Battery Charger

Wilis

Hi,

I would like to purchase a battery charger. I have 12 T105 Trojan batteries, 3-24v strings. I believe that is 675ah of power. Has anyone used the Iota DLS-27-40: 24 volt 40 amp regulated battery charger or would the 25 amp charger be enough to charge these batteries from my 4K generator. This would only be used if the solar is low and the grid is down for a few days. Or does someone think a different brand would be better. Thanks for the great information on this forum. Wilis

hillbilly

Re: Battery Charger

Those Iota chargers do work well, the only thing to be aware of is that they do not go to a high enough voltage for Equalizing. I realized this one "small" drawback only after purchasing two of them to use in parallel. If you are off grid (?), and your solar array is not capable of EQ'ing your battery bank, then this may not be such a great addition to your system. For sealed batteries that don't need to be Equalized, or for on grid back up applications I think that these chargers are far more useful.
Just be aware of that one small detail.

Cariboocoot

Re: Battery Charger

Actually Iota chargers do have an EQ "option":

"The IQ4 Controller allows the DLS charger to operate as an automatic 3-stage "smart charger". This gives the customer the benefit of Bulk, Absorption, and Float stage charging, increasing the charging capacity of the DLS charger and decreasing charge times and insuring proper and safe battery charging. In addition, The IQ4 insures proper battery charging while minimizing over-charging. This "smarter" technology monitors the battery at all times. If the DLS voltage remains in the long term float stage more than 7 days, the IQ4 will automatically deliver an equalization charge for a predetermined time, then automatically return to the normal float stage. The DLS-75 power converter can be ordered with the IQ4 Controller option internally integrated into the unit."

hillbilly

Re: Battery Charger

Cariboocoot wrote: »

Actually Iota chargers do have an EQ "option":

"The IQ4 Controller allows the DLS charger to operate as an automatic 3-stage "smart charger". This gives the customer the benefit of Bulk, Absorption, and Float stage charging, increasing the charging capacity of the DLS charger and decreasing charge times and insuring proper and safe battery charging. In addition, The IQ4 insures proper battery charging while minimizing over-charging. This "smarter" technology monitors the battery at all times. If the DLS voltage remains in the long term float stage more than 7 days, the IQ4 will automatically deliver an equalization charge for a predetermined time, then automatically return to the normal float stage. The DLS-75 power converter can be ordered with the IQ4 Controller option internally integrated into the unit."

I had read that before, two small details:
For one that is assuming that it's connected to a constant power source (grid). Second, unless I completely missed something with the two Iota chargers I have (stranger things have certainly happened) the highest voltage that I could get them to charge at was 14.2V (this was on a 12V battery bank, since reconfigured to 24V).
For me living off grid, the main thing that I needed from a charger was being able to use the generator to help with EQ'ing so I have to say that I was very disappointed with this limitation. No other complaints whatsoever about the Iota chargers, just this...

If I am missing something here with regards to higher voltage EQ charging (in an off grid/ generator powered set up), please enlighten me ...

Cariboocoot

Re: Battery Charger

hillbilly;

I agree with you. The Iota doesn't seem to have a manual EQ setting, and I don't know the specifics of its automatic EQ function. Maybe I should read the manual! Just thought I'd mention that they indicate it has this function (with the IQ4 option). How long it would have to be powered up for before switching to EQ is a question.

My Outback being an inverter/charger is quite capable of performing EQ off the generator, yet for some reason I can't quite put my finger on the EQ works better when done from the panels through the MX60. Perhaps the output of the FX's charger isn't that well rectified?

hillbilly

Re: Battery Charger

Yeah, this was the main reason for a huge system "upgrade" for us. Switched to a VFX3524 inverter, and reconfigured the battery bank to a 24V instead of 12V (and bought a new charge controller)...
All in all though, I've been much happier with our current set up. Like I said, maybe I missed something with our Iota chargers (although their manual is refreshingly brief); but when I realized that I could not bring the battery bank up to a high enough EQ voltage I upgraded.

Maybe on second thought don't tell me if I'm missing the obvious on this :-)

Cariboocoot

Re: Battery Charger

Hmm. Sounds familiar. Well, Great Minds run in the same channel.

Wilis

Re: Battery Charger

Thanks for all the answers. I do have a Magnum MS-AE4024AE inverter that I could do a gen charge. I do a grid power EQ with this inverter, but am afraid to use the MS for the gen charge. My gen is a old Coleman gen and I dont want to take a chance on doing something like letting smoke out of the inverter. I want a battery charger because it costs less if I have problems and would give me a backup way of charging batteries. Also would 25 amps be enough to charge the 675AH of batteries? I never let my batteries get lower then 75%. Thanks again. Wilis

hillbilly

Re: Battery Charger

As far as bulk charging, that 25 amps could work although it is a tad on the low side of charging (meaning increased run time on the Gen). Will you be using this to completely recharge the batteries up, meaning 2-3 hours of absorb time, or just to bulk them up to say 90% full or so? That would make an impact on which charger I would want, as a 40 amp charger would get the batteries up to absorb voltage much quicker from a deeper discharge but then once in absorb your looking at the same amount of run time on the generator with either one... Normally I'd be a bit more inclined to go with the 40 amp charger, but if this is just for a back up option then I don't see any problems with a 25 amp charger other than longer run times on the Generator.

