Lithium and AGM combo system like Hymer

[booster]

Wow, you are on your way! Batteries are due here tomorrow and 12v to 12v adjustable supply Monday or Tuesday. I should have decent information by the time you return.

I have also done what looks to be a very simple wiring diagram for if the charger is needed. It would be for common charging off shore charger or alternator, or individually. I think common will work, though. It would also allow running off either, both, or none an the batteries.

On battery selector switch for the battery connections, one toggle switch for the 12v charger, and the charger. That is it for full capability.

Have a good trip, where are you staying in Moab?

[hbn7hj]

Originally Posted by booster

Have a good trip, where are you staying in Moab?

Last year it was at 7 mile parking at $15 a night. This year I plan to pick a free spot. The retired NFS guy says dispersed camping is limited in Moab. I don't find that to be the case.

My favorite is Goose Island NFS campground but it has a two week limit. If I happen to catch a spot at $7.50, geezer rate, I'll take it, but you have to stand in line in the morning waiting for people to exit to snag one.
Harry

[booster]

Originally Posted by hbn7hj

Last year it was at 7 mile parking at $15 a night. This year I plan to pick a free spot. The retired NFS guy says dispersed camping is limited in Moab. I don't find that to be the case.

My favorite is Goose Island NFS campground but it has a two week limit. If I happen to catch a spot at $7.50, geezer rate, I'll take it, but you have to stand in line in the morning waiting for people to exit to snag one.
Harry

We stayed in one of the BLM campgrounds just north of there a couple of years ago. Beautiful spot right on the river and were lucky that someone happened to be leaving just as we drove by. Unfortunately, it was late fall and very unseasonably hot, in the high 80's low 90's, and the outhouse and garbage dumpster smelled so bad, you couldn't be outside, and barely inside the van. Using the outhouse was essentially impossible with getting physically ill. First day was fine, but by third day they still hadn't done anything and we had to leave it was so bad. Too bad, as it was a really nice spot.

[booster]

I drew up what I think I would do for wiring the system.

You would be able to charge each battery separately or together and also run off either battery when not charging, plus off of both.

[hbn7hj]

Yep, that would do it. Haven't sprung for the A B Both switch yet. I'll get that when I get a B to B charger. Right now I'll use a high amp toggle switch to the lithium and the disconnect switch to the Lead Acid. I expect/hope the both position will get a lot of use.

The campground you mentioned was for many years without facilities, or fee, then restricted to self contained vehicles only when everyone crossed the road to pollute the bushes. They finally added "facilities" which generally aren't that bad. The site has no phone signal. Before cell phones it was our site of choice. There are a lot of free areas with cell signal now. Goose Island works better with a phone signal booster.

My Battleborn battery was shipped by Dragonfly in Reno. How come you know all this stuff!

[booster]

I have everything here to do a sample system experiment except the 3ah lithium battery which is supposed to show up tomorrow. I have started to do some preliminary data collection on AGM batteries so I know what to expect. Glad I did, because I did get some surprises.

Since the van was sitting right there and has shore power and the Magnum charger with built in monitor, I decided to use it to see how much the 440ah bank would accept when at 80% SOC. The results were not what I expected.

I ran the batteries down to 80% on the meter, which confirmed as being down 88ah, let the batteries rest for a few hours and checked the voltage, which came in at 12.9v which is way over the 12.54v that Lifeline says that 80% should be. I have run into this before with other tests, but not quite as extreme a difference. I think it is because Lifeline is basing the chart on "normal" charging that doesn't take the batteries to very full condition of .5%C amps at absorption. The batteries are few years old, but still appear to be in very good shape.

Anyway, I put in on charge with the Magnum 100 amp charger, and it pinned it at 99 amps which was surprising because in the past I have seen tapering by then. Probably has to do with starting at higher SOC than before. This is .23C amps of charging, so it certainly would indicate that a good sized DC to DC charger would be needed or one that safely current limits without just shutting down like the Powerstream ones say they do. It didn't reach absorption voltage and start to taper until nearly 90% on the SOC meter.

This is kind of contrary to the normal knowledge about how long faster charging continues before you get to the long haul tapering that the AGMs need to get full, as running a generator to 90% still be charging at high rate.

