12v Battery Bank in Parallel with 6v Bank
Short version I need a quick fix to get thru this summer boondocking. I know what I am considering doing is bad but I don’t know how bad & need input on what will be happening to batteries when...
Forum Discussion
Alan , all you need now is a charger that can do the 100% shots on them by individual type once you get shore power between off-grid times. I use a VEC1093DBD for that since a regular converter like your Iota won't do the over 15v part. ( it is a good converter though)
Keep them all banked when off-grid and charge them up as can, then on shore power, use the Iota and portable charger to get them all up to "normal full." That will take the first night on shore power plus a few hours maybe.
Now next day use the VEC1093 on Equalize setting (or whatever charger you use for that) to do just the two 24s , then just the 31, then just the two 6s. So that is three separate episodes. Takes more than a minute! Check SGs. If SGs still not back to where you like then do it all again. This is where the 1093 is so good because it does Equalize and shuts that off automatically so you can do that overnight without having to "be there" like with a manual charger. I often have to do two runs of Equalize one right after the other on each set of batts to get them back to baseline SG.
Then (this might not be till day three notice) you can wire them all up together again and Float the whole bunch on the Iota till the next time you go off-grid. I do all that at home between trips off grid. I hated doing it with a manual charger because you have to be there and it takes a long time to get them all done. PITA. With the 1093 is it so easy because it is automatic shut off.
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I was unclear about my recharging in the above post as to how many times while camping last time Four nights. Did one "60-90" while camping on the second day after two nights. Then two more nights and needed a second recharge but did it at home (was down 335AH out of 700(est) on arrival home. I ran the gen for a bit on the second recharge to test out my thermistor repairs on the chargers.
Mena we usually go 70AH/day in summer and somewhere over twice that in winter with the furnace and lights on longer, so let's say 160AH/day. So going two days and being down to 50% second day means being down 320AH (out of about 700AH or whatever the capacity is at the temperature)
Recharging that during the two hour gen time limit in the morning at the park is "interesting" You get a free 10% the first day by starting off from home at full, so I was only down to 60% on the recharge the second day at -274AH on the Trimetric. Started with 140a, tapering after 30 minutes, at 109a at the 1 hr point, pulled the VEC doing the rest on the 100amper only, at the 2 hr point was charging at 50a (about 8a per batt) and at -74 on the Trimetric.
So that was 200AH restored and now at 626 out of 700(est) or 89%. So 200 was about 29% if started at 60 (morning voltage was 12.2 where 12.1 is 50% on these batts)
As a confirmation check-- If 200AH is 29% then 100% is 689AH capacity so pick a number for capacity instead of 700--hard to get it right per temperature.
More reason why I think the Trimetric notion of entering a capacity for "full" and then using the %SOC read-out is bogus. You have to pick your notion of full AH each day and use the AH reading and doing some math on a scrap of paper to get an idea where you really are and it is different every day as temperature varies.
Keep them all banked when off-grid and charge them up as can, then on shore power, use the Iota and portable charger to get them all up to "normal full." That will take the first night on shore power plus a few hours maybe.
Now next day use the VEC1093 on Equalize setting (or whatever charger you use for that) to do just the two 24s , then just the 31, then just the two 6s. So that is three separate episodes. Takes more than a minute! Check SGs. If SGs still not back to where you like then do it all again. This is where the 1093 is so good because it does Equalize and shuts that off automatically so you can do that overnight without having to "be there" like with a manual charger. I often have to do two runs of Equalize one right after the other on each set of batts to get them back to baseline SG.
Then (this might not be till day three notice) you can wire them all up together again and Float the whole bunch on the Iota till the next time you go off-grid. I do all that at home between trips off grid. I hated doing it with a manual charger because you have to be there and it takes a long time to get them all done. PITA. With the 1093 is it so easy because it is automatic shut off.
------------
I was unclear about my recharging in the above post as to how many times while camping last time Four nights. Did one "60-90" while camping on the second day after two nights. Then two more nights and needed a second recharge but did it at home (was down 335AH out of 700(est) on arrival home. I ran the gen for a bit on the second recharge to test out my thermistor repairs on the chargers.
Mena we usually go 70AH/day in summer and somewhere over twice that in winter with the furnace and lights on longer, so let's say 160AH/day. So going two days and being down to 50% second day means being down 320AH (out of about 700AH or whatever the capacity is at the temperature)
Recharging that during the two hour gen time limit in the morning at the park is "interesting" You get a free 10% the first day by starting off from home at full, so I was only down to 60% on the recharge the second day at -274AH on the Trimetric. Started with 140a, tapering after 30 minutes, at 109a at the 1 hr point, pulled the VEC doing the rest on the 100amper only, at the 2 hr point was charging at 50a (about 8a per batt) and at -74 on the Trimetric.
So that was 200AH restored and now at 626 out of 700(est) or 89%. So 200 was about 29% if started at 60 (morning voltage was 12.2 where 12.1 is 50% on these batts)
As a confirmation check-- If 200AH is 29% then 100% is 689AH capacity so pick a number for capacity instead of 700--hard to get it right per temperature.
More reason why I think the Trimetric notion of entering a capacity for "full" and then using the %SOC read-out is bogus. You have to pick your notion of full AH each day and use the AH reading and doing some math on a scrap of paper to get an idea where you really are and it is different every day as temperature varies.
