battery charging

[sonny1]

with regard to not getting out too much at the moment my mind wandered to battery charging . ,how long inactivity would pass before people would recommend putting the batteries on charge ? ... thanks in advance for any input

[Roy54]

Hi Sonny, I would think every 2 to 3 months would be ok but it would really depend on the condition of the battery and the of course Ambient temperature will have a bearing too. I hardly ever charged mine but have recently rigged up a trickle charger/conditioner just to be sure.
Roy

[Limecc]

It depends on a few factors like Roy said but you should always keep a SLA battery above 50% charge. For longer battery life, batteries should remain in the green zone. Occasional dips into the yellow may not be harmful, but continual discharges to those levels will shorten battery life considerably. Generally speaking, the less you discharge the battery before recharge, the longer the battery will last.

I set an alert so my tracker sends me a text when the voltage drops below 12.1v (50%), then I put it on charge. Boat was last used in May, got the alert in late July.

[sonny1]

a further question then ,if i may . my set up has two batteries with three isolation switches . one is for starting the motor and the other is for vhf and garmin, the third switch ,i was told , was if ever the battery struggles to start the motor then switch on the third isolator to link the batteries . the question is ,to charge both batteries where should the isolators be , on or off , or wont it matter. . sorry to be so dim , it has been a lifetime affliction

[CRF999]

personally I would put the switch to off and connect the charger direct to the battery terminals.
Do one battery at a time as it avoids them playing tricks with each other.

[harrison]

Hmmm! Best ask BMC to be on the safe side.

Logic says turn on start and house systems, leave emergency parallel off. Connect charger to accessory 12v socket (seem to recall You have one on rear of seat?) and the DVSR will automatically do its trickery and manage the charging of both batteries, with the start battery first, then the house.

Only guessing so ask BMC.

[Roy54]

I would agree with Harrison, with your system a call to BMC would be the way to go. If no luck with them, I would leave all the switches off and link to the batteries directly in turn.
Roy

[harrison]

I’d hazard Terry’s problem with just connecting charger direct to each battery in turn will be accessibility. Usually twin battery set ups under the seat render one virtually unreachable.

The switchbank/DVSR set up will facilitate remote auto charging of both batteries. Just a case of confirming switch settings.

[sonny1]

thanks to all who answered . ian @harrison , you got it right on both counts , one battery is very difficult to get at ,(need to remove one and then slide the other along) and yes i do have an accessory port behind the seat . the first call i made regarding this question was in fact BMC , but for the few on here who have had any dealings with the ubiquitous laurence at bmc will know its not as simple as just asking a question . if i could have spoken to one of the fitters i would have gotten a concise and full answer but it wasnt to be ,so thanks for the answers and i think i can now set up a trickle charge

[harrison]

Hey @sonny1, I feel your pain, Laurence is great, difficult but still great.

Try and have a word/email either Martin Saggers (sales) or Neil Mason (fit out/servicing) for a more definitive answer.