diy solar

diy solar

Where is @Will Prowse?

RandyP said:
Engine compartment is too hot for LiFePO4 batteries.
CCA is a lead acid starting battery parameter. LiFePO4 battery max discharge is limited by the BMS max amp capacity.
Click to expand...
Yes I plan on storing the battery in the storage boxes of my flatbed, hence the added engine compartment space.

I should get a clamp meter on mine and see what the amp draw is when cold out..
 
Lt.Dan said:
Yes I plan on storing the battery in the storage boxes of my flatbed, hence the added engine compartment space.

I should get a clamp meter on mine and see what the amp draw is when cold out..
Click to expand...
I have read that using lithium batteries with a built-in bms will smoke your alternator when the bms disconnects from the vehicle electrical system at full charge. I cannot verify this.
 
HighDesertOffgrid said:
I have read that using lithium batteries with a built-in bms will smoke your alternator when the bms disconnects from the vehicle electrical system at full charge. I cannot verify this.
Click to expand...
Not with Lithium Titanate. Lots of people running that with high end stereo systems, and the voltage curve is somewhat agreeable with a 14.4v alternator.
 
So to expand my idea a bit more now that I'm not trying to type on a phone:

So one of the topics that has been coming up more often over the last year has been people wanting to add battery capacity to their existing grid tie system. There's AC-coupling and DC coupling methods as I understand, and here's my thoughts:

Since in your legendary "Spare Parts Bin" you've probably already got most, if not all, of the parts to build a micro-array and show/explain/demonstrate how both varieties work, how they differ, where one option would be better than another. It would have to be a 2 or 3 part series (AC, DC, Wrap-up) but I think that not only explaining how they work but Showing how the systems work would be really educational.

I know myself I point a lot of people at your older "How To" videos to explain the basics. Sure, the big 6Kw paralleled setups on a stack of rack batteries is impressive, but beginners need guidance too and I find that technology (especially batteries) has really advanced quite a bit since you were back in the motor home.

Just my thoughts on things I'd like to see that we can start referencing as the batteries-to-grid-tie questions come up.
 
Rednecktek said:
Right, but how would they work in a solar application? What do the parts look like?
Click to expand...
They work fine, but grossly expensive for our needs. It would be like building a cellphone-charger bank out of high-c headways.

I did put a small bank of paralleled Shorai's together as an expensive goof. They make their own prismatic pouch cells. Shorai is considered kinda old-school. No bms. No balancing, BUT they do have a balancing port if you want to go there. Some shorted out by users opening the cap at an angle. Zap. Or trying to use their own multimeter leads to "check it out". Zap.

Others use high-c cylindricals and now with a high-current bms, balancing, reset, you name it. Time moved on and made it more practical for most. It would still be ridiculous to build a storage bank from them. But you could. Even the classic "will it last 10 years, I'm gonna wait" crowd got satisfied with an old EarthX surpassing that mark.

Different application, but taken just as seriously. Getting into massive thread drift, but yeah, Will *could* review them if he was into motorcycles. How does the new Speedballer3K battery match up to an Anti-Gravity? Let's find out! :)
 
HOLY COW! Here's one that might pique @Will Prowse interest!

Anti-Gravity now offers an "energy" 100ah battery (as opposed to their power starting batts), with their own bms, and the usual stuff! Does it truly have a bad-a** bms?

antigravitybatteries.com

DC-100-V2 Lithium Deep Cycle Battery

Our new lightweight versatile Lithium Deep Cycle Batteries for RV, boat, solar and off-grid uses are the first ever with built-in Bluetooth Tracking!
antigravitybatteries.com antigravitybatteries.com

The manual for it is right here:


Warning - most users will toss the manual aside. It's human nature to just buy 4 of these things and slap them together in different states of charge. Don't do that. Charge each individually first! See the notes about how many you can actually put together in different voltage / capacity ratings. READ THE MANUAL.

Saw that baby open and test it! Voids the warranty so this is in Will's wheelhouse! :)
 
Last edited:
Lt.Dan said:
Yes I plan on storing the battery in the storage boxes of my flatbed, hence the added engine compartment space.

I should get a clamp meter on mine and see what the amp draw is when cold out..
Click to expand...
You are not going to get `1800 amps thru a LiFePO4 BMS, even if it uses external relays.
Lead Acid Engine Starting batteries are highly specialized battteries developed over years for that high amp draw of an engine starter. LiFePO4 batteries cannot compare to that ampacity spec. They are a deep cycle battery. different bird.
 
