Hybrid car battery pack for Home power

[Harold in CR]

Been watching fleebay for hybrid battery packs. MOST are x pensive, but, I recently saw one for $350.00. It was 303 V at 6 Ahr. Can't remember the car model, since I have been doing a LOT of searching.

Any, it's NiMh. That's not a problem for me, since, down here, 2 6V Gold Car batteries would cost me $240.00 each to make a 12V system.

Shipping heavy stuff down here is not a problem. Every crate is shipped by SIZE.

I want a 12V system for right now, to be switched to 24V down the road. I need this ASAP, to beat the thunderstorms that try to take out all our electronics. Re configuring the cells to go to 12'13V would not be terribly difficult, I don't think ??
I just don't want lead, especially outside the house, for the local idiots to try to steal. This way, with NiMh, I can just buy more pks and keep adding to the system. We don't have a BIG load, just need to get weaned off the shitty Power Co, system, as much as possible.


Anyone have any bad juju about this idea ??

 

[major]

Been watching fleebay for hybrid battery packs. MOST are x pensive, but, I recently saw one for $350.00. It was 303 V at 6 Ahr. Can't remember the car model, since I have been doing a LOT of searching.

Any, it's NiMh. That's not a problem for me, since, down here, 2 6V Gold Car batteries would cost me $240.00 each to make a 12V system.

Shipping heavy stuff down here is not a problem. Every crate is shipped by SIZE.

I want a 12V system for right now, to be switched to 24V down the road. I need this ASAP, to beat the thunderstorms that try to take out all our electronics. Re configuring the cells to go to 12'13V would not be terribly difficult, I don't think ??
I just don't want lead, especially outside the house, for the local idiots to try to steal. This way, with NiMh, I can just buy more pks and keep adding to the system. We don't have a BIG load, just need to get weaned off the shitty Power Co, system, as much as possible.


Anyone have any bad juju about this idea ??

On the surface it looks like about $0.20/Wh. That's pretty good. A hybrid vehicle battery may not like deep discharges. But would likely be better than Pb-Acid. I see a possible problem with charging a reconfigured HEV NiMH battery. Parallel cells can be problematic to charge. I have seen a couple of meltdowns.

I assume you would then need to invert the battery power to AC for home power. Look at used or salvaged UPS units. I have a couple for emergency home power backup which I bought off eBay for pennies where the only thing wrong with them was a dead battery. These were in the 2 to 4 KVA range and use 48V batteries. They put out a nice sinewave also.

 

[Harold in CR]

Thanks major
My plan is to make up as many 12V packs as possible and hook them together with a balance charger of some sort. That is what I am not sure about. I can ever put 1 solar panel per battery pack and switch them as the run down. I'm usually around the house-shop to do that. I figure there MUST be a way to control charge-discharge. My load will never be as high as a vehicle may be, especially as I go higher Voltage-less Amps.

I have a total of 4 of those UPS's, 2 are 350W & 500W. The other 2 are 1400 KVA, which I think is 1500W or so ?? Memory is fading.

Later on, I can upgrade to 24V or 48V. I have rigged up a few experimental LED lights. At night, that's all we use for house lighting in the main area of Computer and TV. I just bought 2--500' rolls of 14 thhn wire for a GOOD price, to run 12V lighting circuits for the bathroom and 2 bedrooms.

My problem, the Power Co, has a very shitty grounding program, so, lightning runs into the house on both electric line and phone line. They want ME to put 2 groups of 4 ground rods in at my meter pole, 300 feet down the hill from my house.

One time, there was a ZIIP noise, and the computer and tv and a 500W UPS + surge protector outlet strip all fried, from a lightning hit MILES away. Clouds arrived 35 minutes later after the lightning.

Experience as a Lineman for 12 years, I know how unpredictable lightning can be, and how hard it is to steer it to ground.

I follow all your input on the DIY car site, and value your input, greatly. Thank You, Harold in CR

 

[knighty]

look out for a decent used forklift battery.... it should outlast pretty much everything else you're looking at

they're built out of 2v cells, so you can build a pack up however you like

cells weigh about 100kg each (they're tall and thin)

that's what most people living off grid use (powering there entire house, with solar/wind to charge them)


I'm guessing you're going to charge from the grid, and then use them when there's a power cut ?

 

[fechter]

It's generally bad practice to make a pack from parallel groups of Nimh cells. As they approach full charge, the voltage drops and the first group to reach full will tend to hog all the current, even drawing from it's parallel neighbors, causing sort of a thermal runaway situation.