Cariboocoot

Re: Battery Charger

Wilis wrote: »

Thanks for all the answers. I do have a Magnum MS-AE4024AE inverter that I could do a gen charge. I do a grid power EQ with this inverter, but am afraid to use the MS for the gen charge. My gen is a old Coleman gen and I dont want to take a chance on doing something like letting smoke out of the inverter. I want a battery charger because it costs less if I have problems and would give me a backup way of charging batteries. Also would 25 amps be enough to charge the 675AH of batteries? I never let my batteries get lower then 75%. Thanks again. Wilis

25 Amps isn't enough for 675 Amp/hrs. You'd want at least 34 Amps (without loads) and preferably 68.

The Coleman shouldn't be a problem; just don't ground it (or tie the neutral to ground at the gen). I'm not certain of the Magnum's configuration, so even that may not be a problem. This issue seems to come up mainly with MSW type inverters (ground loop problems).

You can 'stack' Iota inverters with the right options (but you have to buy two & the right IQ4 set-up).

hillbilly

Re: Battery Charger

Marc remember that this charger is not supplying power to all loads, just the batteries. I'd agree that 25 amps is a bit low, but will definately bring the batteries up to 28.4V (as high as I think that charger goes). I'd say that especially if the batteries are being shallow cycled, and this is only for a rare back up use then a bit of extra run time on the genny is probably not a huge issue.

Cariboocoot

Re: Battery Charger

hillbilly wrote: »

Marc remember that this charger is not supplying power to all loads, just the batteries. I'd agree that 25 amps is a bit low, but will definately bring the batteries up to 28.4V (as high as I think that charger goes). I'd say that especially if the batteries are being shallow cycled, and this is only for a rare back up use then a bit of extra run time on the genny is probably not a huge issue.

If the batteries are supplying current to run an inverter while they're being charged by a generator-powered charger, then the charge rate is current in minus the loads. The only time you get true charge rate with a gen is when the loads are also switched to the gen, and taken off the inverter & batteries.

I'm probably not explaining this well.

But I think for 675 Amp/hrs would be better charged with the 40 Amp Iota.

BB.

Re: Battery Charger

If you are running a 4kW genset, if can, you should try to run it around 50% load or so:

40 amps * 29 volts * 1/0.80 eff = 1,450 watts (est. genset load)
20 amps * 29 volts * 1/0.80 eff = 725 watts (est. genset load)

You will probably end up consuming quite a bit more fuel to recharge the battery bank with a 20 amp charger (pretty small for the 4kW genset).

The faster charging and running closer to 50% load should be much more fuel efficient.

-Bill

hillbilly

Re: Battery Charger

Marc you're correct on that, I was sort of assuming that the generator would also be handling household loads.
Speaking of which; Wilis what would your household loads likely be during such a time that you'd be wanting to use this unit? Also how is your generator connected? Is this a 120V, or 120V/240V 4kw figure?

Wilis

Re: Battery Charger

Load would be about 2kw max, but some cycling loads. I could cut back on everything for the 2 to 4 hours I would need to run genset. Solar would also be charging if not cloudy weather. I have only 4-210w panels now(2 series, 2 parallel) but will double that after the 1st of the year. I would be connecting the genset with 240v on a 50 foot #10 wire. Genset does have both 120v and 240v output. I have not checked if Iota DLS will allow 240v. Will check that after this post. Thanks again. Nice to be able to get some ideas before spending money. Wilis

Cariboocoot

Re: Battery Charger

You have just barely enough panel for that bank, in my estimation.

As for the gen/load issue, maybe you could get an automatic transfer switch installed to shift the loads on to the gen whenever it's running. This would assure maximum charging of the batteries.

