Charging 3 105 AH batteries with SSG

[Gary Hammond]

Hi,

I bought three 27DC marine batteries on sale back in April. I initially charged them with my 10A12 charger and they've been sitting unused ever since. I plan on building a three battery supply SSG like Peter Lindemann demonstrated at the 2016 Conference but haven't started it yet. So I figured I'd better charge them all up again. Here's a video of them charging on my SSG.

[Faraday88]

Hi,

I bought three 27DC marine batteries on sale back in April. I initially charged them with my 10A12 charger and they've been sitting unused ever since. I plan on building a three battery supply SSG like Peter Lindemann demonstrated at the 2016 Conference but haven't started it yet. So I figured I'd better charge them all up again. Here's a video of them charging on my SSG.

Hi Gary,
Beautiful work!
Faraday88.

[Yaro1776]

Gary,

A blast from the past for sure - good to get back to the original roots here. Looks like it is still works just as well as it did in the past. I assume that you are running the SSG in generator mode (another name for radiant mode) in this arrangement.

Very good of you to take the time to video this setup and to show how it works. Great!

Thanks

[Gary Hammond]

Hi Yaro,

Sorry, but you got it backwards. The so called generator mode is actually the common ground mode, not the radiant mode as you stated.

Gary,
....................................... I assume that you are running the SSG in generator mode (another name for radiant mode) in this arrangement. ...............
Thanks

I ran it for about 24 hours in radiant mode and it never got the three batteries in parallel over about 13.6 volts. Then I switched it over to common ground mode, which is also known as generator mode. It slowed down to 200 rpm and pulled a lot more current without raising the voltage any more, so I only ran it a short time this way.

Then I recharged the run battery with the 10A12 charger for several hours and it wouldn't go above 14.9 volts. Then I charged the other three batteries in parallel with the 10A12 charger and couldn't get them over 14 volts. So I separated them and charged each one individually and they all topped out at 14.9 volts.

A 315 AH load of unconditioned batteries is apparently too much for either my SSG or 10A12 to fully charge. Once the batteries are reconditioned and fully desulfated it might be a different story. I'll find out when I get them set up in a four battery rotation with a modified SSG running with three and resting one like Peter and RS demonstrated.

I just received 8 three pole 10 amp breakers to try and replicate RS's "Poor Mans Battery Swapper". Now I just have to modify one of my SSG's and wire it all up!

[Yaro1776]

Gary,

Thanks for the correction - been away from this way too long. The 10A12 is useful on the 100 Ah Labs and I use it often to keep my battery set topped off with individual charging up to 15.3v. Doing two of these in parallel will still work but it takes a very long time to top them off.

I have also used these 100Ah batteries in parallel to run my cell system with three solar panels and a Solar Tracker 5 - works well and will pump the voltage to 15.3v on sunny days. I have had this system running for over two years.

I am a bit skeptical that a single SSG will have enough guts to drive the three 100 Ah Labs, but then you can only give it a shot to see how it plays out. May work perfectly well!

Thanks for the fun experiment and it will be interesting to all. BTW Peter L. had a battery swapping system (a la Benitez) in operation at this last conference.

[Gary Hammond]

Hi,

Been working on modifying my old SSG and wiring up a "poor man's split the positive" battery rotation to drive it. I'm wiring everything up with 10 gauge wire. This is the SSG that I changed over to hall triggering a few years back. It's coil will use 4 power strands of 18 gauge wire and a separate strand of 18 gauge wire to harvest the spikes.

Here's a couple of pics of the progress so far.

[RS_]

good going Gary, i bet those breakers were not cheap....

[Gary Hammond]

Hi RS,

good going Gary, i bet those breakers were not cheap....

Thanks. I think I got a deal on old surplus items, they were only $12.99 each plus shipping. I ganged them together in pairs with stainless welding rod through the toggles.

[RS_]

even better....

[Gary Hammond]

Hi,

Got my split the positive battery rotator all wired up last night and tried it out. All the batteries had been fully charged a few days ago and were sitting at 12.8 volts. First thing I did was pull 6AH out of the battery in the charge position with my CBA III. It came back up to about 12.7 volts.

