EcoRenovator (
-   Solar Power (
-   -   Chevy Volt battery pack for off grid solar? (

creeky 06-15-16 09:37 AM

Okay. Test #1 complete. A complete success. At aprox. 10 a.m. my batteries reached 48.26, went into absorb and then float.

Unfortunately, duty called, and I missed the "absorb" phase. I have it set for 15 minutes.

This is tough as I was hoping to track the amperage at which it went out of absorb. I had thought the % of amp charge it went into vs exited absorb might have indicated the level of charge attained.

However, the voltmeter reads 4.02 on all cells. This is the exact setting I had hoped to attain.

Huzzah. Huzzah. Huzzah.

It appears that it took a titch over 700 watts to charge from 45.83 to 48.26. Very interesting given that it is a 2.2 kw battery. So 3.83/cell was basically at 50-60% charged. I think my 4.02 is about 80% charged.

And, I'm a bit "wowzah", as a .2 cell voltage change indicates 700 watts of storage. When I multiply by 6 packs. That's 4,200 watts of power. Or two full days of use for me.

Now to find the right inverter. Finish tearing down the pack. Charge up the batteries. Top balancing to 4.02. Yar. Matey. Grab your cutlass we're going overboard.

PS-as the charge seems to have balanced the cells. I am going to try the out of balance pack tomorrow. maybe. See if the charge improves the voltage discrepancy between cells. Again. Triple checked this a.m. All cells but one read 3.83. One reads 3.68. Dang.

creeky 06-15-16 08:37 PM

I tore down the second segment. 120v nominal now 2x48 and 1x24. Tomorrow I test charge the 2x48s.

I also tested all the other cells very carefully. They all come in at 3.83 or 3.84. So the low cell is the only one. Whew.

For the pic of the day. The second part of the BMS. What are those big green things do you suppose?

stevehull 06-15-16 08:57 PM


The big green things that look like electrolytic capacitors (but are not)? They might be reference cells or cabatteries.

The way the wires come out, they could be inductors. Don't look like any wire wound resistors I have seen.

Took some time to read your blog - very impressive. Keep up the work!


creeky 06-16-16 05:05 PM

Thx for the vote of encouragement Steve. The blog is my message to my self 50 years ago. Smile. (Kind of kidding).

I've found some hints online that the BMS is on its own bus/communications network. Evidently I can fire it up if I find the right power connectors. Takes 12v power. We'll see what comes of that. I cannot program. And what I know about CAN is that its spelled c-a-n.

RESULTS: Day two. Charge tests.

As noted, I hooked up 2 x 48 to the controller. Well. Surprise. Surprise. The two batteries charged with 1370 watts. That's 685/pack. Within 25w of the previous single pack (710).

If that isn't good enough. Idle/power load on the TS with ethernet is about 75w/day. So most of that missing 25w can be attributed to the additional load of 1 battery vs 2 carrying the controller.

All 24 cells come in at 4.02. Exactly on target. There is startlingly little capacity fade. After charging (I tried 30 min absorb, seems to have made 0 difference) the battery stays at the charge as set on the controller.

I now have 3 of six packs ready for launch.

I have the inverter (a test inverter, small Victron) coming. I am contemplating doing two isolated installations. Or tough out the low power inverter until something better comes along.

I have 5 meter long M6 threaded rods coming. This will allow me to assemble the reconfigured packs.

Getting there.

creeky 06-30-16 04:27 PM

What happens to time? It runs along. Gallops at times. Yet here I am. Still working. Getting things done between events. One step at a time.

The M6 rod came in. Threaded the packs together.

I know what you're saying. Wow Creek, Nice rod threading jig.

First discharge test. All continues to perform as per spec. Lovely when research works out.

Okay. So then the Ammeter/Voltmeter thingamabob came in. Complete with shunt. 18 bucks. Sheesh. Not sure how accurate it is. Seems to measure a bit off when compared to the Morningstar voltage report and what my Voltmeter says. Still.