RandyP said:
You are not going to get `1800 amps thru a LiFePO4 BMS, even if it uses external relays.
Lead Acid Engine Starting batteries are highly specialized battteries developed over years for that high amp draw of an engine starter. LiFePO4 batteries cannot compare to that ampacity spec. They are a deep cycle battery. different bird.
Click to expand...
If you see my last post, I was talking about lithium titanate, rated for much higher C rates.

1800CCA is different from actual current draw, hence why I wanted to measure current draw. Actual current required might be under 8-900a.

Lithium titanate also doesn't suffer low/high temps like LiFEPo4 either.
 
RandyP said:
You are not going to get `1800 amps thru a LiFePO4 BMS, even if it uses external relays.
Lead Acid Engine Starting batteries are highly specialized battteries developed over years for that high amp draw of an engine starter. LiFePO4 batteries cannot compare to that ampacity spec. They are a deep cycle battery. different bird.
Click to expand...
It is a VERY rare engine that pulls anywhere close to 800A… most gasoline engines are in the 150-300 range. Most diesels are in the 350 to 600 range. My huge v8 IDI high compression navstar diesel takes around 550 so I doubt any exceed that often… what is needed is low fade high duration cranking. The ability to sustain cranking long enough to build heat to start a big diesel. Load the glow system up, AND run the starter. It’s a tough chore for many batteries. Lithium easily handles the capacity and duration, but cannot handle the amperage, THROUGH a BMS. High C rate lithiums can do it. Most LFP cells are rated at 2C max. With a 280Ah cell that’s over 500A, plenty for most starting. Headways are good for 10C, so easily handle the amperage, just not through a BMS. And only LTO can handle much cold weather charging…
 
Supervstech said:
It is a VERY rare engine that pulls anywhere close to 800A… most gasoline engines are in the 150-300 range. Most diesels are in the 350 to 600 range. My huge v8 IDI high compression navstar diesel takes around 550 so I doubt any exceed that often… what is needed is low fade high duration cranking. The ability to sustain cranking long enough to build heat to start a big diesel. Load the glow system up, AND run the starter. It’s a tough chore for many batteries. Lithium easily handles the capacity and duration, but cannot handle the amperage, THROUGH a BMS. High C rate lithiums can do it. Most LFP cells are rated at 2C max. With a 280Ah cell that’s over 500A, plenty for most starting. Headways are good for 10C, so easily handle the amperage, just not through a BMS. And only LTO can handle much cold weather charging…
Click to expand...
I have an old 7.3 powerstroke, im in the same boat as you. I know the glow plug system draws 300a alone, which is a chore itself! Unfortunately my clamp meter only reads to 400a, so I won't be able to find out.
 
300A ... didn't realize it was so much, but I'm finding references to about 25A per plug, 200A for eight.

Glow plug current draw.

Finally got around to getting a Digital Current/Voltage meter. With the shunt on top, it's good for up to 200 Amps and 200 Volts AC/DC. With that meter I can finish doing my GP testing with the GP controller and 8 GP's I made a year or so ago. Stay tuned for futher updates, if I can make a video...
www.oilburners.net www.oilburners.net

Glow plug - voltage and current

The purpose of this test is to check the glow plug voltage and current to ensure correct operation.
www.picoauto.com www.picoauto.com

www.thedieselstop.com

Glow Plug Current Draw?

www.thedieselstop.com www.thedieselstop.com

I have GMC K2500 with 6.5 turbodiesel.
I should check it next time with clamp ammeter.

"draws 300a alone"

You use glow plugs alone, then after they shut off use starter alone, correct? So never both at once?

I would have thought 4x 280 Ah could deliver several "C" for seconds or minutes, or for a big engine 2p4s with 560 Ah.

I'm still thinking of putting battery & inverter in my truck. Might do a cheaper 12V system (rather than 48V). I would want to have self jump-start capability. K2500 is supposed to have 2x 800 CCA batteries in parallel. I've used 700 Ah Optimas, now Oddessy. My hope is 280 Ah LiFePO4 could start it if needed. Would think even if that is abusive, would be OK for occasional use (unlike your replacement plan.)

