Battery capacity question – before I spend a fortune

[Colin Smith]

I have 5 x 110Ah Delphi Freedom batteries that I bought from Vince 3 years ago. I’m trying to estimate what (if anything) is left in them and now that I’ve had a few years using the various electric odds and sods that I have, estimate what I really need in the way of capacity.

 

I charged up the bank then disconnected everything and left them for 2 hours. I checked each battery with a meter and they all showed 12.93v. Connecting everything back up, I then switched on the inverter (Sterling 3500W PSW), the voltage at the batteries then showed 12.75v. Then plugged in my laptop which has an adapter rated at: Input 240v 1.5A, Output 19v 4.74A. Used the laptop for exactly 2 hours then switched it off. Put the inverter on standby (‘power saver’ mode). The voltage at the batteries was then steady at 12.2v.

 

I intend to replace the batteries and add a Smartgauge but I don’t want to underestimate what I really need.

I’ve completed an audit and excluding the Laptop, I estimate a daily requirement of 90Ah. I use the laptop for around 8 hours every day so that will need to be added in. So to my questions:

 

What capacity is left in the existing batteries (can that be estimated from the above)? and suggestions for a suitable battery bank?

 

Thanks

 

Colin

[by'eck]

I would keep the present bank size. A very rough estimate would leave the batteries with a quarter of their rated capacity.

[nb Innisfree]

One advantage of a large bank not often mentioned is the ability to hold a voltage when a smaller bank's voltage gives out. We have 8 x120 ah batts which lost more than 50% capacity over 2 years ago and keep hanging on whereas I am sure 4 of the same batts would have given up a long time ago. In effect more value for money?

[blodger]

IME the 12.2v may be better since inverters seem to drag down the voltage. However, you only got maybe 20ah between being charged and down to 50% SOC, 12.2v, indicating that the 5 batts have had their day. Have they been regularly fully charged or sulphating up? Iknow you are looking at replacing and, if used batts have served you for three years you will probably get longer from replacing with similar open lead acid. I would be inclined to give a good equalising charge to the existing hoping to get through another winter season that can be hard on batts.

IIRC most of Vince's were sealed low maintenance type batts so not much you can do with them beyond trying equalising.

[Colin Smith]

IME the 12.2v may be better since inverters seem to drag down the voltage. However, you only got maybe 20ah between being charged and down to 50% SOC, 12.2v, indicating that the 5 batts have had their day. Have they been regularly fully charged or sulphating up? Iknow you are looking at replacing and, if used batts have served you for three years you will probably get longer from replacing with similar open lead acid. I would be inclined to give a good equalising charge to the existing hoping to get through another winter season that can be hard on batts.

IIRC most of Vince's were sealed low maintenance type batts so not much you can do with them beyond trying equalising.

 

Yep, They are sealed low maint type. I have a Sterling Pro Digital 1250CED 50amp mains charger (set to 14.4v max) which is a 4-step charger and although it says in the (limited) info, that it has an "Automatic 7 day de-sulphation cycle", there isn't anything I can find on the charger to indicate if this is running - I run the charger daily at the moment and usually run it until it's on 'float charge'. It would be great if I could bring the existing bank back to life to some degree but I wouldn't know exactly how to do that (even if there was a chance of restoring them). I guess I don't want to fork out if I could get another 3 or 4 months out of them.

 

If they are toast, then I've a few options of a) getting some new 6v 242Ah US Batteries; b.) going for 6 s/h 2v fork-truck batteries or c) just chucking in 4 new 110Ah leisure type ie Numax or something. They'll all be around the same sort of cost. I'm just not sure what to do at the moment!

Edited October 30, 2012 by Colin Smith

[blodger]

Yep, They are sealed low maint type. I have a Sterling Pro Digital 1250CED 50amp mains charger (set to 14.4v max) which is a 4-step charger and although it says in the (limited) info, that it has an "Automatic 7 day de-sulphation cycle", there isn't anything I can find on the charger to indicate if this is running - I run the charger daily at the moment and usually run it until it's on 'float charge'. It would be great if I could bring the existing bank back to life to some degree but I wouldn't know exactly how to do that (even if there was a chance of restoring them). I guess I don't want to fork out if I could get another 3 or 4 months out of them.