If you never let them reach full, you may get away with it, but for sure you'd want to have fuses in each parallel group and maybe some kind of temperature monitoring. There are also ways to isolate the strings for charging and discharging, but it can get complex and adds some loss to the system.

Another approach would be to use a dc-dc converter to boost the panel output to the pack voltage. Most switching power supplies that are rated for 240vac input could run directly off the pack. This includes a wide variety of typical devices in a house.

 

[Harold in CR]

Electric forklifts are not plentiful here. I know about those type batteries. I don't want to use lead acid for several reasons. Thanks for the suggestion though.

Mr. Fechter, I was hoping you would pop in here and maybe take an interest in trying to figure out how to use these type cells.

When I built my 4KW wind turbine, I used a 120-240V AC alternator. 1 leg (120v) was run through a large Diode, then some sort of adjustable relay I bought through Newark Electronics. That would activate a contactor, so, I set the V at 110, I BELIEVE, and had it set to drop out at 90V. that ran a 36V charger hooked to Train caboose 2V cells, charging a 36V bank. I had 3 banks. The other leg (120v) I ran through a variac, that I could crank up or down the Voltage as the wind blew stronger or not,That ran my Lister 36V golf Car charger. That was hooked to an alternate bank of the same type batteries. I guess you could call that Redneck charging ? :lol: It DID work though.

I just need to find a way to use cheap batteries that I can get shipped down, to get my electronics, at least, off the house wiring, so I don't have to buy TV's and computers every rainy season. ?

 

[fechter]

I think the preferred cells for that application might be nickel-iron Edison cells. Performance/size/weight sucks, but they last virtually forever. Personally, I'd try for some large format LiFePO4 Thundersky or similar cells.

I've had pyrotechnic experiences with putting NiCd batteries in parallel. Nimh is about the same. We don't need any more house fires.

OK, one other way to try using Nimh might be to make a bunch of 10s strings (12v) and place a PTC in series with each string to protect against thermal runaway. If the PTC was thermally attached to the cells, it would increase in resistance when it gets hot.
Another option is to use diodes to allow all the parallel strings to discharge and in series with all of them for charging. You'd have some loss in the diodes, but not too bad. the diodes prevent any large currents from passing between strings. You could still wind up with almost all the charging current going into one string if uncontrolled. Fuses or PTCs are mandatory on each string. Some people reported success using this kind of arrangement as long as the charge rate wasn't too high.

The high voltage/all in series approach still has many advantages. Most modern TVs and computers can run straight off 300vdc. Just don't touch it.

 

[Harold in CR]

Wouldn't it be tough to get +300VDC charging supply ??

I'm VERY Limited on funds, so, trying to do something as inexpensively as possible. Are limit switches made that will automatically disconnect at a preset voltage, or, is the real concern about 1 cell in a pack hogging all the input and blowing ??

I just don't know enough to ask the right questions or do any in depth searching. It's hell to be dumb. :lol:

 

[heathyoung]

Not that hard to get - are you 120 or 240V? Rectified mains is 1.414 X VAC, so at 120V you get 170V, at 240 you get 340V.

You can voltage double the mains at 120V, this gets you the voltage you require.

Capacitive dividers or Variacs will allow trimming of your final voltage. A bloody big motor start cap (or bank) will ensure current limiting.

Easy enough to get a current limited supply at your target voltage.

 

[Harold in CR]

So then, to run 12V Led's and Tv, Computer, maybe the refrigerator, how do I get from 300 down to 12V, and, how do I get 120V for the fridge ?

I know nothing about electronics, so, it may be easy for you guys?

Appreciate the input, guys. Don't quit on me now. 8)

 

[SamTexas]

You need to choose a fixed voltage for your battery (and solar panel if it's part of your overall system). For home use, most people in the US use 12 or 24V. Then you use an inverter (DC to AC) to run the 120V appliances.

I echo others in saying that NiMh is a poor choice for this application.

 

[heathyoung]

Fridge is a problem, as other have said, you need AC for that.

Not sure exactly why you have the aversion to lead acid, its a stationary application, and unless you want to spend big on lithium, not a bad contender.

If you can lay your hands on some good big battery banks, see if you can get hold of a Xantrex/Trace SW2524 (2.5KW 24V) or SW3048 (3KW 48V) - they are an inverter charger, very nice bits of gear (getting a bit long in the tooth) - will happily accomodate remote start generators etc. I was toying with the idea of a SW2512 but the requirement for 4/0 battery cables (ie. 120mm2 EEK!) and 250A HRC fuses kinda doesn't appeal.

