Multiple Chargers

Tony,

Sounds like our setup is similar. I have a EU 1000i in a sound deadening box for those NW Washington days when my 800w of solar output is minimal. It has over 1600 hours with only oil changes needed. Can't be heard 30' away feeding 5a to the Magnum for a 30a charge rate.Onan QD7500 in the coach.

Jim

In 28mo. of ownership, my equipment has documented 105.7 DC kAH of off grid use with 73.6 DC kAH being generated by solar.

I was reviewing all of this today during the install and found the numbers to be surprising!

I'm running three East Penn AGM 8D's along with an Optima under the garage for smoothing voltage sag during higher current radio operations back there. Total of 810AH. Should be able to toss well over both those charger's possible combined outputs providing cool enough battery temps? Neither will run 100% with both running anyway.

Generally my 1110 watts on the roof will top off every day in sun, but foggy conditions on the coast and winter in heavy tree cover requires generator time to top off. Running a generator for 5 hours per day gets old in a hurry..... Figured this would reduce run time and offer redundancy in the event of a charger failure.

Turkey day weekend had 3 of 4 foggy days and all I had was the little backup Yamaha 1000is I keep in the front compartment. It ran for 7-12 hours a day to keep things topped off. Would have been nice to run the 2800is for just 2-3 hours in the evening....

Wet deep cycles can take a 30% charging rate, so 180 amps would go into a bank of 600AH ok. More rate than that, your voltage spikes at the start so high that there is no constant amps stage and it tapers the amps right away. Not sure that does any harm to the batteries, but I like to see at least a few minutes of constant amps in the beginning just to get a good feeling that things are going properly.

Ya, check the specs on your batteries. My AGM's are rated for 5C - 285 AH * 5 = 1425 amp max. Flooded are usually rated for C/3-C/10 or in my case 285 AH would charge from about 65 amps down to about 30.

Tony,

I have the same Magnum inverter/converter and it will put 100a into my 6-6v Full River AGM house batteries. After a normal evening of TV-Internet X2 lights and coffee maker it will be tapered from 102a to 40a in a 30 minutes run of the Onan QD 7500 while coffee maker and DW's Latte maker run. From there on the solar system finished up the charge. The AGM batteries might be fine with adding the additional 80a but If you have flooded lead acid house batteries they "might" not like that much charge. I'm not sure. It probably depends on how many batteries you have. My Magnum is plenty for my 6.

All this reading has caused me to get off my lazy hump and re-install the PD9280 that we disconnected and removed when the Magnum MS-2012 was installed.

Luckily the trailer manufacturer installed a dedicated 20 circuit for this purpose so I can easily isolate it from the 120V system when inverting on the road.

Looking forward to shorter generator run times when we do need big power to top off during the winter.

A 200 amp shunt in each of the feed lines only put 50 mv drop at max, more like 3-15 mv at reasonable levels, allows +-4 amp readings with a cheap off the shelf dvm (1mv) and runs $16 each. A nice Fluke 0.1 mv or similar will give you 0.4 amp resolution. There are 25,50, and 100 amp versions for about the same price if your chargers are lower output - the lower rating on the shunt the higher resolution off the same DVM.

All very strange, don't know what kind of chargers those were to get such dismal results.

Below is a graph showing three Vector 35ampers totalling 105a on the bank, doing their usual bulk stage at 105a for a time, then tapering. There is no tapering as soon as the batts are just up from dead, in fact they start at 50% SOC.

Also shown is a graph of the PowerMax 100 amper set to 14.6v doing the same thing where it does bulk at 105ish amps too. There is no difference--the batts don't care where the amps come from.

I have also run a Paramode 55amp converter set to 14.8v doing 60amps with some Vector chargers and some solar all on the same bank. During bulk stage I was getting their total amps (as seen on the Trimetric)

I have also run the 100a PowerMax with the 40a 1093 for 140a as seen on the Trimetric.

I have confirmed that the Vector amps readouts match the Trimetric amps. Where the converters and solar do not have amps readouts, you can tell what they are doing from the difference. eg. you see 40 and 30 on the Vectors for 70 and 130 on the Trimetric, so the converter is doing 60a. If it is converter and solar both on, each with no amps readout, you can pull one and see the Trimetric amps drop by that much and go back up when you reconnect.



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EDIT--a clamp on meter is needed where trying to put the meter in line with the wire distorts the amps because the meter wires are too thin. When I had two 20a controllers off a Y split and both controllers on the same battery bank, I was unable to individually measure how many amps each controller was doing using the in line method (I don't have a clamp meter) When I tried, the meter would show almost nothing and that meant almost all the amps went via the other leg. Switch legs and same thing. I know both controllers were doing some part of the total but could not find out how much each. So a clamp meter has its advantages for sure.

Good test method above. Long ago I learned that a $50 dc clamp on ammeter is a very valuable tool. Just hook up the chargers and measure the current from each one or even all if desired.