So. Plug in the Victron 48-1200. Wire up the shunt. Turn all on. Run a drain test. Well. It's summer. Plug in the big screen and watch a movie. What you see above is the idle draw on the Victron along with the idle on the TV (off).

TV draws up to 280w and after two hours the ammeter records 518 used. Battery voltage is 45.72 the next morning. Interestingly the voltmeter says 45.8 and the morningstar says 45.83. Eh. Good enough for the funny papers.

Note: for this test I use the first battery I charged. Initially my settings used a 15 minute absorb period. The battery sat for 10 hours attached to the solar controller. So powering the controller overnight. The battery then sat for almost two weeks. Time is moving by.

Next morning I recharge the battery. I'm now using a 30 minute absorb. By the end of the absorb its only asking for 30 watts to maintain 48.26. So I think I have the absorb time dialed.

(I find very interesting that when charging the battery was cheerfully drinking all my pollen / dust clad panels were putting out. 550 watts. When the battery hit absorb voltage the power drawn dropped almost immediately to 250. Then tapered to 30. I missed the final number, but only by a few minutes. If you've charged lead acid you know how wild that is.)

Summing up:

The initial charge used 710 watts from 3.83/cell voltage. Recharge from 3.8v/cell was 650.

So one 48v battery (nominal 2.125kw) used 650 watts between miscellaneous loads. And recharged that amount in 1 and half hours. Primarily due to very dirty panels.

Right. On to battery installation.

Keeping with the light on the earth, recycle, reuse, repurpose theme. I use the pallet the battery came on, some left over 1/2" plywood scraps, to build the battery box.

And now I'm off to make some battery cables. Wish me luck.

PS-as always, more pics online. And even more detail (;)

creeky 07-01-16 10:06 AM

All right. Long day yesterday culminated in

Took a bit of fiddle faddling, but with the help of an able assistant insulation was cut. Old batteries were moved. New to me batteries were placed.

And 12.75kw (nominal of course at 3.8v) at 48v of lithium storage is in place.

I had thought to get this done by September. But my lead acid began to show serious signs of decay. And, hey, it was Canada Day coming up. So I set that as my deadline and voila.

Canada's first lithium based recycled Chevy Volt SESS launches. Huzzah!

ME_Andy 07-01-16 12:31 PM

Dude, that's awesome.

pinballlooking 07-02-16 07:18 AM

I love this project. Great work.

creeky 07-02-16 11:53 AM

It is truly rewarding to take a risk and come out with a win.

Early days. Well. Day. One day of recorded input/output. But the increased efficiency is startling. I love the near absence of voltage drop on surge. My lights used to flicker noticeably when the fridge kicked on. Not sure if it's the lack of voltage drop or the easier time the 48v inverter has converting to 120v.

Ran the dishwasher. And the fridge still kicked on. I was worried that going down a bit in power with the relatively small Victron might cause problems there. But nope. So all is well on Creeky's camp.

I'm also kind of shocked how bad the lead plates in the old batts are. When I checked them last summer they were pretty clean. But not anymore. So I'm going to take them to the recycle depot next week. I had thought someone else might get a few more years out of them ... uh. no.

Still on the hunt for a BMS solution. I'm probably going active. I think I have it figured out wiring wise. Basically 12s6p. Kind of funny. Each battery is 3p per cell. In 12s. And i'm going to balance the 6p tied together in 1 12s string.

Makes my pack 3p12s6p?

The morningstar controllers are both working to spec. Wiring all tested out perfect. All batteries were 47.6 after the first night of discharge. Pack recharged in 2 hours. So all is good there.

At 12v I was over paneled (1kw per 60a controller) to compensate for late fall/early winter cloud. Now I'm getting the full 1kw out of each set. Should be interesting when the cold season comes to see what maximum watts I can pull.

I think I have more "float" voltage adjustments to try. Along with wiring clean up and installation fiddle faddlin' to do.

But she's up and running. Feels good.

NiHaoMike 07-02-16 11:58 AM

Check with the hybrid and EV bicycle builders. They regularly use 48V packs.

All times are GMT -5. The time now is 03:28 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Ad Management by RedTyger