Trojan Boat Forum

I just purchased a 78 f30. both engines were starting up fine until last week. i beleive the battery charger is broken and is not charging one of the batteries (new batteries). so one engine is not getting enough power to turn on.

im not sure if i should buy a charger to the exact specs as the old one or if buying a higher amp would matter?

the charger i have now that i beleive is broke is a truecharge 20+

It won't hurt a thing to go up in battery charger amp rating.

Except your pocketbook.....

No reason to upsize the charger unless you have some special requirements. If you stay with the current size, you will not have to change wiring. Above 30A, it can start getting ugly. Then again, if you have a boat where the charger is located in the engine compartment, you may want to consider moving it out of there - more reason to stay with the xantrex or truecharge 20.

thanks for the replies

I'd recommend verifying if your charger is working before doing anything else. Just take a voltage reading (with a good meter) at each battery (bank) with the charger on. If the voltage is above 13.2, the charger is working and not your problem.

If you find it isn't working, you should select a charger based on your battery bank size. A 10 amp might be fine for a group 31 battery but is going to be overworked for an 8D or 2 4D's. Promariner makes some reasonably priced 2 bank chargers that are completely water proof... a decent option for most locations (10-30 AMPS with selective charging).

3 years at my dock with NO charger!

S O L A R


I use solar panels - and they work great ....

how about getting a 3 bank charger for the generator? would i def have to get a 30 amp then?

Different chargers work differently with respect to bank charging. Promariner has a feature called selective charging. This feature is intended to funnel the full charger amperage where it's most needed.

For axample. A simple 3 bank 30 amp charger might have 3-10 amp charge leads. You hook those up to 3 different batteries and each one will only see it's respective 10 amps (usually less). With a 3 bank 30 amp selective charge, the full 30 amps can go to any single battery on the group of 3 (if the other 2 are fullly charged).

Again, the total amperage you need will be based on the size of the battery banks (in amp hours) you are recharging... not the number of batteries per se.

BTW- I have no affiliation with Promariner... I'm just pretty familiar with thier features becuase I've dealt with a few of their products recently. Their are other very good chargers besides them but for the price and features (the water proof ones especially), I think they are a decent value.

jav wrote:I'd recommend verifying if your charger is working before doing anything else. Just take a voltage reading (with a good meter) at each battery (bank) with the charger on. If the voltage is above 13.2, the charger is working and not your problem.

took your advice and checked with a volt meter and i am getting above 13.2 with the charger on and off. cleaned all battery ports and wires out. according to the guages its getting enough power just not starting. im guessing its a starter problem now.

I also like the Promariner I have the prosport 20 ( mid price Promariner) very happy with it and I have very large batteries l would bet larger then anyone here ( not counting Rossjo and JAV )

took your advice and checked with a volt meter and i am getting above 13.2 with the charger on and off. cleaned all battery ports and wires out. according to the guages its getting enough power just not starting. im guessing its a starter problem now.

You'll need to clarify this statement for me... "13.2 with the charger on and off". You should get over 13.2 with the charger on BUT when the charger is off, the voltage should settle back down under 12.8 within a few minutes. If not - are you not running lead acid batteries? Also, did you check the voltage at the battery while someone tries cranking the engine over?