 

If they are toast, then I've a few options of a) getting some new 6v 242Ah US Batteries; b.) going for 6 s/h 2v fork-truck batteries or c) just chucking in 4 new 110Ah leisure type ie Numax or something. They'll all be around the same sort of cost. I'm just not sure what to do at the moment!

I think you'll find anything above cheap OLA batts rather expensive comparatively. In Stockport, round here, you can trade in your scrap batts and pay 60/65 squid for 110s.

 

I have a charger that so called equalises every 10th switching on. In reality, it does the charging it should do each time instead before going to float.

 

I used to have a Heart EMS inverter/charger that equalised ramping up to 16.5 volts. These days I use an unregulated dynamo driven by a lawnmower engine in the winter. In summer allowing the solar panels to run uncontrolled does a fair job. For single batts a bench power supply does the job.

 

I think most people never equalise, lacking the means, so batts that could be rjuvenated a bit get scrapped.

[nb Innisfree]

Yep, They are sealed low maint type. I have a Sterling Pro Digital 1250CED 50amp mains charger (set to 14.4v max) which is a 4-step charger and although it says in the (limited) info, that it has an "Automatic 7 day de-sulphation cycle", there isn't anything I can find on the charger to indicate if this is running - I run the charger daily at the moment and usually run it until it's on 'float charge'. It would be great if I could bring the existing bank back to life to some degree but I wouldn't know exactly how to do that (even if there was a chance of restoring them). I guess I don't want to fork out if I could get another 3 or 4 months out of them.

 

If they are toast, then I've a few options of a) getting some new 6v 242Ah US Batteries; b.) going for 6 s/h 2v fork-truck batteries or c) just chucking in 4 new 110Ah leisure type ie Numax or something. They'll all be around the same sort of cost. I'm just not sure what to do at the moment!

 

3 years ago we were ready to ditch our 8 agm batts so as a last resort we embarked on regular 8 hrs raised absorption charges (29.6v) using our genny and Victron including a couple of 3 day hook ups. That seemed to do the trick and they are still going strong.

Edited October 30, 2012 by nb Innisfree

[by'eck]

Yep, They are sealed low maint type. I have a Sterling Pro Digital 1250CED 50amp mains charger (set to 14.4v max) which is a 4-step charger and although it says in the (limited) info, that it has an "Automatic 7 day de-sulphation cycle", there isn't anything I can find on the charger to indicate if this is running - I run the charger daily at the moment and usually run it until it's on 'float charge'. It would be great if I could bring the existing bank back to life to some degree but I wouldn't know exactly how to do that (even if there was a chance of restoring them). I guess I don't want to fork out if I could get another 3 or 4 months out of them.

 

I think the Sterling charger has to be on continuously for 7 days or more for the de-sulphation cycle to work. Mine certainly does something since I can hear the fan come on once in a while even though batteries were previously on float with no heavy loads. Since the cycle is so infrequent I haven't actually seen what voltage batts are taken to though.

 

I'm sure you could get another 3-4 months out of your batteries if you can manage with the much reduced capacity i.e. they will need more regular charging.

[Phoenix_V]

I've got some of Vince's Delphi Freedom sealed batteries and have been very impressed by them but they too are loosing capacity and will need replacement soon. I gather the Delphis are no longer available can anyone suggest something similar i.e. sealed same type of construction/quality, thanks

[Proper Job]

Vince's Delphi Freedom batteries.............

 

They were a cracking bargin. £25 each. I had six of them and they lasted just over three years.

 

Pity his mate lost the ATM servicing contract

[smileypete]

Yep, They are sealed low maint type. I have a Sterling Pro Digital 1250CED 50amp mains charger (set to 14.4v max) which is a 4-step charger and although it says in the (limited) info, that it has an "Automatic 7 day de-sulphation cycle", there isn't anything I can find on the charger to indicate if this is running - I run the charger daily at the moment and usually run it until it's on 'float charge'. It would be great if I could bring the existing bank back to life to some degree but I wouldn't know exactly how to do that (even if there was a chance of restoring them). I guess I don't want to fork out if I could get another 3 or 4 months out of them.

 

If they are toast, then I've a few options of a) getting some new 6v 242Ah US Batteries; b.) going for 6 s/h 2v fork-truck batteries or c) just chucking in 4 new 110Ah leisure type ie Numax or something. They'll all be around the same sort of cost. I'm just not sure what to do at the moment!