Obviously you would connect starter bypassing BMS. BMS could disable solenoid at low battery.
But you need to prevent high voltage disconnect which would blow alternator diodes. What you might do instead is shut off regulator (easier said than done for internal regulator.)
 
Hedges said:
300A ... didn't realize it was so much, but I'm finding references to about 25A per plug, 200A for eight.

Glow plug current draw.

Finally got around to getting a Digital Current/Voltage meter. With the shunt on top, it's good for up to 200 Amps and 200 Volts AC/DC. With that meter I can finish doing my GP testing with the GP controller and 8 GP's I made a year or so ago. Stay tuned for futher updates, if I can make a video...
www.oilburners.net www.oilburners.net

Glow plug - voltage and current

The purpose of this test is to check the glow plug voltage and current to ensure correct operation.
www.picoauto.com www.picoauto.com

www.thedieselstop.com

Glow Plug Current Draw?

www.thedieselstop.com www.thedieselstop.com

I have GMC K2500 with 6.5 turbodiesel.
I should check it next time with clamp ammeter.

"draws 300a alone"

You use glow plugs alone, then after they shut off use starter alone, correct? So never both at once?

I would have thought 4x 280 Ah could deliver several "C" for seconds or minutes, or for a big engine 2p4s with 560 Ah.

I'm still thinking of putting battery & inverter in my truck. Might do a cheaper 12V system (rather than 48V). I would want to have self jump-start capability. K2500 is supposed to have 2x 800 CCA batteries in parallel. I've used 700 Ah Optimas, now Oddessy. My hope is 280 Ah LiFePO4 could start it if needed. Would think even if that is abusive, would be OK for occasional use (unlike your replacement plan.)

Obviously you would connect starter bypassing BMS. BMS could disable solenoid at low battery.
But you need to prevent high voltage disconnect which would blow alternator diodes. What you might do instead is shut off regulator (easier said than done for internal regulator.)
Click to expand...
Most diesels have a glow time, then a start sequence.
Many operate the glow, then during cranking the glow continues.
Especially the modern DI diesels with their intake heaters...
 
Yes the 7.3 Powerstroke runs the glow plugs for a duration of time based on intake temperatures and oil temperatures. Once the key is on, the glow plugs are running for anywhere from 30 seconds to 3 minutes, while cranking or running not. The time duration is shorter or longer dependent on temperatures.

With it being a 25 year old truck, I imagine that older wires and higher resistances adds to the current draw. What might be 25a at the glow plug, could be 30a at the battery right?

Idk what mine are for sure, but thats definitely something I can check! I'll try and measure it tomorrow morning when its nice and cold.

As for the alternator, I wonder if separating the alternator from the rest of the vehicle entirely? Just run a dedicated 12v to 12v charger to the battery from the alternator, then all the loads run off the battery terminals, and like suggested above, bypass the BMS for the starter only. This reduces the need for an overly large BMS for the starter, charges the battery like it should, and requires no physical modification to hardware.
 
My 95 suburban diesel works when I remember to trigger the glow plugs.
all Mercedes diesels crank up with varying degrees of success in cool weather.
 
Lt.Dan said:
''''''''''''''''''''

With it being a 25 year old truck, I imagine that older wires and higher resistances adds to the current draw. What might be 25a at the glow plug, could be 30a at the battery right?

.................
Click to expand...
Current into a circuit equals return current to the source.
25 amps in causes 25 amp return. A circuit cannot create current.
 
RandyP said:
Current into a circuit equals return current to the source.
25 amps in causes 25 amp return. A circuit cannot create current.
Click to expand...
... but bad connections and such certainly can increase resistance which would increase current...
 
You must log in or register to reply here.

Similar threads

N
Looking for Will Prowse to respond to Oupes…
Replies
2
Views
509
Steve_S
Steve_S
65NW
Propane tank valve, adapter and refill hose
Replies
2
Views
314
Spartan
S
G
Got off grid solar inverter spf3000TL LVM-ES that Will Prowse reviewed 2 years ago and just now able to set up BUT saw where he said don’t get now ??
Replies
3
Views
296
Mattb4
Mattb4
I
Gobel battery experience?
Replies
0
Views
270
IamDoc
I
Y
Building Will Prowse hand cart solar generator but using eg4 6500
Replies
2
Views
181
Yosemite Fred
Y

diy solar

diy solar
Back
Top