Battery Question

[Gwbru]

I’ve started noticing that the house bank is starting to not hold its charge as well as it did last year. I’m not totally surprised since it is a 2019 R23 and in its 4th season. But when I started investigating further, I noticed that my house bank consists of one 890mca and one 1000mca battery. I assume that the marina mixed them up during spring commissioning.

Is this a problem? The thruster battery is also 890mca. Should I swap them or just do an upgrade. No problems with the thruster or engine battery, yet. Suggestions?


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[Hamster]

Yes, I think they got mixed up. The MCA 1000 should be your engine start battery. On my boat, the 890s were the House and Thruster. I have since replaced the House.

 

[Jared Dunning]

Yes, I think they got mixed up. The MCA 1000 should be your engine start battery. On my boat, the 890s were the House and Thruster. I have since replaced the House.

Hamster is correct. The starting needs to be MCA 1000 and the house is 890s.

 

[ConnorDietz]

Hi Greg,

Yes, the marina switched those around. Both house batteries and thruster battery should be 890mca. Engine should be 1000mcb. Due to the age of those batteries and you noticing that they do not hold a decent charge, I would suggest replacing the batteries. If replacing is not an option currently, you could always test your batteries with a battery tester. If the batteries are still healthy, switch those batteries around and you will be good to go.

 

[knotflying]

MCA is Marine Cranking Rating, which is the number of amps provided for 30 seconds at 32 F. As stated this should be your engine battery. However, if it was accidentally put into the house bank and your engine battery is 890 then your issue should be with the engine not the house. Your issue could be a parasitic draw or something left on or perhaps a bad battery in the house bank. I would charge up both batteries and let them rest for 30 minutes and then do a load test on both. If they show good then switch the batteries to their correct position and start to figure out what might be drawing down the house power.

 

[BB marine]

Four seasons with batteries is not bad. The house bank is the bank that gets the worst treatment if you use your boat for cruising. Lead acid batteries require full charge after each use. If you are a day cruiser you will get better life out of house bank batteries than a boater that uses the house bank for over night and extended time on the anchor. The engine battery bank is a quick high amp discharge and is replenished quickly rarely ever seeing much of a discharge. The same for the thruster battery, couple of quick uses and it will recharge in a short period of time. The house bank is different. Example: a two battery house bank consisting of 2 DP Group 31 batteries will have an Amp hour capacity of around 210 AH. If you deplete this bank to 50% which is not hard to do if anchoring for an extended period of time it needs to be brought back to full 100% charge to complete a cycle. (105 AH) Many times when cruising this doesn't happen. The Outboard, Yamaha has a peek charging of around 50 amps, It's job is to maintain the engine,Thruster bank and the house bank plus all 12 volt accessory uses while operating the boat. Many times the house bank maintains a usable charge while cruising but never gets a full charge to complete the proper charging cycle. The more times the battery bank is depleted to 50% and charged to say 90% but not 100% there is damage done to the battery. It is still a good battery but it starts to loose the ability of reaching 100% charge. I have experienced this with all types of lead acid batteries. I am happy to get 4 years out of a battery bank. I normally start to see a decrease in battery capacity after two years of use and replace after 3. I maintain the batteries but use every AMP hour I can when we are cruising.

It does seem that your batteries got mixed up. Normally the engine battery is a cranking battery HIGHER CRANKING AMPS which is designed with thin plates for quick high amp use. The house bank lower cranking capacity are deep cycle ,larger plates and designed for lower longer amp draw. Mixing the two is not the best but in a short time frame probably did little damage. The same goes for the deep cycle used as a start battery. This is not recommended but in a short period of time it probably did little damage.

If it were my boat and I noticed a depleted battery capacity with 4 year old batteries. I would bite the bullet and replace them all.