For the sealed Delphi Freedom, looks like the minimum absorption charge voltage for cycle use is 14.8V, couple of PDFs:

 

http://dufour31.pagesperso-orange.fr/astuces/charge%20batteries%20delphi%202.pdf

http://www.batterypower2000.co.za/downloads/technical_brochure.pdf

 

The second (later?) one mentions a MINIMUM charge voltage of 16V! for deep discharge well below 50%, so maybe try that with some care as they're nearly kaput.

 

As far as new batts go, the 6V semi traction offer the best long term price performance IF charged and equalized reasonably well to the makers directions. BUT these are likely to be overkill for most unless living aboard without a shoreline.

 

For doing power audits and stuff saw this meter on Ebay which could be handy. Comes with 500A shunt so fine for a big inverter:

 

http://www.ebay.co.uk/itm/170901504188

 

cheers, Pete.

~smpt~

[dmr]

As said above, the 12.2 volts may be just a short term thing due to the inverter load.

As you plan to get a smartguage why not do that now, it will help to assess the performance of the existing batteries.

 

A meter to measure current will also be very useful. Note that the 90w (or whatever) printed on the computer power supply (or whatever) does not give the consumption under normal working conditions, it only tells you the maximum power consumption before something dies/bursts into flames.

 

And as Pete says, The Trojans are the ones to get, but only if you are willing to look after them!

 

........Dave

[by'eck]

For the sealed Delphi Freedom, looks like the minimum absorption charge voltage for cycle use is 14.8V, couple of PDFs:

 

http://dufour31.pagesperso-orange.fr/astuces/charge%20batteries%20delphi%202.pdf

http://www.batterypower2000.co.za/downloads/technical_brochure.pdf

 

The second (later?) one mentions a MINIMUM charge voltage of 16V! for deep discharge well below 50%, so maybe try that with some care as they're nearly kaput.

 

cheers, Pete.

~smpt~

 

The higher voltages mentioned in the charge guide were only I understood, to revive deeply discharged batteries not initially taking any charge current.

 

I was interested in this paragraph though relating to more normal use:

 

On applications with repetitive deep cycling a

charging voltage of at least 14.8 volts is

recommended, however the on charge

voltage should not exceed 15.8 volts.

Chargers with charge rates up to 50 amperes

are generally satisfactory.

 

Confirms my findings on charge regime with sealed lead calcium which I regularly re-charged with absorb cycle at 14.9 volts.

 

When batteries were replaced after six years they were all showing green when fully charged with no low electrolyte indication.

 

A recent extended thread (aren't they all ) on sealed battery charge volts persuaded me to temper my previous findings and limit charge volts to 14.4v, but I think I will now return to higher.

 

I have already changed my Combi to work at 14.8/13.3 volts with current set of sealed leisure batteries. Will now adjust second charger and DAR's to the same from the lower sealed lead acid settings previously set.

Edited October 31, 2012 by by'eck

[Colin Smith]

Thanks everyone for your replies and advice. I've upped the charger to 14.8v for now so I'll see if that has any affect. I'm pretty much resigned to replacing the bank so the plan will be either the 6v US Batteries or a bunch of 'leisure' ones. Depends on budget. I'm also going to add 2 x 100W solar panels and buy a new battery for the laptop!

 

Thanks,

 

Colin

[smileypete]

Thanks everyone for your replies and advice. I've upped the charger to 14.8v for now so I'll see if that has any affect. I'm pretty much resigned to replacing the bank so the plan will be either the 6v US Batteries or a bunch of 'leisure' ones. Depends on budget. I'm also going to add 2 x 100W solar panels and buy a new battery for the laptop!

Maybe try isolating one batt and charging at a higher voltage, and see the approx capacity before and after.

 

cheers, Pete.

~smpt~

[Colin Smith]

Well I've tried charging the Delphi's at 14.8 and seem to have less capacity than before! I'd looked at US Battery a few years ago but at the death Vince popped up with the Delphi's at £25 each so never ordered the them. Must admit the Delphi's have been fantastic and thay have had some hammer - I think I've had my money's worth! Anyway, I've ordered a couple of 6v 283Ah monoblocks to try. The spec looks good - c1150 cycles @ 50% DoD. I've been impressed with the attitude of US Battery in the conversations I've had and if they work out OK, we'll add them to the business product portfolio too.