Lifeline Batteries Charge Rate

[svlamorocha]

Originally Posted by Ip485

Given around a 650AH Lifeline house bank and assuming discharged to 50% of capacity, what would be the maximium rate of absorption during the intial charge phase - in other words what would be the ideal amps for a charger to put back into the batteries? I appreciate the rate of absorption will tail off.

Also I have these;

https://www.mg-solar-shop.de/media/p...M096B00_EN.pdf

what would you expect the real life experience in the tropical zone would be for these panels in terms of amps returned to the bank, given they are flat mounted and not shaded?

I think for a 12V system each panel should produce between 100A and 150A per day, so two panels will produce around 150 - 300A in a day or equivalent to running a charger for 2 to 3 hours, but with the advantage that as the absorption tails off the efficiency increases.

In theory therefore three of these panels might replace somewhere over 300A in a day?

I am interested to see how close panels will get to supporting a 600AH house bank, given a typical draw for fridge, freezer, chart plotters and general lighting etc.

For your numbers to make sense you have to add "h" in a few places. If you are sloppy with units your beer will not be cold enough

A good rule of thumb in the Caribbean is that you can expect to get 4 hours of peak panel capacity per day. Those panels are rated at 320W peak. Therefore (estimating 14 V voltage ) the contribution of that panel can be up to 4 h x 320 V A / day / 14V = 4 x 320/ 14 Ah per day = 91 Ah per day

I say "up to" because when the controller is an absorption or float stage it will be limiting the power fed into the battery to keep voltage from going up above the setpoint. That said, you can manage that by running the freezer flat out and the watermaker early in the morning to leave "space" for the solar panels to contribute while they can.

[svlamorocha]

Originally Posted by john61ct

.2C is the minimum for longevity.

.4C would be sensible

up to .85C is safe but that gets expensive, since acceptance will hold for a short time only

For a 600AH bank that's 120, 240 and 510A rates respectively.

OP is asking about a charge process that starts at 50% DOD.

In my experience with Lifelines (as in most ex Moorings boats in the Caribbean) acceptance current does not exceed .25C at 50% DOD. Therefore IMHO if OP will not discharge the 650Ah bank below 50%DOD, it is enough to have a charger rated (after temp derating if a Mastervolt charger) for .25 x 650 = about 160 amps, which is a lot.

[john61ct]

See my #23 for reasons to err on the high side.

Yes cost starts to come into it, but the OP Q was wrt the optimum, not minimum sufficient.

Also I believe the newer the bank the higher the acceptance, even if the user does not drop below 50% discharge.