They are a serious unit, and weigh 40KG - real iron core transformers and 12W standby usage. The cheap chinese inverter/chargers use a lot more in standby, and have horrendous charge efficiency.

Or a surplus UPS - most of the decent ones run a 48/72V bank.

 

[amberwolf]

As noted the problem with NiMH and parallel charging is that as soon as any cell is full it's voltage drops, and all the current into the whole parallel setup flows thru that one, PLUS the current sucked out of the other cells taht are now higher voltage (though lower SOC) than it is.

If that goes on long enough to heat it sufficently, then BANG. Or burn.

Even if it doesn't go on long enough to burn or explode a cell, it will still damage that cell by overheating it till it vents gas, which used to be electrolyte, and now that cell will have less capacity and perform less well with greater internal heating during charge and discharge. (based on my own accidental overcharging results with the old NiMH from BikeFanatic, my first batteries beyond SLA.)


How to work around that:

You could build a charge monitoring system that monitors every single cell's "delta-V", or change in voltage, so that as soon as one drops in voltage it disconnects it from the rest of the paralleled cells. That's pretty complex, even just for the disconnection system, let alone the monitoring. It will probably make it very expensive, too, just considering parts. At a guess you might be able to order brand new Lithium-chemistry cells of much larger capacity at the cost for just the monitoring system, assuming you build that monitor out of new parts, and that you will damage or destroy some parts and some cells in the development process, and not including any of your labor time in costs.


You could build it as a series-charged unit. That would be a lot cheaper. Basically you'd have to put all your solar panels in series, then use an MPPT of some sort that runs at the voltage desired. If you don't have enough panels/high enough voltage MPPT/etc to use all the cells in one series string, you'd have to create multiple completely independent setups of panels/MPPT/cells that then run their outputs into a single "concentrator" that puts the power as the 12V output into your house system. I don't know that MPPTs come in anything like the voltages required, so you'd have to investigate that.


FWIW, I considered somethign like this myself, when i was given a couple of boxes of old Dewalt NiCD toolpacks (which are probably just going to get recycled now, after the house fire--I'm never going to get to use them or the bunch of SLA I have around, and have to greatly reduce the piles of stuff in order to put it into the sheds). I decided it would be too complex for me to tackle anytime this millennium.

 

[Harold in CR]

OK, Amberwolf has written what I wanted to know. THANK YOU, SIR. 8) 8) Parts of this rant :lol: have been deleted. :lol:

IF I had funds, I would have bought 2-3 of those A123 Modules that were first available. A couple members had a couple that were checked out and good. Cutting out cells would have been tricky, but, NOT impossible. I missed out on that whole episode. That would have been ideal. I was tied up in a payment plan with another member, buying A123 26650 cells for my Bike build. Then I got involuntarily screw into a $1500.00, fiasco, that I had to pay, on time payments, so, Y'all can see what I am up against. SOON, all that crap will be behind me, so, I can breathe a little, and start getting battery serious.

Let me explain why I have the aversion to Lead acid. First, down here, they nearly don't exist. I go to battery stores and ask for prices on 4 Golf Car batteries. They never get back to me. I visit them 1 more time, and, ALWAYS hear, No existe'. Well i DO know they exist, in Gringoville, CR. I would buy used batteries, but, down here, EVERYTHING Goes directly for scrap ASAP. They do off gas, so, I don't want them near the house. The fumes will deteriorate the concrete plaster on the outside of the house. I have that problem now, with a lawn tractor battery I use as the computer back up, sitting 3 inches from the block portion of our house. It creates a white fungus looking stuff. Also, If I don't build cast iron case to house them, the transient thieves will steal them, or destroy them. I have thought about shipping down AGM batteries, but, they are MOSTLY built as Marine dual purpose, and, they are expensive.

My wife wants to bar all the windows and doors, to prevent breakins. I refuse to do that and live in a prison cell. I would rather shoot and bury them, thin them out, so to speak. The best price I can get is $220.00 EACH for a 6V golf car battery. Then, I have to travel over 50 miles 1 way to purchase them. I CAN NOT find any delivery service that will bring them to my house, at ANY cost ?? I can have a NiMh pack shipped down in a crate, from Florida, along with a LOT of other stuff that's not available here, for around $300.00 Delivered to my front door.

Presently, I am up to my ears trying to get my green house finished plumbing and producing. I still need to build the 3 solar panels I have parts for, but, building them and having no battery bank is kind of stoopid.