I let the charger complete the charge, which did take the normal 6 more hours approximately. When I looked at returned AH screen it got obvious what is going on as the returned amp hours were nearly 94AH to get full. This is the charge efficiency showing up so you need more amps back in than you took out. If it were a deep discharge the difference would be even more than 10% of the discharge AH from what I have seen in the past. The monitor is supposed to auto adjust over time to keep the SOC % correct at recharge by using charge efficiency, but it can't keep up with varying discharge amounts and is never correct on recharge, but is correct on discharge.

All this really says is that when you are 80% on recharge you actually have over 20%C left to charge and would help explain the no tapering right away.

Because of this, going be SOC on recharge is probably not the best way to determine when to shut off the charge source and let the lithium battery finish off the charge. I think I would wait until the absorption voltage is reached and the amps start down, regardless of what the SOC% is. The exception would be if you find you always have lithium capacity left when the charging tops off and want to shorten the charging time as much as you can.

I then did the same test on the 12AH AGM that is going to be used in the test and at 80% it took nearly 10 amps of charge which is over .8C amps. It held absorption voltage right away because it was on a 40 amp charger. If you have a hugely oversized charger like an engine generator would be, I think I would just test what the right charging amps are, based on the lithium finishing the charge, and stop charging that way.

All this will complicate my testing a bit because the DC to DC charger I got is not current limited and would be beyond capacity at 10 amps by quite a bit. I will either have to use just the lithium without the charger initially or ramp up the voltage slowly on the charger. Neither should alter results, though, as the test is if the lithium will have the capacity to adequately finish the AGM charge, and by the end of charge the amps will be down so the charger can hold the voltage up.

Hopefully, in the next couple of days I should have more complete information.

[hbn7hj]

The. Last of my parts are "out for delivery" at the moment. I think I am going to run both a lithium charger and lead acid charger in parallel with the batteries separated but that is something to deal with later. It would reduce my generator run time.

The 1-2 both switch is also on it's way. Just an FYI but a battery delivery has a lot of restrictions and after two days of trying to let someone else pick it up at the office, I gave up and delayed my departure. They won't hold it. If it bounces it goes back to the shipper and the only way another person can receive it is to be at the address when delivery is attempted.
Harry

[booster]

Sounds good to me. With the large lithium capacity than I am testing you will some extra options available, I think.

You could stop the AGM charging sooner in the recharge (lower SOC) as you will have more lithium capacity to fill the rest of the charge.

Or you could charge the AGM to a SOC that would leave some capacity in the lithium for use after finishing the AGM charging, as the AGM will still be accepting large amps from the charger.

Both are very nice to have.

[GeorgeRa]

Just got a note from Powersaver, I will sens an email to France but I think this is going nowhere.

" HI ,

There is no stock of the SDC-1140A in the US.

After checking , the SDC-1140A is available at the below company.

Please contact :

Franck SCHEIBER

SCHEIBER S.A.
Bellevue - 85120 Saint-Pierre du Chemin • France
Fax +33 (0)2 51 51 74 05
Mob. +33 (0)6 08 86 75 05
fscheiber@scheiber.com - Scheiber | Equipementier électrique français


Kind regards,
Billy
Powersaver Technologies Ltd.
email : billy@powersaver.com.hk
Powersaver Technologics Limited - Your Power Solution Partner

----- Original Message -----
From: George
To: 'Marketing and Sales'
Sent: Tuesday, February 27, 2018 11:38 AM
Subject: RE: 回覆： US availability?

Hello Billy,

A reminder, are you still interested in providing me further purchasing details in US?

Thank you,

George."

[booster]

Looking at B to B charging, including the Kisae you posted earlier, which looks promising because it has a power supply setting that is likely constant voltage charging which is what we need. Also show good input voltage range where many only will run if source voltage is higher than destination. Do you happen to have access to the operating manual on that one?

One huge question is if it current limits or not.

[GeorgeRa]

Originally Posted by booster

Looking at B to B charging, including the Kisae you posted earlier, which looks promising because it has a power supply setting that is likely constant voltage charging which is what we need. Also show good input voltage range where many only will run if source voltage is higher than destination. Do you happen to have access to the operating manual on that one?

One huge question is if it current limits or not.

Here it is.

