Power tool batteries as power source?

luthj

Engineer In Residence
The math can be done in watts (if using a DC-Dc converter) or amps if you want to try 18V direct (sounds like a fire to me...)

Watts is amps times volts. watts over time are watt-hours. 100W for an hour is 100 watt-hours.

If i was going cheap heater, I would get one of the ~200$ chinese D2 clones. Then just run it off a tank of kerosene or diesel. They don't use much fuel anyways. With a Dc-Dc converter you could run it for a fair while.

At high power they use about 2.5A @ 12v/ So that 2.5 x 12 = 30W A 9Ah 18V battery is 9AH x 18V = 162 Watt-hours. 162/30 = 5.4 hours of operation. Thats rough though. You will loose a little bit to converter efficiency, and the heater is not likely to run at high power most of the time.
 

jonyjoe101

Adventurer
get one of these buck converters, cost about 8 dollars. They drop the 18 volts to 12 volts. Most 12 volt devices won't run long at higher volts, I lost many fans,pumps, led lights from voltage surges.
I prefer these buck converters over the 12 volt stabilizers (which output voltage can be below 12 volts). With these buck converters you can set the output voltage to 12 volts, 12.6 volts, 13 volts, whatever your preference. You can find on ebay from us sellers, you get in less then a week.


300 watt buck converter.jpg
 

john61ct

Adventurer
Just realize amps / watts ratings are very "optimistic".

Test thoroughly, and if your usage level makes it get hot, beef up the heat sinking, and/or add active cooling.

Or buy better quality converters like Vicor, Samlex, Victron etc
 

Ducky's Dad

Explorer
I think it's kind of a silly idea with a lot of unnecessary complexity. I had a Cherokee long ago and I think I'd rather fit something like a small Odyssey automotive battery somewhere so that I had backup starting capacity. If you must go with power tool batteries, I'd go with Ryobi for reasons previously mentioned. They are always on sale at Home Depot, and the 4ah are currently only $79 for a pair. I think they also come in 6ah and 9ah capacities, but those can get pricey. The shop that rebuilds my Dewalt nicads has told me that Ryobi uses high quality cells in their packs. Re the issue of battery compatibility going forward, I have found Dewalt to be about the best in that regard. I can run old 9.6v tools on 12v batteries, run some 12v tools on 14.4v batteries, and can run 18v tools on nicads or on lithium-ion post batteries, and with the Dewalt adapter I can run all of the 18s on the 20v Max batteries.
 

luthj

Engineer In Residence
If you can stand wider temperature swings, its usually more economical letting heater run to the point of almost too warm inside before thermostat switches off.
A bit off topic, but the diesel air heaters use about the same watts per KW output regardless of heat setting. Since the GP only needs to cycle during startup, its typically more battery/electric efficient to have the heater running continuously. Assuming the heating demand is not below the heaters minimum output.
 

wjeeper

Active member
Just realize amps / watts ratings are very "optimistic".

Test thoroughly, and if your usage level makes it get hot, beef up the heat sinking, and/or add active cooling.

Or buy better quality converters like Vicor, Samlex, Victron etc
I know ratings on all sort of things are very optimistic. Especially the cheapo made in china stuff I have/ am using. I played around with some of the lights I am planning on using over the weekend for a few minutes. I may not need as many lights as I originally thought, they are way brighter than I remembered. Not going for stadium bright lighting, just a gentle glow so you don’t head headlamps immediately around the Jeep.


here's you heater solution -
Propane could be really nice. No power draw and simple. There is only one problem with propane heat. Moisture! I used a buddy heater in my van and every surface that was a thermal bridge to outside temps was soaked. The top of my rig is a lot like an old Westphalia van and I foresee a propane heater causing a lot of condensation on the canvas.

The heater I have is an Espar B4, runs on gasoline. (one less fuel source as it would pull from my fuel tank) I assume the gasoline versions still have a glow plug, but I really don’t know……..I need to look at it and make sure it works right before I move beyond this theoretical exercise.

