also have my spare alternator built as a 24-volt too. I have the big 460 that has the air pump and cat system I can pull off nowadays. I have an extra alternator to dedicate to this purpose with a modifiable bracket already in place. I had thought about remote mounting the rectifier and regulator so as not to have to run a heavier and more expensive wire back to the charger and batteries.

 

[Cajunwolf]

Charge from engine while driving?
Alternator output is limited, probably mostly by diodes for positive side (poorer heatsinking).
I once tapped off the three stator windings and added an external rectifier.
24V? Boost converter. Or 12V/24V transformer(s) fed from AC of stator.
An over-temperature shutdown on the charger load would be a nice feature.



Congratulations, a roof of your own is what matters.

After I bought a mountain lot, I looked into porta-potty and holding tank service. Old RV was cheaper.
Late '80's, cost me about $1000 for an 18 footer, registration penalties, replacing missing fixtures.

Yeah, I paid $4k and she has 63k original miles. New tires too. Everything works, but it's 32-years old.

 

[HRTKD]

Yeah, I paid $4k and she has 63k original miles. New tires too. Everything works, but it's 32-years old.

I hear ya. My dad bought a 70's GMC motorhome a couple years ago. He's paid more to get it road worthy than he purchased it for. And I can't say that everything works on it.

 

[Hedges]

Yep, and Victron makes a sweet 12ro 24-volt 15 amp charger. I could also have my spare alternator built as a 24-volt too. I have the big 460 that has the air pump and cat system I can pull off nowadays. I have an extra alternator to dedicate to this purpose with a modifiable bracket already in place. I had thought about remote mounting the rectifier and regulator so as not to have to run a heavier and more expensive wire back to the charger and batteries.

Separate sounds good. If you kill it, vehicle's 12V system still works.
Any difference in windings for 24V? If only regulator, and if that is external, swapping cable would let the "24V" one substitute to charge 12V battery.

Negative 3 diodes have body on alternator case, better heatsinking. Positive 3 on a small plate. I've seen them fail first. I saved the alternator from my K2500 when I replaced it, planning to upgrade in that way.
If you put all 6 on real heatsinks, with air flow, should handle much more.
I'd like to see regulator have a shutdown or derate based on alternator temperature.

 

[Cajunwolf]

Separate sounds good. If you kill it, vehicle's 12V system still works.
Any difference in windings for 24V? If only regulator, and if that is external, swapping cable would let the "24V" one substitute to charge 12V battery.

Negative 3 diodes have body on alternator case, better heatsinking. Positive 3 on a small plate. I've seen them fail first. I saved the alternator from my K2500 when I replaced it, planning to upgrade in that way.
If you put all 6 on real heatsinks, with air flow, should handle much more.
I'd like to see regulator have a shutdown or derate based on alternator temperature.

Exactly, and why one wants a separate chassis and house batteries. I don't know what's involved, but I have this guy who is the son of the guy who owned an alternator/starter shop not far from my apartment. It's all they do, and he told me he'd rebuild it heavy-duty to 24-volts output for $64. heck yeah! I'd run ten ga wire from there to the 12 to 24-volt charger. I want to be able to run the 6000-BTU window unit in the back while driving in warm climates like Texas, AZ., Nv, etc. During the day, I should be able to run the top 15k BTU (brand new), being I have a 24-volt 4kw inverter being fed by batteries panels and alternator. That little dash A/C isn't going to cut it in the summer. This may be wishful thinking, but we shall see.; where there's a will, there's is a way.

 

[WYtreasure]

Where did the web pages go for the 24v 1kW off grid system? I was using that as a basis for my system.

Thank You OP.

Seems a shame to learn how to do it, then burn the book.

 

[JJJJ]

When I made the decision for 24v it was the gold standard at the time. 48v was out there but it was advertised by the experts as more expensive and requiring a higher level of expertise due to the additional voltages.