Very soon, I will have my house rewired for DC use for LED lighting. My experiments so far, are VERY encouraging. Just need a few more of the rolls of LED's from China, for $10.00 a roll, shipped. Then I will not need 100 year old tech bulbs, OR mercury gas filled lighting.

Refrigerator can be converted to a 12V or 24V DC compressor. I just need to learn refrigeration techniques, in my ultra spare time, to do a conversion. Motor home fridges use DC compressors or used to. Problem is, I can't stuff one of them into a 2' X 2' X 3' crate, but, I can get a DC compressor into one with room to spare.


Another member mentioned Edison type Ni-Fe cells. They exist, made in CHINA, so, what quality and price are we talking, again. I have read about problems with many of these Chinese cells.

I am a member of 3 other forums, DIY Electricar, Elmoto and Fieldlines. I try to keep up with new details and ideas. This one of mine seems to be shelved because y'all live in the land of plenty. Ain't SO down here, where a person can AFFORD to live, especially if he could GET stuff locally, instead of importing it.

Rant over. :lol: :lol: Anyone can respond to this thread. Doesn't matter if it helps or shoots down my plans. I also try to use bits and pieces of any advice that I can.

 

[fechter]

That's a tough situation.

Lead-acid is likely to be the most cost effective, but availability seems to be a problem. Off gassing can be largely prevented by using the right charging voltage and/or by using sealed AGM batteries. I never had a problem with this, but it's a lot lower humidity around here.

Nickel-iron is pretty hard to mess up, even in china. They have higher internal resistance and are physically larger than equivalent lead batteries. After a certain number of cycles when capacity drops off, you replace the electrolyte and they're like new again. If you can get these at a reasonable price, it would be a good long-term solution. Around here, they're very expensive.

Reconfiguring a hybrid car pack to 12v or 24v is not simple but people have done it successfully. It would suck to spend a bunch of money on one only to have it burn up.

If possible, use a 24v system rather than 12v. It reduces the losses quite a bit.

 

[Harold in CR]

Yes, 24V is much better, but how does one use 12V LED's and such ? Converting wastes electric also ??

 

[fechter]

Sorry, I haven't abandoned you, just really busy lately.

24v will be better for running an inverter. Smaller 12v items can be run off a converter with some loss or you can put two in series if that's handy. There are pros and cons either way, so depends on what your loads are.

Keeping in line with the original topic title, let's just look at what might happen using a hybrid car pack.

What is your charging current (specify voltage)? This will have a lot to do with how Nimh cells will behave.

If you have a bunch of parallel strings, there is really no issue during discharge and they should all be happy as long as they are all matched when you connect them. Charging is the problem. Nimh cell terminal voltage is very temperature dependent. As they get hotter, the terminal voltage drops. When they reach end of charge, the excess power goes into heating the cells, which causes them to drop in voltage. In a parallel setup, if one gets hot before the others, it can hog all the charge current or even worse, draw current from the other cells, causing thermal runaway.

If the charge current is low enough so the cells never really heat up, it might be OK to run them in parallel. I think you still need some kind of protection against the thermal runaway condition, but perhaps just simple fuses on each string might be enough. PTCs might be better if you can get them. These act like self-resetting fuses that go open when they get too hot. They can be thermally attached to the cells in some cases, so that if the cell overheats, it opens the circuit. One PTC per cell would probably not be practical. Honda uses one per cell, but only as an overheat safety, the charge current does not pass through them.

 

[Harold in CR]

We have 120-240 V AC, except when it drops down to 95-180 or so. I have seen it drop to 87V on the 120 side. Down here, as long as a light bulb lest you walk around the house without banging into things, that's "good enough".

People here don't realize how low V affects the fridge motor and electronics. Also, the spikes will blow electronics as easily as lightning will, in the right situation. My uphill neighbors have a milk bulk tank cooling the milk, a ½-¾ HP Jet pump, and a milking machine, and a green fodder chopper, besides the house use, ALL on #6 aluminum neutral and #4 aluminum running over 800 feet total

Is it any wonder I don't have any juice ??

This is all fed by a 15Kva transformer located another 500 feet away, and fed from an open wye 7400V power line.

It seems pretty risky to use the NiMh batteries. I really didn't know the reason everyone was against using them. I like to try to understand things, instead of just accepting peoples free advice.

I was just offered a bunch of AGM batteries, out of the USA, but, no extra funds at this time.

Are there ANY hybrid packs that have usable cells other than NiCd or NiMh that I could keep looking for ?

Thanks My Fechter for getting back to me. I understand busy very well.