I just priced out a 2nd Optima battery as I have had great luck with them in the past (the one in my jeep is 10-12 years old. Holy moly the price has gone up on these!
 

luthj

Engineer In Residence
The B4 uses the same glow plug as the diesel version. The B4 uses the plug a bit less (shorter or no cycle during shut down).
 

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john61ct

Adventurer
Optima since moved from Enersys to JCI is no longer well suited for true deep cycling, just a HD winching / Starter and yes overpriced.

If you need AGM look at Odyssey G31 PCM-2150
 

john61ct

Adventurer
Yes anything unvented produces excess humidity.

Propex HS2211 is a great vented propane unit, much more efficient than RV style furnaces, can be mounted outside.
 

calicamper

Expedition Leader
The power tool batteries are expensive for the wattage but for a quick flexable power source you probably already have its not a bad idea. Especially if there is a simple socket you can drop them into that then powers your small basick power needs
 

john61ct

Adventurer
OP question was, is 9Ah enough for a House bank, including running parking heaters in winter?

Answer is no.

Recharging a screen gadget, a couple LEDs maybe a decent fan for a short time, maybe.

Building up to 100Ah using these modules as is, can you? sure. Should you? IMO no.

But a new big pack made from cells harvested from new packs? Sure, but then there's the higher fire risk.

So, much better to stick to lead or LFP.
 

DaveInDenver

Expedition Leader
Optima since moved from Enersys to JCI is no longer well suited for true deep cycling, just a HD winching / Starter and yes overpriced.
FWIW, Optima was never part of EnerSys (of Odyssey, Genesis, Hawker, etc.). Optima was originally started as a division of Gates Rubber, who made them in Denver in the 1980s and early 1990s. Gates sold the division to a European company named Gylling Group in 1992 who built a bigger factory in Aurora (east of Denver) in 1994. Johnson Controls bought Optima in 2000 and later moved production to Mexico in 2007. A lot of people around town used to get seconds from the Aurora factory. They were always fine for me but I've never personally bought a Mexican-made Optima because of the quality decline rumors. It seemed to me the decline may have started before the move to Mexico, though.
 

john61ct

Adventurer
FWIW, Optima was never part of EnerSys (of Odyssey, Genesis, Hawker, etc.). Optima was originally started as a division of Gates Rubber, who made them in Denver in the 1980s and early 1990s. Gates sold the division to a European company named Gylling Group in 1992 who built a bigger factory in Aurora (east of Denver) in 1994. Johnson Controls bought Optima in 2000 and later moved production to Mexico in 2007. A lot of people around town used to get seconds from the Aurora factory. They were always fine for me but I've never personally bought a Mexican-made Optima because of the quality decline rumors. It seemed to me the decline may have started before the move to Mexico, though.
Interesting, I was always told it was Enersys sold to Gylling in the mid-90's.

They definitely had spiral tech long before they started developing their TPPL tech, and later spawning Northstar and Lifeline.

Trying to reach Bruce Essig to confirm your revelation.

Doesn't really change anything relevant, but IMO accuracy is important, and people I really trust have been telling it that way for over a decade.
 

DaveInDenver

Expedition Leader
Interesting, I was always told it was Enersys sold to Gylling in the mid-90's.

They definitely had spiral tech long before they started developing their TPPL tech, and later spawning Northstar and Lifeline.

Trying to reach Bruce Essig to confirm your revelation.

Doesn't really change anything relevant, but IMO accuracy is important, and people I really trust have been telling it that way for over a decade.
Gates Rubber used to have a division called Gates Energy, which invented the technology that eventually became both Hawker (flat plate AGM, which were at one time called Hawker-Gates) and Optima (spiral plate AGM). What I know of EnerSys is that it organized from Yuasa around 2000 so perhaps the Hawker line was acquired from Gates (or at that time Tomkins, who bought Gates in 1996).
 
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