Battery Information
We are getting a lot of questions on batteries so we have put some information together for you on how to get the best out your batteries. However, we are not battery experts and these are only our own findings.
The first thing is the use of a solar charger on the bank; even on dull days they still put charge back in the battery. The new generation of solar chargers are small and light, some of the older Vipers have a phono type socket on the rear of the boat which a solar charger plugs into, but remember to switch your boat to off, and then on to charge on the other switch. The minimum we would recommend is a 10 watt; lower watt ones can be used but will not make much difference to the battery.  Larger ones are much better but require a regulator so the battery does not become overcharged. The more watts the more charge is put back in your battery. Your boat can be unused for some time on the bank so you might as well charge your battery while it is there, it makes a massive difference to your battery life.
Second is the condition of your battery. Lead acid batteries have a short life span, if they are looked after you should manage 3 years but the battery’s ability to last gets shorter all the time. The AH (amps per hour) your battery is retaining governs how long your battery lasts. Even if your battery charges up to its full voltage it does not mean that it is retaining its AH. You will require an ACT meter to test this. These are very expensive, but you can usually take it to your local mobility shop* where for a small charge they will test it for you.
How to test: fully charge your battery and leave for 30 minutes, then test with an ACT meter or take to your local mobility shop.
(*Mobility scooters run on lead acid batteries so they need to have the ability to test them.)
Lead Acid battery storage: never store your battery uncharged, always fully charged, and top up every 2 months. A flat battery that has been left for a while will more than likely be scrap.
Lithium batteries: We have no experience of running the older boats on lithium batteries and we can’t say whether they would be okay or not. So we would advise against it and if you choose to do so it is at your own risk
There are two main types of lithium batteries that can be used in Viper Bait Boats:
Lithium-ion constructed from 18650 cells – these are a 3s batteries with a voltage rating 11.1 volts each cell being 3.7v x 3 cells =11.1. They will charge up to 12.6 volts. They need to be charged at a constant voltage and must have the correct charger and never be left on their own when charging. They have a high fire risk. You can get very high AH batteries up to 20AH so they can last a long time.
Lithium Lifepo4 – these are a 4s battery and are constructed from 3.2 volts cells 3.2v x 4 cells = 12.8 volts. They can charge up to 14.6 volts. They are by far the saftest lithium batteries to use. Because the voltage is slightly higher than 12 volts  some speed controllers will not operate and you must make sure that you have high voltage ones rated 4s or over. All our new boats are now fully compatible with Lifepo4 batteries.
Lithium-ion batteries need the correct solar charger regulator to be used with any solar panel.
Lithium lifepo4 batteries can use standard 12v solar chargers under supervision.
Pros and Cons
Lead Acid
Pros:
Cheap to buy, easy to get hold of, easy to charge on the bank, boat goes slower as battery discharges so you know it's time to change batteries
Cons:
Heavy, short lifespan, don’t last long
Lithium
Pros:
Long lifespan, light, easy to transport, last longer, higher AH available  
Cons:
Expensive, don’t let you know when they are about to run out – you need to monitor the voltage as they just shut down and your boat could be out in the lake. Lifepo4 cut off 10 volts, Lithium-ion 8.5 volts, check with manufacturer specs as this could be different.
Please do your own research on the batteries that you are going to use, we are not battery experts and these guidelines are only our findings and thoughts and other peoples may differ. For information only.