[booster]

I found a manual for the Kisae, and it does seem to pretty well suited as it will up the voltage, is current limit setable, and in lithium mode can set voltage and ending transition current. The low voltage cutouts are a bit confusing, but look like they would work out with just a battery with no alternator on the input.

As of now, I would put it at the top choice with a chance of working well.

http://pdf.donrowe.com/dmt1230_dmt1250_owners_guide.pdf

[GeorgeRa]

Good price -
https://www.amazon.com/gp/product/B0...=ATVPDKIKX0DER

[hbn7hj]

Got all my parts except the Blue Sea switch which is due Friday. With Booster and George figuring things out I should be ready for a smoke test around March 14, when I get back. Freezing my butt off in Borrego Springs! It is supposed to be warm here.

I took the Kisae thing to be a solar controller, not a B to B charger.
Harry

[booster]

Originally Posted by hbn7hj

Got all my parts except the Blue Sea switch which is due Friday. With Booster and George figuring things out I should be ready for a smoke test around March 14, when I get back. Freezing my butt off in Borrego Springs! It is supposed to be warm here.

I took the Kisae thing to be a solar controller, not a B to B charger.
Harry

It lists it as a solar controller, so I thought so also. It has dual inputs for the addition of alternator or battery to battery charging, and is one of the few that can be set constant voltage and end amps, it appears. It also will handle the low and/varying input voltage, so looks pretty good. Of course until you actually set one up and program it, you really don't know for sure.

[booster]

Tiny little lithium battery showed up today. 3ah. It doesn't appear to have high acceptance of the larger lithium LiFePo4 that we are used to as it would not accept even 5 amps from the bench charger limited to 5 amps. Had to slowly nurse it up be ramping the voltage to control charge amps to under 1 amp. Wouldn't go past 14.1v but that is pretty full and past the knee of the charge curve.

The AGM was already at 80%, and I figured the current would be too high for the lithium if I just connected them, so I used the B to B little charger I got and did the same ramp up of voltage to do the current limiting. Went until the lithium was dead, and after resting the AGM was sitting at over 13 volts, so has to be close to full. I will put the charger on it to see how many amps it will pull at absorption as that will tell me how full it is.

As far as the process goes, it worked just as hoped, so I am really quite confident this will work, but you need a B to B current limiting charger that can run with the input lower than many do because they are counting on alternator voltage all the time. It certainly looks like the Kasai would do the trick.

Really am looking forward to seeing how Harry's full size testing goes, as it is looking very encouraging at this point.

[hbn7hj]

I am going to assume we want the 30 amp Kisae charger rather than the 50 because we intend to top off the lead acid. Amazon doesn't sell the 50.

In reading the manual the Kisae charger never will boost voltage? The little charger you are testing does, correct?

[booster]

Originally Posted by hbn7hj

I am going to assume we want the 30 amp Kisae charger rather than the 50 because we intend to top off the lead acid. Amazon doesn't sell the 50.

In reading the manual the Kisae charger never will boost voltage? The little charger you are testing does, correct?

30 amp should be fine as it is current limiting so it can't hurt itself. The smaller size also allows you to select a lower amount of end amps to stop the charging.

It appears that the Kisae does boost the voltage on the battery to battery input side, maybe not on the solar side as it wouldn't be needed. The specs call out the input voltage being able to go considerably lower than the lithium battery would be while doing the charging. Of course this is just speculation based on the manual. Real world can get in the way, sometimes.

Yes my little charger did boost the voltage, that is what made it work very well.

IMO you do need a B to B charger that is current limiting and voltage boosting, which is pretty hard to find, so if the Kisae really does both, it will make things run very well, I think.

[hbn7hj]

OK, I'll get the Kisae. If it doesn't boost voltage we could put a voltage booster ahead of it. Reading the specs again it appears it does. 10.5v in 13.8v out.

Let me know ASAP if you think it won't work. I'll hit the "buy now" button tomorrow. I'd like to have all major parts before going to Moab. ACE hardware and I are gonna get along fine putting this together.

It can be difficult getting packages delivered with no verifiable address. I have a P.O. Box in Silverton which will make things easier come June.

As for the expense, $50/night buys a lot of toys and that is the going rate in Silverton.

[booster]

I think it will also give higher than 13.8v out if you set it that way, as they show 14.4v absorption, so near perfect if it does.