Wilis

Re: Battery Charger

Yes Cariboocoot it takes most all of my solar each day to keep the batteries up this time of year. This time of year in Tennessee is not the best for solar. That is why I will be adding to the PV's as soon as I can. I am being careful not to damage my batteries. I have read many time the first set is a training set. I have tried to not let this happen. I have checked the SG every month for the 3 months I have been running. I can grid charge through the inverter if I see the batteries are down more then 80% one day.
I can run the genset through the 200 amp main panel when it is running. I have done this before when that way the only backup I had. I have wired a solar outlet to the areas of the house I want solar and I still have the orginal AC outlet there.
I see the Iota uses 120v, so I can use one of the 120v plugs for the charger and one of the 240v plugs to run the loads when the genset is running. Thanks everyone for the good posts. Wilis

Brock

Re: Battery Charger

The 40 amp iota would be better match for the batteries and the Coleman charger. BUT a 25 amp charger could be powered by an idling car and a 1200w inverter. The 40 amp one could be as well, but you would need to up the idle on the engine or have a larger alternator 100 amp or more. Just throwing another wrench out there...

mike95490

Re: Battery Charger

Could run the genset in the AM, to bulk up the batteries, use solar to top them off, then start genset again to EQ, but you really need to switch off all loads for the day, while you are trying this.

Cariboocoot

Re: Battery Charger

mike90045 wrote: »

Could run the genset in the AM, to bulk up the batteries, use solar to top them off, then stat genset again to EQ, but you really need to swith off all loads for the day, while you are trying this.

This brings up a little detail several of us keep forgetting to mention when talking about Equalizing batteries: they should be disconnected from all loads (including the inverter) during the process.

Okay, maybe it's just me that forgets to mention it.

niel

Re: Battery Charger

Cariboocoot wrote: »

This brings up a little detail several of us keep forgetting to mention when talking about Equalizing batteries: they should be disconnected from all loads (including the inverter) during the process.

Okay, maybe it's just me that forgets to mention it.

or was it you speaking from experience in forgetting to disconnect the loads?:p

Cariboocoot

Re: Battery Charger

niel wrote: »

or was it you speaking from experience in forgetting to disconnect the loads?:p

I have a 'dual bank' system that allows me to keep the inverter running off one set while EQ'ing the other.
Or I did have up until that plate collapsed! It's a bad thing to have one battery in a series that's 2 Volts below normal while the other is two above.

BB.

Re: Battery Charger

Which reason(s) are you using to justify removing operating loads from equalizing battery banks?

To ensure there is enough current to Equalize?

Or because many DC appliances don't like >15 volts very much?

-Bill

mike95490

Re: Battery Charger

BB. wrote: »

Which reason(s) are you using to justify removing operating loads from equalizing battery banks?

To ensure there is enough current to Equalize?

Or because many DC appliances don't like >15 volts very much?

-Bill

In this underpowered thread, To ensure there is enough current to Equalize

vcallaway

Re: Battery Charger

Why not just use a transfer switch?

The IOTA switch has a 30 second delay to allow the generator to warm up. It then will switch the load to the generator.

So long as you don't have a huge load you can put one leg of the genny on the transfer swtich and the other powering the charger. Use something like a Xantrex battery monitor to start and stop the genny based on battery levels.

Someone tell me if I'm wrong because that is what I'm planning to do to my place next.

Cariboocoot

Re: Battery Charger

vcallaway wrote: »

Why not just use a transfer switch?

The IOTA switch has a 30 second delay to allow the generator to warm up. It then will switch the load to the generator.

So long as you don't have a huge load you can put one leg of the genny on the transfer swtich and the other powering the charger. Use something like a Xantrex battery monitor to start and stop the genny based on battery levels.

Someone tell me if I'm wrong because that is what I'm planning to do to my place next.

If you have an inverter like the Outback VFX3524 that hillbilly & I both use there is no need for a separate transfer switch: then gen will automatically take the AC loads while charging. Many other inverter/chargers function this way too.

The OP was concerned about using his old Coleman gen with his Magnum inverter. I don't see there's really any issue there; should be fine.

As for Bill's question about why no loads: a bit of both. My old "12 Volt" inverter would shut down at 15V and EQ required 15.5 so that wouldn't work. But even with the new set-up I, like many off-gridders, run a pretty small array for getting the necessary power to run loads and EQ at the same time. Keep in mind batteries have to be fully charged before equalizing, and there's only so much daylight. The usual method is to bulk charge with the generator to start with, then let the panels finish things off nicely. Especially handy if you have to run multiple EQ cycles in a day on some troublesome batteries.

FWIW: I only EQ when a cell is off by "one zone" on the hydrometer, and then only for an hour. If necessary, I'll repeat for another hour. If there's no improvement after an EQ cycle, there's probably no sense in doing it over again.

vcallaway

Re: Battery Charger

Right now I'm still setup as a backup power system. My inverter is a Samlex that was salvaged from a crashed RV. It shuts down at 16.5 volts. I have not run the charger and the inverter at the same time. Probably should check that.

I have no budget to work with. Most things are being done as I find deals on various components. I'm hoping by spring to be able to buy the solar panels new. Already figured out I can't cheap out on those.

The worst part echos an old saying: The more I learn, the more I find I don't know.