I ran thru a complete rotation of all four batteries charging each one in turn up to about 13.3 volts. The one I had discharged took over an hour and the others varied from 30 minutes to 45 minutes. The SSG was only pulling 0.75 amps, so getting to a higher charge voltage was going to take a lot longer than I had anticipated. Took the Bradley GT to a car show this morning so didn't get back to the SSG til this afternoon.

Since the c20 rate of these batteries is 5.25 amps, I decided to add an additional load in parallel with the SSG by hooking a 35 Watt headlamp across it. This brought the current flow thru the batteries up to 3.25 to 3.5 amps depending on which battery was being charged. With the light in the circuit it is taking about 15 minutes to bring each battery up to 13.8 volts except for the one I discharged first. I'm in the process of giving it a longer charge time and stopping it at 13.5 volts.

I'm hoping to get all of them equalized and topping out at 13.8 volts in 15 minutes. This may take awhile. But it appears, just starting out, that the load is running mostly off the radiant and maybe stealing the surface charge.

Adding the fast diode between the buses didn't help at all. It actually reduced the size of the radiant spike and lowered the charge rate, so it's running with the buses wired directly together. The batteries must be absorbing all the spike as it doesn't show much at all when scoping the radiant collection winding (2.16 volts without the 30 watt headlamp installed). But the transistors show an 80 volt spike without the headlamp installed, and a 50 volt spike with it.

Here are some photos of it running.

[Gary Hammond]

Hi,
.........I'm hoping to get all of them equalized and topping out at 13.8 volts in 15 minutes. This may take awhile. But it appears, just starting out, that the load is running mostly off the radiant and maybe stealing the surface charge. ..................

Well that isn't happening. After running for several hours each battery was either taking longer to charge to the same voltage or if always charged the same length of time would charge back to a lower voltage. So all the batteries were very slowly loosing charge.

The batteries must be absorbing all the spike as it doesn't show much at all when scoping the radiant collection winding.

I scoped again directly across the radiant collection winding with the 30 watt headlamp in the circuit and it showed about a 15 volt spike. About 1/3 the value of what was appearing across the transistors. I think I need a stronger SSG with more collection windings for this to work properly with these size batteries.

[John_Koorn]

Hi Gary,

Yes. I was going to suggest that the batteries are too big for that SSG. You need to be able to take them up to ~15.8V otherwise you'll slowly kill them.

John K.

[Gary Hammond]

Hi,

Shortly after my last post in this thread, I rewired the five strand coil to run on three strands and collect the radiant on two strands. This didn't really make much difference in the way it performed, as it still ran about the same speed and charged at the same rate. The batteries were still losing charge over time. So I stopped working on it until this past week.

I decided to try splitting the negative and using my better SSG with seven strands running in conventional radiant mode. This is the SSG I showed in my first post of this thread. I discovered that by rearranging the battery locations in the 3 battery supply (using a common positive and taking power between the negatives) I could apply the radiant directly to the battery being charged from the regular SSG output. The charging looked pretty good, so I had my grandson help me rewire the circuit breakers last Thursday so I could easily rotate the batteries.

I've just started testing this new set up and don't have any meaningful results yet. It does, however, bring the charge battery up a little faster and a little higher than the other SSG and "split the positive" did. Will post some photos and data results after I've ran it some more. This one is double pulsing and running at 206 RPM. I want to get the speed up and into single pulsing if I can by readjusting all the parameters.

[John_Koorn]

Hi Gary,

A good rule of thumb I use is about 1 watt of input power for 1 amp hour of battery you're charging. When I set my SS SG to this I get about a C20 rate of charge. So for a 100AH battery you'll need an SG that takes about 100W to run.

John K.

[Aaron Murakami]

Hi Gary,

A good rule of thumb I use is about 1 watt of input power for 1 amp hour of battery you're charging. When I set my SS SG to this I get about a C20 rate of charge. So for a 100AH battery you'll need an SG that takes about 100W to run.

John K.

I find that a typical coil with 7-8 power windings will draw a ballpark of about 20 watts - so it would take a 5 coiler ideally for the 100 ah battery bank. Would you say that matches what you've seen?

A single coil with 7 power windings for example can barely push a 35 amp hour battery into the 14 volt range.