 

[fechter]

All the newer hybrids are using lithium batteries, which you could parallel easily. Since most of the newer ones are still working, there isn't much market for packs out of wrecked cars yet. Go for one of those if you can. You may need to research individual models to see what the chemistry is. A Honda CRZ, for example uses a lithium battery.

 

[dnmun]

if you are seeing those levels of voltage drop on the service lines then there is a bad connection on the service entrance.

if you have aluminum as the conductor it is most certainly a corroded twisted or crimped connector.

your power supply distributor will come out and repair the bad connection for you on their side of the service entrance.

you can do the same on your side if you have aluminum wiring in your service. you most likelly will have to do that on regular basis even with the anitoxidation gel because of the high humidity there.

 

[Harold in CR]

Thanks for the hybrid lithium battery advice.

I know about the aluminum wiring-corrosion-needs regular tightening stuff. Thanks for the advice. I( will have to check it all out, again, since the last time, about 1 year ago.

 

[dnmun]

i had this problem when a tree wore a break in the ground wire for my service entrance from the pole. one side went 150V and the other went to 70V when they added a load to one side or the other.

i had to ask an electrical contractor to work on it since i was 1200 miles away. they did nothing but add a new unneeded ground rod and charge me $500 but when i got here then i realized what the problem was and the power company came out and repaired it for free. now you can understand why i hate these guys who pretend they know all about electric wiring and how the real world works because they are union electricians so i don't have any rights to work on my own electric service, just them. otherwise they call the city on you.

 

[Harold in CR]

I hear ya dnmun. I have never needed an electrician to do my stuff. 1 year out of high school, I got a job with an electrician. I knew nothing and he was recovering from a heart attack. I caught on to do things correctly, or, he would make me undo whatever was wrong and do it correctly.

I worked as a Lineman up to 1st class, for 12 years for a Power Co. I was head generator man and electrician in "Nam for a year, replacing the previous guy and never had a replacement sent for him. Even had to repair out 40KW generator, after if was hit with lots of shrapnel from a couple mortar attacks.

Down here, you can call, go to the office, and otherwise hold your hand on your butt, until someone finally shows up, MAYBE. Even had the meter booted one time for lack of payment, which was a computer glitch, not my fault. I took the meter out, pulled the boots, plugged it back in, then, went to town a couple days later and threw the boots on the clerks desk and told to NEVER cut my power again, without contacting me, first.

I know what you are saying about a bad neutral connection. I have done trouble shooting for folks down here and found just what you described. I also put PVC tubing over any place that MIGHT wear through my service lead, that I installed, NEW, 7 years ago.

It;s just that I have measured the V in several places between me and the transformer, and, it IS low V or high V problem with the distribution.

This is my main reason to get off the grid, other than it costing me 25 cents a KWhr.

Right now, we are way behind on rainfall, and, the lake that produces the electricity is not going to keep up with demand, come another couple of years, so, I want to get ahead of the panic. :lol: :lol:

 

[dnmun]

i met a guy yesterday who is moving to central mexico. solar panels all over the roof and propane generator. miles and miles form the grid.

my neighbor here has a mountain cabin and they use a generator. it failed to produce power one day so they took the generator down the hill to town here and the generator guys just rooked them for $100 inspection and told them it would be $400 more to fix it.

so he brought it home because i had told him i would fix it. i was able to figure out that the Automatic Voltage Regulator AVR had failed. took maybe 3 minutes!

honda wanted $300 and i found one for $18.49 on amazon made by another chinese generator manufactuurer Amico. he just took it back up there for the weekend.

 

[Harold in CR]

YUP
Same down here. John seems to have a couple guys that might be OK. Me, I just do what I can, a little at a time.

Right now, I'm having green house problems.
Here is a couple of LED lights I have thrown together for experimenting. Pretty bright for what they are. The one on the desk is so y'all can see how the LEDs look wrapped around a plastic bottle, that is glued into a bulb socket. These are 12V. This one is bright enough to not stumble over things on the floor as you walk.

The one that's lit has more wraps, 8½ compared to 5½ on the unlit one. The lit one gives off plenty of light. I have it dangling nearly over my computer desk, and, it gives enough light to go into the adjoining kitchen and see with no problem. You can see the glare on the curtain behind the lamp that's hanging.

Not bad for the roll of LEDs mailed out of Hong Kong, for $8.00 including mailing. Still have a little bit left on the roll. Might try to do a small light for the bathroom. Need to find a small bottle or similar to glue a bulb socket onto.