Admittedly higher voltage allows smaller wires and a smaller initial investment in wiring. I think back in history when DC power plants were competing with the new AC. DC plants, out of necessity were built on many street corners, AC could travel for many miles and ultimately won.

The thing I like about 24v is the opportunity for redundancy. Ultimately the investment can be transitioned if desired. Shifting to a larger serial configuration allows the move. If one invested in larger gauge wire for 24v, that investment can be preserved. Solar panels can be recombined for higher voltages. Charge controllers and inverters can be upgraded for fancier options.

In 5 years who knows what voltages and technologies will be on the discussion table. I suspect diy will transition to turnkey options for many, much like it has for other technologies.

On the other hand, finding a car mechanic who can take apart a module and repair it (instead of a full swap out) is still worth their weight in gold.

 

[Hedges]

he told me he'd rebuild it heavy-duty to 24-volts output for $64. heck yeah! I'd run ten ga wire from there to the 12 to 24-volt charger. I want to be able to run the 6000-BTU window unit in the back while driving in warm climates like Texas, AZ., Nv, etc. During the day, I should be able to run the top 15k BTU (brand new), being I have a 24-volt 4kw inverter being fed by batteries panels and alternator. That little dash A/C isn't going to cut it in the summer.

24V output from alternator, then you don't need 12 to 24V charger.
Main thing is, recharging house battery from empty is a lot more than recharging starter battery from empty.
Instructions on replacement alternator say, "do not recharge a dead battery with alternator".
There are alternators made for some vehicles (e.g. ambulance) intended to put out lots of power.

But I think a temperature sensor that pulls down regulator voltage (or interrupts voltage to slip rings) to prevent running when hot would be good. Ideally, varies output to regulate temperature to maximum target, but that takes some electronics design.

where there's a will, there's is a way.

A rich uncle's will?

 

[Wibla]

24V is still relevant, especially for boats/trucks/RVs, as well as an upgrade path for smaller offgrid systems where you already have two lead acid batteries but want to add more solar. Most MPPT's are dual (or more) voltage, so a 12V -> 24V move doubles the amount of power you can get out of that MPPT.

 

[JWLV]

I like 24 volt. I think 12 volt is just too small and if you want to expand later on, you may have to use low gauge thick wires. 48 volt good, but it is high enough voltage that could give you a shock. 24 volt is a happy medium where you won't get a shock touching live wires (unless you have salty sweaty hands or something), and you can take advantage of using higher gauge, smaller wires.

 

[Nickatnyt]

Thanks, OP, for bringing this subject up. I too had wondered where that page went?

Now let's do our part and hit that page everyday to bring the page count up!

 

[JJJJ]

24V is still relevant

I think there is agreement here. If one is planning on charging an electric car then the 48v system makes more sense. In 10 years who knows???

In the meantime, for many of us will do fine with 24v. If motors are involved, a quality low frequency inverter provides the horsepower needed for startup (or a soft start option if needed). For those utilizing 12v appliances or lighting, 24-12v converters are readily available.

 

[eXodus]

A step down converter, 48V>12V can be used to run DC loads efficiently.

What advantage does a 24V system have over a 48V system when you still need to use a converter?

Availability of 24v components in Truck world. primary outside of US.

You get almost all appliances in 24V: A/C units, refrigerators, Microwave etc.

While I agree for a Inverter based system, it really doesn't matter if 24v or 48v. For a native DC system it depends what people want to hook up.

Next with a full charger 48v battery you get in dangerous close territory to getting shocked through the skin. The barrier is about at 60V with dry skin.

When recommendating 48V I would definitely start adding safety disclaimers.

 

[eXodus]

In 5 years who knows what voltages and technologies will be on the discussion table. I suspect diy will transition to turnkey options for many, much like it has for other technologies

My main hope is that we get less power hungry appliances.
The whole 48v only stems from large systems discuss.

There are two parts to the equation. You only need a large system because we are wasting to much power.

We need better direct to DC Air conditioner units and better insulation in RVs